Soil organic matter (SOM) is the organic matter component of soil, consisting of plant and animal residues at various stages of decomposition, cells and tissues of soil organisms, and substances synthesized by soil organisms. SOM exerts numerous positive effects on soil physical and chemical properties, as well as the soil’s capacity to provide regulatory ecosystem services. Particularly, the presence of SOM is regarded as being critical for soil function and soil quality.

The positive impacts of SOM result from a number of complex, interactive factors; a non-exhaustive list of SOM's effects on soil functioning includes improvements related to soil structure, soil aggregation, water retention, soil biodiveristy, absorption and retention of pollutants, buffering capacity, and the cycling and storage of plant nutrients. SOM increases soil fertility by providing cation exchange sites and acting as reserve of plant nutrients, which are slowly released to feed plants. As such, there is a significant correlation between SOM content and soil fertility.

SOM also acts as a major sink and source of soil carbon (C). Although the C content of SOM is known to vary considerably, SOM is typically estimated to contain 58% C, and the terms 'soil organic carbon' (SOC) and SOM are often used interchangeably, with measured SOC content often serving as a proxy for SOM. Soil represents one of the largest C sinks on the planet and plays a major role in the global carbon cycle. Therefore, SOM/SOC dynamics and the capacity of soils to provide the ecosystem service of carbon sequestration through SOM management have received considerable attention in recent years.

The Proceedings of the National Academy of Sciences said: ‘The World’s soils have lost 133 billion tonnes of carbon since the dawn of agriculture’, and “The incredible rise of human civilizations and the continuing sustainability of current and future human societies are inextricably linked to soils and the wide array of services soils provide’’.

Traditionally this is the feeding of the soil life by adding organic matter, but Carbon Farmer techniques allow organic matter to be produced by the plant, right in the root zone.

Brought in organic matter may be Farm Yard Manure, it may be composted vegetables, or simply the remains, the stubble or the plants of the last crop. In all these operations, large quantities of organic matter provide a food for the soil. However, this takes place nearby to where such material is easily and cheaply available, such as near to livestock farms. But once farming is distant from a ready source of bulk organic matter, such as in many parts of Africa their addition becomes costly and difficult.

Growing green manures or leys, is a crop grown to be only ploughed back in again. Clovers and other legume plants take atmospheric nitrogen and convert it to soil available nitrogen. It is another example of the energy of the sun absorbed by a plant which is turn feeds bacteria in its roots to do this work and benefit the soil.

Green manures are tried and tested in many parts of the world, and the backbone of organic farming systems. But African smallholders will not abide an idea of putting time, money and land into a crop they will not directly harvest and sell.

So all organic matter is a plant (or seaweed) residue. As such photosynthesis has powered their growth. Where carbon dioxide from the atmosphere is absorbed into their leaves where the natural process of photosynthesis puts molecules of carbon dioxide and water together to make simple sugar molecules. The by-product from this is oxygen, so plant life is essential to life on earth by turning carbon dioxide into oxygen. The greenhouse gas whose concentration is rising and stimulating global warming is carbon dioxide and a plant that is growing well sucks it up.

Carbon farming takes in all of these ideas, but at the centre is the technique that makes the plant work harder and feed the soil better. Growing sustainable crops without fertilisers while the soil life stores carbon dioxide as organic matter.

To sustain a soil – there are physical, chemical and biological aspects to manage.

The driving force in a soil is the biology, soils are alive teeming with life from plants and bacteria to fungi, protozoa and insects. Billions, each with its own job. Some bacteria converting atmospheric nitrogen into a form plants can use, some breaking down straw and weeds left from crops into sugars, worms eating and digesting soils, making complex compounds into simpler molecules and leaving behind worm castes and lots of air pores and passageways that allow air and water access, and many more doing jobs we do not yet understand. This puts structure into soils, an environment in which the soil biology thrives.

Plants naturally work in symbiosis with this activity, the big difference is they can access sunlight above ground. This puts sunlight energy into the process, to power photosynthesis in the leaf, which create sugars in the plant. These sugars give the plant energy to grow, make seed or fruit, but up to 20% of these sugars may be sent from the leaf to the root systems, from where and they simply leak or exude back into the soil.  Why would a plant that has evolved over millions of years leak?? Perhaps this was part of the evolution, a symbiosis that brought the suns energy, via simple sugars, to feed the living soil around the root. Indeed, this feeding the the root zone and it one of the oldest partnerships in the world. Sugars are given in exchange for an environment where the plant can find water, air and nutrients in simple molecular forms that can pass through the root membranes and taken into the plant. Carbon Farmer is bringing techniques to make this engine work faster, bigger and better

But the physical and chemical aspects need to be ideal to make this biological engine work at all. Soils cannot be waterlogged or compacted – otherwise air and water cannot get to sustain the biology. Soil cannot be eroded by water or wind otherwise the biology that lives in the top soils is simply washed or blown away. Soils polluted by chemicals, such as salt and fertilisers, cannot function as nature had planned, and much of the biomass is killed. Some of the soil activity tries to break down such chemicals and make them less toxic, and that is the way a soil acts as a buffer. Sometimes it works and the soils restores itself, sometimes it is overwhelming and becomes biologically inert.

More responsible farming systems can try to manage soil in a sustainable manner. Organic farming puts soil health at the heart of its operations, and asks for a 2 or 3 year conversion period, with no inputs at all, as it changes from conventional farming systems. This simply allows the soils to recover and the biology of the soil to build up. Conservation farming tries to minimise the disturbance of the top soils, avoiding cultivations and soils disturbance particularly in more fragile soils and unpredictable climates. This allows straw and crop waste to stay in the top soils, where it cools, feeds and reduces water loss.  Climate Smart farming combines some of these but looks to deeper cultivations that open up soils to a greater depth, allowing air and water to penetrate deeper to sustain a bigger volume of soil life and plant root. Carbon farming takes in all of these ideas, but at the centre is the technique that makes the plant work harder and feed the soil better. Growing sustainable crops without fertilisers while the soil life stores carbon dioxide as organic matter.

Carbon Farmer increases soil organic matter by conserving the biology that is already there and by careful farming. If stimulated by good physical conditions, no erosion, no waterlogging, good aeration and correct chemical conditions, no pollutants, no fertilisers, the soil biology will work.

We suspect that Carbon farmer techniques, through the careful addition of diesel engine emissions can supercharge the photosynthesis with carbon nanotubes, we know that the nitrous oxides feed the soil and the carbon dioxide and soot can stimulate soil life. But the reduction or elimination of fertilisers allows the soil biology to work in the natural root environment that was intended.  

A supercharged plant will exude more sugar into the soil and feed this engine. In tropical crops this process works quickly, making more sugars, which lets the roots exude more food for the soil life, which makes more soil organic matter faster.

Pioneering work in Tanzania has shown organic matter levels in poor soils substantially increased. This process has added up to 10,000kg over 3 seasons into impoverished lands, with no need for haulage and spreading of organic matter, locking away carbon dioxide and making soils more productive.

By the implementation of all these substances into the soil it renders the use of most fertilizers redundant. By avoiding the use of fertilisers not only does this help promote soil health it allows for resources to be saved. The energy used in the industrial production of fertilisers is huge, not to mention the transportation of these fertilisers from factories to farmers worldwide. By reducing the need for these fertilisers, the cost to the small African farmer is cut massively; a huge amount of energy is saved and the carbon emissions associated with its production and transport are also reduced.

Carbon Farmers worldwide, using techniques developed by Gary Lewis are on the first step of understanding how to use these ideas. Africa has warm soils, few if any frosts and higher temperatures to push this engine to work faster and harder. Support Carbon Farmer Africa to take this technologies to the next level, and to push them to the African horizons.

The concentration of SOM in soils generally ranges from 1% to 6% of the total topsoil mass for most farming soils. Soils whose upper horizons consist of less than 1% organic matter are mostly limited to desert areas, while the SOM content of soils in low-lying, wet areas can be as high as 90%. Soils containing 12-18% SOC are generally classified as peats.

Fertilisers are distilled inorganic compounds which are added to fields and crops. The form in which they are delivered is as predominantly salts which typically decrease pollute soil life. Crop roots will react unnaturally to these compounds due to the differentiated environment created by fertilisers which alters the synergy between crop and soil. Over use of fertilisers can lead to soil health degradation, resulting in diminished crop health and therefore decreased crop production.

Avoiding the use of fertilisers allows root development to take place in a healthy soil environment. Roots are able to exude sugars naturally which feed the soils flora and fauna allowing their numbers to rapidly increase, especially with the help of warm African climates. These flora and fauna work synergistically with the plant, breaking down soil organic matter and soil particles enabling trapped nutrients to become available to the plant. This leads to a healthy and beneficial balance between the soil and plant.

More responsible farming systems can try to manage SOM in a sustainable manner. Organic farming puts soil health at the heart of its operations. Conservation farming tries to minimise the disturbance of the top soils, avoiding cultivations and soils disturbance particularly in more fragile soils and unpredictable climates. This allows straw and crop waste to stay in the top soils, where it cools, feeds and reduces water loss.  Climate Smart farming combines some of these but looks to deeper cultivations that open up soils to a greater depth, allowing air and water to penetrate deeper to sustain a bigger volume of soil life and plant root.

This is any situation that deprives the soil of the ideal chemical, physical and biological make up. The opposite of sustainable soil management, and these practices are carried out through ignorance or simply economy. 

The most visual is the physical management. Those familiar with Africa will have seen the numerous ravines through the countryside, where soils that once were stable and stayed where they were created, now are easily washed away. Overgrazing by animals, where cattle, sheep and goats are allowed to graze grass down to its roots. Once the roots are physically removed there is nothing holding the soil together and it will flow with the rain, or blow with the wind. This erosion removes the topsoil, where the biology lives. So once it has gone, it is hard or impossible to turn what is left into a living soil.

The less visually identifiable is the chemical imbalance, and this can be done by simple soil tests. Soil contains many nutrients, those used in quantity by a growing crop are called macro nutrients, Nitrogen, Potassium, Phosphates, Calcium and Magnesium, those used in minute quantities, but non-the-less essential are Iron, Boron, Manganese, Zinc, Molybdenum and Copper. Most soils contain most of these elements, but the issue is that they are not in the simple form that plants need to absorb through their roots.  In Sustainable Soil Management section, it describes that a teeming healthy soil biology will do this job nicely, breaking down complex macro and micro nutrients into easily available plant nutrients. But if there is not a healthy soil biology the process does not work anymore, so we need yet another sack of fertiliser to make up the shortfall.  Gary Lewis who first identified the potential of the Carbon Farmer process has not used fertiliser on his crops for over 10 years. Organic farmers again, where soil biology is positively encouraged, do not add fertilisers, and after a number of years stop taking soil analyses.  And, of course, if there is not a soil biology working then there is no sequestration of Carbon dioxide. 

Fertiliser and their management are talked about in the ‘overuse of agrochemicals’ section.

Carbon Farmer increases soil organic matter by conserving the biology that is already there and by careful farming. If stimulated by good physical conditions, no erosion, no waterlogging, good aeration and correct chemical conditions, no pollutants, no fertilisers, the soil biology will work.

We suspect that Carbon farmer techniques, through the careful addition of diesel engine emissions can supercharge the photosynthesis with carbon nanotubes, we know that the nitrous oxides feed the soil and the carbon dioxide and soot can stimulate soil life. But the reduction or elimination of fertilisers allows the soil biology to work in the natural root environment that was intended.  

A supercharged plant will exude more sugar into the soil and feed this engine. In tropical crops this process works quickly, making more sugars, which lets the roots exude more food for the soil life, which makes more soil organic matter faster.

Pioneering work in Tanzania has shown organic matter levels in poor soils substantially increased. This process has added up to 10,000kg over 3 seasons into impoverished lands, with no need for haulage and spreading of organic matter, locking away carbon dioxide and making soils more productive.

By the implementation of all these substances into the soil it renders the use of most fertilizers redundant. By avoiding the use of fertilisers not only does this help promote soil health it allows for resources to be saved. The energy used in the industrial production of fertilisers is huge, not to mention the transportation of these fertilisers from factories to farmers worldwide. By reducing the need for these fertilisers, the cost to the small African farmer is cut massively; a huge amount of energy is saved and the carbon emissions associated with its production and transport are also reduced.

Carbon Farmers worldwide, using techniques developed by Gary Lewis are on the first step of understanding how to use these ideas. Africa has warm soils, few if any frosts and higher temperatures to push this engine to work faster and harder. Support Carbon Farmer Africa to take this technologies to the next level, and to push them to the African horizons.

The biological processes have been described, but these can be bypassed, in the very short term by a sack of fertiliser. The past 50 years have seen the rise of the use of chemical fertiliser. Why wait for the soil to break down the organic matter and soil into simple root available molecules of nutrition, when you can buy it in a sack and spread it on.  In the short term, when the organic matter is at a good level, little difference is seen in the crop. In fact, you can replace most of what the plant needs from a sack of fertiliser, there are thousands of acres of crops grown in artificial soil with no biology whatsoever, roots swimming in a solution of chemical fertilisers. We do not see much difference to the crop, which satisfies the economics, the difference is that we have killed off a soil engine designed for this job, that now is no longer making organic matter indirectly from carbon dioxide. Worse is that without the biology alive and kicking in the soil, the carbon dioxide that is locked up in the organic matter will itself begin to break down. This degrades the soil and puts carbon dioxide back into the air. Then the farmer who used one sack of fertiliser to grow an economical crop, now needs 2 sacks. 

This is exactly what Gary Lewis, the Carbon Farmer founder, means when he says bringing fertiliser into a soil is like bringing sunshine in a sack. Fertilisers are replacing most of what a plant can naturally do given the right conditions.

Soil pH, the balance between acid and alkali in the soil also has a large impact on nutrient availability. Soils become acidic when fertilisers are overused. The problem is what else was in the sack of chemicals beside the nutrient. If I wanted to add Potassium from a sack, I could use Potassium Chloride or Potassium Sulphate. The first is very cheap, so that is obvious which one most of the world would use. But for every atom of Potassium added, one atom of Chloride is also added. Plants hate chlorine and chlorides. Now in the early days, the soil biology may take and render the chloride inactive.  (It is no coincidence that the organic matter of soils, mainly carbon and carbon complexes bear a resemblance to the carbon-based compounds used in gas masks!). But if the biology is being killed and not replaced, it dies and degrades into carbon dioxide, so the soils actively begin to produce carbon dioxide, rather than lock it up. Then unsurprisingly, without the buffer, soils slowly become poisoned by the presence of chlorides, and cannot grow the crops they once did. Then this chloride washes into the groundwater and locals begin finding it in the drinking water of their boreholes. 

Then we move to pesticides, the insecticides, fungicides and herbicides in the agrochemical armoury.  The chemicals designed to kill the fungi, insects and plants that we do not want on our plants, do not stop working when they reach the soil, where they will to an extent, continue to kill the insects, fungi and plants that make up the engine of the soil biology.  The extreme is soil sterilisation by biocides, that kill all life in the soil. A practice still routinely carried out in the growth of many high value crops.