Article highlights:

• When the rain comes it’s a relief, but the problems don’t end there.
• Pastures that have undergone drought stress need enough time to fully recover.
• After the drought breaks, make sure you observe the new growth and manage your horses’ grazing time accordingly as it may put both plants and horses at risk!
• While it’s tempting to keep horses longer in paddocks or turn them on to green emerging pastures, you have to delay and utilise where possible designated sacrifice areas or dry lots.
• You may even have to stable or contain your horses in yards to reduce pressure during the first stages of pasture recovery and growth.
• Make sure you have a post-drought plan in place for you pastures and horse management.
• Identify paddocks that most likely need to be restored and graze only those paddocks that have sufficient density and leaf area.
• When pastures are back in full production, make sure you rotate your paddock to allow for recovery and avoid overgrazing new growth.
• If you have the possibility to harvest fodder, make sure you start planning your haymaking or alternatively build into your long-range ‘fodder conservation’ strategy to reduce the effects of the next drought.

Hold your horses!

Pastures are under a great deal of pressure when the drought breaks. Roughage and supplementary feeding is less available and more expensive during droughts, so it’s tempting to let horses continue grazing paddocks in the hope that the growth will improve dramatically and gradually meet animal needs. However, it pays not to, as this is very damaging to your pasture.

The effects of drought on pastures are extremely variable and subject to a large number of factors. Often, pastures that have experienced drought have limited ground cover and can even be bare. This affects the soils’ fertility. Compaction due to set stock grazing often contributes to other pasture/soil problems such as erosion, water logging and weeds!

After the drought breaks, weeds commonly accumulate in large quantities, as pastures are weakened and less able to compete with vigorous weeds, especially annual species. If these weeds accumulate secondary compounds that can cause toxic effects, horses and livestock are at risk of getting sick.

Therefore, it’s important as a horse owner to be aware of these challenges after the drought breaks, and develop appropriate management strategies that will allow you to establish sufficient and healthier pasture to safeguard your horses.

Drought is tough for pasture plants

It is not a surprise that drought is tough for pasture plants. Without water they cannot survive or grow. One of the most obvious effects of drought is thinning out of large areas of perennial pastures. The level of thinning out largely depends on:Advertisement

Grazing pressure by animals: Research has shown that where grass stubble has been retained, the survival of perennial grasses was significantly greater than where feed was grazed out completely.

The species involved and soil fertility: It has also been shown that on good-fertility soils shallow-rooted pasture species such as ryegrass and cocksfoot were lost in significant numbers, whereas phalaris, fescue and native grasses such as wallaby grass and weeping rice grass survived.

The severity of the drought: Studies have demonstrated that losses of pasture were greater following prolonged dry conditions (where some green feed may still be available) than losses from severe drought. This is because in long-term drought plants stop growing, whereas in dry spells plants continue to grow and are grazed off, which depletes their energy reserves, resulting in death of the plants or very weakened plants that don’t recover well.

Management matters

Our management significantly affects pastures in drought.  During drought times and because grass is not growing, horse owners usually keep their horses longer in paddocks. This, however, results in continued grazing and compaction of your soils.

Following the break, this will often create further problems, such as erosion, waterlogging and/or weeds.

As highlighted above, keeping some stubble is the key to the future survival of grasses after drought. It is therefore important that you still rotate your pastures during winter and drought.

However, if rotation is not an option, then it’s important that you lock up some paddocks and designate only certain areas as a sacrifice area or a dry lot. Alternatively, you may have to consider keeping your horses for parts of the day in stables or yards to reduce grazing/trampling of drought-affected pastures.

Each drought is different, with the current drought being exceptionally severe in many areas. Understanding the effects of drought on plants is important, because it guides the management of both, your pasture and horses.

Assess your pastures: What has survived?

When the drought breaks, it is essential that you monitor your pastures and assess what plants have survived and what may be growing that is less favourable – such as specific weeds.

There will be many factors that influence the survival of your grasses and legumes such as, total and frequency of rainfall, pasture composition, soil condition, type, slope and aspect, grazing pressure, management strategy and the pasture’s health before the drought.

Check your horse paddocks after growth has recommenced, determine what is left, but also establish what the potential of the remaining pasture is, given a reasonable chance of recovery and reasonable seasonal conditions.

For some grass types such as annuals and tropical grasses, you may have to wait till later in spring/summer (warm-season grasses) or autumn (for cool season grasses). If you need some help with identifying plant species seek advice from your local landcare or catchment organisations or ask a pasture consultant.

There are also many free online grass species guides and database programs that you could access on the Internet.

After checking the potential for survival and for future regeneration of your pastures, rank them according to their potential value after the drought.

You can rank your pastures as follows:

1. The paddocks that have moderate to good density of desirable species but have been under severe stress from drought and grazing pressure will be Group 1.
2. The paddocks that have moderate to good density of desirable species but have not been under severe stress from drought and/or heavy grazing will make up Group 2. These paddocks offer the possibility of some grazing as conditions improve but will need management to allow full recovery in the short term. Consider only short term grazing or alternate with locking up horses in stables or yards for parts of the day.
3. The paddocks where the pasture density is too thin in order for it to become worthwhile pasture after a return to more normal conditions are Group 3. This last group can be considered for immediate grazing (sacrifice paddocks), cropping, re-sowing or pasture renovation treatment.

Once you have identified the pasture species that have returned and you have ranked your pastures as per the above, you will have to develop strategies where:

• Paddocks and pastures identified as ‘1’ (high-potential) are given priority for rest and recovery.
• Pastures and paddocks that are classed as ‘2’, should be scheduled for rest as soon as practicable.
• Paddocks and pastures in the last group ‘3’ can be used as sacrifice paddocks where drought feeding can continue until growth on better paddocks improves. These paddocks are suitable for re-sowing, renovation or being sown down to grow forage/fodder crops.

Managing what is left

Horse owners rarely consider post-drought management and often, pasture management is compromised by resting pastures less (if at all) or grazing pastures harder and for longer periods, and grazing to a height that is shorter than recommended. This causes energy reserves to depleted and the plant is weakened, often to the point of death.

Where pastures are compromised in this way, they need to be compensated.

A good fall of rain in itself does not overcome drought stress. The plant has to be allowed a period of recovery to build up the energy reserves that will allow it to reach its full potential.

You often need to help your pastures with additional input such as mulching, composting and/or spreading (bio) fertilisers to optimise the environment for soil organisms and nutrient exchanges with the plants.

Check our previous series on ‘All About Soil’

Rest is recovery

Rest is the key to preventing overgrazing. The length of time that a plant needs to recover following grazing depends on several factors including the type of forage species, plant vigour, and the level of utilisation.

Recovery time also depends on the season or time of year, which determines conditions such as day length and temperature. Soil condition, fertility and moisture also impact plant growth rates.

If we want to rest paddocks and allow recovery, we must manage the grazing time of our horses.

So, when can we graze pastures again? 

To answer this question we need to look at the pasture growth stages.

The efficiency with which plants convert the sun’s energy into green leaves and the ability of animals to harvest and use energy from those leaves depends on the phase of growth of the plants.

Plants go through three phases of growth that form an “S” shaped curve. The timing of the growth curve for each forage species is unique and these growth characteristics are an important factor when determining proper season of use for grazing.

For example, cool-season grasses start growing in spring and again in autumn, whereas warm-season grasses peak later, when it’s closer to summer.

The growth stage will dictate when plants are most vulnerable or when the plants have created enough biomass to survive grazing attacks! Therefore, avoid grazing pastures when plants are in phase 1.

In this first growth stage, the plants are weak and have insufficient leaf area to produce biomass quickly. After such a long, severe stress period of drought, pastures should be allowed to reach phase 3 and reach flowering.

At this stage, the plant’s energy reserves have been replenished, assuming flowering has not been premature (i.e. forced by dry conditions). If this is difficult to manage for all paddocks, at the very least, after drought, delay grazing some paddocks until pastures are into phase 2, at which stage they are growing actively and have sufficient leaf area to produce feed efficiently.

Where you are forced to graze paddocks early, plan to rest them (and preferably allow perennial grasses to seed down) as soon as conditions permit.

During the growing season, rotate your horses more frequently. The golden rule is fast growth = fast moves (shorter recovery) whereas slow growth = slow moves (longer resting). The height of pasture at these growth stages will vary considerably, depending on species, density, growing conditions etc., but as a guide, a typical healthy dense perennial grass/legume pasture would be in phase 2 between 5 cm and 15 cm high. It may take a few weeks to reach this stage depending on the vigour.

Weeds

It is also important that you keep track of the type of weeds that may be growing after the drought breaks. You might find that you get weeds you have never seen before or the quantities are much higher than usual.

The weeds that you can find after the drought breaks will vary depending on seed bank, location and soil condition. Often, weeds grow first as they have deep-tap roots and establish more vigorously when water becomes available, outcompeting shallow-rooted grasses.

Weeds can accumulate sugar, starch, or fructan under drought stress. This makes weeds a lot more appealing to your horse, especially when pasture is not abundant.

Dandelion, thistle and chicory are common weeds that often are relished by horses even under normal conditions.

However, there are some weeds that are more of a concern such as capeweed, flat weed, marshmallow weed, Paterson’s curse, St John’s wort, common heliotrope, mintweed, pigweed, fireweed, wireweed, and caltrops.

Many plant toxins concentrate under drought conditions. Weeds can accumulate nitrates, oxalates, alkaloids, prussic acid, and cyanogenic glycosides, which can cause a wide variety of equine health problems including staggers, digestive upset, laminitis, mineral imbalances, photosensitivity, and liver, kidney, and neurological damage.

For more information see the guide on toxic plants for horses published by RIRDC.

It is important that you remove horses from pastures where you have identified weeds that may put your horses at risk, especially if they are in large quantities.

These paddocks will need to be restored and managed to ensure that weeds are removed and no new weeds emerge. Don’t forget your sacrifice or dry lot areas as well!

Your horse’s health

The most common fear horse owners have in spring or when drought breaks is the quick growth of lush, green pasture and accumulation of non-structural carbohydrates. This can put horses at risk of developing digestive problems and/or trigging metabolic conditions, such as laminitis and EMS.

As we explained above, when conditions are favourable – a rise in temperature, sunlight hours and water availability – plants will start using their energy reserves (fructan or starch) to create more leaves, to increase their surface area, and accumulate more simple carbohydrates for new growth and seed production. Re-watering stimulates production of enzymes that break storage carbohydrates into shorter chains, and ultimately to the sugar components.

Those first new green shoots can therefore, be very high in sugar. The type of sugar produced after the drought breaks can vary depending on the species of grass.

Typically, improved pastures are more adapted to grow rapidly and allocate sugars for more growth, whereas native pasture species can survive well during drought conditions, but typically accumulate biomass slower (hence why native pastures are more susceptible to overgrazing pressure).

Grazing pastures that are in phase 1 should be avoided where possible, not only to protect the plant, but also to protect your horses, especially those with weight or metabolic problems.

Aim for the mid to end stage 2 or the beginning of stage 3 (before flowering). This is when production of sugars slows down and when the sugars are fully utilised by the plant.

As mentioned earlier, allowing pasture to set seed is important to add to your seed bank and diversity.

Nevertheless, research has shown that, if you slash pastures just before seeding, you can increase leaf production whilst avoiding the sugar increase from the seed heads. It is therefore advised that you check the ranking of you pasture and decide which pastures you allow to set seed and which ones you prep for grazing.

During the times when grazing should be avoided, manage your horses in sacrifice areas/ dry lots and yards or stable them as required. It does mean, however, that you have to continue feeding conserved forages and alternative fibre sources!

Regeneration of pastures

Where you have the ability to rest your paddocks (group 1 or 2), it’s important that you check your soil’s condition and organisms. Soil analysis is recommended to provide you with a point of reference as to what you may have to do to improve your soil and pasture condition to reach its full potential.

Often, topsoil is lost during drought periods due to thinning out of plants which creates bare patches that turn to dust and are exposed to wind erosion.

Increasing your organic matter (mulching), adding compost and fertiliser should be considered to increase fertility and support soil organisms. But make sure that you plan this when water is available.

If you are dealing with moderate to very degraded pastures (group 3) or experience problems such as erosion, water logging or weeds, you often will need to tackle the underlying problem – compaction.

See our previous articles on how to de-compact your soils and manage weeds.

If the pasture has significantly deteriorated, re-sowing may be necessary. Your options include a full seed-bed preparation for a forage crop, or direct drilling to re-establish a permanent pasture. Some annuals can be surface-applied in higher-rainfall areas.

Fast-growing forage crops fit in well to a pasture regeneration program after drought. Once established, they can take the pressure off the high-potential pastures, allowing them to recover.

Fast-growing forage crops are also useful for cleaning paddocks of weeds prior to re-sowing pasture and for replenishing hay and fodder reserves quickly.

Pasture re-sowing is expensive, however, and should be used only when the pasture is unlikely to improve through other techniques.

The bare ground situation, reduced sward density and lowered stock numbers (in some grazing areas) can provide an ideal opportunity for you to sow improved and/or native pasture species or to thicken up a sward where plant numbers have been reduced by drought.

Please note that after drought, the availability of locally produced pasture seed may be limited but there should be adequate seed available from other states. Of course, the price of seed is likely to rise and supply/demand generally will keep prices higher for some time after the drought.

The takeaway…

• When the rain comes it’s a relief, but as this article has highlighted, the problems don’t end there.
• Pastures that have undergone drought stress need enough time to fully recover.
• After the drought breaks, make sure you observe the new growth and manage your horses’ grazing time accordingly as it may put both plants and horses at risk!
• While it’s tempting to keep horses longer in paddocks or turn them on to green emerging pastures, you have to delay and utilise where possible designated sacrifice areas or dry lots.
• You may even have to stable or contain your horses in yards to reduce pressure during the first stages of pasture recovery and growth.
• Make sure you have a post-drought plan in place for you pastures and horse management.
• Identify paddocks that most likely need to be restored and graze only those paddocks that have sufficient density and leaf area.
• When pastures are back in full production, make sure you rotate your paddock to allow for recovery and avoid overgrazing new growth.
• If you have the possibility to harvest fodder, make sure you start planning your haymaking or alternatively build into your long-range ‘fodder conservation’ strategy to reduce the effects of the next drought.

This article was published in Horses and People September-October 2019 magazine.

We learned about sampling and DIY home soil tests (Part 3), which allowed us to get a first glimpse of what our soils are doing or not doing! To get a more detailed profile and a quality check of our soils, we explained the importance of soil lab testing and what the results may tell us (Part 4). 

So far, we have gathered a lot of soil information, but this is of little use if we are not implementing it on our properties. Even though soil tests results may vary from place to place in the same paddock, and between seasons (when sampled at the same point), we can still use them as a general reference and help guide us in developing our soils. 

In this, the last part of this series, we will explain how these test results can assist you in your soil and pasture management on your property and, specifically, what tools and materials may be required in order to improve the nutrients and health of your pastures. 

Evolution of soil tests and modern agriculture

Soil tests are often used in conventional farming as an explicit directive of the required inputs for crops or pastures (what fertiliser, seeds and chemicals to add), and inform on their potential yield. Agronomists interpret these lab results and inputs, and make recommendations to improve the soil and pasture. This is known as ‘prescription’ agriculture or farming, and it has been very effective in increasing yield and mass food production around the globe. Unfortunately, it has often resulted in a loss of overall soil health, particularly a loss of soil carbon.

Over time, prescription farming has become a more streamlined process and has evolved into precision farming. Incorporating ‘smart technologies’, along with modern GPS/rate controlling equipment, has led to more fine-tuning of seeding prescriptions, nutrient application and pest/weed control.

Using precision farming via GPS, the farmer has the ability to locate their precise position in a field, allowing for the creation of maps of the spatial variability of as many variables as can be measured by sensor technologies (for example, crop/pasture yield, terrain features/topography, organic matter content, moisture levels, nitrogen levels, pH, EC, Mg, K, and others.

Using this technology, the old lab soil tests may seem redundant and, to a certain degree, this may be the case for large production farms moving fully to these types of precision farming layouts.

Nevertheless, for accuracy and to get a greater profile of your soils status, the ‘old-school’ lab tests will always play a role and also allow for accurate calibration of these sensor technologies.

In addition, even with precision farming technology, it will be impossible to quantify the microbiological health of soils – we still require laboratory analysis, including DNA tests, to identify bacteria, fungi and protozoa species. Keep in mind soil biology (the soil-food-web) has been understudied compared to the above ground biology, yet it is vital for the health of our crops, pastures and forests (as discussed in Part Two of this series). This highlights the importance of close human observation of soil quality and dynamics at the soil-food-web level.

Permaculture and soil tests

Permaculture prioritises the restoration of soil health because healthy soils produce healthy plants and grasses, which, in turn, help produce healthy crops and animals.

Permaculture, as well as other organic/alternative farming principles, approaches soil health from an understanding of fundamental ecosystem processes, with special attention to soil microbiology and closed system management.

Soil tests are essential in permaculture and, initially, the approach is to use DIY tests and observations. Soil lab testing is typically used as a follow-up tool after the initial observations to obtain a more complete picture of the nutrient availability, contaminations in certain regions of the farm and, specifically, to check the microbiology profiles of soils.

Lab results can also be used as a starting reference, but often, visual and DIY testing alone make it obvious the soil is in poor condition. It is more likely, therefore, that lab soil tests are used during the soil development phase to identify improvements when different strategies and inputs have been adopted.

Permaculture and other organic farming principles work on supporting and enhancing natural ecosystem processes to improve soil and pasture health. There is a main focus on close system management techniques and reducing the need to use/import fertilisers (especially chemical-based products) and pesticides, or even totally eliminating these products.

When we talk about closed system management, it is important to realise, within an ecosystem, a number of fundamental processes play a role in the recycling of nutrients, including:

• The water cycle,
• The mineral cycle,
• The community dynamics (i.e. the relationship between organisms in the ecosystem), and
• The energy flow.

In a natural system, many species of plants and animals play a role in these processes (See Part Two of this series). However, on horse properties, the manager (which is you!) is responsible for overseeing the animals and returning waste (via compost or mulch) to the soil and plants.

Actively creating soil in pastures becomes the property owner’s role, whereas in nature, many other processes and species carry out that function. In permaculture, the intent is to actively support these fundamental processes by using systems and species that can actively restore soil (providing they are not locally rampant and invasive).

Soil issues and how to fix them using the Permaculture approach

As a landholder, you will encounter many soil (and pasture) issues, but some are more common than others, especially on horse properties and, in this article, I focus on the three most common issues you may have identified either through your DIY tests or soil lab analysis.

1. Soil organic matter

In your lab soil tests, this will be mentioned as estimated soil organic matter (OM), which is a surrogate for soil carbon and is measured as a reflection of overall soil health. Levels of soil OM are measured/estimated by soil testing for soil organic carbon (SOC), as soil OM is composed of approximately 60% carbon.

Organic matter results from partly decayed plant and animal residues in various degrees of decomposition. Soil OM matters for several reasons. First, soil OM holds up to 90% of its own weight in water, so it acts like a giant sponge. Soil scientists have found a one percentage point increase in soil OM can increase the soil’s water holding capacity by 75,000 to 100,000 litres of water per acre, which is nearly one acre-inch of water going back into your soils!

Soil OM is also a sponge for nutrients. It can hold up to 20 times more nutrients than an equivalent weight of sand, silt or clay. As soil OM increases, so does the soil ability to hold cations (positively charged ions), such as calcium, magnesium, sodium and potassium, as well as the soil total nitrogen (N) content. OM also provides the energy source for micro-organisms in the soil, and improves the structural stability and pH buffering capacity of the soil.

When monitored for several years, it gives an indication whether soil quality of your pastures is improving or degrading.

If soil is low in organic matter, the soil test will result in a low organic carbon level. Preferred organic carbon levels are above 2%, but this also depends on the rainfall. For low rainfall pastures, 2-3% is considered normal and for high rainfall pastures, 3-6% is considered normal. Anything above this is considered high.

Organic residue, such as leaf matter deposited in or on the soil, is the most active pool of OM, but may be rapidly lost (has low stability). Just think about when you mow your grass and how quickly it is broken down.

Humus (made up of resistant compounds derived from decayed organic residues) is a slow, more stable pool. Charcoal is very stable, but is not biologically active and, therefore, is an inert or passive pool.

Soil cultivation and soil degradation result in losses of organic carbon, which is released as CO2 into the atmosphere. Land clearing and over-grazing also contribute to the loss of soil carbon.

So, how can we increase soil organic matter in our soils?

Soil OM is in a constant state of turnover, where it is decomposed and replaced by new organic material. The balance between inputs and the rate of loss will determine the relative flux in soil OM content. In many instances, soil OM is still declining and in ‘negative feedback’ mode; thus, current land management is typically taking more from the system than it returns and this should be carefully managed. We do this by implementing the following practices:

1. Growing roots: To produce more soil OM, one must stimulate new root growth. The roots of grasslands, whether in a pasture, hay or silage field, should be regularly turned over. The frequency of this turnover is dependent upon how frequently the pasture is cut or grazed. As regrowth begins, new roots are formed and a new flush of exudates is released. But, you don’t have to worry about the root exudates from the last growth cycle. Research suggests many of the root exudates may last for over 50 years in the soil if it remains in grass, and is not tilled or aerated. Even the roots themselves take a while to deteriorate, as their lignin content is more than two times greater than the lignin concentration in the above-ground mass.
2. Perennial plants: Deep-rooted plants, like perennial grasses (but also shrubs and trees), provide continuous carbon input and store more carbon than shallow plants, because their longer roots are surrounded by a nutrient-rich region of soil where micro-organisms convert CO2 into organic matter in a process called soil carbon sequestration. We can jump-start this process by spreading grasslands with a layer of compost (see point 4), which seeds the soil with good micro-organisms, resulting in more soil carbon sequestration.
3. Mulching and slashing: As roots grow underground, we also want to stimulate the leaf area and grass cover above ground, as the defoliation will return plant residues to the soil. Therefore, any standing tuffs and weeds that are not grazed by your horses should be slashed and turned into mulch. This is extremely beneficial before Autumn and Spring (when we have rains and good temperatures), or before Summer in (sub)tropical regions. If you have limited grass cover or even bare areas in the paddock, you can also bring in mulch, such as old hay or straw, to start covering these areas to add organic matter and, at the same time, retain moisture and create an ideal environment for seed germination and regrowth.
4. Compost/manure: In addition to returning plant residue (mulch), you can also add other organic waste products that add organic matter and nutrients to the soil, such as manure and compost. If you are managing horses, you have manure! You can harrow this or spread it onto your pasture, but be aware not to return any horses to the pasture until the manure has been broken down and taken up by the soil, otherwise you may create parasite problems. Add some brown organic waste to your manure and you can start making compost, which, if done correctly, is high in nutrients and beneficial micro-organisms, and can be directly spread on to pastures.
5. Irrigation: Blue (water) before Green (pastures) before Black (soil). We need water to grow plants, but water is also essential for the soil workers that break down the plant and other organic residues to humus. Therefore, water management on your property is important. Irrigating pastures after slashing, mulching and/or composting will help speed up the breakdown, and increase nutrient infiltration and seed germination.
6. Adding soil workers: By introducing soil workers, such as earthworms and beneficial bacteria (for example, using biological ferments, such as compost tea), you can speed up soil creation, and increase soil carbon levels and water infiltration.
7. Ground cover: You must maintain and conserve ground cover. In order to maximise wind erosion control, grass stubble should cover a minimum of 70% of the soil surface and preferably be standing (anchored by its roots).
8. Grazing management (leaf area management): Avoid over-grazing your pastures below 4-5cm for temperate grasses and 9-10cm for tropical grasses. If pasture plants are grazed too short, the roots will also reduce in length and become less efficient in obtaining water and nutrients (resulting in decreased vigour). Grazing regimes that encourage pasture regeneration, such as ‘graze and spell rotation’, are effective contributors to the maintenance of higher organic carbon levels. If you have limited rotation/spell options, then it’s important to incorporate sacrifice/loafing areas where you can manage your horses for short or longer term to allow pasture to rest, and to work on improving soil organic matter and pasture growth!

Soil pH level

Soil pH is the measure of the acidity or alkalinity level of the soil. It affects plant growth, as it determines the availability of plant nutrients in the soil. Soil pH is measured on a scale from 0-14, with 7 being neutral. A highly acidic soil can have as low as pH 3, while a highly alkaline soil can be close to pH 10.

Most soils have a pH 6-8 range and plant growth is usually best in a soil of pH 6-7. So, what can you do when you have less than the ideal range?

To raise soil pH

In all acid soils, pH can be raised by the combined use of organic matter and the addition of calcium ions in the form of dolomite or lime.

• Agricultural lime – (Calcium carbonate) is finely ground limestone (chalk). Mined limestone, i.e. not chemically treated, is a safe choice to raise pH in pastures and garden beds. Although it takes several weeks to have an effect, it is longer acting than other sources of lime and can be watered in around plants.

It takes less lime to raise the pH of sandy soils than it does to change clay soils. A basic recommendation is to apply at regular rates of 1 tonne/ha until top and subsoils have reached the required levels. Approximately 1 tonne/ha of agriculture lime increases pH in 10cm depth of soil by around 0.7 units in sandy loam, 0.4 units in loam and 0.2 units in clay. To avoid an excess amount of calcium in soil, apply rates based on outcomes of your soil tests (consult with soil scientist or pasture consultant), and test soil a few months later.

• Dolomite – (Calcium magnesium carbonate) is limestone with a higher proportion of magnesium than agricultural lime, and is applied in the same way. It is a good way to raise soil pH on sandy soils with fairly low organic matter content, because both calcium and magnesium leach easily from these soils. In soils with high magnesium content, agricultural lime is the preferred way to raise soil pH.
• Gypsum – Known as calcium sulphate, it can be used to amend soil acidity and is also useful for lightening the structure of heavy clays.

To lower soil pH

Adding organic matter as compost, green manures and animal manures without including lime or dolomite can be enough to adjust the pH of slightly alkaline soils, because organic matter produces hydrogen ions as it decomposes.

Manure from cows, horses and sheep that have grazed on herbicide-free pasture can be used more liberally on alkaline soils. It has been calculated 2-3kg of manure per square metre of pasture will reduce soil pH from 8.0 to 7.0. Manure release hydrogen ions as it breaks down, replacing calcium ions on the charged sites.

Elemental sulphur, sometimes sold as flowers of sulphur, can assist organic matter in reducing soil pH in more alkaline soils. However, it reacts slowly and may take several months as soil bacteria convert the sulfur to sulfuric acid. It often requires multiple applications to see results and is best applied in warmer months when soil activity is greatest.

The soil texture or percent sand, silt or clay determines how much sulfur is needed to lower the pH. Elemental sulphur is available from produce stores/ agriculture wholesellers. The application rate will largely depend on the soil type, alkalinity and to what pH you want to bring it down to. The application rate per acre could be over 100kg. Test soil after two to three months to see if further applications are necessary.

Acidic fertiliser (eco or organic) can assist when alkaline topsoil contains some organic matter and herbicide-free manures are not available. The concentrate is very acidic and diluting it in water should modify the acidity somewhat. It can be watered into the soil or used as a foliar feed for plants in alkaline soils.

Nutrient levels

For plants to be healthy, they need a steady supply of nutrients from the soil. Nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca) and magnesium (Mg) are required in relatively large quantities (known as macronutrients). Others are required in small quantities (these are micronutrients or trace elements), such as copper (Cu), zinc (Zn) and manganese (Mn).

A shortage or absence of any one of these essential nutrients can severely hinder plant growth. Too many nutrients can be as bad as too few.

Soil tests results can be viewed in three categories, including:

• Low or yes, a fertiliser addition will likely increase growth and productivity;
• High or no, a fertiliser addition will not likely increase growth or yield;
• Intermediate or maybe, a fertiliser addition may increase growth or productivity.

This categorisation is based on the sufficiency/optimal level range, and is often displayed per soil types, or can be presented in a bar figure for selected soil type or crop types. Categorisation of soil test results into ‘Yes (low)’, ‘No (high)’, and ‘Maybe (medium)’ assists in understanding the limits and benefits of using soil test results for making nutrient and soil management recommendations.

So, what can you do to improve your nutrient levels?

When your soil test results show low nutrient levels, it will be beneficial to apply a fertiliser to your soil/pasture, as this will support greater plant vigour and increase biomass for your horses to graze, or for hay harvesting! There is variety of fertilisers, soil conditioners and bio-stimulants to choose from.

A fertiliser, soil conditioner or bio stimulant is any material added to the soil, or applied to a plant to improve the supply of nutrients and promote plant growth. This definition includes both inorganic and organic fertilisers and soil conditioners, such as lime and gypsum, which may promote plant growth by increasing the availability of nutrients that are already in the soil or by changing the soil’s physical structure. Soil conditioners are materials that make the soil more suitable for the growth of plants, including increasing microbiology activity. Most organic amendments function as a fertiliser and soil conditioner.

Inorganic fertilisers

• Sometimes called commercial or artificial fertilisers, they mostly contain chemicals with the essential plant nutrients in available forms – the production of which involves some industrial process. Examples include urea, superphosphate and muriate of potash. These do not have an ability to condition the soil.

Organic fertilisers

• Often referred to as natural fertilisers, they include natural soil conditioners, bio stimulants or recycled organics.
• Are made up of organic material containing carbon from animal and plant products. These materials are usually generated from livestock operations and municipal authorities.
• Examples include blood and bone, biochar, seaweed liquid, biosolids, compost, livestock/horse manure, dairy factory effluent and fishmeal products.

Using organic fertilisers and soil conditioners

There is growing landholder interest in using alternative nutrient sources, such as natural or organic fertilisers and soil conditioners, instead of traditional manufactured fertiliser, to improve productivity and soil health. Organic fertilisers provide nutrients to promote plant growth (fertiliser), whilst also improving the physical and biological composition of the soil (soil conditioner).

Inorganic fertilisers generally do not have the ability to condition the soil. Nutrients in organic fertilisers are available more slowly, over a longer period, than those in most manufactured fertilisers. This may be a disadvantage when plants have an immediate need for nutrients, but it can be an advantage under high leaching conditions, in that nutrient loss from the soil is reduced.

The benefits of improved soil health using these natural alternative sources are widely accepted. However, there are numerous questions around whether the products being sold to improve soil health actually change soil biological activity and, ultimately, are cost effective in maintaining or increasing production. It is, therefore, important you check your suppliers, ask about the typical analysis/composition and what results they have generated with other landholders.

Organic wastes (composted manures and recycled organics)

Uncomposted animal manures have a higher proportion of immediately available nutrients, like nitrogen (as ammonium), phosphorus, potassium and micronutrients than composted materials. Consequently, the plant production benefits of compost may not be as be apparent until several years after application, but can significantly help with increasing organic matter in short-term.

Composting is the biological decomposition of organic materials by micro-organisms under controlled, aerobic conditions to a relatively stable humus-like material called compost. Composting may be done successfully in numerous ways using a variety of materials, methods, equipment and scales of operation.

For agricultural operations, the common materials or feedstocks that are composted are livestock manures and bedding, and various residual plant materials (straw, garden clippings, on-farm processing wastes, and so on). Compost is a valuable source of organic matter for soils and contains nutrients that are slowly available for plant growth.

Like every production process, the quality of your compost largely depends on the quality of the organic materials you start with. If it is done properly, the high temperatures of the composting process can sterilise weed seeds and pathogens that may be present in the raw organic materials. On-farm-based composting can be done relatively cheaply if the right equipment is available or you can design passive composting systems that require minimal human input.

Summary

In this article, we only provided a few management practices you could implement on your property to improve the overall health of your soils and, ultimately, your pasture plants. Some of these we have discussed in more detail in previous articles. It is important to acknowledge each farm will have its own soil profile and soil/pasture problems that may require a different solution due to limitations, such as climate.

The strategies we may adopt will also largely depend on the available time we have to develop our soils/pastures, or available budget for soil improvement. So, keep learning about soil and, where possible, consult with soil scientists and pasture consultants who can take you in the right direction for your property.

The most important take-home message when it comes to pasture and soil development is we should prioritise repairing soils’ healthy food web! When practicing pasture management, it’s not the plants that are replenished, but the soil, through the process of breaking down organic matter with the help of soil micro-organisms!

It is our great duty to shepherd the basic building blocks of soil, bacteria and fungi, so the higher predators (nematodes, micro-arthropods and earthworms) can take part in this soil-food-web connection. These beneficial interactions produce plant-available nutrients, which create conditions for optimal photosynthesis to occur.

When the food web is strong, the plants are strong, which helps with pest and disease resistance and, with richer soils and diversity of plants, we can outcompete weeds. When we eliminate the need for pesticides because we have used diversity, we improve the hydrological cycle, and bio-diversity flourishes above and below the soil surface. As the plants build in complexity and diversity, they become carbon cyclers through root exudates, and they deliver carbohydrates to the root zones that micro-organisms use and exchange for nutrients the plants require (a symbiosis relationship).

The growth and decay process are a continual flux of energy – mixing the energies of the sun’s light and heat with the Earth’s minerals and nutrients, and the force that connects them: water. Water feeds and loosens the paths of soil micro-organisms, and is perspired out plants to help bring more rain. It’s stored extensively in the soil, in the plants and is all around us in varying states of composition. There is no separation between soil, water and vegetation!

However, it is not to say we cannot help nature along the way, and correct and speed up fundamental processes, so we can benefit quicker from richer soils, and greater pasture diversity and cover. Using tools and ingredients (including those imported onto the farm) to facilitate this are all part of the overall management plan, and go hand in hand with your horse management to maintain pasture availability and avoiding over-grazing.

DIY soil tests, including observational analysis, as well as soil lab testing, play an important role in monitoring the progression of your soil development and pasture management, and allow you to adjust your inputs or management practices! So, keep this ‘All About Soil’ series as reference and start soil building!

This article was published in the Horses and People Magazine June 2018
By Mariette van den Berg, PhD, BAppSc (Hons), RAnNutr

Mariette has a PhD in Equine Nutrition and Foraging Behaviour, is a RAnNutr equine nutritionist, a Certified Permaculture Designer and a dressage rider. She is the founder of MB Equine Services.

In Part Three, we described soil sampling and started to investigate some important parameters of soil health using DIY techniques. In this Part Four, we will continue with soil laboratory tests and how to interpret these results. 

You can use soil tests as a diagnostic tool or to identify trends through time, which can help you in your decision-making process on how to improve your soils and, ultimately, enhance your pasture health. 

Soil laboratory testing

The primary goal of soil testing is to inform efficient and effective resource management on your property. Soil testing is the most accurate way to determine the current state of your soils, its composition, what nutrients it may need (or that are in excess) and other characteristics, such as pH and salinity. Soil testing is also useful for identifying contaminated sites (e.g. elevated levels of heavy metals, pesticides, etc.).

Once you have collected your soil samples (see Part Three), you will have to send these to a soil-testing laboratory to have them accurately analysed.

It is important to recognise the values obtained when a soil sample is analysed are of little use as raw analytical data. In order to make use of the values in predicting nutrient needs, the test must be calibrated.

These calibrations are based on nutrient response research with representative soils (and conditions) – ranging from deficient to adequate for each nutrient of concern. These calibrations are also plant/crop or soil-specific. The sufficiency/optimal range (or typical range, in some cases) is usually provided in the column to the right of your results (for quick comparison).

Soil testing laboratory methods vary, which may influence results and sufficiency ranges. This means if you send the same soil sample to two or three different labs, you may see some variation in the results, as this is largely determined by the analysis techniques and calibrations used at that lab, and may be specific to a region (i.e. state).

Therefore, it is important to check lab techniques/methods used and if the lab is accredited by an authority, such as NATA (National Association of Testing Authorities) or ASPAC (Australian Soil and Plant Analysis Council).

There are other national and international accreditation systems. By visiting the lab’s website, you can find most of this information, as well as their pricing!

Interpreting results

You finally received your soil report of your soil samples, but what does it tell you and how should you interpret these results to make an informed decision?

As mentioned earlier, there are different parameters we can measure in soil and the selection of these listed parameters is determined by the soil analysis packages that you chose when you submitted your samples. Some of these parameters are reasonably simple, such as identifying soil type, which you may already have done yourself by following the instructions outlined in Part Three in the last issue.

When it comes to the nutrients, it is important to note soil tests measure nutrients that are expected to become plant-available, rather than the total amounts of nutrients in soil. Measurements of total nutrient content are not useful indicators of sufficiency for plant growth, because only a small portion of the nutrients in the soil are plant-available.

Roots take up plant-available nutrients as positively (cations) or negatively (anions) charged ions from the soil (see Image B) with the help of structural elements, such as carbon (C), hydrogen (H) and oxygen (O). So, when you see your soil tests results, keep in mind nutrients are expressed as plant-available or extractable/exchangeable (using various test methods, such as Merlich, Morgan, Bray, Olsen, DTPA, etc.). These testing methods will typically be listed in your results as reference.

It is also important to recognise soil test results can be viewed in three categories:

• Low or yes, a fertiliser addition will likely increase growth and productivity;
• High or no, a fertiliser addition will not likely increase growth or yield;
• Intermediate or maybe, a fertiliser addition may increase growth or productivity.

This categorisation is based on the sufficiency/optimal level range, and is often displayed per soil types or can be presented in a bar figure for selected soil type (see Image D on the next page).

Categorisation of soil test results into ‘yes (low), ‘no’ (high) and ‘maybe’ (medium) assists us in understanding the limits and benefits of using soil test results for making nutrient and soil management recommendations. This will be discussed in more detail in the last part of this series in a future issue!

Let’s now look at the different nutrients and other soil characteristics that are listed on your report, and discuss what they tell you. Please note, your results may be expressed in different measuring units, such as parts per million (ppm) or m/kg (which is the same 1:1 for soil).

Soil type

Soil type is reported as the colour and texture of the soil. Both colour and texture are indicators of properties of the soil, and are taken into account when interpreting other soil chemical results, such as Cation Exchange Capacity (CEC).

Soil colour

Soil colour has little direct influence on its chemical, physical or biological attributes, but when considered with other observations, can be very useful.

Often, soils of darker colour are higher in organic matter than lighter coloured soils. Red colour can be related to un-hydrated iron oxides present in well drained soils; yellow or mottled coloured soils may be related to hydrated iron oxides, which may occur where soils are saturated for long periods and/or poorly drained.

The Munsell Soil Colour Charts are internationally accepted as being the standard guide to discern soil colour classification. You can view it online at: https://bit.ly/2HPfNNu.

Soil texture

The texture of a soil is an indication of soil type and its properties. It is always taken into account when interpreting the other results and preparing fertiliser recommendations due to leakage issues. Soil texture is measured separately for Mineral Soils and for Organic Soils; for example, peat.

Soil texture can be measured in two ways, including:

• Field method: Where a small handful of moistened soil is squeezed between the thumb and forefinger to produce a ribbon. The length of the ribbon before breaking and the ‘feel’ of the soil (sandy, silky, etc.) provide an indication of the texture. To improve consistency of results, this test is usually done by experienced laboratory technicians. However, the method remains subjective and the results may differ slightly between assessors. Slight variations are of no real concern to the final fertiliser recommendations.
• Mechanical method: A mechanical sieving process is used to separate and quantify the percentages of sand, silt and clay in a soil. This method is more time-consuming and expensive than the field method, so it is used where greater accuracy is required (e.g. for research).

Organic carbon

Soil organic matter (OM) is a surrogate for soil carbon and is measured as a reflection of overall soil health. Organic matter results from partly decayed plant and animal residues in various degrees of decomposition in the soil.

Soil organic matter assists in maintaining soil structure, and the supply and retention of nutrients, air and water. When monitored for several years, it gives an indication whether soil quality is improving or degrading.

Soil OM is important to a wide variety of soil chemical, physical and biological properties. As soil OM increases, so does CEC, total nitrogen (N) content and other soil properties, such as water-holding capacity and microbiological activity. If a soil is low in organic matter, the soil test will result in a low organic carbon level. Preferred levels are above 2%.

Soil pH

Soil pH is a measure of the alkalinity or acidity of the soil. A pH value of 7 is neutral. Values below 7 are defined as acidic and those above are alkaline. The soil pH can influence the availability of nutrients to plants, and potential toxicity of aluminium and hydrogen.

In most Australian soil tests, the pH of the soil is measured in water (pH(water)) or calcium chloride (pH CaCl2). Soil pH CaCl2 values are usually between 0.5 to 1.1 units lower than pH(water). The pH(water) value readily reflects current soil conditions, but is subject to seasonal variations. The CaCl2 test is useful for long-term monitoring of pH and is less subject to seasonal variations. Aim to keep the pH level above 5.3 (water) or 4.5 (CaCl2).

Plant-available nitrogen

It is difficult to measure the amount of nitrogen (N) available for plant growth in soils, because the form and availability of nitrogen in the soil can change quickly, particularly in improved pastures. Therefore, by the time the soil samples are received and analysed by the laboratory, the amount of mineral N in the sample may have changed.

Even if the amount of mineral N is correctly analysed by the laboratory, by the time the soil test results are returned to the farmer, changes may have already occurred in the N content of the soil.

The plant-available forms of nitrogen are ammonium-N (NH4-N) and nitrate-N (NO3-N). The abbreviation NH4-N means nitrogen in the ammonium form and the abbreviation NO3-N means nitrogen in the nitrate form.

Soil concentrations of NO3-N and NH4-N depend on biological activity and, therefore, fluctuate with changes in conditions, such as temperature and moisture. Nitrate is easily leached from the soil following high rainfall or excessive irrigation.

Soil tests can determine NO3-N and NH4-N concentrations at the time of sampling, but do not necessarily reflect future conditions.

Available phosphorus

Phosphorus (P) is essential for plant growth and is vital for early root formation. Soil minerals can react strongly with applied phosphorus and only a small proportion may be available for plant uptake.

Plant-available phosphorus can be tested using different methods, such Olsen, Bray or Colwell (depending on the region), and results are presented in milligrams per kilogram (or mg/kg) or parts per million (or ppm).

Available potassium

Potassium (K) is needed for a wide range of important processes within the plant, including cell wall development, flowering and seed set. Available potassium can be measured by different methods, such as Exchangeable K soil tests. Because the holding and supply capacity of potassium in soils can differ, the appropriate target for available potassium depends on soil type. When potassium levels are high, potassium inputs can be reduced from the fertiliser regime until levels fall.

Available sulphur

Sulphur is essential for nitrogen (N) fixation by legumes, such as lucerne or clovers. It is usually measured by the potassium chloride (KCl 40) test and is reported as mg/kg. This test takes into account some of the sulphur that will become available during the growing season from the breakdown of organic forms of sulphur.

Sulphur is considered adequate when the levels are > 4 mg/kg using the CPC test. Sulphur is considered adequate when the levels are > 8 mg/kg using the Blair (KCl 40) test. Plant analysis, especially a nitrogen-sulphur (N:S) ratio, is useful for diagnosing a sulphur deficiency.

Nutrients calcium, magnesium, sodium, aluminium and hydrogen are also typically recorded as plant-available values in the report, in addition to the extractable/exchangeable values.

Cation exchange capacity

The cation exchange capacity (CEC) of a soil is the measure of the soil’s capacity to hold important cations (positively charged ions), such as calcium, magnesium, sodium and potassium. Some laboratories also include aluminium.

The CEC measure provides an indication of the types and amount of calcium, potassium and magnesium available, and associated ratios, while exchangeable sodium is useful for determining potential soil structural problems. The CEC of the soil is largely dependent on the amount and type of clay and organic matter that is present (which results in greater CEC values than sandy soil).

The exchangeable cations are usually reported in unit of milli-equivalents per 100 grams (meq/100g) soil and also as a percentage of total cations.

Exchangeable calcium

Calcium is a necessary plant nutrient that plays a key role in maintaining soil structure and is generally present in high concentrations in the soil solution, even at low pH. Calcium deficiencies usually are found only on very acidic soils.

Exchangeable calcium should be > 5 meq/100g and in the range of 65-80% of the total cations present.

Exchangeable magnesium

Magnesium is also a necessary plant nutrient and is usually present in sufficient quantities to satisfy plant requirements. Exchangeable magnesium should be > 1.6 meq/100g and in the range of 10-20% of the total cations present. If exchangeable magnesium is more than 20% of the sum of cations present, it may result in potassium deficiency in plants and animals.

Calcium to magnesium ratio

Well-structured soils generally have twice the amount of exchangeable calcium to exchangeable magnesium. If the calcium to magnesium ratio is less than 2:1, this may indicate reduced soil stability.

In contrast, a calcium to magnesium ratio of more than 10:1 indicates a potential magnesium deficiency in plants and animals, including horses.

Exchangeable potassium

Potassium is an essential plant nutrient and is required in larger amounts. Exchangeable potassium should be > 0.5 meq/100g and in the range of 3-8% of the total cations present. If the exchangeable potassium level is more than 10% of the sum of cations, it may cause magnesium deficiency in plants and animals.

Magnesium to potassium ratio

The amount of magnesium should be one and a half times greater than the amount of potassium. If the ratio of magnesium to potassium is less than 1.5:1, this indicates an increased likelihood of magnesium deficiency in plants and potential grass tetany in classes of grazing animals.

Exchangeable sodium

Ideally, exchangeable sodium should be < 0.1 meq/100g and less than 1% of the total cations present.

If sodium makes up 6% or more of the total cations present, then the soil may be sodic and susceptible to dispersion – where a soil may lose structural integrity, compact and form surface crusts. The application of gypsum (CaSO4) can help alleviate excess sodium in the short term.

Exchangeable aluminium

High exchangeable aluminium concentrations can be common in very low pH soils and may be toxic to plants. High aluminium levels can be reduced by applying lime. Aluminium levels generally fall to harmless levels once the pH (water) exceeds 5.6-5.8. The exchangeable aluminium level should be less than 1% of the CEC.

Salinity (conductivity)

Soil salinity is a measure of the total soluble salts present. High levels of soluble salts in the root zone may affect water and nutrient uptake, and adversely affect plant growth. Plants are more susceptible to salinity in their germination and seedling stage than in later stages of growth.

Soil salinity is generally determined by measuring the electrical conductivity (EC) of the soil sample, with results decisiemens per metre (dS/m). Ideal levels are less than 0.2 dS/m.

Different pasture species have varying tolerance to soil salinity. Salt tolerance of plants is usually based on a different test – the electrical conductivity of a saturated extract method, ECe, which is also measured in dS/m. Salinity levels are satisfactory for all pasture species if the ECe is under 1 dS/m.

Summary

This article is meant to provide a basic understanding of how to read your soil tests and what some of these parameters tell you. Some soil reports may be more extensive and will report more values, such as trace minerals or heavy metals. This also depends on your chosen analysis package.

Additionally, the lab may record different measuring units. If this seems like too much information to digest at once, keep this article as a useful reference because I’ve aimed to bring the points that are more relevant to Australia and a horse property setting in particular.

Be sure to check the lab’s website, as they may provide additional information (or even services) than can help you with the interpretation of your results. You can always opt to get your soil test done and reported by a soil service or agronomist that, at the same time, may assist you with soil and pasture recommendations.

This article was published in the Horses and People Magazine May 2018
By Mariette van den Berg, PhD, BAppSc (Hons), RAnNutr

Mariette has a PhD in Equine Nutrition and Foraging Behaviour, is a RAnNutr equine nutritionist, a Certified Permaculture Designer and a dressage rider. She is the founder of MB Equine Services.

If you missed those articles, you can find them by clicking on Part 1 and Part 2

In the following parts, we focus on the importance of soil tests – in the lab and DIY – interpreting these soil test results, and, finally, in our last part, we will explain how these tests can help your property’s soil and pasture management. 

In Parts 1 and 2, we learned soils are complex mixtures of minerals, water, air, organic matter, and numerous micro and macro-organisms that are the decaying remains of once-living things.

Soil forms at the surface of land – it is the ‘skin of the Earth’, it supports plant life and is vital to life on Earth. Although we know taking care of our soils will help us grow healthy pastures to feed our horses, soil continues to be overlooked, underrated and taken for granted.

How much do you spend, as a horse and property owner, getting to know your soils – reading up on soil facts – compared to the time you spend planning and managing your pastures?

The importance of soil testing

Soil testing or analysis is a valuable tool for your farm. It determines the current condition of your soils, and the inputs that may be required to improve soil health and fertility.

Soil fertility is determined by the soil’s chemical, physical and biological properties. Some properties, such as soil texture, colour and structure are visible to the eye. However, the chemical composition of soil needs to be measured. This is why soil sampling and testing is essential.

Soil tests are used to determine the soil’s nutrient content, organic carbon content, pH level and even microbiology. Armed with this information, you can define the exact type and quantity of fertiliser that will improve your soil. This is important because healthy, fertile soils grow healthy, fertile pastures.

Soil testing can also be used to check pastures are not over-fertilised. Many nutrients tend to be over-applied – resulting in imbalances in the soil and harmful effects on the environment.

For example, an excess of nitrogen can cause leaching and groundwater contamination, or contamination of waterways from run-off. We see the effect of the latter with algal blooms in dams and waterways.

In addition, over-fertilising can cause problems with excessive growth of high-producing pasture species that are not always ideal for managing ‘good doers’, or horses in maintenance or light work.

Over-fertilised pastures have also been linked to an increase in plant and fungi toxins, which can cause health problems in horses. To learn more, read the ‘Your Pasture Pharmacy’, available on the Horses and People website.

While it is best to get to know your soils with a comprehensive laboratory analysis and soil report, you can also do some of the basic tests yourself! Keep reading…

Taking soil samples

Soil conditions vary from paddock to paddock and region to region. Each paddock should be considered on a case-by-case basis when making soil and pasture management decisions.

For a soil test to provide a reliable guide to the condition of your soil, the sample tested must truly reflect the soil in the area sampled.

If the soil type varies within the area to be tested, sample the predominant soil type only.

Choosing an area to sample

Areas with major soil type variations, or that differ in appearance, pasture growth or past treatment should be sampled separately – provided the area can be treated separately. A pasture/soil map or satellite image can be helpful in distinguishing areas, and in recording where the samples were taken.

Once you’ve selected the area to be sampled, use one of the following patterns to take between five and 10 cores at regular intervals: network (a), Z-scheme (b), diagonal (c) and in rows (d).

The minimum recommended is five to 10 cores per sample. The more cores, the more representative the sample will be – and more accurate the results.

Choosing the core sites

Although you may be following a set pattern, the cores should be taken from sites of average pasture growth.

You should avoid sampling areas of bare ground (unless they are predominant) and where there is very good growth (the ‘roughs’, which have an excess of urine and manure).

Stay 10 metres away from contaminated or deceptive parts, such as the area around gateways, farm or animal tracks, loafing areas, sheds, fence lines, troughs, trees, fertiliser and lime dumps.

Avoid the bottom of gullies and water holding depressions, areas where timber windrows have been burnt and extremely wet soils.

Taking the cores

There are several different tools you can use, such as an auger and sampling tube, but a clean spade works just as well. It is important you use a clean, plastic bucket to collect your core samples, because a metal one can contaminate the sample for trace element analysis.

At each sampling site, remove all surface material, such as pasture or weed growth, and surface litter, to expose the bare soil and take a uniform slice of soil about 20mm thick to the required depth.

Core depths of 100 mm (3-4”) are recommended for pastures. Subsoil (deeper cores) sampling can also be beneficial to determine deeper storage of nutrients (for deeper, tap-rooted plants) and in areas where salinity, acidity or heavy metal contaminations are suspected in the soil.

Repeat at each core site until you have at least five to 10 core samples in your plastic bucket.

Break up clods and mix thoroughly, then spread the total sample from the bucket evenly onto a clean surface. A plastic tarp works well (make sure you pin it down on windy days or find a sheltered area!).

By this time, you will probably have more soil than you need for analysis (the typical requirement is between 200-300g). Although, if your budget allows, you should duplicate the samples for better accuracy.

To reduce the sample size, but maintain a good representative sample, divide the total mix into quarters, discard the two diagonal quarters and remix the remains, then continue this reduction process until you achieve the amount required for the soil.

Remember also, as well as bagging and sending a sample to a laboratory for a comprehensive report, you can do some DIY tests at home, so keep some soil separately for that purpose. Keep reading to learn how to do this…

Place the sample into the bag, label it with all relevant details, and number or code it, so you can keep track of your sample bags. Include details such as name, address, date of sampling, site of sampling, depth of sampling and, if applicable, any fertiliser details. Some soil labs offer sample kits and soil bags, but ziplock or plastic bags work just as well.

For a laboratory analysis, you will have to fill out a form with all relevant details and you will have to select your analysis package. These packages are tailored to specific soil types or are based on the number of tests conducted to provide you with either standard or more comprehensive details. We will discuss lab soil testing in the next issue.

Now you have collected your samples, let’s use some of the soil for our at-home, DIY tests!

Do it yourself soil tests

If you search online, you can find many soil or garden websites that offer you DIY soil testing kits and even online testing tools. These can be very useful, but the quality and costs of testing kits may vary. Alternatively, there are low-cost solutions for doing basic tests yourself using limited tools.

1.  Squeeze test – composition

One of the most basic characteristics of soil is its composition. In general, soils are classified as clay soils, sandy soils or loamy soils (check Part 1 of this series).

Clay is nutrient-rich, but slow draining. Sand is quick draining, but has trouble retaining nutrients and moisture. Loam is generally considered to be ideal soil, because it retains moisture and nutrients, but doesn’t stay soggy.

To determine your soil type, take a handful of moist (but not wet) soil and give it a firm squeeze. Then, open your hand. One of three things will happen:

• It will hold its shape and, when you give it a light poke, it crumbles. Lucky you… This means you have loam!
• It will hold its shape, and, when poked, sits stubbornly in your hand. This means you have clay soil.
• It will fall apart as soon as you open your hand. This means you have sandy soil.

Now you know what type of soil you have, you can work on improving it.

2. The compaction test

Plunge a wire flag vertically into the soil at different locations. Mark the depth at which the wire bends. The sooner it bends, the more compacted the soil. A foot or more of easily penetrable soil is ideal for healthy pastures.

Compacted soil inhibits root growth, water availability, and keeps earthworms and other vital soil fauna from circulating freely. It is, therefore, important you work on de-compacting your soils before even attempting more soil tests! See our previous article on how to de-compact horse pastures at: https://www.horsesandpeople.com.au/article/renovating-damaged-pastures-and-soils

3. The percolation test

It is also important to determine whether you have drainage problems or not. This one is often related to compaction problems. Good infiltration gets water to plants where they need it (at their roots), prevents run-off and erosion, and let’s air move more efficiently into soil pores. Water-logged soils/pastures can cause problems with building up of weeds and anaerobic bacteria.

To test your soil’s drainage:

1. Dig a hole about six inches wide and one foot deep.
2. Fill the hole with water and let it drain completely.
3. Fill it with water again.
4. Keep track of how long it takes for the water to drain.

If the water takes more than four hours to drain, you have poor drainage and this could be an indication of compaction.

4. The pH test

Knowing the pH of your soil will help your pasture plants grow by absorbing nutrients better from the soil. Their ability to do this depends on the nature of the soil and its combination of sand, silt, clay and organic matter.

The makeup of soil (soil texture) and its acidity (pH), as well as the abundance of micro-organisms, determine the extent to which nutrients are available to plants.

pH is tested on a scale of zero to 14, with zero being very acidic and 14 being very alkaline. Most plants grow best in soil with a fairly neutral pH, between 6-7.

When the pH level is lower than five or higher than eight, plants just won’t grow as well as they should. pH testing can be done with soil pH kits or pH probes. These kits are fairly accurate, but you must make sure you follow the testing instructions precisely.

Alternatively, there are two other ways you can test the pH yourself without kits or probes! Keep reading…

Option 1: Vinegar and baking soda pH test

Collect one cup of soil from different parts of your pasture (use soil you collected for sampling) and place two teaspoons of soil into two separate containers. Add 1/2 cup of vinegar to the soil. If it fizzes, you have alkaline soil with a pH between 7-8.

If it doesn’t fizz after doing the vinegar test, then add distilled water to the other container until the two teaspoons of soil are muddy. Add 1/2 cup baking soda. If it fizzes you have acidic soil, most likely with a pH between 5-6.

If your soil doesn’t react at all, it is neutral with an ideal pH of seven and you are very lucky!

This test is fun to do. After you added vinegar and you do not observe a reaction in your bowl, don’t think your experiment didn’t work! You can do a check by adding distilled water to another bowl of soil and pour on just a sprinkling of baking soda. You get instant fizz! It just means you have acidic soil.

Once you know whether your soil pH is a problem or not, you can begin working to correct the problem.

Option 2: Cabbage water pH test

Measure two cups of distilled water into a saucepan. Cut up and add one cup of red cabbage. Simmer for five minutes. Remove from heat and allow it to sit for up to 30 minutes.

Strain off the liquid, which will be purple/blue. This will have a neutral pH of seven.

To test, add two teaspoons of pasture or garden soil to a jar and a few inches of cabbage water. Stir and wait for 30 minutes. Check the colour. If it turns pink, your soil is acidic. If it is blue/green, your soil is alkaline.

These tests give you some indication if you are dealing with problem soils, which may be one of the reasons why you won’t be able to grow certain pasture species or why you have weed problems.

In the last part of this series, we will discuss in more detail how you can restore your soil’s (pH).

5. The worm test

Worms are great indicators of the overall health of your soil, especially in terms of biological activity. If you have earthworms, chances are you also have all of the beneficial microbes and bacteria that make for healthy soil.

To do the worm test:

1. Be sure the soil has warmed to at least 13 degrees and it is at least somewhat moist, but not soaking wet.
2. Dig a hole one foot across and one foot deep. Place the soil on a tarp or piece of cardboard.
3. Sift through the soil with your hands as you place it back into the hole, counting the earthworms as you go.

If you find at least 10 worms, your soil is in pretty good shape. Less than that indicates there may not be enough organic matter in your soil to support a healthy worm population, or that your soil is too acidic or alkaline.

6. Soil organisms

Measure the animal life in your soil by digging down at least 15cms and peering intently into the hole for a few minutes. Tick off the number and species of each organism observed, such as centipedes, ground beetles and spiders.

Because most soil organisms spurn daylight, gently probe the soil to unearth the shy residents. If you count less than 10, your soil does not have enough active players in the food chain.

A thriving population of diverse fungi, bacteria, insects and invertebrates is one of the most visible signs of soil quality. The more that creeps and crawls under your pasture or garden, the less opportunity there is for pests and disease.

Each level of soil life does its part to break down plant residue and make more nutrients available for plant growth. See our previous article on soil-food-web interactions at: https://www.horsesandpeople.com.au/article/all-about-soil-part-2 to learn more.

7. Plant residue

If you have good grass cover, dig down 15cms into the soil and look for plant matter at that depth. The range of organic material is important to notice here. The presence of recognisable plant parts, as well as plant fibres and darkly-coloured humus indicates an ideal rate of plant decomposition.

The single most important component of healthy soil is organic matter. But, plants and other organic materials decompose only when soil organisms are there to do the work. Any sign of this process is a good sign, but the speed of decomposition is important too. Fast decomposition is another indicator of soil quality. In poorly-aerated soil, plants break down slowly – a condition that gives off a faintly sour scent.

8. Plant vigour

Start this test during the active growing season, and look for healthy plant colour and size that’s relatively uniform. Overall health and development must be judged based on what’s considered normal for your region, but will also depend on local weather conditions.

Plant vigour indicates soil with good structure and tilt, a well-regulated water supply and a diverse population of organisms. It’s, by far, the best sign of effective soil management you’ll have above ground.

9. Root development

Use a shovel or hand trowel to dig gently around a selected plant; if you choose a weed, you won’t miss. Once you’ve reached root depth, pull an annual plant up and check the extent of root development, searching for fine strands with a white, healthy appearance. Brown, mushy roots indicate serious drainage problems. Stunted roots might also indicate disease or the presence of root-gnawing pests. When you look at the roots, you can really see what’s going on.

Roots have the most immediate connection with and reliance on soil quality. Without air, water, biological activity and crumbly soil to grow in, roots can’t do their job.

Summary

Learning as much as you can about your soil will help you decide what needs to be done to make it ideal for the pasture plants you want to grow (and outcompete weeds!). The above-mentioned tests are easy and fun to do, and are a good start to gain some information about your current soil condition and what you may have to improve.

Of course, if you want a more comprehensive analysis of your soils, you will have to send your samples to a certified soil laboratory.

Search online for soil services in your region or state, although many offer national services. They will provide information about collection of soil samples and sending it into their laboratory for analysis.

Based on the package chosen, they will return a report that will alert you to any nutrient deficiencies in your soil. The pricing of soil tests will depend on the package chosen. Basic soil tests will be relatively cheap around $50. However, a microbiology tests can be as high as $250-300 per sample. Often, the labs also provide additional consulting services and advise steps to correct the issues observed.

Alternatively, you can also work with an agronomist or soil scientist who do all the work for you and produce a recommendation report. There are many options, depending on your time and budget!

We will discuss some of the soil parameters and lab results in the next part of this series.

This article was published in the Horses and People Magazine April 2018
By Mariette van den Berg, PhD, BAppSc (Hons), RAnNutr

Mariette has a PhD in Equine Nutrition and Foraging Behaviour, is a RAnNutr equine nutritionist, a Certified Permaculture Designer and a dressage rider. She is the founder of MB Equine Services.

Soils are complex mixtures of minerals, water, air, organic matter, and numerous micro and macro-organisms that are the decaying remains of once-living things. It forms at the surface of land – it is the “skin of the earth.” Soil is capable of supporting plant life and is vital to life on earth. In many Equine Permaculture articles we have focussed on the importance of taking care of our soils so that we can grow healthy pastures to feed our horses. The soil is perhaps the most overlooked, underrated, taken for granted but major partner in growing plants. When managing your pastures, how many horse and property owners have passed over getting to know their soil—reading up on soil facts—in favour of pasture planning and management?

In this brand new Equine Permaculture series, we will ‘dig deeper into soils’ and explore what soils are, how soil is formed, the different types of soil and how they sustain life through the soil-food-web.

Furthermore, we will discuss the importance of soil tests, in the lab and DIY, interpreting these soil test results, and how they may assist our soil and pasture management on the property.

Before we start digging up the dirt, let’s brush up on some facts about the soil – food –web!

Soil biology
An astonishing variety of organisms contribute to the soil food web. They range in size from the smallest single cell bacteria, algae, fungi, and protozoa, to the more complex nematodes and micro-arthropods, to the recognisable earthworms, insects, small vertebrates, and plants. As these organisms eat, grow, move through, die-off and decay in the soil, they create humus (which is the organic material in soil) and contribute to clean water, moderated water flow, clean air, and very importantly healthy plants that can feed our horses.

Figure 1. The soil environment. Organisms live in the microscale environments within and between soil particles. Differences over short distances in pH, moisture, pore size, and the types of food available create a broad range of habitats.

The exchanges between these organisms form a web of life, just like the interactions between flora and fauna that biologists study above ground. What most people forget to realize is that the above ground interactions wouldn’t survive without the below ground systems in place and functioning. Soil biology is understudied, compared to the above ground, yet it is vital for the health of our pastures, gardens, shrub lands, and forests. If pasture soil is healthy, there will be high numbers of beneficial bacteria and bacterial-feeding organisms. If the soil has received heavy treatments of herbicides, chemical fertilizers, soil fungicides or fumigants that kill these organisms, the tiny critters die, or the balance between the pathogens and beneficial organisms is upset, allowing the opportunist, disease-causing organisms to become problems not to mention how this may affect the growth and quality of your pasture.

There are many ways that the soil food web is an integral part of landscape processes. Soil organisms decompose organic compounds, including manure, plant residue, and pesticides, preventing them from entering water and becoming pollutants. They sequester nitrogen and other nutrients that might otherwise enter groundwater, and they fix nitrogen from the atmosphere, making it available to plants. Many organisms improve soil aggregation and porosity, thus increasing infiltration and reducing runoff and soil erosion. Soil organisms prey on crop pests and are food for above-ground animals.

The Soil Food Web
The soil food web is the community of organisms living all or part of their lives in the soil. A food web diagram shows a series of exchanges (represented by arrows) of energy and nutrients as one organism eats another (see figure 2).

All food webs are fuelled by the primary producers, these are photsynthesizers (first trophic level) such as the plants, lichens, moss, photosynthetic bacteria, and algae that use the sun’s energy to fix carbon dioxide from the atmosphere and convert it into carbohydrates (which allows them to sustain themselves and grow)

Most other soil organisms get energy and carbon by consuming the organic compounds found in plants, other organisms, and waste by-products (second to fifth trophic levels). A few bacteria, called chemoautotrophs, get energy from nitrogen, sulfur, or iron compounds rather than carbon compounds or the sun.

As organisms decompose complex materials, or consume other organisms, nutrients are converted from one form to another, and are made available to plants and to other soil organisms. All plants – grass, trees, shrubs, agricultural crops – depend on the food web for their nutrition. In many articles I have highlighted that we do not directly feed pasture plants, but we feed them through soil organisms that make up the soil-food-web.

Figure 2. Relationships between soil food web, plants, organic matter and birds and mammals. Image courtesy of USDA Natural Resources Conservation Services.

The role of soil organisms
Growing and reproducing are the primary activities of all living organisms. As individual plants and soil organisms work to survive, they depend on exchanges with each other. By-products from growing roots and plant residue feed soil organisms. In turn, soil organisms support plant health as they decompose organic matter, cycle nutrients, improve soil structure, and control the populations of soil organisms including crop and pasture pests.

Lets have a closer look at some of the soil organisms that make up the soil-food-web and their functions.

Bacteria
Our native soils are full of bacteria, both beneficial and pathogenic. A spoonful of ordinary backyard soil may contain billions of bacteria of thousands of different kinds, many of them specific to a region. In general, they help water move through the soil more easily, they recycle organic matter, and they help ward off soil diseases. There are many types of bacteria, but one of the most important groups is the nitrogen-fixing bacteria. These bacteria are especially found on the roots of leguminous plants and shrubs (for example clover, lucerne and acacias). Nitrogen-fixing bacteria are capable of transforming atmospheric nitrogen into fixed nitrogen (inorganic compounds usable by plants). They dine on particles of humus (organic matter), creating a waste product called bacteria manure that adds new forms of organic content to soil. Many plants absorb nutrients most efficiently through this bacterial waste product, so the more nitrogen-fixing bacteria in the soil, the better. This is why we often want to plant grasses with leguminous plants. Lucerne is one of those that we like to have for its ability to increase nitrogen and it offers great feeding value to grazing animals. Bacteria and bacteria’s waste products are also eaten by fellow soil dwellers of many kinds, so they feed other organisms in the soil in addition to feeding our plants. Our pastures and gardens soils are typically dominated by beneficial bacteria.

Protozoa
Protozoa, comprised of the three groups; (1) flagellates, (2) amoebae (both naked and testate), and (3) ciliated, are important in maintaining plant-available nitrogen and mineralisation processes and, as bacterial-feeders, are important in controlling bacterial numbers and community structure in the soil. The presence or absence of certain protozoa species is indicative of the presence of certain hazardous wastes and therefore may be highly useful indicator organisms of certain types of environmental impacts.

Fungi
Many horse owners assume that fungi must be bad for the soil, but this is far from the truth. When most people think of fungi, they think of mushrooms. They also tend to think of fungi as plants. A characteristic of plants is that they inhale carbon dioxide (CO2) and exhale oxygen (O2). Fungi actually breathe in oxygen (O2) and exhale CO2 like humans. Interestingly, fungi have survived two mass extinctions over 65 million years, and the only plants that also survived these extinctions are the ones that formed associations with fungi. From this, we can easily understand the health implications of not correctly managing soil and the life it contains.

Fungi are vitally important to soil health, and beneficial forms are found in virtually every kind of soil on earth. Like bacteria, fungi break down organic matter by digesting and excreting humus, thus recycling nutrients through the soil food web. Mycorrhizae are among the best known fungi. They attach themselves to the roots of plants and create a mesh of fine feeder “rootlets” that act like pumps, pulling nutrients and water into the host plant’s root system. It’s a symbiotic relationship because in return the plants exchange carbohydrates with the mycorrhizae fungi. In effect, they increase the surface area of the roots and thus the plant’s ability to absorb nutrients. Plants send out chemical signals to fungi that they require magnesium, an element essential for plant growth. Fungi networks — chains of microscopic mycelium (fungi) strands that have been recorded at lengths and depths of approximately 10 kilometres, can search out the required nutrient and deliver it to the plant in exchange for the food that the fungi need: carbohydrates. Healthy woodland soils are dominated by fungi, meaning that there are more fungal creatures than bacteria in the soil.

Nematodes
Nematodes, like fungi, are usually assumed to be pathogens, but beneficial nematodes abound in the soil. Nematodes are one of the most ecologically diverse groups of animals on earth, existing in nearly every habitat. Nematodes eat bacteria, fungi, algae, yeasts, and diatoms and may be predators of several small invertebrate animals, including other nematodes. In addition, they may be parasites of invertebrates, vertebrates (including humans) and all above and below ground portions of plants. Nematodes range in length from 82 μm (marine) to 9 m (whale parasite) but most species in soil are between 0.25 and 5.5 mm long.

Nematodes are recognised as a major consumer group in soils, generally grouped into four to five trophic categories based on the nature of their food (see figure 2), the structure of the stoma and oesophagus and method of feeding. Plant-feeding nematodes possess stylets with a wide diversity of size and structure and are the most extensively studied group of soil nematodes because of their ability to cause plant disease and reduce crop yield. Fungal-feeding nematodes have slender stylets but are often difficult to categorize and have been included with plant-feeders in many ecological studies. Bacterial feeding nematodes are a diverse group and usually have a simple stoma in the form of a cylindrical or triangular tube, terminating in a teeth valve-like apparatus.

Predatory nematodes are usually large species possessing either a large styles or a wide cup-shaped cuticular-lined stoma armed with powerful teeth. Omnivores are sometimes considered as a fifth trophic category of soil nematodes. These nematodes may fit into one of the categories above but also ingest other food sources. For example, some bacterial feeders may also eat protozoa and/or algae and some stylet-bearing nematodes may pierce and suck algae as well as fungi and/or higher plants. Stages of animal parasitic nematodes, such as hookworms, may also be found in soils but generally are not common in most soil samples.

Nematodes and protozoa function as regulators of mineralisation processes in soil. Bacterial- and fungal-feeding nematodes release a large percent of nitrogen when feeding on their prey groups and are thus responsible for much of the plant available nitrogen in the majority of soils. Nematode-feeding also selects for certain species of bacteria, fungi and nematodes and thereby influences soil structure, carbon utilization rates, and the types of substrates present in soil.

Arthropods
These recyclers are the critters that feed on bacteria, fungi, and earthworms, as well as plant particles. They include micro-arthropods— very small organisms like mites—and larger organisms like sow bugs, springtails, spiders, and centipedes. The micro-arthropods stay put in the soil, consuming debris and making nitrogen and other nutrients more readily available to plants and other soil biota. Arthropods also control the population levels of other organisms in the soil, keeping things balanced naturally.

Earthworms
Of all the members of the soil food web, earthworms need the least introduction. Most people become familiar with these soft, slimy, invertebrates at a young age. Earthworms are hermaphrodites, meaning that they exhibit both male and female characteristics. They are major decomposers of dead and decomposing organic matter, and derive their nutrition from the bacteria and fungi that grow upon these materials. They fragment organic matter and make major contributions to recycling the nutrients it contains. Earthworms occur in most temperate soils and many tropical soils. They are divided into 23 families, more than 700 genera, and more than 7,000 species. They range from an inch to two yards in length and are found seasonally at all depths in the soil.

The fuel of the food web: organic matter
Organic matter is comprised of different types of compounds – some more useful to organisms than others. In general, soil organic matter is made of roughly equal parts humus and active organic matter. Active organic matter is the portion available to soil organisms. Bacteria tend to use simpler organic compounds, such as root exudates or fresh plant residue. Fungi tend to use more complex compounds, such as fibrous plant residues, wood and soil humus. As mentioned before bacteria dominated soils are typically pastures whereas fungi dominated soils are woodlands and forests.

Intensive cultivation of soil triggers spurts of activity among bacteria and other organisms that consume organic matter (convert it to CO2), depleting the active fraction first. Practices that build soil organic matter (reduced tillage and regular additions of organic material – by spreading compost) will raise the proportion of active organic matter long before increases in total organic matter can be measured. As soil organic matter levels rise, soil organisms play a role in its conversion to humus – a relatively stable form of carbon sequestered in soils for decades or even centuries.

Soil organic matter is the depot for the energy and nutrients used by plants and other organisms. Bacteria, fungi, and other soil dwellers transform and release nutrients from organic matter. These micro-shredders, immature oribatid mites, skeletonize plant leaves. This starts the nutrient cycling of carbon, nitrogen, and other elements such as minerals ultimately feeding our pasture plants!

Habitat of soil organisms
The organisms of the food web are not evenly distributed through the soil. Each species and group exists where they can find appropriate space, nutrients, and moisture. They occur wherever organic matter occurs – mostly in the top few inches of soil (see figure 1), although microbes have been found as deep as 16 km in oil wells. Soil organisms are concentrated:

On the surface of soil aggregates. Biological activity, in particular that of aerobic (requiring oxygen) bacteria and fungi, is greater near the surfaces of soil aggregates than within aggregates (which lacks oxygen). Within large aggregates, processes that do not require oxygen, such as denitrification, can occur. Many aggregates are actually the faecal pellets of earthworms and other invertebrates.

In litter. Fungi are common decomposers of plant litter because litter has large amounts of complex, hard-to-decompose carbon (such as lignin). Fungal hyphae (fine filaments) can “channel” nitrogen from the underlying soil to the litter layer. Bacteria cannot transport nitrogen over distances, giving fungi an advantage in litter decomposition, particularly when litter is not mixed into the soil profile. However, bacteria are abundant in the green litter of younger plants, which is higher in nitrogen and simpler carbon compounds than the litter of older plants. Bacteria and fungi are able to access a larger surface area of plant residue after shredder organisms such as earthworms, leaf-eating insects, millipedes, and other arthropods break up the litter into smaller chunks. Interestingly by adding different type of litters green (nitrogen) vs. older (carbon) litter to your compost/ manure pile you can create more bacterial or fungi dominated compost. Bacterial dominated compost is more preferred for pastures.

Around roots. The rhizosphere is the narrow region of soil directly around roots. It is swarming with bacteria that feed on discarded plant cells and the proteins and sugars released by roots. The protozoa and nematodes that graze on bacteria are also concentrated near roots. Thus, much of the nutrient cycling and disease suppression needed by plants occurs immediately nearby to roots.

On humus. Fungi are common here. Much of the organic matter in the soil has already been decomposed many times by bacteria and fungi, and/or passed through the guts of earthworms or arthropods. The resulting humic compounds are complex and have little available nitrogen. Only fungi make some of the enzymes needed to degrade the complex compounds in humus.

In spaces between soil aggregates. Those arthropods and nematodes that cannot burrow through soil move in the pores between soil aggregates. Organisms that are sensitive to dehydration, such as protozoa and many nematodes, live in water-filled pores.

When are soil organisms active?
The activity of soil organisms follows seasonal patterns, as well as daily patterns. In temperate systems, the greatest activity occurs in late spring when temperature and moisture conditions are optimal for growth. In tropical systems this is more during the summer months (wet-season). However, certain species are most active in the winter, others during dry periods, and still others in flooded conditions.

Not all organisms are active at a particular time. Even during periods of high activity, only a fraction of the organisms are busily eating, breathing, and altering their environment. The remaining portion is barely active or even dormant.

Many different organisms are active at different times, and interact with one another, with plants, and with the soil. The combined result is a number of beneficial functions including nutrient cycling, moderated water flow, and pest control.

The importance of the soil food web
The living component of soil, the food web, is complex and has different compositions in different ecosystems. Management of our pastures benefits from and affects the food web.

When practising pasture management, it is not the vegetation that is replenished but the soil. The best means to achieve this is to replicate naturally occurring nutrient cycles: we need to feed the soil through a process of breaking down organic matter with soil microorganisms, bacteria, and fungi. In a natural system, many species of plants and animals play a role in these processes. However, on farming land, it is the owner or manager’s responsibility to oversee the animals and return waste (via compost or mulch) to the soil and plants.

Permaculture is concerned with the restoration and development of soil as a priority, because healthy soil produces healthy plants and grasses — which help produce healthy horses! One of the most difficult aspects of teaching people about working with natural systems and improving pasture health is that permaculture is a way of thinking. It is not a product, something that can be bought off the shelf from the local rural supplier, spread, sprayed, or watered. The difference is that, once natural health has been allowed to return through interaction in the soil food web (as illustrated in figure 2), natural balance can be restored. Natural systems are the only science recognised by nature. All over the world, when natural systems are disregarded, the land suffers, and in the long-term, attracts high input costs (herbicides, chemical fertilisers etc).

However this not to say that we can use certain human tools and agricultural and biological manufactured products, but we need to be aware that there is no one solution or fix to our soil, weed or pasture problems, but rather we need to adopt an integrated whole-system approach to our management. One of such tools is conducting soil tests, which offers us a reference (current status of our soil) and allows us to monitor our outcomes of our farming practices. These soil tests should not only provide us with a nutrient/mineral profile but also with an indication of our soil carbon and soil biology, often-overlooked aspects! Thus in the next edition we will discuss the importance of soil tests, in the lab and DIY and how to interpret these soil test results.

Further reading
Soil Biology Primer – Natural Resources Conservation Services (United States Department of Agriculture) – www.nrcs.usda.gov
Soil Health, Soil Biology, Soilborne Diseases and Sustainable Agriculture. A Guide. By G. Stirling et al. 2016. CSIRO Publication, QLD, Australia

Food Sources for Soil Organisms
• “Soil organic matter” includes all the organic substances in or on the soil. Here are terms used to describe different types of organic matter.
• Living organisms: Bacteria, fungi, nematodes (earthworms), protozoa, arthropods, and living roots.
• Dead plant material; organic material; detritus; surface residue: All these terms refer to plant, animal, or other organic substances that have recently been added to the soil and have only begun to show signs of decay. Detritivores are organisms that feed on such material.
• Active fraction organic matter: Organic compounds that can be used as food by microorganisms. The active fraction changes more quickly than total organic matter in response to management changes.
• Labile organic matter: Organic matter that is easily decomposed.
• Root exudates: Soluble sugars, amino acids and other compounds secreted by roots.
• Particulate organic matter (POM) or Light fraction (LF) organic matter: POM and LF have precise size and weight definitions. They are thought to represent the active fraction of organic matter, which is more difficult to define. Because POM or LF is larger and lighter than other types of soil organic matter, they can be separated from soil by size (using a sieve) or by weight (using a centrifuge).
• Lignin: A hard-to-degrade compound that is part of the fibers of older plants. Fungi can use the carbon ring structures in lignin as food.
• Recalcitrant organic matter: Organic matter such as humus or lignin-containing material that few soil organisms can decompose.
• Humus or humified organic matter: Complex organic compounds that remain after many organisms have used and transformed the original material. Humus is not readily decomposed because it is either physically protected inside of aggregates or chemically too complex to be used by most organisms. Humus is important in binding tiny soil aggregates, and improves water and nutrient holding capacity.

This article was published in the Horses and People Magazine March 2018
By Mariette van den Berg, PhD, BAppSc (Hons), RAnNutr

Mariette has a PhD in Equine Nutrition and Foraging Behaviour, is a RAnNutr equine nutritionist, a Certified Permaculture Designer and a dressage rider. She is the founder of MB Equine Services.

Furthermore, we will discuss the importance of soil tests, in the lab and DIY, interpreting these soil test results, and how they may assist our soil and pasture management on the property.

Before we start digging up the dirt, let’s brush up on some facts about soil.

Soils are complex mixtures of minerals, water, air, organic matter, and numerous micro and macro-organisms that are the decaying remains of once-living things. It forms at the surface of land – think of it as the “skin of the earth.” Soil is capable of supporting plant life and is vital to life on earth. In many Equine Permaculture articles, we have focused on the importance of taking care of our soils, so we can grow healthy pastures to feed our horses.

The soil is perhaps the most overlooked, underrated, taken for granted, but major partner in growing plants. When managing pastures, how many horse and property owners have passed over getting to know their soil – reading up on soil facts – in favour of pasture planning and management?

What is soil?

Like many common words, the word soil has several meanings. The word “soil” is also known as “dirt”, “waste” or  “earth”. In its traditional meaning, soil is the natural medium for the growth of plants. Soil has also been defined by the FAO (Food and Agriculture Organization of the United Nations) as a natural body consisting of layers (soil horizons) that are composed of solids (minerals and organic matter), liquid, and gases that occurs on the land surface, occupies space, and is characterised by one or both of the following: horizons, or layers, that are distinguishable from the initial material as a result of additions, losses, transfers, and transformations of energy and matter or the ability to support rooted plants in a natural environment.

Lengthy definition, that. But reading closely, soil has many things in it: nutrients; minerals; dead, decayed stuff; water and other liquids; and air and other gases. And–surprise?– soil has horizons just like the atmosphere and each is easily identifiable from the other. We will explain these in a bit more detail further in the article.

Soil is the end product of the combined influence of climate, topography, organisms (flora, fauna and human) on parent materials (original rocks and minerals) over time. As a result soil differs from its parent material in texture, structure, consistency, colour, chemical, biological and physical characteristics.

Soil is an essential component of  “Land” and “Eco-systems” that both are broader concepts encompassing vegetation, water and climate in the case of land, and in addition to those three aspects, also social and economic considerations in the case of ecosystems.

Seven roles of soil
Soil performs many critical functions in almost any ecosystem (whether a farm, forest, prairie, marsh, or suburban watershed). There are seven general roles that soils play:

1. Soils serve as media for growth of all kinds of plants.
2. Soils modify the atmosphere by emitting and absorbing gases (carbon dioxide, methane, water vapour, and the like) and dust.
3. Soils provide habitat for animals that live in the soil (such as groundhogs and mice) to organisms (such as bacteria and fungi), that account for most of the living things on Earth.
4. Soils absorb, hold, release, alter, and purify most of the water in terrestrial systems.
5. Soils process recycled nutrients, including carbon, so that living things can use them over and over again.
6. Soils serve as engineering media for construction of foundations, roadbeds, dams and buildings, and preserve or destroy artefacts of human endeavours.
7. Soils act as a living filter to clean water before it moves into an aquifer.

Soils are complex mixtures of minerals, water, air, organic matter, and numerous micro and macro-organisms that are the decaying remains of once-living things. It forms at the surface of land – think of it as the “skin of the earth.”

Soil Composition

So, soil is a mishmash of many things from all over the place—small pieces of broken rock, fallen leaves, dead critters, decomposed tree branches, and of course, decayed plants, to name a few. Additionally soil acts like a sponge storing 0.01% of the total water on Earth within its pores. To be exact, a typical healthy soil sample contains the following:

•    45% minerals
•    25% water
•    25% air
•    5% organic matter

Soil holds also many living organisms. An acre of soil can hold about 5-10 tons of living beings. If you would conduct a microbiology soil test you may find that one gram of soil could hold as much as 5,000-7,000 bacteria species.

Soil Formation

Soil formation typically happens over many years. Natural processes like weathering, erosions, rains, floods, hurricanes, thunderstorms, tornadoes and the like all contribute to soil formation. Lichen and plant roots also help break down rocks into little pieces to become part of the new soil.

Because of the different materials and processes that affect its formation, soil comes in different colours and textures. Soil could have such lively colours as red, yellow and white but most of the time, soil is black, brown or grey. Due to the sand, silt, clay and other mineral particles in it, soil could be smooth, creamy, rough, crumbly and sticky to the touch.

Parent materials

Soil minerals form the basis of soil. They are produced from rocks (parent material) through the processes of weathering and natural erosion. Water, wind, temperature change, gravity, chemical interaction, living organisms and pressure differences all help break down parent material. The types of parent materials and the conditions under which they break down will influence the properties of the soil formed. For example, soils formed from granite are often sandy and infertile. On the other hand, basalt under moist conditions breaks down to form fertile, clay soils.

There are five main interacting factors that affect the formation of soil:

1) Organisms

Soil formation is influenced by organisms (e.g. plants), micro-organisms (e.g. bacteria or fungi), burrowing insects, animals and humans. As soil forms, plants begin to grow in it; they mature, die and regrow. Their leaves and roots are added to the soil. Animals eat plants; their wastes and eventually their bodies are added to the soil. This begins to change the soil. Bacteria, fungi, worms and other burrowers break down plant litter and animal wastes and remains, to eventually become organic matter. This may take the form of peat, humus or charcoal.

2) Climate

Climate (rainfall, temperature and wind) influences the rate of weathering and also affects plant growth. Temperature affects the rate of weathering and organic decomposition. With a colder and drier climate, these processes can be slow, but with heat and moisture they are relatively rapid. Rainfall dissolves some of the soil materials and holds others in suspension. The water carries these materials down through the soil. This is known as leaching. Over time this process can change the soil, making it less fertile.

3) Topography

The shape, length and grade of slope affects drainage. Aspect determines the type of vegetation on a slope and the amount of rainfall received. These factors cause variation in soil formation.

4) Time

The length of time that soil materials have been weathered, influences soil properties. Minerals weathered from rocks are further weathered to form materials such as clays and oxides of iron and aluminum.

5) Natural erosion

Soil materials are progressively moved within the natural landscape by the action of water, gravity and wind for example: heavy rains erode soils from the hills and deposit it in lower areas, forming deep soils. The soils left on steep hills are usually shallower. Transported soils include alluvial (water transported), colluvial (gravity transported) and aeolian (wind transported) soils.

Soil horizon (soil layers)

There are different types of soil, each with its own set of characteristics. Dig down deep into any soil, and you’ll see that it is made of layers, or horizons (O, A, E, B, C, R – see soil layer figure). Put the horizons together, and they form a soil profile. Like a biography, each profile tells a story about the life of a soil. Most soils have three major horizons (A, B, C) and some have additionally organic horizon (O), eluviated horizon (E) and/or bedrock horizon (R).

Horizon O (humus or organic) is the topsoil that we walk on. It’s one-inch thick and made up of decayed, organic stuff that feeds the soil and keeps it healthy. Horizon O is the most fertile, productive layer because it contains humus and lots of microorganisms that make nutrients available to plants.

Horizon A (topsoil) is the layer after Horizon O. It’s also part of the topsoil, composed of roots and beneficial microorganisms like mycorrhizae and fungi that feed on the waste materials shed off by roots. Of course, this horizon is also home to those hardworking critters -like earthworms, centipedes and dung beetles.

Horizon E (eluviated) is layer after Horizon A that some soil types may have such as older soils and forest soils. This layer is leached of clay, minerals, and organic matter, leaving a concentration of sand and silt particles of quartz or other resistant materials.

Horizon B (subsoil), the layer that follows, is a very tough layer. Rich in minerals that leached (moved down) from the A or E horizons and accumulated here. The soil is so hard that no root or critter can penetrate this barrier.

Immediately after that is Horizon C (parent material). These are rocks and old soil that form all the horizons above it. This layer contains primary bedrock, secondary materials from other places, old soil formations and the like.

Horizon R – (bedrock) is the last layer and consists of a mass of rock such as granite, basalt, quartzite, limestone or sandstone that forms the parent material for some soils – if the bedrock is close enough to the surface to weather. This is not soil and is located under the C horizon.

Soil types

Soil can come in many different soil types and identifying the type of soil you have will help to identify the types of plants that you can grow in your pastures. Soil can be categorised into sand, clay, silt, peat, chalk and loam types of soil based on the dominating size of the particles within a soil.

Sandy soil – are light, warm, dry and tend to be acidic and low in nutrients. Sandy soils are often known as light soils due to their high proportion of sand and little clay (clay weighs more than sand). These soils have quick water drainage and are easy to work with. They are quicker to warm up in spring than clay soils but tend to dry out in summer and suffer from low nutrients that are washed away by rain. The addition of organic matter can help give plants an additional boost of nutrients by improving the nutrient and water holding capacity of the soil.

Clay soil – are heavy soils that benefit from high nutrients. Clay soils remain wet and cold in winter and dry out in summer. These soils are made of over 25 % clay, and because of the spaces found between clay particles, clay soils hold a high amount of water. Because these soils drain slowly and take longer to warm up in summer, combined with drying out and cracking in summer, they can often test gardeners.

Silt soil – are light and moisture retentive soils with a high fertility rating. As silt soils compromise of medium sized particles they are well drained and hold moisture well. As the particles are fine, they can be easily compacted and are prone to washing away with rain. By adding organic matter, the silt particles can be bound into more stable clumps.

Peat soil – are high in organic matter and retain a large amount of moisture. This type of soil is very rarely found in a garden and often imported into a garden to provide an optimum soil base for planting.

Chalk soil – can be either light or heavy but always highly alkaline due to the calcium carbonate or lime within its structure. As these soils are alkaline they will not support the growth of ericaceous plants that require acidic soils to grow. If a chalky soil shows signs of visible white lumps then they can’t be acidified and gardeners should be resigned to only choose plants that prefer an alkaline soil.

Loam soil – are a mixture of sand, silt and clay that are combined to avoid the negative effects of each type. These soils are fertile, easy to work with and provide good drainage. Depending on their predominant composition they can be either sandy or clay loam. As the soils are a perfect balance of soil particles, they are considered to be great for pastures and gardens.

An important feature of soil is that it changes with depth.

Soil texture

Soil texture (e.g. loam, sandy loam or clay) refers to the proportion of sand, silt and clay sized particles that make up the mineral fraction of the soil. For example, light soil refers to a soil high in sand relative to clay, and heavy soils are made up largely of clay. Texture is important because it influences the amount of water that the soil can hold, the rate of water movement through the soil as well as its workability and fertility. For example, sand is well aerated but does not hold much water and is low in nutrients. Clay soils generally hold more water, and are better at supplying nutrients. Texture often changes with depth so that roots have to cope with different conditions as they penetrate the soil. A soil can be classified according to the manner in which the texture changes with depth. The three profile types are: uniform—same texture throughout the profile, texture-contrast—abrupt texture change between surface and sub-soil, gradational texture changes gradually from light to heavy down the profile.

Structure:

Soil structure refers to the way soil particles group together to form aggregates. These aggregates vary in size and shape from small crumbs through to large blocks. Very sandy soils are structure less because sand grains do not cling together. Some soils resemble a large solid, featureless mass—referred to as massive and have little or no structure. Good soils fit in between the two extremes. A well-structured soil breaks up easily into aggregates or peds with a definite shape (e.g. granular or blocky) and size (1-60 millimeters).

Organic matter helps give a soil good structure by binding soil particles together. Good structure is important, as it allows water to soak into the soil and excess water to drain away. It also allows air movement through the soil. Soil, air and water are vital for healthy plant growth and continued nutrient supply.

Colour

Soil colour is strongly influenced by humic (organic) materials, which are brown or black, iron oxides (red or yellow) and features of the parent material. Poorly drained soils may contain blue, grey and green colours.

Soil pH level

Soil pH is the measure of the acidity or alkalinity level of the soil. It affects plant growth, as it determines the availability of plant nutrients in the soil.

Soil pH is measured on a scale from 0-14, with 7 being neutral. A highly acidic soil can have as low as pH 3, while a highly alkaline soil can be close to pH 10. Most soils have a pH 6-8 range and plant growth is usually best in a soil of pH 6-7.

Nutrients

For plants to be healthy, they need a steady supply of nutrients from the soil. Nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca) and magnesium (Mg), are required in relatively large quantities (macronutrients). Others are required in small quantities (micronutrients or trace elements), eg. copper (Cu), zinc (Zn) and manganese (Mn). A shortage or absence of any one of these essential nutrients can severely retard plant growth. Too many nutrients can be as bad as too few. The availability of nutrients is affected by the pH level of the soil. For example, in very acid soils, manganese and aluminum may be present in toxic concentrations. The nutrient status of a soil can be determined by a laboratory analysis of the soil or the plants that grow in it.

Dispersibility

This is characteristic of some clay rich soils that have a high concentration of sodium or magnesium in the clay fraction. A ‘sodic’ soil has a high sodium ion concentration. When these soils come into contact with water, they may become unstable and disperse. Dispersion in the surface soil leads to crusting and surface sealing, dispersion in the subsoil accelerates erosion and may lead to the formation of gullies and tunnels.

Permeability and porosity

Permeability is a measure of how easily water moves through the soil. At the surface, it affects the rate at which water can enter a soil, called the infiltration rate. It is affected by soil structure and texture. Porosity is the amount of space around mineral grains that can be filled by water or air, which contribute to a soil’s permeability. Particularly large pores that are visible are called macropores.

Soil organic matter and soil carbon sequestration.

Soil organic matter is the component of soil derived from all biological sources—whether living or nonliving. Soil organic matter is a vital indicator of soil health because of its impact on a variety of soil functions and properties. It provides the energy source for micro-organisms in the soil, is a reservoir of nutrients and improves the structural stability, water holding capacity and pH buffering capacity of the soil.

Soil organic matter content is difficult to measure directly but can be visually inspected. Laboratory tests actually measure soil organic carbon (SOC), which makes up about 58 % of total soil organic matter. Soil organic matter is made up of several pools that vary in their contribution to soil functions and their longevity in soil systems. Organic residue deposited in or on the soil is the most active pool, but may be rapidly lost (has low stability). Humus (made up of resistant compounds derived from decayed organic residues) is a slow, more stable pool. Charcoal is very stable, but is not biologically active, and therefore is an inert or passive pool. Soil cultivation and soil degradation result in losses of organic carbon which is released as CO₂ into the atmosphere. Land clearing and overgrazing also contribute to the loss of soil carbon.

Improved soil management strategies such as crop stubble retention or leaf area management (for pasture) on the soil surface and reduced grazing pressure have the potential to increase the store of soil carbon, thereby acting as sinks for atmospheric carbon.

Understanding soil facts for better pasture management

The soil sustains most living organisms, being the ultimate source of their mineral nutrients. Soil management is an integral part of land management and may focus on differences in soil types and soil characteristics to define specific interventions that are aimed to enhance the soil quality for your pastures. For example many horse properties are established on overgrazed farmland that exposes subsoil. Many horse owners are not aware that this is not the correct soil layer that we need to work with to build pastures. We need to build a healthy top layer (top soil) before we can sustain healthy plants. Specific soil management practices are needed to protect and conserve our soil resources, as well as build more soil!

Soils are neither “good” nor “bad” because the distinction is often based on their intended use. However many soils have characteristics that make specific management interventions desirable to avoid problems for grazing purposes. Good management of soils assures that mineral elements do not become deficient or toxic to plants, and that appropriate mineral elements enter the food chain (soil – food – web). In the next edition we discuss in more detail the soil food web interaction and how this supports healthy pastures for our horses.

This article was published in the Horses and People Magazine February 2018
By Mariette van den Berg, PhD, BAppSc (Hons), RAnNutr

Australia has more than 500 species of native dung beetles and 23 species of dung beetles introduced from Hawaii, Africa and southern Europe. The introduced dung beetles are very useful in Australia’s agricultural regions. Where they are well established, these dung beetles bury large volumes of cattle and horse dung. Some species can remove a pat in less then 24 hrs! The removal from dung under ground by beetles have many benefits for soil, water and pasture, as well as biological control of the bush fly and parasitic worms.

Most native dung beetle species eat marsupial dung (from kangaroos and wallabies) and they don’t process the moist dung of domestic farm animals very well. A few native species (mainly in southern Australia) can consume the moister dung of horses, sheep and cattle. Thus as part of a larger Dung Beetle project about 40 species of exotic dung beetles have so far been introduced to break down the manures of farmed animals (only 23 have been successful). The Australian Dung Beetle Project (1965–1985), conceived and led by Dr. George Bornemissza, of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), was an international scientific research and biological control project with the primary goal to control the polluting effects of cattle dung.

Climatic and geographic limitations necessitate 6-10 species be colonised on farms to get year round activity in dung removal. Most dung beetle activity takes place in spring, summer and autumn but recently a winter active species has been identified for introduction to farms in southern Australia. And, in any case, earthworms are at their most active during the winter converting organic material into plant food and aerating the soil.

The life cycle of dung beetles sees beetles actively consuming dung and burying it for 2-3 months followed by a hibernation period. Only when similar seasonal conditions prevail do the beetles once again become active, coming out of dormancy from the eggs that were laid up to 300mm in the soil during the previous active season. Depending on species, some dung beetles will go through 1-2 life cycles during an active season. Each mature female beetle will lay 60-80 eggs in a season thereby increasing population by this factor in one generation. Dung beetles are known to spread up to 2km per year if unimpeded by bush or barrier and will diminish in density for a period of time after their release before consolidating their population.

Dung beetles and benefits on horse properties

Dung beetles are very beneficial to our pastures, our horses and us. For us horse owners this means, less cleaning paddocks and poo shovelling, and free soil development without any efforts! They also help controlling fly and parasitic worm populations, which is great news for our horses.

So if you have dung beetles – take good care of them and if you don’t have them.. you probably have them in the ground.. but you need to create the right conditions for them to establish. It is also possible to buy or get dung beetles from organisations/ institutions in your region that you can release. Make sure that they suit your soil conditions, as they are very fussy about the type of soil as well

Taking care of dung beetles

Dung beetles help break down poo, transporting it underground, which helps with soil decompaction and fixing nitrogen. But be aware that if your pastures are severely compacted, even dung beetles cannot do the work for you. If the soil is too hard, they will die as the spikes on their legs get eroded and without them they cannot burry themselves into the ground. Thus if you find that you don’t have beetles or very small amounts you may need to first look at soil development such as decompacting using Keyline ploughing or composting and mulching strategies.

Also dung beetles require fresh dung, so its important that you don’t remove all the good manure and allow beetles to establish. Remove older pats that have been decomposed at least 3-4 days. You typically can see that the pat is all broken down and spread and only larger fibre components are visible. They also have a greyish colour and are dried out.

Care with wormers and other chemicals

Many treatments for the control of cattle or horse parasites and pests have negative effects on dung beetle survival, breeding capacity and activity.

A thorough review of the effect of macrocyclic lactone(ML) drenches on dung beetles has shown that that toxicity rankings against non target species was greatest for doramectin, followed by ivermectin and eprinomectin, with moxidectin being significantly less toxic to non-target species.

Ivermectin is a very effective anti-parasitic drug that has been used as a preventative in livestock since its discovery in 1981. Since then its use has increased exponentially to become a standard drug in the treatment and prevention of common parasites, including in human beings. While considered by the World Health Organization as an essential medication and proven very effective, its widespread use comes at a price.

The issue, researchers have found, is that the ivermectin molecule can survive its journey through the animal and be excreted unchanged. Also, once on the ground, residues can remain active in animal dung for at least a month. This means the drug hits the arthropod populations as hard as it does the parasites it is intended to prevent. The ingestion of ivermectin affects even mature dung beetles, seriously compromising their mobility, orientation and reproductive capacities. These findings contradict international veterinary manuals and yet offer a compelling explanation for the decline in population levels reported in other research.

While invermectin may be harmful to beetles it is not to say you cannot use it, as many horse owners like them for the control of bots. You just have to be aware of the timing – either late autumn (when it gets colder) or very early spring before it warms up. This avoids the period (summer) when most dung beetles are active.

Other dewormers like fenbendazole and oxibendazole are also commonly used, but they are less toxic compared to invermectin or other avermectins. Dewormers with moxidectin aren’t as lethal to immature beetles and have a shorter time of toxicity (only 3 days after drenching). Choosing this drench will ensure that management decisions for parasite control will have no effect on dung beetle activity. However you will need to review the chemical used as resistance in horses is another factor you need to consider when choosing the type/ brand of dewormer. Before you take action and buy your de-wormer, its advised that you do a faecal egg counts (FEC) check for each horse on the property, which helps with identifying the severity of the worm burden. Faecal egg counts (FEC) of less than 200 eggs per gram is regarded as a ‘low’ and no further action is required. So often only a few horses require treatment. However FEC won’t work for encysted worms, tapeworms or worms at the life-cycle stage where eggs are not being laid.

To ensure that you don’t kill many dung beetles in your pasture it is generally advised to manage your horses for at least 3-7 days in a sacrifice area, central point or yards after drenching, so that you can collect the poo for these days. As mentioned earlier avermectins such as invermectin may still be active for many weeks – but in this way you reduced some of the toxic effects.

Pasture management

When horses graze they are very selective. They can eat down some areas until it’s almost bare, whilst leaving other areas in which they dung and urinate untouched. If these paddocks and pastures are not managed properly you can get over-grazing and “horse-sick” pastures with poor quality grasses, accumulation of weeds, compacted and eroded soils, manure build up and populations of parasites. Horse-sick pastures may be more evident when there is insufficient land, but also larger horse properties can have these problems. These horse-sick pastures not only affect the health of your horse, but also negatively influence the shape of the land and can reduce the value of your property or land to which it is attached.

To manage both soil and parasites; pasture rotation, strip grazing and cross-grazing (alternating with livestock) are effective ways to reduce parasite survival. Also rotating horses to “fresh” pastures ensures recovery of grazed pastures and allows you to work on soil development (e.g. composting, mulching, keyline ploughing), which helps with keeping the soil healthy for your soil workers. As mentioned earlier in severely compacted soils dung beetles cannot survive, so taking care of this problem is important. Understandably we will never fully avoid compaction along boundaries, water and feeding points, but by timely grazing and moving animals frequently this compaction is less severe and can be easily restored using mulching techniques or just recovery time if you have healthy soils to start with.

Additional husbandry strategies

Another solution is to use track and sacrifice/central point systems that can take some of the regular congregating of animals. As the word is suggesting, this is an area that you sacrifice for pasture/ plant growth and clearly allow compaction. Typically these systems are used to provide a central space for water, feeding or to move horses off pasture for plant recovery or reducing pasture intake. The design of your sacrifice/ central points will largely depend on the number of horses, space available and budget. While you allow compaction to happen in these areas it is important that you pay close attention to the drainage and footing of these areas so you avoid mud build up which can be very dangerous for you and your horses. You will need to look at the shape of the land and review if you need to level and prepare this area in such away that it allows water to slowly be drained without causing quick run off (and erosion). The sacrifice area will need to be fenced off and requires a border around the footing to avoid run off. You can even build a (rock) rain garden that can take some of the extra run off water (kind of like a mini swale!).

There are many types of materials that can be used as footing and your choice will largely depend on your preferences, availability and budget. River sand, pea rock gravel, and wood chips are regularly used for their comfort and/or price and can be applied to different areas. You can even decide to use ground stabilising products such as plastic pavers with a cell-like structure (honeycomb or diamond). Typically sand or pea rock can be used to fill the grid spaces and this will allow water to pass through, without making it into a muddy area. This system can be very useful for high impact areas such as gateways, tracks and water points. However, it still needs to be managed and manure should be taken away regularly to avoid build up that can turn into a slurry.

Summary

If you have horses and manage them mostly on pasture- You WANT dung beetles!! They muck out your paddocks, build carbon and increase the availability of nutrients and water. Dung beetles, but also other soil workers such as earthworms, fungi and bacteria are all important for the health of our soils and pastures. We never feed plants directly – its through the process of breaking down organic matter which is done by our soil workers. While they do all the work – we still need to be involved with the process, guiding it in the right direction and creating conditions that the soil workers thrive in. This means that we need to have an integrative approach for the management of our horses and pasture. Selective worming, pasture rotation/resting and cross-grazing with livestock will all contribute to maintaining healthy soils, reducing parasite burden and resistance in horses.

Stay turned for the next blog post – I have a dung beetle expert and students from the University of New England visiting  my own property to check out the species I have. I will report on our findings and dicuss the management I have done so far to manage my soil workers

Further information & Links

• Horses Bugs & Beetle – Aimed to raise awareness amongst horse property managers, owners and agistees about sustainable horse keeping through promoting dung beetle health and reducing the use of chemicals. This website offers free fact sheets for horse owners.
• Australian Government National Landcare Program
• Dung Beetle Solutions Australia (here you can purchase the Book Dung Down Under by Dr Bernard Doube)
• The dung beetle expert – John Feehan (http://dungbeetleexpert.com.au)
• Graeme Stevenson – author of the book Ruminations of a poo-ologist : dung beetles in Tasmania
  
• Feacal egg counting kit
• Equiculture
• Equine Permaculture
• Horses for Clean Water
• Horse SA
• Horseslandwater
• Landcare Australia
• MB Equine Services

Dung beetles are very cool creatures! They eat your horse or cow poo (how fantastic!), decompact soil and increase the availability of nutrients (and water)!

Dung beetle behaviour has fascinated humans for thousands of years – including the ancient Egyptians, who observed that the beetles’ ball rolling is influenced by the sun. We now even know that some species of dung beetles even use the moon and galaxies to navigate! They are currently the only known non-human animal to navigate and orient themselves using the Milky Way!! Super cool Check out the video here: https://youtu.be/BHdtktnb3ms

Dung beetles evolved at least 65 million years ago, as the dinosaurs were in decline, and the mammals (and their droppings) starting to dominate. There are about 6000 species worldwide, concentrated mainly in the tropics where they feed mostly on the dung of terrestrial vertebrates. Dung beetles have been cleaning up the planet ever since; but what on earth do they do with all that poo? Here are some interesting facts:

Dung specialists

A dung beetle can bury dung 250 times heavier than itself in one night. There is one species Onthophagus Taurus that can pull a load 1,141 times it own weight! It’s named the strongest insect in the world!

Many dung beetles, known as rollers, roll dung into round balls, which are used as a food source or breeding chambers. Others, known as tunnelers, bury the dung wherever they find it. A third group, the dwellers, neither roll nor burrow: they simply live in manure. Dung Beetles can grow to 3 cm long and 2 cm wide.

All the species belong to the superfamily Scarabaeoidea; most of them to the subfamilies Scarabaeinae and Aphodiinae of the family Scarabaeidae (scarab beetles). As most species of Scarabaeinae feed exclusively on faeces (some also on mushrooms and decaying leaves and fruits), that subfamily is often dubbed true dung beetles. There are dung-feeding beetles which belong to other families, such as the Geotrupidae (the earth-boring dung beetle).

Eating dung!

Vulgar, but true, dung beetles eat dung from herbivores and omnivores. But they are fussy eaters, picking out the big bits and concentrating on the tiniest particles, 2-70 microns big (1 micron = 1/1000 of a millimetre), which is where most of the nitrogen in dung is to be found.

All organisms need nitrogen to build proteins, such as muscle. Dung beetles get theirs from dung. By eating poo, dung beetles may be selecting the cells from the gut wall of the herbivore which made it. These are a protein-rich nitrogen source. The latest studies show that obesity and diabetes in humans might be linked to our individual gut microbiomes. Dung beetles might be using their gut microbiome to help them digest the difficult components of dung. In a way plant material is fermented double before it’s returned to the soil– for example first by the cow or horse– then the poo is again fermented by the dung beetle!

Dung transport

The majority of dung beetles (~90%) tunnel directly beneath the dung pat and make an underground nest of brood balls in which they lay eggs. You’ll never see them unless you are prepared to poke around in the stuff. So if you have them in your pasture – go out there and check underneath the poo. You will see them quickly moving away, burring themselves back into the soil.

On the other hand, the roller dung beetles transport their prize on the soil surface. They use celestial cues such as the sun or the moon to keep to a straight track away from competitors that might steal their ball. Yes you read it well – roller dung beetles need to run fast, otherwise their poo ball gets stolen! A species of dung beetle (the African Scarabaeus zambesianus) navigates by polarization patterns in moonlight, the first animal known to do so. Dung beetles can also navigate when only the Milky Way or clusters of bright stars are visible, making them the only insects known to orient themselves by the galaxy, allowing it to dominate the midnight market in dung transport.

 The broodball; the packed lunch for larval beetles

This is what the brood ball represents to the larval dung beetle. Hatching from a single egg inside each brood ball, the larva eats its way around the interior of the ball. This dung is coarse and crunchy, so the larva has chewing mouthparts not found in the adult beetle, and doesn’t have the luxury of selecting what it can eat or discard, so it eats everything – several times. Therefore, its microbiome is different from their parents’, and might contain symbiotic microorganisms living in a mutually beneficial relationship with the host larva. That gives the larva access to sugars in otherwise indigestible cellulose, and may even “fix” nitrogen from the atmosphere.

Other uses for dung

Dung beetles also uses dung as a token to attract females, or they stand on a poo ball to cool their feet in hot dessert enrichments. On a hot day in the Kalahari the soil surface can reach 60°C, which is death to any animal that can’t control its body temperature. To avoid overheating dung beetles while rolling their balls in the blazing midday sun, climb on top of the ball to momentarily cool off, before hot-footing across the sand looking for shade. Giving them chilled dung balls from the fridge allows them to roll further before going back onto the ball. Heated balls have the opposite effect. And giving them insulating silicon boots lets them tolerate high temperatures for longer, showing that the dung ball is used as a thermal refuge from the heat. A very interesting evolutionary adaptation!

These facts clearly show how amazing dung beetles are, but which species do we have in Australia and how can they specifically benefit horse properties?
Read our next blog post!

When it comes to horse property layout, it pays to consider the permaculture design approach because it aims to build systems that are easier to manage, more efficient and sustainable, whilst considering the health and wellbeing of all – people, horses, plants and the soil that sustains them.

Following on from last month’s look at how the shape of the land influences design and layout of a property, in this Part 6 of this exclusive Equine Permaculture Design Series, Mariette van den Berg gives some practical solutions for managing water run-off and controlling erosion – one of the major problems on horse properties.

When we design the layout of our horse properties, we cannot ignore the importance of the shape of the land. Especially when we are dealing with uneven ground, with, slopes, hills and valleys, further design considerations need to be taken into account because the contour of the land has a pronounced effect on the flow of energy in our system!! If you are managing horses on a hilly property, you for sure have experienced the effect of this on water flow, soil condition and grass cover. Erosion and run-off is one of the major problems on horse properties. While soil erosion may be more obvious on hillier or smaller properties with higher stocking density, flatter and larger properties are not exempted.

Soil erosion is a naturally occurring process that affects all landforms. In agriculture, soil erosion refers to the wearing away of a field’s topsoil by the natural physical forces of water and wind or through forces associated with farming activities such as tillage and animal grazing. Erosion, whether it is by water, wind, tillage or animal grazing, involves three distinct actions – soil detachment, movement and deposition. Topsoil, which is high in organic matter, fertility and soil life, is relocated elsewhere “on-site” where it builds up over time or is carried “off-site” where it fills in creeks, rivers or drainage channels. Soil erosion reduces cropland productivity and contributes to the pollution of adjacent watercourses, rivers, wetlands and lakes.

Soil erosion can be a slow process that continues relatively unnoticed or can occur at an alarming rate, causing serious loss of topsoil. Soil compaction, low organic matter, loss of soil structure, poor internal drainage, salinisation and soil acidity problems are other serious soil degradation conditions that can accelerate the soil erosion process. In the case of horse properties that deal with large grazing animals, compaction is typically the main cause of soil erosion and soil degradation.

In the previous edition we already briefly describe how the shape of the land (i.e. slope) affects natural energies such as water, materials, heat, erosion control, fire control and aspect. In this article we would like to focus primarily on erosion control and how we can manage run-off, specifically we will be discussing 8 ways to prevent/manage erosion on horse properties.

1. Understanding contours and shape of the land.

If you want to work with natural patterns and prevent erosion you must familiarise yourself with a contour map of your property. A contour map is illustrated with contour lines, which shows valleys and hills, and the steepness of slopes. The contour interval of a contour map is the difference in elevation between successive contour lines. From these contours, a sense of the general terrain and slope can be determined. The steeper and longer the slope of a field, the higher the risk for erosion.

Soil erosion by water increases as the slope length increases due to the greater accumulation of runoff. Consolidation of small fields into larger ones often results in longer slope lengths with increased erosion potential, due to increased velocity of water, which permits a greater degree of scouring (carrying capacity for sediment). Therefore its essential that if you are dealing with a hilly property and/or lot of water run-off that you work as much as possible on contour lines and integrate methods such as keyline design (ploughing), swale design and on contour vegetation planting/mulching and fencing to prevent erosion.

2. Contour ploughing and Keyline planning (ploughing)

Contour ploughing or contour farming is the farming practice of ploughing and/or planting across a slope following its elevation contour lines. These contour lines create a water break which reduces the formation of rills and gullies during times of heavy water run-off; which is a major cause of top soil loss and soil erosion. The water break also allows more time for the water to settle into the soil. In contour ploughing, the ruts made by the plough run perpendicular rather than parallel to slopes, generally resulting in furrows that curve around the land and are level. This method is also known for preventing tillage erosion. Tillage erosion is the soil movement and erosion caused by tilling a given plot of land.

A similar practice is contour bunding where stones are placed around the contours of slopes. Soil erosion prevention practices such as this can drastically decrease negative affects associated with soil erosion such as reduced crop productivity, worsened water quality, lower effective reservoir water levels, flooding, and habitat destruction. Contour farming is considered an active form of sustainable agriculture.

Fig 1. shows keyline ploughing on a hillside. Notice the plough lines on the ridge fall and rise in the valley. Movement of water is then slowly directed to the dry ridges. Compaction layers are shattered and the 3 life forces, air, light and water are allowed to penetrate the ground and kickstart life back into the earth.

Keyline planning/ploughing works slightly differently from contour ploughing. The Keyline design and plough concept was originally developed by P.A. Yeomans in the 1950s to address issues of dwindling water supplies and soil erosion on Australian rangeland. Yeoman developed a system of ‘amplified contour ripping’ that maximises productive use of rainfall and facilitates the uniform irrigation of land.

The name Keyline was given to the particular contour that runs through the Keypoint, in all small headwater valleys where the slope change occurs. This contour is the primary contour in Keyline planning. The Keypoint is the found at the break of a slope where the land goes for convex to concave. Keypoints are often characterized by the beginning of a discernable channel, where subsurface flow from higher in the slope surfaces — in effect, like the end of a pipe — and can be captured and redistributed. This is also the best place for farm dams. It’s the point of deposition and this is where all clay forms (we also addressed this in our previous article). Identifying the Keypoint, and attendant Keyline, is the starting point for Keyline design. A Keyline is the contour line that intersects with the Keypoint. As opposed to contour lines, which often vary in distance along their length, Keylines fall off contour at the same elevation along the length of the line such that Keylines always run parallel to one other, making the creation of Keyline cuts particularly amenable to mechanical management using a tractor and (P.A. Yeomans) plough.

The main idea behind Keyline design is to capture water at the highest possible elevation and comb it outward toward the (often drier) ridges using gravitational forces, reversing the natural concentration of water in valleys. The result of Keyline cultivation is an overall drift of surface run-off water, which prevents run-off concentration and the resultant gully erosion. It increases the time of contact between the rain and the earth and has the effect of turning storms into steady soaking rain. Rain may have become less frequent in some parts of Australia, but its intensity and volume over a twenty-four-hour period is growing.

3. Swales/ contour banks

Water flows the fastest straight down a slope, and the effects of erosion will be most pronounced when water has the most direct path down a slope. Additionally, when water flows fast down a slope, very little of it is absorbed into the soil. By digging trenches on contours of the slope (swales), the flow of water can be slowed down, and diverted sideways on its downhill journey, to allow it to soak into the soil. Swales are not the same as contour banks. Contour banks actually redirect the water slightly off contour and drain to a central point to slow water and to stop erosion. Swales are level banks that follow contour from start to finish. Swales as used in permaculture are designed to slow and capture run-off by spreading it horizontally across the landscape (along an elevation contour line), facilitating run-off infiltration into the soil (figure 2).

Figure 2: Swales with inclusion of trees (MB Equine Services).

A swale is created by digging a ditch on contour and piling the dirt on the downhill side of the ditch to create a berm. The soil that is excavated from the ground is placed, uncompacted, on the lower side of the excavation in a rounded mound shape. Once the topsoil on the pasture is at 100% water-holding capacity, surface run-off flows into the swale. The water is absorbed and taken deep underground to recharge the subsoil and replenish underground springs. This process slows water in the landscape and retains it in the ground for longer periods of time.

4. On contour fencing

Likewise, when constructing paths, tracks, laneways (for example for paddock paradise set ups) and fences, it is best to have these run along the contours of the site, and not downhill, as downhill running paths will create significant soil erosion, because there are no ground cover plants protecting the soil on a cleared path. Fences holding horses will become tracks as horses walk the fence-line day after day, so we also avoid running these straight downhill if possible.

5. Vegetation/ Planting

The simplest and most natural way to prevent erosion is through planting vegetation. Plants establish root systems, which stabilises soil and prevents soil erosion.Having vegetation such as shrubs and trees will help control soil erosion and a forested steep slopes also warms the cool night air to create a thermal belt as described in our previous article. When water runs downhill, it will carve its own watercourses and gullies, washing away the soil in the process. Trees, vegetation and ground covers absorb the flow of the water, and by creating a buffer between the flowing water and the soil, they control the problem of soil erosion. That is why it’s also important to think in terms of ground/ grass cover for your pasture areas. Healthy topsoil and good grass cover will act like a sponge, soaking up the water (and reducing direct and fast run-off).

6. Mulching (and slashing)

Many materials are used as mulches, which are used to retain soil moisture, regulate soil temperature, build soil, suppress weed growth, and for aesthetics. They are applied to the soil surface, around trees, paths, flowerbeds, to prevent soil erosion on slopes, and in production areas for flower, vegetable crops or pastures. When applied correctly mulches can dramatically improve soil productivity. Mulch layers are normally two inches or more deep when applied. A mulch is usually but not exclusively organic in nature. It may be permanent (e.g. plastic sheeting) or temporary (e.g. straw, bark chips). Mulches together with manure or compost improves the activity of worms and other organisms, which are important for building soil and increasing nutrient availability. Mulch is applied at various times of the year depending on the purpose. Towards the beginning of the growing season mulches serve initially to warm the soil by helping it retain heat which is lost during the night.

On horse properties you could mulch your pastures by slashing long-standing weeds and old bunch grasses. This allows early seeding and transplanting of certain crops, and encourages faster growth. As the season progresses, mulch stabilises the soil temperature and moisture, and prevents the growing of weeds from seeds. In temperate climates the effect of mulch is dependent upon the time of year they are applied and when applied in fall and winter, are used to delay the growth of perennial plants in the spring or prevent growth in winter during warm spells, which limits freeze thaw damage.

7. Geotextile and geocells

Using geotextiles is an effective method because it also stabilises soil. When used in conjunction with growing vegetation, it is even more effective. Geotextiles are filter fabrics that are used to stabilise loose soil and increase stability from wind and water erosion. Made from synthetic and natural fibres, geotextiles help in the filtering, separation, and drainage of water from the soil. Geotextiles can be woven, non-woven, or knitted.  All these different fabric compositions are suitable and can be used in various applications.

Geotextiles are mainly used in civil engineering, agricultural and erosion control applications. It has been proven to stabilise locations such as roads, railroads, canals, construction sites, coastal engineering, and dams. Another variant of the textile concept is the geocells/ matting, which is a three-dimensional mat or tile made from polyethylene grids (cells or honey-combs). The structure retains a layer of top soil and anchors the growing grass roots thus providing a stable surface highly resistant the forces of rain drops and run off. Other materials such as pea-rock and sand can also be used to fill the cells.

The cellular design allows for custom sizes, configuration and adaptability to a variety of terrains. The hydraulic properties are influenced by the type and compaction of the fill material. Geocell/matting has many applications; slope protection, horse sacrifice areas, tracks, roads, livestock/horses water points, ditches, ponds/dam walls etc.

8. Retaining Walls (and Terracing)

Retaining walls can be built around the area of erosion to prevent water run off. Runoff water leads to further erosion, and if used with other methods (terracing), retaining walls can be a very effective way to prevent soil erosion. Retaining walls such as Rock (or Straw) gabions can be very useful. Rock gabions are baskets made from flexible steel wire mesh and filled with granite or basalt rock.

Rock gabions are constructed in various sizes and are commonly used for along creek banks, over soft ground, steep slopes and rock fall areas to trap sediment. The purpose of rock gabions is to prevent undercutting and/or scouring at the base of steep slopes. Vegetation may be incorporated into the gabion by placing cuttings between the gabion layers. The cuttings will take root in the gabions and the soil behind the structure. The vegetation provides additional stability once the root structure has developed.

Fig. 3 Gabion example (MB Equine Services)

Summary

These solutions to control water run-off can be used in combination to prevent and manage soil erosion in different areas on your horse property.

The structures and materials you choose to use will largely depend on the shape of your land, your budget and property design ideas. The most important aspect of erosion control is understanding land contours, and the effect slope has on water and animal traffic, and learning to work with them to reduce damage to your land.

For example, if you are planning on fencing areas for your horses’ pastures or planting trees/shrubs, use contours for placement. This small adaption won’t cost you necessarily more (maybe you have to run a few extra meters), but in the long run, it will avoid damage and loss of soil and, consequently, grasscover, which will always cost much more in labour and money to restore!

Companion articles of this EP series can be found on the H&P website: https://www.horsesandpeople.com.au/

When it comes to horse property layout, it pays to consider following the permaculture design approach because it aims to build systems that are easier to manage, more efficient and sustainable, whilst considering the health and wellbeing of all – people, horses, plants and the soil that sustains them.

In this Part Three of our Equine Permaculture Design Series, Dr. Mariette van den Berg explains the first two techinques that permaculture desing consultants use when deciding where to place all the elements needed, why they do it this way, and how the same principles can be applied to designing a horse property – either from scratch or to identify any changes that could be made to an existing layout to make it more efficient.

Permaculture is a creative design process based on whole-systems thinking informed by ethics and design principles, which we introduced briefly in our previous articles (part 1 and 2). This approach guides us to mimic the patterns and relationships we can find in nature and can be applied to all aspects of human living, from agriculture to ecological building, from technology to education and even economics.

While there are many principles that are important, key to permaculture is the wise husbandry of natural resources, in particular in terms of energy. In nature, when energy is cycled, living systems grow. Therefore, permaculture farming places an enormous emphasis on enhancing soil fertility through composting, thereby minimising the loss of energy. Likewise, the perennial edible landscape associated with permaculture, including food trees, fodder trees, pastures, herbs etc decrease the energy input required for food production for our grazing animals and ourselves.

A design concept

The same principles can even be translated into design concepts for our houses and properties with the aim to capture energy, to increase the growth of our living systems and set in place cycles; a process which eventually leads to greater energy and chore efficiency.

To accomplish this, we need to have a close look at the layout of our properties and permaculture uses zone and sector planning to help us identify what the best placement of elements is for our site.

In particular, zone and sector analysis is a tool to determine the best locations for the activities you wish to integrate into the system, so they can be performed efficiently and sustainably.

Zone and sector analysis techniques are regularly covered in permaculture texts and permaculture design courses, and can be easily applied to horse properties.

Permaculture zones

The design principle of zones and sectors is concerned with efficient energy planning, that is, planning the placement of elements in the design, such as trees and plants, animals, structures and buildings, to make to most efficient use of energy. Zone planning is a system where the location of an element in a design is determined by:

1. How often we need to use the element
2. How often we need to service the element

The use and service of the elements are quantified using 0 to 5, and can be thought of as a series of concentric rings moving out from a centre point, where human activity and need for attention is most concentrated, to where there is no need for intervention at all.

This is a basic logical principle, whereby the things you use most often, and the things you have to pay the most attention to, are placed closest to the house in the design. Subsequently, the things that are used the least often, or that require little or no attention, are placed furthest away in the design, and things that fall somewhere in between are placed accordingly. By situating the most often used or serviced elements in a design closest to the home, it makes it easier to access them. This means less energy is expended to access them, making for a more energy and chore efficient design.

As a practical example, a kitchen garden containing the most often used vegetables and herbs would ideally be located in close proximity to the kitchen itself, so when the need for herbs and vegetables arises, it’s only a quick step outside the back door of the house to get the required cooking ingredients. It would be highly inefficient, and extremely wasteful of energy if you had to walk across your whole property, to some remote back corner, to get what you need to prepare a meal, for the following reasons.

For horse properties it is also important to have your horse yards or stables reasonably close to the house site (zone 2) because we visit them daily. Keeping this in mind, we also have to remember animals gathering close to the house (for example in a sacrifice area, central point or holding yard) can increase the soil and pasture problems in ways that are neither healthy for horses nor do they support the aesthetics of the property.

This is why property layouts, which are based on a central point system, always recommend the area where horses will spend time in (called loafing), has a suitable surface or footing. This helps prevent soil degradation (erosion, compaction, mud/dust and weeds, etc.), and keeps the environment healthier for horses and people.

Whether you are designing a central point system or not, when looking at your property’s zoning you also have to consider the connection between the stables and yards closer to the house, and the grazing areas (zone 3). Laneways systems are one option, the other is that all the paddocks are fenced in a way that allows them to connect directly with the central area that is closer to the house (zone 2).

It’s important to understand that:

• Zones are not separated by hard boundaries; they do not need to be defined with fences or other hard structures.
• Zones can blend into each other. This is most often the case in real life designs.
• Zones are not circular, they can be any shape and become defined by how accessible they are from the house.

Summary of Permacultural Zones

ZONE 0 — The house, or home centre. Here permaculture principles would be applied in terms of aiming to reduce energy and water needs, harnessing natural resources such as sunlight, and generally creating a harmonious, sustainable environment in which to live, work and relax.

ZONE 1 — Is the zone nearest to the house, the location for those elements in the system that require frequent attention, or that need to be visited often, e.g., kitchen garden, compost area, small animals, rain water tanks, shed, etc. This is the most intensively used zone, and the most managed and controlled. Keep in mind that this zone is defined by access, so if there is an area near the house that you don’t visit, or is hard to get to, even if it sits next to the house itself, then it is not included in Zone 1. If you leave your property daily to go go work for example, then the path from the street to your house and the immediate areas alongside it will be included in Zone 1, as you visit these areas twice daily.

ZONE 2 — This zone is also used quite intensively, but a bit less than Zone 1, and accommodates some of the larger and slightly less frequently used elements, that still need fairly frequent attention. Elements that are located in this zone include all the things that you need reasonably often, or that need the fairly frequent attention, such as: perennials and vegetables which have longer growing season, fruit trees, chicken coop and horse stables/yards etc.

ZONE 3 — This zone is basically farmland, where the main crops are grown (for personal use and/or to sell), where orchards of larger trees are located, and where livestock and horses are kept and grazed. Once these areas are established, they only require minimal maintenance and care. This area also includes: dams, swales and fodder trees/ shelter belts.

ZONE 4 — This zone is a part wild/part managed, and its main use is for collecting wild foods, timber production, as a source of animal forage, and pasture for grazing animals.

The trees in this zone are managed by allowing animals to browse to control new growth, or by thinning (removing) seedlings to select the variety of trees that will be allowed to grow.

ZONE 5 — The wilderness. There is no human intervention in zone 5 apart from the observation of natural eco-systems and cycles. Here is where we learn the most important lessons of the first permaculture principle of working with nature, not against. Zone 5 is a wilderness conservation area, and space that provides us with the opportunity to step down from our role of controlling nature, to one where we can just witness nature. The wilderness area does not have to be restricted to the outer perimeters of a property in a design. Zone 5 can extend as a wedge all the way from the outer perimeter right up to the house, to create a wildlife corridor as part of a design that brings natural ecosystem close the home.

Practical Zone Diagrams

Now that we have discussed some of the guidelines of what we place in each zone, it is appropriate to now revisit our zone diagram, but with a more practical focus on a horse property. The reason zones are rarely circular is because ground is rarely flat, and even apparently flat ground will have a measurable slope. Furthermore, areas of land can be irregularly shaped, so real world zone diagrams can appear very different from our previous conceptual zone diagram.

Here is an example of a zone diagram, which is closer to a real-life example, where each zone is shown in a different colour for illustrative purposes. Here, we can see that the zones can be irregularly shaped, they can overlap rather than form concentric circles and a particular zone can appear more than once. This highlights the flexibility we have in mapping zones in zone diagrams, and how far from the circular conceptual diagram real-life examples can be.

Zone size

The size of a zone is driven by two factors:

1. the distances that are practical to cover on a human scale, and
2. the amount of space required to yield produce to support a given number of people or animals.

With these factors in mind, here are some practical design guidelines for the ideal amount of area allocated to each zone.

Zone 1 – is ideally around 1000 sq. m (1/4 acre) in size for a family of four, this size is manageable as an intensive food production system.

Zone 2 – is ideally 4000 sq. m (1 acre) in size for a family.

Zone 3 – can range from 4 to 20 acres for a family.

Zone 4 – can be any size

Zone 5 – is a wilderness (can be any size).

Of course the size is variable and depends largely on your family size, number and type of animals you manage and acreage available! Keep in mind that zoning is primarily based on energy and chore efficiency!

Summary

Zones are concerned with the flow and use of energy inside our site, optimising it by the use of distance, and the strategic placement of elements, according to their frequency of use and the attention they require. However, zone planning does not account for all the systems of energy interacting with the site we are designing. A site does not exist in isolation; it exists as part of a larger environment, where external energies, the elements of nature (e.g. wind, sunlight, water), which come from outside our system also act on it. To plan for these energy systems, we use a system of energy planning known as Sector Planning. The importance of sectors (and slope) on our property was dicussed in the September edition of Horses & People Magazine https://www.horsesandpeople.com.au/