'Biodiversity benefits of organic farming are small'

Washington, May 6 : A new research from the University of Leeds has suggested that organic farms may be seen as wildlife friendly, but the benefits to birds, bees and butterflies don't compensate for the lower yields produced.

While comparing organic and conventional farming to date, the researchers found that the benefits to wildlife and increases in biodiversity from organic farming are much lower than previously thought - averaging just over 12 percent more than conventional farming.

The organic farms in the study produced less than half of the yield of their conventional counterparts, so the research raises serious questions about how we can use agricultural land to maximise food production and still protect our wildlife.

"Over the next forty years, we''re going to have to double food production worldwide to keep pace with population increases. Our results show that to produce the same amount of food in the UK using organic rather than conventional means, we''d need to use twice the amount of land for agriculture," says Professor Tim Benton, who led the project.

"As the biodiversity benefits of organic farming are small, then the lower yield may be a luxury we can''t afford, particularly in the more productive areas of the UK," he added.

Benton and colleagues looked at two areas in Central South West England and the North Midlands, taking into account over 30 variables covering climate, topography, socio-economic conditions, land use and soil type.

Thirty-two organic and non-organic farms were paired together, some in ''hotspot'' regions with many organic farms and others in ''coldspots'' with very few, to help identify any cumulative impacts over a wider area. Comparisons were made also between individual fields, with 192 fields sampled in all.

The research looked at birds, insects (including butterflies, bees and hoverflies), earthworms and plants.

Comparing farm by farm, the researchers found a 55 per cent drop in yield compared to a 12.4 per cent increase in biodiversity.

However, comparisons between larger areas found that ''hotspots'' with a greater density of organic farming showed a 9.1 per cent increase in biodiversity across the board.

The study has been published online in Ecology Letters.