The meta-analysis reviewed 66 studies comparing the yields of 34 different crop species in organic and conventional farming systems. The researchers included only studies that assessed the total land area used, allowing them to compare crop yields per unit area. Many previous studies that have showed large yields for organic farming ignore the size of the area planted — which is often bigger than in conventional farming.
Crop yields from organic farming are as much as 34% lower than those from comparable conventional farming practices, though in some cases, notably with strawberries and soybeans, the gap is as small as 3%."
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