This album released by Genesis in 1973 brings to mind the most recent story in the press regarding the NHS and Person Protective Equipment (PPE.) The Government budgeted and spent £8.7 billion of taxpayers’ money to buy PPE during 2020-21. It paid very high prices, had a late delivery and then was not sure what it had bought and where it had been stored. Currently that leaves us in the situation where hundreds of millions of pounds-worth of PPE will not be used for its intended purpose. Something similar to the current U.K. government plan for agriculture regarding soils and carbon.
Humus: Genesis and Definition.
If we are to capture carbon, long-term, within the soil what we are really interested in is the creation of soil humus.
The formation of humus although complicated may be described rather simply. Once organic tissue is incorporated into a moist warm soil it is immediately attacked by a host of different soil organisms. The easily decomposed compounds quickly succumb, first yielding intermediate substances and finally the simple, soluble products such as carbon, nitrogen, sulphur, phosphorus and a host of others.
In other words the process of decomposition releases carbon dioxide back into the atmosphere. This is commonly referred to as the carbon cycle and occurs both within and without the soil. It is a process of nature and something we mere mortals cannot alter.
As decomposition occurs two major kinds of organic compounds remain: (a) resistant compounds of higher plant origin such as oils and fats and especially lignin; and (b) new compounds such as polysaccharides (complex sugars.) These are synthesised by microorganisms and held as part of their tissue.
The compounds of microbial origin are not insignificant, studies have shown that up to 1/3 of the organic carbon may be in this form. Apparently these two groups of compounds, one modified from the original plant material and one newly synthesised by the action of microorganisms, provide the basic framework for humus.
Here in lies some of the long-term carbon storage within our soils.