There are no magic bullets in agriculture but if you were aware that a substance in your soil could increase productivity, reduce pest pressure, enhance water use efficiency, reduce fertiliser requirements and spare the planet the chaos of global warming, you might prick up your ears and listen. This “magic” substance actually exists but it is not some commercial “cure-all”. It is, in fact, an essential component of soil that has been mercilessly mined for twelve decades of extractive agriculture. Organic matter (or humus) is measured in all soil tests but the critical importance of this remarkable substance is rarely recognised. Not only does it offer the most cost-effective and efficient water storage option, but humus is actually the essence of high-production fertility.
Banking on Biology
The National Bank discovered this some years ago when they commissioned research to determine the key players in farming profitability. The bank had been using their existing criteria to determine the worthiness of applicants seeking to buy their neighbour’s farms, but the ‘fall over’ rate was proving unacceptable. In a comprehensive study involving 800 properties in the Hilston region of NSW, they set out to determine what makes a new farming venture successful. To the surprise of everyone involved, the one thing that stood out head and shoulders above the next closest contender, was organic matter levels in the soil. In fact, researchers actually put a monetary value on humus to the extent that organic matter gains of just 0.15 % substantially increased the associated land value. The financiers had literally discovered that they could bank on biology. The humus byproduct of microbial activity was of more import than all other inputs.
The Ultimate in Water Storage and Delivery
Wars will be fought over water in the future; in fact, it is probably already happening! Just 3% of the planet’s water is fresh and of that meager total, 90% is used to irrigate crops. Climate change is currently impacting this precious resource by delivering unprecedented droughts and, in some cases, unanticipated rainfall. There is a problem here in that rain is often falling where it has rarely fallen before and there is little infrastructure to capture and store the bounty.
Dams are the most common method of storing water but they are notoriously inefficient. In the Australian climate, there are massive losses of water through evaporation. A large carbon footprint is often involved in pumping the water to its destination and then more evaporation and energy is involved in pumping water through centre pivots or flood irrigation ditches.
Organic matter is a vastly superior water storage and delivery medium. It can hold its own weight in water and the plant can access this moisture, right beside the roots, at will. An increase of 1% organic matter means your soil can hold 170,000 L/ha of water that it could not previously hold. If we bring this down to a home garden comparison, each square meter of your humus-enriched garden can now store and deliver 17 litres more water per square meter. There is a great win/win situation here in that carbon is now stored in your soil rather than contributing to the heat-trapping blanket of greenhouse gases that is overwarming the planet and changing the climate for better or for worse.
Humus houses trillions of soil bacteria (at least 2.5 tonnes of these organisms per hectare) that release a sticky biofilm in which they congregate to provide protection from the ravages of their fellow soil foodweb inhabitants. This biofilm offers an additional moisture-retaining medium associated with humus. In fact, this slime exudate works very similarly to water crystals in the soil and can retain moisture accordingly. For example, it is common for NTS to receive reports of substantial reductions in irrigation requirements associated with regular applications of brewed Nutri-Life 4/20™.
Costly Fertilisers Wasted
There are two storage systems in the soil and they involve the clay and humus components. Positively charged minerals, called cations, store on the negatively charged clay particles (colloids), while negatively charged anions are attracted to the positively charged humus colloids. If you have depleted the organic matter levels in your soil, you have reduced your capacity to retain and utilise some key minerals and the efficiency of your expensive fertilisers is seriously reduced. Phosphate, for example, is much more likely to become locked-up and unavailable in the absence of humus. Up to two thirds of applied phosphate can rapidly become part of a massive frozen reserve of this mineral when organic matter is missing.
Sulfur is another important anion that is seriously impacted in low humus soils. Sulfur, which is so critical for nitrogen utilisation and protein formation, is amongst the most leachable of minerals when humus, the ‘sulfur storehouse’ is missing. Boron, the most leachable of trace elements, is also an anion can that can only be stored on the humus colloid. However, it is the most widely used nutrient in agricultural production that is most seriously affected by humus depletion and the loss of this mineral affects more than your bank account.
Nitrate nitrogen is another anion that can only store on the humus colloid and, in the absence of organic matter, nitrates flood our waterways and increase our likelihood of succumbing to a deadly disease. There are multiple published papers linking nitrates in the food chain to the current cancer plague.
The bottom line here is that the humus levels in your soil will directly influence the amount you waste on fertilisers susceptible to lock-up and leaching. However, there is more than leaching and lockups involved here. The delivery of minerals to your crop involves a biological link and the organisms responsible for enhanced nutrient density and resilience survive and thrive in organic matter.
Nurturing the Delivery Boys
Organic matter levels are directly related to biological activity and reflect the health of your soil life. Microbes serve as the bridge between the soil and the plant and when we bomb that bridge with farm chemicals and poor soil management decisions, there is a price to pay. That price involves compromised mineral delivery and an associated reduction in plant resilience (necessitating more chemical intervention).
Nitrogen fixers are the link to the “free gift” of atmospheric nitrogen, phosphate solubilising organisms allow access to frozen reserves of P and potassium mining organisms deliver the third mineral in the NPK trio. Manganese and iron reducing organisms deliver these two trace minerals to the plant and we have yet to discover which microbes are responsible for solubilizing silica from clays and sand. The creatures involved here have obviously been impacted by modern agriculture, however, as it is extremely rare to find a soil with its full complement (100 ppm) of mono-silicic acid (plant available silica).
Organic sulfur is converted to the plant available, sulfate form by microbes and there is a microbe link to the uptake of all minerals. The higher your organic matter levels, the greater the delivery of minerals to your crop and the lower your need for expensive chemical intervention. Hopefully, it is now becoming more obvious why The National Australia Bank found such a profound link between profitability and organic matter.
Organic Matter and Pest Pressure
Pest pressure is based upon a combination of mineral and microbial imbalances. From a mineral perspective this might, for example, involve an excess of nitrate nitrogen, which enters the plant with water and dilutes nutrient density as a result. The nitrate-packed plant then becomes a calling card for both insects and disease.
Alternatively, a healthy, active soil food web deactivates pathogens through a variety of mechanisms ranging from competitive exclusion, predatory control and biochemical stimulation of plant immunity. In both cases humus has a major role to play. Humus buffers imbalances. In fact, the higher the humus levels, the less important the mineral imbalance. Similarly, the more humus, the more beneficial microbes and the lower the opportunity for opportunistic disease organisms. Insect resistance is a function of plant immunity, fueled by micro-nutrients that are more available in a high humus soil, along with a strengthened cell wall (determined by calcium and silica).
Humus levels also have a direct effect upon the level of mycorrhizal fungi in your soil and it is these creatures that play a key role in the delivery of calcium to the plant. These fungi increase root surface area by up to 1000% and this massive maze of root extensions releases biological acids that break the bond between locked up calcium and phosphorus in the soil. We have often monitored the increase in calcium levels in the leaf following inoculums of our highly successful mycorrhizal inoculum, Nutri-Life Platform®.
Organic Matter and Global Warming
All of the wonderful benefits of humus pale in significance to the importance of this substance in relation to the greatest challenge mankind has yet confronted. Global warming has huge implications for agriculture (as it has for all human enterprises) and, in turn, agriculture can offer a huge contribution to the solving of the problem. In fact, it is the only solution!
There must surely come a time when it is acknowledged that the current approach of reducing carbon emissions to address climate change will not actually do the job in time. Any contribution is of value but we need to recognise the fact that this may simply be too little too late. Here are the facts. If the entire world was to reduce carbon emissions by 100% tomorrow morning (which, obviously could never happen) then, in 200 years time, we would be down to the CO2 levels in the atmosphere that were present in 1975. Unfortunately, that is still too high. The oceans continue to heat and acidify and the sad truth is that we do not have 200 years! Are we locked into a train wreck or is there a way out?
Thankfully, there is a solution but we need the decision makers to recognise the potential and to legislate accordingly. Carbon credits need to be paid to farmers as an urgent priority to encourage the building of humus. There are several facts that need to be understood here. The first of these relates to how carbon works on the planet. There have only ever been the same number of carbon molecules on the planet since time began. We have not made new carbon, it is just stored in different places. Carbon is stored in the soil, the biomass or the atmosphere and it moves between the three as part of the carbon cycle. Unfortunately, a great deal of what was stored in the soil as humus is now stored in the atmosphere as CO2. This lode is thickening the blanket of greenhouse gases that is trapping heat in our atmosphere and negatively influencing our climate.
The scale of this problem is not widely understood but it is best exemplified with the following statistics. Since 1860 (the height of the industrial revolution) 470 gigatonnes of CO2 have moved from the soil to the atmosphere in relation to the huge loss of soil humus that has marked the advance of extractive agriculture. Global humus levels have fallen from an average of 5% to an average of just 1.5% during that period. During that same period, all of mankind’s other activities including industry, motor vehicles and 6 billion lungs breathing out CO2, have contributed 277 gigatonnes. The reality is that most of the offending CO2 came from the soil and we need to put it back there as a matter of urgency.
Farmers are literally charged with the task of saving the planet but it will be a wonderful win/win situation. You will, in effect, be paid to increase the presence of the most precious substance on your farm. However, the building of humus is a biological process. Many conventional agricultural practices destroy humus and the creatures that build it. We now know, for example, that mycorrhizal fungi are responsible for the creation of one third of the stable humus in our soils via the production of an exudate called glomalin. This sticky, carbon-dense substance triggers the building of soil humus to the extent that the global decline from 5% organic matter to 1.5% appears directly linked to the loss of 90% of our mycorrhizal humus builders. Einstein accurately noted that no problem can be solved with the same level of consciousness that created it and this is particularly relevant here. Biological agriculture is the shape of the future or we simply may not have one!
I believe that we are at the dawn of the golden era of agriculture. Farmers will have a secondary income from carbon sequestration in their soils and the humus they will build will profoundly demonstrate the validity of the universal law “give and you will receive”. They will produce more resilient crops, more profitably and we will all enjoy nutrient dense food with forgotten flavours, extended shelf-life and much less chemical contamination. The soil, humans and the planet will benefit immeasurably from a biological approach to food production and farmers will be recognised for their involvement in the most important profession of them all!