Comment: Soil strategy should go organic
Defra has launched a consultation into its draft Soil Strategy which aims to stop carbon loss from soil and support food production. The Soil Association's Robin Maynard explains why the organisation wants this strategy to put organic farming methods at its heart.Given our name, you would expect the Soil Association to be responding to Defra's consultation on its proposed soil strategy. We are.
Our founder, Lady Eve Balfour stressed the fundamental importance of maintaining a vital, healthy soil in her book, The Living Soil first published in 1943, inspiring the setting up of the organisation three years later.
She wrote: "My subject is food, which concerns everyone; it is health, which concerns everyone; it is the soil, which concerns everyone - even if they do not realise it."
The priority given to soil husbandry by our founders has been borne out over the intervening years, as intensive farming methods based around increased use of heavy machinery and reliance on chemicals, rather than rotational farming, has led to increases in soil erosion, damage to soil structure as the organic matter content of UK soils has decreased, and reductions in the levels of minerals and trace elements found in UK staple foods.
The Strutt report, Modern Farming and the Soil, published by the Ministry of Agriculture, Fisheries and Food (MAFF-Great Britain) in 1970, concluded that "some soils are now suffering from dangerously low organic matter levels and could not be expected to sustain the farming systems which have been imposed on them".
More recent figures from Defra's National Soil Inventory show that that organic content of our soils has fallen significantly. Whereas in 1979-81 22% of our soils had organic matter over 7%, by 1995 this had fallen to 13%.
Organic farming methods increase soil carbon matter, derived from crop plant residues, and consequently sequestration of atmospheric carbon dioxide is increased.
The US Rodale Institute's 23-year study found that organic arable systems increase soil carbon between 15-28%, accumulating up to 1000 pounds of carbon per acre foot of soil each year.
In contrast, the UK's National Soil Resources Institute 25-year soil survey, published in 2005, found that the UK's soils generally are losing carbon "on an enormous scale" - some 13m tonnes annually, which is almost as much as the official estimate of total greenhouse gases from UK agriculture (14 MtC in 2005).
Organic farming's reliance on crop and livestock rotations, composting and ploughing-in crop residues ensures far more organic matter in the soil, so maintaining soil structure and also increasing its capacity for water retention.
During recent droughts in the US, organic farmers found their crops survived six weeks longer than their non-organic neighbours' shallow-rooted, fertiliser-fed plants - a critical period, enabling them to get their crops to harvest.
Use of artificial fertilisers and pesticides also significantly reduce the numbers of soil fauna and flora, which help maintain soil structure and capture carbon.
A 21-year long field-trial in Switzerland comparing organic and non-organic farming showed dramatic differences in soil microbiology, with populations 85% higher in the organically managed field than that treated with artificial chemicals.
Eve Balfour's concerns about the negative impact on UK soils and their long-term fertility through the switch to chemical-based agriculture have been confirmed by government studies showing declines in minerals in UK fruit and vegetables of up to 76% between 1940 and 1991.
Robin Maynard is a campaigns director for the Soil Association