Soil. The sustainable fossil fuel?

UK Agriculture has been under increasing scrutiny after being labeled one of the main contributors to Greenhouse gas (GHG) emissions in recent times. The increasing pressure to reverse global warming on Governments worldwide has led to the introduction of ambitious targets which will be followed by new legislation. The Environmental Land Management scheme (EMLs) has had its third reading in Parliament and with Brexit looming its introduction is imminent.

ELMs replaces the Common Agricultural Policy (CAP) and will focus on public money for public goods. This means future payments will revolve around managing landscapes, protecting water courses and reducing emissions. This emphasis on protecting the environment will refocus the minds of farmers and mean a return to more traditional farming methods, similar to those seen pre-1950s and the agricultural revolution.

The last agricultural revolution, somewhat ironically named “The Green Revolution”, came after the second world war when an emphasis was placed on the use of inorganic fertilisers and pesticides, however, the real Green Revolution is happening now. This time record-breaking yields, crop genetics and increased fertiliser / pesticide use will be replaced with high yield efficiencies, the regeneration of lost top soil and the rebuilding of organic matter, nitrogen and carbon in soils.

The world in which we live has finite resources. Take coal for example; Millions of years ago fallen trees scattered the Earth’s surface. At that time, microbial populations were unable to decompose the sheer volume of complex organic compounds. This meant trees piled higher and higher slowly compressing themselves under the weight of yet more trees, creating what we now refer to as coal, a fossil fuel. With extreme weather events, historical climate change and the evolution of Agriculture, coal is no longer produced as it once was. Instead complex organic compounds are broken down into more useable, simpler ones meaning no more coal and in its place, humus.

Humus has become the newest fossil fuel and is, by far, the greatest thing mother nature has ever given us. Almost all living organisms exists because of organic matter and if maintained it can sustain life for eons. There are the same amount of Carbon elements in

the world today as there was one million years ago, even one billion years ago. The amount of carbon hasn’t changed but where that carbon is stored, has. It is thought that somewhere between 50 and 70% of carbon stored in the soil has been released by modern farming practices. Despite this, soil still stores three times more carbon than can be found in the atmosphere and four times more than in living organisms.

The recycling of carbon throughout the soil, plant, animal, manure cycle is what sustains life on this planet and without it, life would look very different.

The understanding of this cycle and the increasing knowledge of soil science is showing us that agriculture can feed the world and that regenerative practices are sustainable and profitable.

When you consider 1kg of humus can hold 4kgs of water and 1kg of humus contains approximately 50% carbon by weight, increasing humus in soils by 1% would mean an increased water holding capacity of 160,000 litres/ha and a very rough approximate of 40,000kgs/ha of carbon stored. This addresses the lions share of objectives set out by ELMs. Less flooding, less CO2 in the atmosphere, healthy ecosystems and plenty of nutritious food.

If looking after soil and creating humus, is the answer, then Bokashi is the solution. To support this, Agriton commissioned a three year trial comparing Bokashi to traditional composting and a control. The trial highlighted a number of positive effects with the results promising enough to extend the trial for another four years.

What is Bokashi? “Fermented organic matter”

Decomposition is the chemical breakdown of organic matter into its constituents by the action of bacteria and other micro-organisms. In other words, it is the return of nutrients broken down by microbes to provide food for the next generation of living organisms. There are a number of different ways in which organic matter can be decomposed or composted (see table 1).

Composting has received a lot of press lately, largely good, but a simple Google search highlights the large quantities of misleading advice and misinformation. This misinformation can be put down to personal bias or a less than full understanding of the decomposition process.

In Agriton’s opinion zymogenic fermentation provides the greatest returns with minimal environmental impact compared to the accepted industry standard; aerobic decomposer composting. The trial looked at which method provided the best decomposed material to be used as a soil improver for the regeneration of humus.

After three years the data showed that Bokashi increased soil organic matter over the control by 13.1% and by 10.6% over composting. In real terms a soil with a starting organic matter content of 2% would see a 30% increase in total organic matter and the ability to capture an additional 96,000 litres of water/ha. As well as this increases were also seen in Carbon, Nitrogen, Potassium, Phosphorus, Magnesium and Sulphur stored in the soil.

Using Bokashi for three years also improved average yields and had less instance of disease and lodging compared to both the control and composting. When all the results were considered there was an overwhelming amount of evidence showing the positive effects of Bokashi and ensuring the trial was extended to further show the longer-term benefits of using Bokashi compared to the control and aerobic composting.

Of particular concern were the losses observed during aerobic composting. From the starting material (13,400kgs) composting lost 59% of the Carbon or 2.3 tonnes of CO2. Comparatively Bokashi lost 3% of the Carbon or 0.1 tonnes of CO2 meaning Bokashi saved 20 times more Carbon than composting.

The additional material retained during Bokashi fermentation means more organic matter, more carbon and more food for the soil. This means more humus, greater quantities of nutritious crops, better water retention, less atmospheric CO2 and a healthier ecosystem, all of which will be required under ELMs.

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