Friday 15 July 2011

The decline of agriculture?

A feature article on Al Jazeera's English-language website provides further arguments against the use of modern agro-chemicals due to on their impacts on soil.  This blog post is a direct extract from the article, the full version of which can be read here.

Professor Michael Bomford, a research scientist at Kentucky State University and a fellow of the Post Carbon Institute, is concerned about how our dependence on oil to feed ourselves is leading to soil depletion and degradation, as well as increasing prices.

"The farm is a very small proportion of the economy in the US and other developed countries, but it has a disproportionate impact on global change," Professor Bomford, who has a Master's of Pest Management and a PhD in Plant and Soil Sciences, told Al Jazeera.

"Clearing land for farming releases carbon into the atmosphere and that contributes to climate change.  Then by farming it, using cultivation causes soil to be lost in wind and erosion, and that topsoil took thousands of years to form.  One extreme weather event can cause us to lose thousands of years of soil."

Modern farming impacts soil by the use of nitrogen fertilizers, which are energy intensive to produce and which deplete carbon in the soil.

"This erodes the soil's ability to hold nutrients, and starts a positive feedback loop," added Professor Bomford.  "A lot of our soils now rely on irrigation rather than rainfall, which depletes groundwater reserves, and these have huge impacts on the soil."

William Ryerson, founder and president of the Population Media Center and president of the Population Institute, is also very concerned about fertilizers' impact on soil. He has questioned how, in the long run, this will impact agriculture.

"The world's agricultural systems rely substantially on increasing use of fertilizers," Ryerson told Al Jazeera.  "But now, the world's farmers are witnessing signs of a declining response curve, where the use of additional fertilizer yields little additional food product.  At the same time, fertilizers and intensive cropping lower the quality of soil.  These factors will more and more limit the possibilities of raising food production substantially and will, at a minimum, boost relative food prices and resulting hunger for many."

Carbon stored in soil allows the soil to hold nutrients and water, and losing soil contributes to climate change.  Bomford is worried about other contributing factors to climate change borne from the use of chemical fertilizers.