Wednesday, 10 December 2014

Organic Yields Are Only 20 Percent Lower Than Traditional Agriculture, Says Meta Analysis

The $105 billion organic food industry is not terribly worried about yields. Their customers are primarily wealthy and concerned more about the perception of benefit than they are cost.

But to the real evangelists, who insist that the organic process can feed the world, yield differences are a substantial hurdle to overcome. The low hanging fruit in food has already been picked, as it were, wealthy people educated by advertising are already buying organic food, and the rest of the marketplace thinks about price. So yields are a killer.

A new review of studies by environmentalists finds that organic process yields are not as bad as believed. The fertilizers and pesticides they use may be archaic compared to modern ones but they still do something - and adopting some practices while still avoiding the science their customers don't accept could improve yields even more. It will never be a solution for the world but at least it can make it possible for Whole Foods to open up outside wealthy neighborhoods. 
The meta-analysis of 115 studies found that organic yields are about 19.2 percent lower than conventional ones, a smaller difference than in previous estimates. 
The researchers believe that studies comparing farming methods were often biased in favor of conventional agriculture, so they went the other way and did an unweighted random-effects meta-analysis, with three times as many papers, which meant they included a lot of large outliers in the results. And so they were able to easily close the gap, even though in real life it may not be any different at all because they did no actual studies. That is the problem with agenda-driven meta-analysis. Using meta-analysis, they further project that multi-cropping (growing several crops together on the same field) and crop rotation could reduce the organic-to-conventional yield gap to 9 percent and 8 percent, respectively - because someone claims they did.

When controlling eligibility criteria and methodological quality is not done, and everything is just synthesized using a random effects model, almost anything is possible.  
"Our study suggests that through appropriate investment in agroecological research to improve organic management and in breeding cultivars for organic farming systems, the yield gap could be reduced or even eliminated for some crops or regions," said the study's lead author, Lauren Ponisio, a graduate student in environmental science, policy and management. "This is especially true if we mimic nature by creating ecologically diverse farms that harness important ecological interactions like the nitrogen-fixing benefits of intercropping or cover-cropping with legumes."
The researchers suggest that organic farming can be a very competitive alternative to industrial agriculture when it comes to food production. Farmers agree - if we want 30 percent of the world to starve.

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