A study published in the journal Nature has questioned whether organic farming can feed the world effectively without adversely affecting the environment, as exponents of the approach suggest. In the study, researchers from McGill University, Canada and the University of Minnesota looked at research on crop yields from organic and conventional management practices.

Following “comprehensive analysis of existing science,” the researchers revealed yields are lower under organic management. As critics of organic methods often state, lower yields mean more land would have to be given over to production, causing biodiversity loss and deforestation, were the use of damaging artificial inputs abandoned.  

The Nature study’s authors also came to the conclusion that, in order to feed a rising population, some conventional methods are necessary. The researchers from McGill stated, "To achieve sustainable food security we will likely need many different techniques – including organic, conventional, and possible 'hybrid' systems – to produce more food at affordable prices, ensure livelihoods to farmers, and reduce the environmental costs of agriculture."

Their analysis revealed organic yields are 5 to 34 per cent lower than conventional across a range of crops. Reviews of 66 studies, covering 34 crops showed that, for fruit and oilseed crops, the difference between organic and conventional yields was minimal, but for vegetable and cereal production there was a more distinct difference in yields. Although overall organic yields were shown to be 20 per cent lower than for conventional, when best practice was observed this gap shrank to just 13 per cent.

In February, UK government scientist Tim Benton criticised the organic movement and recommended that the most productive areas of land be farmed intensively whilst the less productive areas are given over to environmental regeneration. His comments were slammed as short sighted by conservationists and organic aficionados.

Just days before Professor Benton’s comments, UK certification body the Soil Association publicly lamented the lack of funding for organic research, stating that most research funding into organic management, which could go towards improving aspects of both conventional and organic farming practices, is instead concentrated on comparing the two approaches. The Soil Association said policy makers and agriculturalists should take a more holistic view of farming systems and called for further research into agroecological approaches, which it claims have wider benefits than merely raising yields.  

The McGill and Minnesota researchers acknowledge that their study only examined yield. They said they will now focus on examining the environmental impacts of organic and conventional agriculture. Organic farmers maintain that, as prices rise for non-renewable inputs like oil and artificial fertilisers, which are essential to secure high yields delivered by conventional agriculture, organic systems will become increasingly viable.

A 2002 study from Switzerland showed that, although yields for organic wheat and potatoes were 20 per cent lower than conventionally grown crops over 21 years, input of fertilizer and energy was reduced by 34 to 53 per cent under organic management and pesticide use was reduced by 97 per cent. This led the researchers to conclude that “Enhanced soil fertility and higher biodiversity found in organic plots may render these systems less dependent on external inputs.”

Commenting on the findings of her research, Verena Seufert, one of the authors of the Nature study, said, "These results suggest that today's organic systems may nearly rival conventional yields in some cases – with particular crop types, growing conditions and management practices – but often they do not. Our study indicates that organically fertilized systems might require higher nitrogen inputs to achieve high yields as organic nitrogen is less readily available to crops. In some cases, organic farmers may therefore benefit by making limited use of chemical fertilizers instead of relying only on manure to supply nitrogen to their crops.

"At the same time, conventional agriculture can learn from successful organic systems and implement practices that have shown environmental benefits, such as increased crop diversity and use of crop residues."

Professor Jonathan Foley, of the University of Minnesota's Institute on the Environment, who was also involved in the study added, "The results point to a need to get beyond the black-and-white, ideological debates that often pit advocates of organic and local foods against proponents of conventional agriculture, Prof. Foley adds. By combining organic and conventional practices in a way that maximizes food production and social good while minimizing adverse environmental impact, we can create a truly sustainable food system."

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