As part of our Caring for our country Community Landcare grant- “healthy soils, healthy people, healthy communities” project and in partnership with Holbrook Landcare Network the Heffernan’s Creek Landcare have been fortunate to host 3 soil health workshops with the highly esteemed agricultural consultant from Victoria, Gwyn Jones. The three workshops were held at Brian Frost’s “Hillden” at Bannister and addressed a wide range of soil care concepts, educating participants on how to score and record their soil health without the need for soil tests and providing monitoring and recording tools to assist decision making including the popular 10 paddock concept.
Gwynn has kindly provided a whole lot of follow up reading material which is available here: We look forward to welcoming Gwynn back to the Upper Lachlan in 2015 in the International year of soils.
Workshop Notes and Reading Material provided by Gwyn Jones – to download copies of these click on the blue links. Some of the chapters are provided below.
How to get the best out of your soils- by Gwynn Jones _
Soil is essential to our farming practices and modern civilisations and yet it is often overlooked. We often ignore this valuable resource as we walk or drive over it. In regards to Natural Resource Management often the emphasis has been on trees, weeds and rabbits together with the modern topics on water quality, ecosystem services and maintaining or rehabilitating biodiversity. Yet soil, and to a greater extent topsoil, is the foundation from which agriculture yields its abundance.
A starting point for discussion on how to get the best from your soil is to ask yourself this question. Where did my soil come from? Most soil originates from bedrock that comes from the breaking down of parent material [e.g. sandstone, igneous rocks and even limestone] and are called “residual” soils. However, most soil has been transported via gravity, water [Alluvial], wind [Aeolian] or ice to their current positions.
On your property you may have many different soil types. Can you work out if your soil[s] is “home grown” or transported in? Sometimes the transported soil is over the top of the original soil or over the top of the parent material. Transported soils are often similar in texture as their individual particles are often the same size. Some are light enough to be carried by the wind. Others are small enough to be suspended in water. True silt soils that are, or have been, next to rivers or streams often have physical soil structure problems. In a fast moving body of water, soil particles remain in suspension, for example in the middle of the river or stream. As the body of water slows down the soil would settle out. Imagine if you took a small amount of soil and put it in a jar of water, screwed the lid on and shake it for a few minutes. If you left the jar for a while you would see soil particles slowly settle to the bottom. The heavy bits settle first and lastly the clay content of the soil, which in some cases could take days. To get the best out of silt soils they must not be overly cultivated and deep rooted plants are needed so that their root systems can force apart individual soil particles and press against other soil particles to form aggregates. Another, water transported soil is “swampy” soils or old lake beds. Often these soils are high in organic matter and have a higher clay content to them. For example they will crack in dry periods and in wet periods the soil will stick to your boots. To get the best out of these soils a different approach is often needed as although they have a physical soil structure problem the answer is to approach their management from a soil chemistry perspective. Heavy clay soils are chemically low in Calcium [which has been leached out during the acidification of the area] and often high in Magnesium, which has accumulated. To get the best out of these soils the use of a good agricultural lime that has no Magnesium in it, will start to open up these soils and improve their chemical, physical and biological components.
Having discussed the larger soil groups it is necessary to define soils into two general groupings being “gradational” or ‘duplex”. When you dig up a gradational soil it all looks generally the same with no major colour changes. Duplex soils are very different as the word “duplex” means two parts and when you dig up the soil at a full shovel depth, the soil will have two colours and often different textures. In general, the top part of the soil is more like a loam and the bottom part of the soil has a higher clay content. To get the best out of a duplex soil which often has less depth of topsoil compared to a gradational soil, the aim is to increase the depth of loam and to turn the “clay” into loam. At this point is would be good timing to introduce the “golden rules” to get the best out of your soil. These principles work with most soils and are becoming associated with Best Management Practices of soil health.
The first golden rule is to maintain a minimum of 70% ground cover, particularly over summer. The aim should be 100% cover 100% of the time. Ground cover protects the soil surface and acts as an insulation blanket. Ground cover can be living [plants] or dead material [dung, stones, standing summer feed etc..]. Ground cover in the form of dead organic matter is a vital food source for soil biology, which plays an important role in recycling nutrients and maintaining or rehabilitating biodiversity. If ground cover is substantially lost there is an increased risk of accelerated soil erosion occurring. Natural resource management practices favour the retention of ground cover to a minimum of 70%, so that the long term asset of the soil is not degraded.
What many landholders may not realise is that on many healthy soils, the soil surface is covered with [the remnants of] earthworm castings! In fact healthy topsoil [on high rainfall country with reasonable Calcium levels] can be 100% earthworm castings. Casts act as a protective mantle or covering over the original soil surface and they grow your soils depth. A minimum of two earthworms per shovelful should be seen in Spring.
The second golden rule is to maintain optimum stocking rates and ideally according to land classification and rainfall. Rotational or Strategic Grazing as opposed to Set Stocking can encourage deep rooted perennial plants [including native grasses] that use water and nitrates deeper in the soil profile, hence, improving nutrient efficiency and recycling, improved summer growth and better ground cover over high risk times. Utilizing nitrate also reduces soil acidification and reduces the need to “Lime” a soil. Good grazing practices reduce stock camps, increase biodiversity in the pasture [root zones] and the soil.
In times of drought strategic decisions have to be made early about stocking rates and the potential use of sacrifice paddocks. The equation is: to de-stock / reduce stock numbers or remove ground cover in the form of dry standing feed. The decision is a classic example of trying to maintain eco [economically and ecologically] sustainability.
The third golden rule is to minimise soil disturbance, in cropping situations minimum tillage practices are preferred together with stubble retention. The burning of stubble exposes the soil and should be only a last resort. The use of crop rotations, which include a pastoral phase to increase the percent of time with improved ground cover, assists organic matter retention and associated improved water infiltration and reduces compaction and slaking. There is one contradiction with the third rule in that heavy stock impact / tramping for a short period of time can be beneficial. The on / off grazing with large numbers can have a “herd” effect, which when done properly does not have a adverse affect on the soil and can rehabilitated biodiversity.
In summary to get the best out of your soil, you need to think about the history of your soil and its origins. Look at the landscape, what it can tell you? What can you learn from its shape, slope, which way it faces. How many different soil types do you have on your property? What characteristics do they have? How can you best work with their strengths and avoid their weaknesses? The three golden rules: maintaining a minimum of 70% ground cover, optimum stocking rates and minimum soil disturbance, will assist you in getting the best from your current soil situation. You may wish to consider further and ask yourself the question “How can I enhance my soil resource, plant succession and productive capability.
For further information please contact Gwyn Jones 0n 042667 1191.
The information contained in this publication has been formulated in good faith, the contents do not take into account all the factors which need to be considered before putting that information into practice. Accordingly, no person should rely on anything contained herein as a substitute for specific professional advice. Soil HEALTH Rev 1.0 2007 All rights reserved ã Gwyn Jones M: 0427 761 191 E: firstname.lastname@example.org
SOIL HEALTH & AGRICULTURAL PRODUCTIVITY
Advance Australia Fair
Australians all let us rejoice
For we are young and free;
We’ve golden soil and wealth for toil;
Our home is girt by sea;
Our land abounds in nature gifts
Our beauty rich and rare;
In history’s page let every stage
Advance Australia fair;
In joyful strains then let us sing
Advance Australia fair.
By Peter Dodds Mc Cormick
In order to Advance Australia Fair as a nation and individuals, we need to take the topic of soil health seriously and invest resources in better understanding, what is a healthy soil and how we can improve our current level of soil health? A healthy agricultural soil is a living renewable resource that has the ability to increasingly reproduce itself in the form of topsoil in a sustainable manner. If a soil cannot re-produce itself it is simply not self sustaining.
Soil Health is a measure of a soil’s vitality to renew and increasingly reproduce itself in the form of topsoil over a two to five year period. For example, a healthy soil “grows” topsoil and stores carbon. Sick soil has a net loss of soil and carbon due to accelerated erosion and associated agricultural production. This is often associated with declining soil structure, low biodiversity, poor water holding capacity and low agricultural productivity.
Soil health can be related to chemical, physical and biological components of the soil. Soil health has six main enemies with the first three relating to the chemical component of the soil, that is salinity [excess of Sodium], acidity [excess of Hydrogen] and contaminates [excess of Chemical Residues]. The other three enemies involve the physical component of the soil, especially when aggregation breaks down. They include:
Soil Erosion = Soil particles detachment & transportation
Soil Structure Declining = Lack of aggregation pattern
Soil Compaction = Lack of Oxygen & pore space.
Chemical imbalances and aggregation breakdown limit the biological activity within a productive agro-ecosystem and make for a unique natural system.
There are three principles that promote sustainable soil health. Firstly, to conserve the soil that you have via erosion control; secondly, to protect the soil surface with a minimum of 70% groundcover, particularly over summer and ideally, in a high rainfall district, the soil should be covered with 100% earthworm castings. Preference should be shown for deep rooted perennials over annuals. With regard to cropping the use of crop rotation would be preferred with minimum tillage, stubble retention and minimum stubble burning.
The most important key principle is to learn how to progressively grow topsoil at a rate quicker than soil erosion removes it. This process is mainly driven by the plants’ ability to develop and shed roots that together, with the appropriate soil chemistry and environmental conditions. Decomposing roots and surface litter act as a food source for soil biology [via earthworms] and ultimately can develop into “active” humus. Remember that healthy soils are the foundation for healthy plants that give us eco-sustainability. There are many management tools that can be used to enhance topsoil growth and these will be covered in another article.
ã Gwyn Jones 2007 Contact details: email@example.com
IS YOUR SOIL A RENEWABLE RESOURCE?
Soil means so many things to so many people. An engineer can view it as a problem to be removed due to its potential instability. Yet to farmers and landholders it is a precious resource that not only has a commercial value, but an inherent and ethical value. But is it a renewable resource that can be viewed from a sustainable perspective? Or is it non renewable that can, and should, be mined. The pivot able point of this debate revolves around a soil’s ability, or inability to increasingly regenerate itself in the form of topsoil. Therefore a healthy soil has the ability to “grow topsoil” and under a sustainable management system the soil literally becomes younger as new soil is formed.
So how does this occur and how can we optimise this natural process? The answer is to work and learn from nature. How soils become younger can be seen when for example earthworm castings are left on the soil surface. Often the origin material is subsoil and yet the end result is different, because it has been ground in the gizzard, which increases the surface area and availability of the minerals in the soil. Earthworm digestion is carried out by enzyme producing and nitrogen liberating bacteria to create an end product that Darwin called “Vegetable Mould”. Another example is to dig up a thistle and note the quality of soil close around the main roots. How long did that plant and the associated biology take to produce new soil? Plant roots and associated biology is the workforce to growing soil.
The plants release carbohydrates from its root system. Soil organisms are living and dying in less than twenty seconds, the soil pH is changing along the rootlets, which unlocks and makes available different elements. The root hairs themselves get knocked off and are consumed by the soil microbes, that in turn produce excrements that are toxic to some soil microbes and may be food to others. Micro-organisms are eating one another and competing for exudates which the plant produces from the root. It is almost a war zone! As this fight between the microbes continues, the root cap pushes on its endless search and a main mature root is left. When the mature root dies we have a small hole in the soil, this is called a micro pore. If conditions are favourable the strongest animals on earth – a worm, may make an appearance. Have you noticed how earthworms follow down old root channels? The earthworm is nature’s plough. This small root channel has now been bored out by an earthworm and becomes a macro pore. Now increased gaseous exchange can take place and the soil can start to breathe better. Increased oxygen supplies to the soil aid the increase of microbial populations. As the earthworm moves through the soil it leaves a smear of shiny almost silver slime. You may notice it as worms move over a concrete or brick pathway. This slime is mainly calcium carbonate. The plant root systems seize the opportunity to utilise a relatively available form of calcium and new roots go down the worm channel (old root channel) and you can see them clinging to the side of the worm channel. So the regenerative cycle continues. The end result of the biological factory moving through is some form of humus formation, that covers the old or original soil particles and binds them together. Hence a soil will become darker due to an increase in carbon content, improved aggregation leading to greater soil pore space, water holding capacity, aeration and recycling.
The development or degradation of soil is one of the key issues between a renewable or a non-sustainable farming system and indeed the continuation of human civilisation. To conclude healthy soil is sustainable and renewable when given appropriate management. The next article will review the practical management strategies to develop healthier soil.
ã Gwyn Jones 2007 Contact details: firstname.lastname@example.org
DEVELOPING A HEALTHY SOIL
There are many challenges that face landholders and rural communities such as drought, fires and floods. Developing strategies to develop healthy soil can also be challenging as what do you focus on? The answer is to support existing plants with associated root development, leading to root shedding and recycling of organic matter within the ecosystem. In an agro-ecosystem soil disturbance through cultivation or grazing is often part of the dynamics of modern production systems. Therefore in order to work with existing plants one of the first practical strategies is to identify and appreciate plant succession on your property. To take an extra example, what plants grow on high fertility sites eg stock camps? Often these “indicator” plants are associated with excess nitrogen in the soil. What plants grow on low fertility shallow soil? [Remember that aspect will greatly affect this]. Your current plant species will often range in succession somewhere between lower fertility to extra fertility indicator species. Can you name your dominate plant species? Do you want to change them? From an agricultural perspective, landholders often wish to improve the plant species that they have by killing off existing plants and reintroducing new ones. For example, the cultivation and reseeding of an “improved” pasture? Alternatively, strategies can be put in place so that less desirable species decrease and more desirable species naturally volunteer as conditions better suit their growth.
If stock were part of an agricultural ecosystem, the selection and implementation of a grazing method is a critical management strategy, because if over grazing occurs desirable species are often reduced together with root depth and nutrient cycling. In relationship to the soil a key strategy is to conduct a soil audit of the physical, biological and chemical components of the soil. Many landholders think of a soil audit in association with a soil test. Independent soil tests are of value, especially to identify Ca/Mg, K/Na ratios and other essential elements including the trace elements Boron, Iron, Manganese, Copper, Zinc and also Aluminium. Beware of the dangers of mineral antagonisms. Remember “A little Knowledge is a dangerous thing – it is not the Knowledge, but the little”! Experience has shown me that every soil can tell a story. So grab a shovel and have a dig. A shovel audit can assist you in identifying the physical components of the soil. You can assess a soil for its texture and structure. If, soil aeration is poor, management strategies would be needed to address these matters and a strategy could be to do nothing. If you wanted to become proactive, ask yourself; is it a physical problem? For example, a hard pan and plant roots going at right angles. Should an aeration tool be used? Is a multi tyned aerator needed to get under the hard pan and shatter it? Your soil may benefit from mechanical aeration in order to enhance topsoil development.
Your shovel audit may have also highlighted your abundance or lack of soil biology. In favourable conditions soil life, or the resulting decomposition, can be seen. If you are not happy with your existing biology and biodiversity, you have two choices as to which management strategy to take. Firstly, improve conditions for your existing biology by “feeding” them. For example, seaweeds, limes, fish, sugar etc.. Or secondly, adding “Better Bugs” to your seed / soil with compost teas or commercial “off the shelf” products.
Finally, the last strategy is the review of soil energy levels. This topic can be complex; however the simple aim is to raise paramagnetic levels by positively influencing carbon, oxygen and silica levels in your soil. A healthy well structured soil has naturally high paramagnetic levels, thus good paramagnetic levels can be the result and not the direct cause of a healthy soil. In summary, we are ultimately trying to improve management strategies and practices that have, as a by product, the formation of “active” humus through carbon sequestration and nutrient cycling in a healthy soil. If we fail to achieve this, we will ultimately fail as a civilisation. So, when was the last time you made the decision, to grab a shovel, dig some soil and sniff some earth?
ã Gwyn Jones 2007 Contact details: email@example.com
Soil Biology: Your Unseen Workforce
The world of soil biology is one of the last frontiers that scientific investigation is yet to explore. For every unit of knowledge we have on soil biology there is an estimated over 10,000 units of knowledge that we don’t know. How could this be the case? To find this answer, it is worth asking the question. “What biology is in a healthy teaspoon of soil?” You could have 100,000,000 bacteria, 50,000 metres of fungal hyphae (fungi feeder shreds) 100’s of beneficial nematodes and even a baby (egg) earthworm. When I first pondered this question, I was not ready for the quantity and complexity of the answer. The soil ecosystem and its services are dynamic, complex and have many self regulating mechanisms. Another good way of thinking about soil biology is that generally you have more “livestock” below the ground than above it. Farmers often ask the question; “So how quickly does biology breed?” A Gippsland farmer told me this story. “One day, I wanted to go fishing, so I went and bought twelve large worms. The big thick, five inch ones. We only used four and took pity on the others and took them home. I filled up a rubbish bin with soil and put them in it. A few weeks later I went and checked on them and they were all gone! So I gave up on them, thinking the conditions weren’t right. Anyway, a few months later, I found them happy in the garden. They then escaped into the paddocks and in two years they had migrated [downhill] two kilometres away!”
The above example illustrates that if the conditions are right, soil biology can and will breed up quickly in your soils. So should we buy in biology or let it occur naturally? To make a point, consider the following question? When was the last time you went and bought Capeweed seed or Patterson’s Curse seed and put it on your pastures? Your answer could be something like – “Don’t be stupid, I have never done nothing like that deliberately.” My further question is “Where did the seed come from?” The answer is often that it arrived or invaded naturally and the same can be said for soil biology. So a simple choice has to be made. Do you aim to create the beneficial conditions to encourage beneficial soil biology or do you buy it in with the aim to compress time? How many people have bought soil biology and applied it to their soil? From my experience the answer is very few, but the numbers are growing. Those that have are often initially pleased with the results; yet adverse weather conditions have greatly slowed the much awaited results. The good news is that many commercial bugs have survived the last two droughts. So, what are the practical ways I can improve my exciting biology and create a suitable environment to encourage a greater biodiversity, hoping that new ones will arrive? A good place to start is to maintain groundcover. Dr Maarten Stapper [Ex – CSIRO Plant Industry] reminds us that groundcover is like the roof that is on the house of the soil biology. Groundcover gives; insulation, improved moisture retention, a food warehouse and minimises the adverse effects of wind and rain erosion. Stocking rates and grazing management are closely linked to groundcover management and after adverse weather conditions paddocks with a minimum of 70% groundcover appeared to recover a lot quicker than those with lesser cover. The management systems that encourage a diversity of plant species with different root depths and seasonal growth is beneficial, however, there is increasing evidence to suggest that perennial plants, with their longer growing season and nutrient cycling, should be encouraged. Beneficial soil biology can also be encouraged with the correct use of fertiliser, soil conditions and stimulates. The appropriate use of Lime can stimulate the reproduction of Nitrogen fixing bacteria, which inturn aids the decomposition of raw organic matter as Carbon to Nitrogen ratios become closer. There is a new trend to stimulate different forms of soil biology with the use of humic acid, molasses, sugar, seaweed and even Vitamin B12.
We are approach changing times with the weather, is it also time to review and potentially change our attitudes to soil biology – the unseen workforce of agriculture?
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