----- forwarded message ----- Date: Tue, 02 Jul 2002 14:50:45 -0700 From: radtimes <[EMAIL PROTECTED]> Subject: 20-year study backs organic farming
20-year study backs organic farming http://www.newscientist.com/news/news.jsp?id=ns99992351 30 May 02 by Fred Pearce The world's longest running experiment in comparing organic and conventional farming side-by-side has pronounced chemical-free farming a success. "We have shown that organic farming is efficient, saves energy, maintains biodiversity and keeps soils healthy for future generations," says Paul Mader of the Research Institute of Organic Agriculture in Frick, Switzerland, which carried out the 21-year study. Although crop yields on organic plots in the experiment were on average 20 per cent lower than those on conventional plots, the ecological and efficiency gains more than made up for it, Mader says. Soils nourished with manure were more fertile and produced more crops for a given input of nitrogen or other fertiliser. "The input of nutrients like nitrogen were as much as 50 per cent lower, so overall the organic system was more efficient," he told New Scientist. Not all crops did equally well. Potato yields on organic plots were only 60 per cent of those on conventional plots. But organic winter wheat achieved 90 per cent, and grasses fed on manure did just as well as those fed on fertiliser. Mader argues that the biggest bonus is the improved quality of the soil under organic cultivation, which should ensure good crops for decades to come. Earthworms and fungi Organic soils had up to three times as many earthworms, twice as many insects and 40 per cent more mycorrhizal fungi colonising plant roots. Soils microbes went into overdrive, transforming organic material into new plant biomass faster than microbes in conventional plots. More predictably perhaps, organic plots contained up to 10 times as many weed species as conventional plots sprayed with herbicides. "Under European conditions, we can clearly grow our food with much less chemical input than we do now," says Mader. "But of course a 20 per cent yield reduction in a country like India would have fatal consequences." However, in practice, where poor farmers cannot afford expensive agrochemicals, switching to organic methods boost yields, he says: "Last year I visited a project in India, the Maikaal Project near Indore, where more than a thousand farmers are growing food organically - and increasing their yields compared to neighbouring conventional farmers." Jules Pretty, director of the Centre for Environment and Society at the University of Essex, who recently completed a global study of organic farming, said the findings confirmed his conclusion that "organic farming is more efficient and in many circumstances can increase yields for farmers". Journal reference: Science (vol 296, p 1694)
