While organic agriculture yields less than conventional farming systems, it surpasses on a wide spectrum of sustainability benefits, according to a review study published in Nature Plants. The paper used sustainability criterion defined by the National Academy of Sciences, which says a farm can only be deemed “sustainable if it produces adequate amounts of high-quality food, enhances the natural-resource base and environment, is financially viable, and contributes to the wellbeing of farmers and their communities.”
The paper was written by John Reganold, a Washington State University professor of soil science and agroecology, and doctoral candidate Jonathan Wachter.
Looking at meta-analyses of yield studies, the researchers found that organic generally yields 8-25 percent less than conventional farming, but with important caveats. Rice, soybeans, corn and grass-clover do much better, yielding 6-11 percent less, while fruits and wheat yield 28 and 27 percent less, respectively. The paper also said that “under severe drought conditions, which are expected to increase with climate change in many areas, organically managed farms have frequently been shown to produce higher yields than their conventional counterparts.”
In addition, the paper said conventional agriculture often pursues yield at the expense of the other three sustainability goals.
Organic food products had “significantly less to no synthetic pesticide residues compared with conventionally produced foods.” Of 15 meta-studies looking at the nutritional value of organic food, 12 found “some evidence of organic being more nutritious.” The paper said that the meaning of those differences was subject to debate.
Organic farming generally had advantages environmentally, the paper said, citing reviews and meta-analyses. “Organic farming systems consistently have greater soil carbon levels, better soil quality and less soil erosion compared with conventional systems. In addition, organic farms generally have more plant diversity, greater faunal diversity (insects, soil fauna and microbes, birds) and often more habitat and landscape diversity.”
Organic farms are also profitable. “Although price premiums were 29 to 32 percent, break-even premiums necessary for organic profits to match conventional profits were only 5 to 7 percent, even with organic yields being 10 to 18 percent lower.” It also said that economic studies rarely include external costs of various farm systems — such as soil erosion or nitrate leaching into groundwater — in measures of overall profitability. If they did, organic would appear even more profitable.