Organic agriculture produces smaller yield, but requires less resources than conventional farming, a Swiss study has revealed.

An article to this effect appears in today’s [Friday’s] Science magazine based on the work of Paul Mader of the Research Institute of Organic Agriculture in Frick, Switzerland.

Mader compared potato, barley, wheat, beet and clover crops grown using organic and traditional methods over 21 years. Volumes of nitrogen, phosphorus and other nutrients added to the soil were 34 to 51% lower in organic fields. Organic harvests were 20% smaller, suggesting that organic methods use resources more efficiently, according to Mader.

The researchers attributed the sharper reduction in potato yields on organic farms to a low potassium supply and to an infestation of insect pests. Conventional farms control such problems with fertilisers and pesticides.

“Our results suggest that, by enhancing soil fertility, organic farmers can help increase biodiversity. These results should be encouraging for farmers, because they can see that yields are stable over time, and that soil fertility has increased,” Muder said.

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