The Importance of Soil Organic Matter

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This article is taken from Graeme Sait’s blog.  In it, he lists the benefits of healthy soil organic matter content.

http://blog.nutri-tech.com.au/author/graeme-sait/

Humus Saves the World

Following my recent address to a crowd of climate change activists on the steps of City Hall in LA, I was flooded with urgent enquiries about the spelling of a word I had used several times during my presentation. I immediately assumed that word was “mycorrhizal”, as this truly is a spelling bee special. To my amazement, the mystery word was “humus” and I was shocked to realise that my uncommon passion for this wonderful substance was just that. It was horrifying to realise how disconnected from the source of our food many of us have become. I was dumbstruck to think that the very life blood of our planet could remain anonymous.

If climate change activists were not aware of the critical importance of humus at this point in time, what hope for the rest of us? This article is designed to address that lack of understanding and to motivate an action plan. Humus can save the planet and you will soon understand how and why.

What is Humus?

The etymological root of the word “humus” is strongly linked to the word “human” with both words meaning “of and for the earth”. The biblical “dust to dust” concept is about the simple reality that we came from humus and it is to humus that we all return. Both words are also linked to the word “humility” and ironically it is our lack of humility, our arrogant attempts to master Earth that may well prove our downfall.

Humus is the chocolate brown, sweet smelling substance that drives healthy, productive soils. Humus is created by soil biology but also serves as the living quarters for this vital workforce. Humus is the soil glue without which our rivers run brown and dust storms strip our thin veil of precious top soil. Humus provides the single most efficient storage of waterminerals and carbon and it is this trio that will most impact soil health, human health and planetary health in the coming years. The reclamation of humus is the shape of the future or we may not have much of one.

I have recently completed intensive study of the latest climate change research for my TEDx presentation. The findings are so grim and the trends so alarming, I often found myself fighting back the tears. One thing became increasingly clear. If we do not act urgently our world will be a very different place. Our current inaction represents the greatest example of collective denial in the history of mankind. The new studies often refer to “irreversibility” and the only debate seems to relate to whether the estimated temperature increases peak out at 3, 4 or 5 degrees. There is little mention of the fact that a 5.5 degree increase in global temperatures is considered to be beyond human adaptability. You may be thinking, “Big deal! I won’t need a singlet in winter”, but it’s a bit more serious than that. We are currently witnessing the climatic disruption linked to a rise of just one degree and the chaos does not simply double at two degrees, it is exponential. Here in Australia we have just experienced the hottest January in recorded history and across the Tasman in New Zealand they are suffering the worst drought in their history. England has just experienced their coldest March in history and the list goes on. However, there is more bad news. These extremes in climate are actually less serious than the more pressing issue of ocean acidification from excess CO2. The oceans have absorbed almost 50% of the man-made CO2 produced since the industrial revolution and we should be thankful for this planetary, self-balancing act. However, the resulting 30% increase in acidity threatens ocean life dependent on calcium to build their outer shell. This includes corals, shellfish and algae. 500 million people are directly reliant on coral reefs for their food. Algae and krill are the building blocks for ocean life as we know it and phytoplankton produce over 50% of the planet’s oxygen. The impact is already measurable but will become serious in just 20 years. It doesn’t get much more serious than this and action must replace apathy.

It has become increasingly obvious that emission reductionswill not stem the tide. If we were to reduce emissions by 100% tomorrow morning, then in 200 years time, the CO2 in  the atmosphere will drop down to 1975 levels, which is still too high. The oceans continue to heat and acidify and not many experts will agree that we have 200 years to play with. Are we too late and are now locked into a planetary calamity? No we are not! The sense of despair that can sponsor the shutdown of a personal action-based response is not necessary. There is a solution that can save the day and I would like to think that some of you may soon feel motivated to share this message.

The Message

There has only ever been the same number of carbon molecules on the planet and they alternate between the soil, the biomass and the atmosphere as part of the carbon cycle. Currently a great deal of what was once in the soil is now in the atmosphere. In fact we have lost two thirds of our humus to the atmosphere following two centuries of extractive agriculture. This represents 476 gigatonnes of CO2 that is now stored in the atmosphere where it thickens the greenhouse blanket, traps the heat and sponsors climate extremes. Just for a sense of perspective – all of mankind’s other activities since 1860 have released a total of just 250 gigatonnes of CO2. We desperately need to redistribute atmospheric CO2 back into the soil as humus and everyone can contribute.

Here’s how it is done.

Planet-Saving Strategies

  1. We buy our food from those that practise regenerative farming. i.e. organic or biological growers – the rise and rise of farmers’ markets supports this kind of discretion.
  2. We pay carbon credits to primary producers for increases in soil humus. We need to motivate rapid action in a sector that is often already reeling from the economic impact of climate extremes.
  3. Composting becomes the mantra for everyone including farmers, home gardeners, Councils and Governments. Councils, for example, could collect food scraps and plant matter separately to avoid the methane emission linked to anaerobic decay in rubbish tips. These scraps are a good protein base for composting green waste and biosolids. Vermi-composting (utilising earthworms) is the ultimate composting technology as it produces an end-product that is twenty times more effective than any other compost option. Large scale vermicomposting of city wastes has been mastered by a New Zealand company in Auckland and these specialists are prepared to share their hard won technology with any council anywhere. Of course, consumers must recognise the importance of these critically important initiatives and support them by purchasing this compost as their primary soil fertility tool.
  4. We inoculate our soils with the organisms that build stable humus in the soil, with a particular emphasis upon beneficial fungi. Mycorrhizal fungi are directly responsible for 30% of the humus in the soil and their numbers are just 10% of what they were before the advent of extractive agriculture. These creatures burrow into the plant root and provide a massive attachment of fine filaments that represents a tenfold increase in root surface area. This fungal root extension scavenges difficult-to-access minerals, retains moisture and nutrients and produces a range of beneficial biochemicals to boost the immune system of its host. Mycorrhizal fungi can be reintroduced to our soils for as little as ten dollars per hectare and soil, plant, animal, human and planetary health are improved as a result. Other free living cellulose digesting fungi have also been seriously depleted and they can be easily and inexpensively brewed (multiplied) to repopulate biologically depleted soils.
  5. We legislate to protect the organisms that will save the day. Anything that compromises the humus-building performance of these key organisms must be restricted. This includes some farm chemicals, over cultivation and faulty grazing practices. Dr Margaret Roper from the CSIRO in Perth has shown that Paraquat and Atrazine seriously impact humus building organisms. Nematicides are similarly destructive and the world’s most widely used farm chemical, glyphosate, has recently been shown to be a serious microbicide.
  6. The burning of crop residues should be immediately banned. Not only are we destroying the soil food that could become humus and sustenance for precious soil biology but we are directly contributing large amounts of CO2 to the atmosphere. Particulation, where ash rises from the flames and is deposited elsewhere by the breeze, is also a form of demineralisation, as this ash effectively contains the minerals that grew the crop.
  7. We include a carbon source with every nitrogen-based fertiliser to buffer the microbial damage, reduce emissions of nitrous oxide and to prevent nitrogen stimulated bacteria from consuming humus to satisfy their tight C:N ratio of 5:1. Mismanagement of nitrogen is actually a major root cause of humus loss, as the bacteria, when fed excess nitrogen, seek out carbon to balance out this tight ratio (and humus is lost in the process).
  8. Humates extracted from brown coal become indispensable humus-building tools for everyone. Humic acid promotes cellulose digesting fungi while fulvic acid promotes beneficial bacteria. These are accessible, inexpensive, high carbon inputs which also buffer salt fertilisers and magnify mineral uptake.  It is ironic that the brown coal, that is the biggest contributor of CO2  to the atmosphere (via coal-fired power stations) can be of so much more value if it is used to boost soil fertility.
  9. We direct our superannuation/pension funds to invest in enterprises involved in developing renewable energy rather than those adding to the problem. The relatively new concept of a carbon budget is rapidly gaining acceptance around the globe. Here we recognise that 80% of the known carbon reserves (coal and oil) must stay in the ground if we are to have a viable future. Why then are just 2% of total pension funds currently supporting renewable enterprises, while 55% of our money supports the carbon polluting enterprises? Why would we be so actively funding companies seeking to discover more coal, oil and gas when most of what we have already found must stay locked within the ground. This is our money and our future and we should all pressure for a redirection of these funds. Well funded human initiative is the key to success here and there are massive amounts of money available that could be directed to planet saving enterprises (assuming cash-strapped governments don’t plunder this resource beforehand).

Humus Offers More than Climate Change Reversal

Humus determines profitability – Several years ago the National Bank in Australia conducted a comprehensive study to ascertain exactly what determines profitability in farming. In an attempt to better understand why so many rural loans were failing, they discovered that the single most important factor in farming success was organic matter (humus).They actually priced the farms in their large study based upon relative humus levels. A variation of just 0.15% organic matter attracted a substantial increase in the proposed valuation of the farm land involved.

Humus saves water – 74% of the planet is covered by water but only 3% of that is fresh.  Most of that fresh water is tied up in ice and glaciers and only 0.3% is in liquid form. 90% of that fresh water is used for irrigation. Water is a precious resource for which wars will be fought in the future. Large dams are our preferred water storage strategy at present but they are notoriously inefficient. Evaporation accounts for massive losses; there is often a large carbon footprint involved in pumping the water around the countryside and more energy involved in the actual irrigation process on-farm. A percentage of water applied as overhead irrigation accounts for more evaporation, and flood irrigation is even less efficient. Humus holds its own weight in water and it is the obvious way to store and deliver water. There is no evaporation beneath the ground and there is also no delivery energy involved. The plant roots simply take water from the humus as required. A 1% increase in organic matter (humus) in your soil means that soil can now hold 170,000 litres per hectare of water it could not previously hold. That is 17 litres of extra water per square meter. Humus offers a double benefit here because it is the home base for bacteria which produce a biofilm that absorbs and stores additional moisture. This sticky exudate stores water in much the same fashion as commercial water crystals.

Humus improves the nutritional value of our food – Humus stores more than water. It is also the primary vehicle for mineral storage and delivery. Humus features both negative and positive charged sites which can attract and hold all minerals, preventing them from leaching. There is no other storage facility in the soil with this capacity. The loss of humus from our soils spells the loss of mineral storage and it also impacts mineral delivery. Science is increasingly realising that every mineral has a microbe behind it. Microbes are the bridge between the soil and the plant and humus is the living quarters for these beneficial organisms. Many studies have chronicled the declining nutrition in our food and there is a direct link to the declining humus levels in our soils. Nutritionists contend that our food now contains just 20% of the nutrition found in the food consumed by our grandparents when they were children. We suffer a plague of degenerative illness and very often the root cause can be linked to nutrition. We are what we eat and what we eat comes from soils that are a shadow of their former selves.

Humus reduces chemical contamination of our food – This is a major health issue as chemical safety trials did not factor in the largely unresearched, cocktail effect or the phenomenon of bio-accumulation. Studies with rodents may have determined minimum residue limits of farm chemicals on our food but there was no consideration of how the body manages these contaminants. In many cases our detox systems are not equipped to process man-made chemicals and they are shunted off to the fat cells to keep them away from key organs. Here they accumulate and can pose health problems. When considering strategies to reduce our reliance upon farm chemicals it is a worthwhile exercise to consider the root cause of pest pressure in plants. A fungal disease does not reflect a deficiency of a fungicide. Disease is a response to compromised plant immunity based upon a lack of key supportive minerals or a lack of the bio-chemicals produced by microorganisms to enhance the resilience of their hosts. It is very much a case of “I will look after you if you look after me” and there is a direct parallel to our relationship with our own gut biology. At the soil/plant interface, the plant feeds glucose to the soil microbes in return for delivery of immune-enhancing minerals and biochemicals. However, the protection is even more profound than this. Many of the beneficial organisms surrounding the roots can also predate upon or antagonise disease organisms. The good guys literally eat our enemies. Humus, as the home base for minerals and microbes, is the key to enhanced pest resistance and less need for farm chemicals. The higher the humus, the less the chemical contamination of our food and the greater our health.

Humus cleanses soil contaminants and prevents nitrate leaching – Nitrates are a proven carcinogen and our ground water is seriously contaminated with this byproduct of nitrogen fertilisers. Humus is the only storage system in the soil for nitrate nitrogen. The loss of 2/3 of our humus means we have much less capacity to prevent nitrates from leaching and hence contamination of waterways is currently inevitable. Humus also serves as a carbon filter isolating heavy metals and farm chemicals that might otherwise enter our food chain.

Humus sponsors soil structure improvements – The bacteria living in humus constantly release a sticky, alkaline substance that binds together soil particles to form tiny aggregates. Fungi then bind these particles into larger aggregates to form crumb structure, the most desirable of all soil conditions. When crumb structure is present, plant roots can expand readily and as earthworms and beneficial nematodes can move unimpeded in these soils, their numbers increase. These soils also facilitate gas exchange, where oxygen moves freely into the soil to satisfy the requirements of plant roots and the organisms surrounding those roots. When the roots and microbes “breathe out”, the resulting CO2 can also move freely upward where it is captured by the tiny breathing pores on the underside of the plant leaf called stomates. The capacity of a soil to “breathe” in this fashion determines the amount of CO2for photosynthesis and, of course, photosynthesis, in turn, governs production and impacts resilience.

In Conclusion

Humus is literally the lifeblood of this planet and we have used and abused this magical substance to the point that our future viability is at stake. When we build humus in the soil, we reclaim carbon from the atmosphere, we improve plant, soil and animal health, we manage precious water more effectively and we lift the vitality and resilience of every last one of us. We need to refer back to the ancient wisdom where the words “humus” and “human” mean “of and for the earth” and we need to rediscover the humility to work with nature rather than striving for mastery. We can all contribute; lobby your Councils, pressure your super fund, compost, compost, compost and buy your food from those doing the right thing. We can all help save the world with humus.

About the Author:

Wildlife habitat manager and consulting forester from Central PA. Studied environmental Agriculture specializing in wildlife management and Forestry. B.S. Agriculture, Masters degree in Forestry. 30 years experience in land investment, forestry and wildlife habitat improvement. Currently working as a Farm Bill Forester for Pheasants Forever on Game Commission and Golden Winged Warbler Initiative.

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