by Jako Pieterse
My mind-shift happened in 2000 at a farm study group meeting covering organic farming. During this time, I was managing a conventional fruit farm for 10 years. The farm was developed on virgin land from scratch, using the best technology and techniques known at that time. I had a keen eye for observation and could see changes happening on the farm.
During the first 5 years we experienced only a couple of minor production issues but this gradually changed to a point where certain pests and diseases became major problems. This happened despite following meticulously conventional spray programmes and doing everything “according to the book”.
At this study group meeting we had an organic wine farmer giving a talk about soil health and it being pivotal to the success of organic farming. As he explained the importance of microbial diversity and the importance of root exudates, I had an epiphany. For the first time I could understand the reason for the downward spiral on the farm I was managing at the time and appreciate the importance of soil microbes.
It took us 5 years of monoculture and the use of pesticides, fungicides, weedicides and synthetic fertiliser to destroy the microbial diversity to the extent that pest and diseases could no longer be controlled naturally. Once the diversity was gone, everything went downhill from there. Many pests became problematic and were difficult to control chemically. Soil compaction and water infiltration also became a problem. We were applying 3 times as much nitrogen than what was actually removed by harvesting the crop.
Having realised the root cause of the problem, I looked into various options to restore soil health. Compost Tea was something new in the year 2000, and it promised to be a cheap and effective option in restoring soil health. I was one of the early adopters and applied Compost Tea through the irrigation system and also did foliar sprays to see if I could control pests and diseases that way. All prunings were kept on the “bankie” and weeds were utilised to grow tall before being killed by a weedicide. This allowed us to feed the micro-organisms and make compost in the orchards, a far more economic and easy solution to restore soil life.
It took a year before I saw results, but I was amazed at how well it worked. Weevils, that were previously a huge problem, became manageable within the second season of using Compost Tea and it was no problem at all after 3 seasons.
Many other pest and diseases were controlled and soil compaction was completely eradicated. Over 5 years, we lowered our nitrogen applications by 70% and stopped applying phosphorous completely. Our trees were looking and growing better than ever before.
The take away message of my story is:
- It takes a few years to destroy a functional soil ecosystem but it is also relatively easy to restore it back to health.
- Inorganic fertilisers are directly and indirectly harmful to soil organisms and this has many unintended consequences that are responsible for the downward spiral of soil degradation.
- The use of pesticides is ineffective – they do not address the root cause of the problem, they contribute to the downward spiral of soil degradation.
- Feeding soil organisms with crop residues and with root exudates derived from weeds or cover crops are essential to the restoration of soil function.
I was absolutely fascinated by what I experienced. Nature is very complex but effective. By studying nature, we come to appreciate the interconnectedness of everything and the intelligence involved. By embracing nature, working with her natural rhythms and cycles, we can farm much more effectively and regeneratively.
Eventually in 2005 it became clear that I needed to do this work full time and that is when Ecosoil was born. Since Ecosoil’s humble beginnings, we have helped numerous farmers farm more regeneratively. We continuously reinvent ourselves, adopting new strategies and products that are researched and tested. Ecosoil is based in Grabouw, Western Cape and distributes nationally as well as selected SADC countries.
I would like to give credit to those scientists I have learned from and of whose material I have used so liberally. Most notably in this regard are Dr. Elaine Ingham, Dr. Christine Jones and Graeme Sait. There are many others whom I quoted verbatim. To them all our sincerest appreciation is expressed for their contribution to science and the earth in general. It is important that the message of soil health is spread as far and wide as possible.
The new scientific view is that plants are dynamic, intelligent and highly sensitive organisms. They are capable of accurately computing their circumstances, using sophisticated cost-benefit analysis and taking defined actions to mitigate and control their environmental conditions.
Some examples of this include:
- Humans have five basic senses, but scientists have discovered that plants have at least 15 different senses used to monitor complex conditions in their environment such as humidity, gravity and electromagnetic fields.
- Plants are capable of a refined recognition of self and non-self and this leads to territorial behaviour – if siblings of the plant are growing alongside them, the adult will grow their roots more downward and the siblings will be taller as a result, whereas if alien plants are living beside them, they will grow their roots outward and the alien plants will be shorter and grow less.
- Plants have developed a very robust communication, signalling and information-processing apparatus. Besides abundant interactions with the environment, plants communicate and interact with other living systems such as other plants, fungi, nematodes, bacteria, viruses, insects, and predatory animals.
- Roots also form close associations with fungi. This creates a sophisticated root/fungus communal network, similar to the internet network, that can extend over vast distances. This connects all the plants in a particular ecosystem into one self-organized whole that, by itself, possesses capacities not perceivable in any of the parts. If plants in the system detect that another plant in the mycelial network is ill, unique compounds are intelligently generated by the plants most able to do so and sent through the mycelial network to where they are needed.
Plants are as intelligent and sophisticated in behaviour as animals but their potential has been masked because it operates on time scales many orders of magnitude longer than animals do. Plants, in fact, possess a highly sophisticated neural system and while it does not look like our brain, it really is, in actuality, a “brain”.
In short, plants possess a highly developed, conscious root “brain” that works much as ours does to analyse incoming data and generate sophisticated responses. This is located at the root apex of every root hair which acts as a neuronal organ in the root system.
The numerous root apices act as one whole, synchronized, self-organized system, much as the neurons in our brains do. Our brain matter is, in fact, merely the soil that contains the neural net we use to process and store information. Plants consciously use the soil itself to house their neuronal nets. This allows the root system to continue to expand outward, adding new neural extensions for as long as the plant grows.
There are many documentaries on the internet in this regard. Please refrain from watching “The Secret Life of Plants” since it contains material since refuted. Recommended are these two short TEDx videos in this regard:
Watching these videos, there is no doubt that plants are much more intelligent than what was previously thought. If we see the soil as the grey matter of the plant’s “brain”, it follows that we need to treat soil as an important living organism that determines the wellbeing of plants.
Compare a compacted, diseased soil with low organic matter with a well aerated, loose and healthy soil with ample organic matter. In the first case, the root volume will be much smaller with fewer root apices (“brains”) and will be prone to attack by pathogens. It is therefore not difficult to understand that soil fertility directly impacts plant health and therefore production.
Natural systems are healthy and do not need external inputs for their nutritional or pest control requirements.
(As illustrated by this banana plant in a forest setting.)
By understanding how this process functions, strategies and practices that mimic nature can be adopted and implemented on the farm with ease and at low cost which will ensure continued profitability and resilience.
One can view the other plants as weeds and would expect them to inhibit the growth of the banana plant, but the opposite seems to happen. What’s more, the leaves of this plant are much shinier and healthier than its commercial counterpart.
At closer inspection, the forest floor is completely covered by decomposing plant litter and living plants. A crumbly, loose, well aerated, dark fertile soil is the result.
Microorganisms can be divided in two groups – aerobic (with oxygen) and anaerobic (without oxygen). The organisms in fertile forest soil is mostly aerobes. It is also true that most beneficial organisms are aerobes and most pathogenic (disease causing) organisms are anaerobes.
In healthy, highly diverse ecosystems the soil is well aerated, with beneficial organisms in the majority and pathogenic organisms in the minority. It is this balance that makes life possible. When this balance is disturbed, life becomes difficult and a continuous battle against disease is follows.
Most agricultural soils are compacted and thus anaerobic, meaning it contains very little pore space and, as a consequence, has low oxygen levels. Most pathogens are anaerobic and thrive in these environments. Most beneficials are aerobic (needing oxygen) and are not present in anaerobic soils, therefore compacted soils lack natural predators that keep pests and diseases in check.
Anaerobic micro-organisms produce fermentative materials such as alcohols as by-products of their metabolic pathways which are toxic to plants. Aerobic bacteria can decompose these toxic materials and improve plant growth.
Many farmers make the mistake of treating compacted soil with organic acids in an effort to stimulate soil organisms and make the soil healthier. This will only exacerbate the problem as it will stimulate the organisms that are present – anaerobic organisms and pathogens – to multiply.
To control pest and diseases naturally, diverse aerobic microbial populations and thus, well aerated soils are a prerequisite. An inexpensive and efficient solution is to inoculate the soil regularly with diverse aerobic organisms as found in Ecosoil’s Compost Tea.
Being aerobic, they need oxygen for their survival and will immediately upon application start working, decomposing organic matter, producing glues and gums to bind soil particles into aggregates and thus create the pore space necessary for air to enter the soil.
These conditions, as well as competition, inhibition and predation will ensure that the numbers of pathogens will drastically decrease over time. This process usually takes 3 years to complete, but can take as little as a year, provided an appropriate soil building program is followed in conjunction with Ecosoil’s Compost Tea applications.
The carbon cycle has 3 phases – a gas, a liquid and a solid. Plants transform carbon gas into a liquid or a solid form in a process called photosynthesis. Light energy is converted into biochemical energy by utilising carbon dioxide (CO2) and water to synthesize carbohydrate molecules, such as sugars and in the process release oxygen.
These dissolved sugars are also called “liquid carbon”. Some of these carbohydrate molecules are utilised in the formation of plant structures like leaves or roots but between 30% and 40% are excreted through the roots into the soil to feed the micro-organisms.
Soil organisms act as the bridge between the plant and the soil and can be regarded as the regulator of the soil building and plant feeding processes. Healthy soils contain about 8 to 15 tons of bacteria, fungi, protozoa, nematodes, earthworms, and arthropods per hectare. Carbon is the currency for most transactions within and between living things.
Each plant species communicates with soil microbes by exuding a unique blend of sugars, proteins, enzymes, hormones and other biological compounds, many of which act as signals to plant microbes instructing them what their requirements are.
Exudates from living roots are the most energy-rich of the carbon sources found in the soil. This attracts a huge diversity of beneficial microbes that form a protective shield around plant roots, called the rhizosphere.
They protect plants against pathogens, increase the availability of minerals and produce organic compounds that plants utilise for growth, health and vitality. Microbial activity also drives the process of aggregation, enhancing soil structure, aeration, water infiltration and water-holding capacity.
The greater the diversity of plants, the greater the diversity of microbes and the more robust the soil ecosystem. It is the diversity in microorganisms that makes it possible for natural systems to be so functional and healthy compared to the sterile, lifeless and thwarted systems offered by monoculture with their limited microbial diversity.
Somewhere between 85% and 90% of the nutrients plants require for healthy growth, are acquired via carbon exchange, in other words, where plant root exudates provide energy to microbes in order to obtain minerals and trace elements otherwise unavailable. So, in effect plants pay a 30% to 40% carbon tax for services rendered by soil organisms and in return get 85% to 90% of their nutrients. Not a bad deal!
It is now well recognized that all plants, and nearly all tissues within the plant, are inhabited by a variety of micro-organisms, many of which offer benefits to the host, improving nutrient uptake, preventing pathogen attack, and increasing plant growth under adverse environmental conditions.
With root exudates, the plant grows a beneficial microorganism shield around its roots that controls pathogens naturally in the following manner:
Beneficial organisms out-compete pathogens for living space and food, covering the roots and leaves, and protecting it them from infections.
Anti-biotics and other chemical compounds are produced by beneficial organisms that inhibit the growth of pathogens. In some instances, plant-microbe communication is so advanced that, when threatened by above-ground pathogens, they signal soil microbes with specific root exudates to produce anti-fungal or anti-bacterial compounds that will be absorbed by the plant and translocated to the infection site to inhibit the pathogen.
Certain microbes feed off other microbes, which help to keep pathogenic populations under control. It is estimated that 75% of all insects spend a part of their life cycle underground. A healthy soil with diverse microbe populations will keep pest populations under the economic threshold value.
4. Immune Response
Healthy plants are stronger and less attractive to pests and diseases. Plants photosynthesising at an elevated rate have a higher sugar content and Brix level. Once Brix gets over 12, plants are largely resistant to insects and pathogens. Certain bacteria-plant interactions can induce mechanisms in which the plant can better defend itself against pathogenic bacteria, fungi and viruses. This is known as induced systemic resistance (ISR). The inducing rhizobacteria triggers a reaction in the roots that creates a signal that spreads throughout the plant which results in the activation of defense mechanisms, such as reinforcement of plant cell walls, production of anti-microbial phytoalexins and the synthesis of pathogen related proteins.
So, an important conclusion in the above regard is that lots of different species and lots of different individuals of each species are needed to have functions performed at all times in all types of habitats and environments towards soil health and fertility.
A vibrant microbial community can protect plants against pests and disease. Plants also absorb metabolic by-products from microbial communities that eventually gets transferred to animals and humans consuming it. These compounds and minerals are essential to our health and survival.
Most pests and diseases have part of their life cycle in the soil. In nature their numbers are naturally controlled. If conditions arise that promote the temporary proliferation of pathogens, its natural predators will sense this proliferation and will also proliferate to bring nature back into balance. By inoculating soils with Ecosoil’s Compost Tea, beneficial predators are re-established that will control pests and diseases naturally.
Foliar sprays of Compost Tea will supply essential organic nutrients and cover leaf surfaces with beneficial micro-organisms, protecting them against pathogen attack. The organism diversity found in Ecosoil’s Compost Tea will outcompete pathogens for food resources, will cover and protect root and leaf surfaces, will inhibit and predate pathogens and reduce their numbers significantly.
The production of vitamins, hormones and other metabolites will improve the immune response and health of the crop. This will greatly reduce crop losses and will lower the need for costly and counter-productive pesticide programs over the long term.
Systemic Acquired Resistance
The vines in the control block received six chemical anti-fungal spray applications, whilst the vines on the right received two years of Compost Tea soil applications and only required four chemical anti-fungal applications. Far less mildew was observed on the block receiving Ecosoil’s Compost Tea combined with less ant-fungal sprays.
Ecosoil Compost Tea
Percentage shoots infected with woolly apple aphid (WAA) and mildew:
EARLY RED ONE
Weevil damage measurements on apples:
Soil Building Process
Soil building is a plant driven process whereby carbon is sequestered from the atmosphere and locked into the soil and in so doing, changes the overall biological, chemical and physical properties of the soil – in a beneficial way.
Soil organic matter can be divided into 3 parts – the living, the dead and the very dead.
The living part – huge diversity of micro-organisms, such as bacteria, viruses, fungi, protozoa, algae and nematodes; also, plant roots, insects, earthworms, and larger animals.
The dead part – dead plant roots, crop residues, root exudates, deceased micro and macro organisms, and animal manures. This is the active, or easily decomposed, fraction of organic matter that is the main supply of food for the various organisms.
The very dead part – humus – very stable, complex and well-decomposed organic matter. Humus is an organo-mineral complex comprising about 60% carbon and between 6 and 8% nitrogen, phosphorus and sulphur. Proportionally, it has a huge surface area and can store both cations and anions and is an essential factor in soil fertility. These organo-mineral complexes form a stable and inseparable part of the soil matrix that can remain intact for hundreds of years.
The ultimate goal in soil building is the formation of humus.
There are 2 pathways whereby humus can be formed and they differ substantially in their effectiveness.
1. Pathway One is the decomposition of organic materials such as – crop residues and manures
To obtain the energy contained in cellulose, lignin, starches, oils or other compounds formed by plants, microbes have to break this material down. This is called mineralisation. In so doing, between 60 and 80% of this carbon is released as CO2 back to the atmosphere through a process called oxidation and respiration. The efficiency of this process is determined by the digestibility of the material, the microbial community present, soil moisture content and other environmental conditions.
The type of vegetation also has a major impact on the amount of carbon sequestration. In forest soils, most of the soil organic matter (SOM) is distributed in the top few centimetres, mostly as a result of leaf litter. Tree roots are high in lignin and do not die off on a regular basis and thus do not contribute much to SOM. In comparison, tall grasses form deep fibrous root systems of which 50% die off yearly. Their decomposition happens at depth and thus these soils are high in SOM throughout the soil profile making them highly productive because they hold more nutrients, contain more microbes, and have better soil structure due to larger fungal populations.
2. Pathway Two is liquid carbon exudates resynthesised into highly complex carbon polymers
The carbon found at the soil surface are mostly short-chain, labile (easily altered, less stable) carbon, indicative of rapid turnover. This is the active carbon that is important for the health of the soil food-web. In recent scientific studies it was found that on average only 8,3% of this carbon was converted to stable soil humus.
The carbon in root exudates is already in a useable form for microbes. Very little carbon loss occurs through respiration (CO2 release) and virtually no losses occur through oxidation. The same study found that on average 46% of root-derived carbon was stabilised making this pathway 5 times more efficient than the Pathway One alternative involving ground biomass. The liquid carbon pathway allows for carbon sequestration deeper down in the soil profile, building top soil at depth, so to speak. The deeper the sequestration, the greater the likelihood that the carbon will be protected from oxidative and/or microbial decomposition.
two pathways of carbon sequestration
Every green plant is in effect a solar-powered carbon pump and it is the photosynthetic capacity and the photosynthetic rate of plants that drives the sequestration of stable soil carbon. If plants are force fed with inorganic fertilisers, it shuts off this pump. Reduced carbon flows consequently impact a vast network of microbial communities, restricting the availability of essential minerals, trace elements, vitamins and hormones required for plant tolerance to environmental stresses such as frost, drought and resistance to insects and disease. Decreased nutrient densities in plants also translate to reduced nutritional value of food – a deadly and futile downward spiral of soil degradation.
The use of inorganic fertilisers can be minimised by using it in conjunction with organic fertilisers, organic acids and Compost Tea. This will prevent the shut down of the carbon pump and will counter the oxidation of soil carbon.
Living plants are at least 5 times more efficient at building soil carbon than the decomposition of mulches. It is the photosynthetic capacity and the photosynthetic rate of plants that determines the effectiveness of the process.
Photosynthetic capacity is the amount of light intercepted in a given area. This can be optimised through the use of multi-species crops, stacking different height plants together. For instance, in fruit orchards diverse under-storey cover crops or weeds can be utilised to increase light interception and thus root exudates. Bare soil has zero photosynthetic capacity, is detrimental to soil health and should be avoided at all costs. The more active green leaves there are and the more roots there are, the more carbon is added.
Carbon sequestration is less efficient with crop residues
Carbon sequestration is more efficient with cover crops
With pastures it is recommended that stock be bunched into large mobs and moved frequently. During the grazing period (usually one to three days), a useful guide is to aim for approximately 20% of the available forage to be trampled to form surface litter and approximately 20% to be left standing (ie. no more than 60% utilised for animal consumption). This will prevent that palatable forage is overgrazed and will ensure that enough photosynthetic capacity remains for regrowth.
Treating fruit trees with Ecosoil’s Compost Tea will make them more complex, resulting in more shoots but shorter and more productive trees. Since the overall growth is more, this will increase the photosynthetic capacity.
Photosynthetic rate is the rate at which plants are able to convert light energy into sugars. There are many factors playing a role here – light intensity, temperature, moisture, nutrient availability, plant health, as well as microbial communities around roots and on leaf surfaces. Photosynthetic rate can be assessed by measuring sugar (Brix) levels with a refractometer. Diverse microbial communities perform soil functions that increase the photosynthetic rate of plants, increasing their mineral and sugar content and making them less prone to pest and disease. This in turn allows for more liquid carbon exudates, that in turn improves soil fertility and offers an upward spiral of soil regeneration.
Most of the ‘deficiencies’ observed in today’s plants, animals and people are due to soil conditions not being conducive to nutrient uptake. The minerals are present, but simply not plant available. Adding inorganic elements to correct these so-called deficiencies is an inefficient practice. Rather, the biological causes of dysfunction must be addressed.
Soil aggregates are a fundamental unit of soil function
Soil aggregates are soil particles glued together into larger structures by micro-organisms. A great deal of biological activity takes place within aggregates. For the most part, this is fuelled by liquid carbon.
Most aggregates are connected to plant roots, often to very fine feeder roots, or to mycorrhizal networks unable to be detected with the naked eye. Mycorrhizal fungi, which form symbiotic relationships with plants are totally dependant on liquid carbon from green plants. They trade this carbon with colonies of bacteria located at their hyphal tips in exchange for macro-nutrients such as phosphorus, organic nitrogen and calcium, trace elements such as zinc, boron and copper, and plant growth stimulating substances. Mycorrhizal fungi then trade these nutrients for more liquid carbon from the plant.
Liquid carbon streams into the aggregates via these roots and fungal linkages, enabling the production of glues and gums by micro-organisms that hold soil particles together. These glues make the soil aggregates very stable against soil erosion.
Macroaggregates are essential to soil tilth, structure, aeration, infiltration, water-holding capacity, biological nitrogen fixation and carbon sequestration. In short, it is not possible to maintain healthy soils without them.
Nitrogen-fixing bacteria require a partial pressure difference in oxygen and water which is present between the inside and outside surface area of the aggregate. These conditions are essential to the functioning of the nitrogenase enzyme utilised for biological nitrogen fixation and also to the formation of humus.
As a result, nitrogen-fixing bacteria cannot function properly in compacted soils. Crops will not be able to obtain sufficient nitrogen and the tendency is then to add nitrogen fertiliser, exacerbating the downward spiral of soil degradation because it interrupts the carbon flow to soil, further reducing aggregation.
The chemical properties (minerals) of soil are also regulated by micro-organisms and facilitated by the production of humus
Humus contains about 60% carbon and between 6-8% nitrogen (N), phosphorus (P) and sulphur (S). Organic carbon, organic nitrogen and moisture holding capacity always move together. When soil carbon increases, so too do levels of organic nitrogen and the ability of the soil to infiltrate and store water. Soils become more fertile as a result. Higher organic matter content also buffers the soil against salt damage and pH fluctuations.
For every 1% organic matter, the soil can store 20 to 30 kg/ha of N and 4 to 7 kg/ha of P. Where soil was regenerated to contain 5% organic matter, it will be able to store 100 to 150 kg/ha of N and 20 to 35 kg/ha of P for free!
Amino forms of N are the most metabolically efficient form for plant uptake
In well-functioning soils, 85-90% of plant nutrient uptake is microbially mediated and N is no exception. The atmosphere contains 78% nitrogen. Biologically fixed ammonium (NH4+) and NH4+ derived from decomposition of organic matter is rapidly incorporated into organic molecules such as amino acids and humus in healthy soils.
Some of the inorganic forms of nitrogen derived from organic matter breakdown and from applied fertilisers are immobilised in the bodies of soil microbes. This prevents the leaching of these minerals. These are later cycled back into the system as organic nitrogen when they are consumed by other microbes, typically by protozoa, nematodes and other predators. Amino forms of N are the most metabolically efficient form for plant uptake. This pathway closes the nitrogen loop, reducing losses due to nitrification, denitrification, volatilisation and leaching. Additionally, the storage of nitrogen in the organic form prevents soil acidification.
Mineralisation of soil nutrients
Phosphorous is a major macronutrient needed by plants but is not easily taken up due to it’s reactive nature with iron, aluminum, and calcium. These reactions result in the precipitation of phosphorous, thus making it unavailable to plants in the absence of microbial activity. Some soil organisms in Ecosoil’s Compost Tea can convert phosphorous into a more plant attainable form, such as orthophosphate. Iron is also another essential nutrient, but it is scarce in soil. Microbes can produce compounds called siderophores, which acquire ferric iron (Fe3+), which plants can then take up.
Plant growth hormone production
Microbes found in Compost Tea can regulate plant growth promotion by the production of hormones and other compounds. Auxin is a class of plant hormones important in the promotion of lateral root formation. Increased lateral root formation leads to an enhanced ability to take up nutrients for the plant. Other classes of plant hormones include Gibberellins and Cytokinins, which both stimulate shoot development.
Hormone production and the uptake of N in organic farm can be the reason why we see better fruit colour development on trees treated with Ecosoil’s Compost Tea.
Compost Tea organisms also have indirect effects on plant growth and thus fertiliser use
- They degrade toxic substances that inhibit root growth, typically by-products from anaerobic bacteria and pesticide residues.
- By reducing soil compaction, plants expend less energy on forcing roots through hard soil.
- Our microbes increase stress tolerances against drought, pathogen attack, salinity and frost.
- They increase the photosynthetic capacity and photosynthetic rate of plants.
- The breakdown of organic matter is more efficient, creating stable humus that function as a bio-filter, preventing nutrients from leaching and improving water holding capacity.
- They improve soil aeration allowing oxygen and nitrogen to enter which is crucial to root development and nitrogen fixation.
The mineral cycle improves significantly when soils are alive. The sun’s energy, captured in photosynthesis and channelled from above-ground to below-ground as liquid carbon via plant roots, fuels the microbes that solubilise the mineral fraction. A portion of the newly released minerals enable rapid humification in deep layers of soil, while the remaining minerals are returned to plant leaves, facilitating an elevated rate of photosynthesis and increased levels of production of liquid carbon, which in turn can be channelled to soil, enabling the dissolution of even more minerals.
The organisms in Ecosoil Compost Tea produce vitamins, plant growth hormones and enzymes which encourage strong root growth and release tied up nutrients. Many species of bacteria and fungi can access nutrients such as nitrogen and sulphur from the soil atmosphere, while others facilitate plant uptake of phosphorous, nitrogen and trace elements such as zinc, copper and molybdenum.
When bacteria proliferate, they require nitrogen and other minerals and temporally tie up these nutrients and so, indirectly prevent the leaching thereof. When plants require these nutrients, they signal protozoa species to proliferate and consume bacteria and to release the tied-up nutrients. These nutrients are in an organic form which plants prefer. Application of Compost Tea in conjunction with fertiliser programmes will save unutilised nutrients for the next season. So, typically fertiliser usage can be cut drastically from the second season onward.
Most parts of South Africa have experienced extended and unseasonal periods of drought these past few years. Climate variability is becoming an increasing problem. Most agricultural soils are not equipped to handle heavy down pours of rain, followed by long dry periods. Most soil surfaces are bare and capped, with little structural integrity. Rain drops hit bare soil with a tremendous force, dislodging soil particles and washing away valuable topsoil. This caps the soil, preventing water and air to infiltrate the soil.
Rivers in pristine areas, covered with vegetation and organic residues, are clear and fresh, compared to rivers running through agricultural areas which are brown with sediment and polluted with salts and nitrates. Crop residues play an important role in absorbing the force and reducing the damage that rain water can cause. Soil is never capped under organic residues. They slow down the surface flow of water, allowing more water to infiltrate the soil.
Soil covered with organic matter – can breathe
Capped soil – cannot breathe
Water holding capacity
One part of humus can retain 4 parts of water. Soils with 3% carbon (approximately 6% organic matter) can store around 500 m3 of water per hectare, in addition to the water-holding capacity of the soil itself. As explained earlier, carbon sequestration through root derived carbon is 5 times more efficient than the breakdown of above ground organic residues. Therefore, year long green cover is the best way of building soil carbon levels and water storage capacity.
The use of Ecosoil’s Compost Tea in conjunction with other soil building practices will build soil carbon levels, improve water infiltration and water holding capacity. Many organisms in Compost Tea make plants more drought resistant. Besides producing chemical compounds that protect plants against desiccation, it also stimulates root branching and fine root development. Mycorrhizal fungi can supply moisture to plants in dry environments by exploring micropores not accessible to plant roots.