• From Science Adviser –

One of the key aims of organic farming is to reduce the use of harsh pesticides, as these can damage the environment and have off-target effects. But it turns out that organic farms can lead to an overall increase in pesticide use in a region—if they’re interspersed with conventional farms.

That’s the unexpected conclusion of a paper in the latest issue of Science, which analyzed data from about 14,000 fields in California.

Organic farms surrounded by other organic farms used notably less pesticides, but conventional farms in the same situation used more. And so, right now, increasing the amount of organically farmed cropland by about 1% would lead to an overall increase in pesticide use.

Eventually, though, if organic farm acreage were to exceed that of conventional farms, then additional switches to organic methods would reduce pesticide use, the team found.

The findings also suggest a somewhat straightforward way to increase the share of organic farming in the interim without increasing pesticide use: keep like with like.

“Clustering organic cropland has the potential to mitigate the collateral impact on pesticide use for conventional cropland,” writes Erik Lichtenberg in a related Perspective.

But he cautions that further research is needed. “As organic farmland continues to expand, adverse interactions of the kind studied… are likely to grow.”

Read the Perspective here.

Source: Science Adviser

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