World Soil Day 2020 - 4p1000
To the untrained eye, a mature agroforestry plot looks just like a forest
RAIN recently became a member of the “4 PER 1000 initiative”. The aim of the initiative is to demonstrate that agriculture, and in particular agricultural soils can play a crucial role where food security and climate change are concerned. It acknowledges that an annual growth rate of 0.4% in the soil carbon stocks, or 4% per year, in the 30-40 cm top layer of soil, would significantly reduce the CO2 concentration in the atmosphere related to human activities.
Boosting soil carbon levels is a big win/win. It has the potential to buffer against climate change by taking circulating carbon out of the atmosphere, and it is a key barometer of soil health. Soil carbon is a measurable component of soil organic matter, which plays an important role in the physical, chemical and biological function of soils. It contributes to nutrient retention and turnover, soil structure, moisture retention and availability, degradation of pollutants, carbon sequestration and soil resilience.
Modern intensive agriculture tends to apply synthetic fertilisers, without adding organic matter, supplementing soil carbon. This threatens the future viability of soils. Soil also has the potential to be a far greater carbon sink than the vegetation and trees that grow upon it. It has been estimated that the world’s cultivated soils have lost between 50-70% of their original carbon stock.
Many scientists feel that regenerative agricultural practices such as that of syntropic agroforestry championed by RAIN could help turn back the carbon clock, reducing atmospheric CO2 while boosting soil productivity and increasing resilience to floods and drought at the same time. Both sustainable agroforestry practices and reforestation are highly effective ways of achieving this.
There are more carbon residues in soil than in the atmosphere and all plant life combined - an estimated 2,500 billion tonnes of carbon in soil, compared to 800 billion tonnes in the atmosphere and 560 billion tonnes in plant and animal life. Compared to other proposed geoengineering fixes, storing carbon is simple: it’s simply a matter of returning it to where it belongs.
The very first intervention RAIN co-ordinated was to take a bus-load of conventional farmers to the CAV Agroforestry centre in Minas Gerais.
The picture shows a test comparing microbial activity in degraded soil (right), normally farmed soil (left) and the soil of an agroforestry plot (centre)
One principle of agroforestry is to keep the ground covered with pruned material. This protects it from the sun, keeping the moisture in to support the microbial life, and constantly builds up the soil with decaying organic matter
