Some organic crops produce nearly as much as conventional agriculture, but most still fall short, according to a new analysis. With a growing world population and limited land available to feed it, the study has implications for the debate on how to feed the world sustainably. But some note there is more to sustainability than just crop yields. Organic advocates say farming without artificial fertilizers and pesticides has less environmental impact.
But skeptics note organic farming generally produces less food per hectare. Lower yields means feeding the world organically would require clearing more land. Deforestation for agriculture is already a major contributor to climate change and biodiversity loss. The new study in Nature looks at how big the gap is between conventional and organic yields.
More productive
The study combines 66 earlier yield studies. “Conventional yields are typically higher than organic yields, but with certain management practices, certain environmental conditions, and certain crop species this yield difference can be quite small,” says lead author and McGill University researcher Verena Seufert. On average, organic crops produced 25 percent less than conventional. Vegetables and cereal crops (maize and wheat, for example) performed worse: 33 and 26 percent, respectively. But organic fruits and other perennials nearly matched conventional yields. So did legume crops like soybeans that produce some of their own fertilizer.
The organic penalty was smaller on organic farms that relied on rainfall, which were 17 percent less productive, compared to irrigated farms, which fell behind by 35 percent. “Under rainfed conditions where water supply varies depending on weather conditions, the organic soil can actually provide water better to the crops because it can capture and maintain this water for longer,” Seufert says.
Harder to manage