Study: Most organic crops fall short on yields
Voice of America this week reported on a new analysis that concludes that while some organic crops produce nearly as much as conventional agriculture, most still fall short. And lower yields mean feeding the world organically requires clearing more land.
But, the article pointed out, some people note there is more to sustainability than just crop yields.
Organic advocates say farming without artificial fertilizers and pesticides has less environmental impact.
The new study, which appeared in Nature, combines 66 earlier yield studies. From the Voice of America story:
“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 (corn 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.
One area where organic farmers could improve, she says, is giving their crops enough nitrogen fertilizer. Those that received more nitrogen had smaller yield differences, she says.
But that’s harder to do organically with just manure and crop rotations, she says.
Ken Cassman, an agronomist at the University of Nebraska at Lincoln, told Voice of America that the real problem, when talking about global food security, is the land issue. He said researchers need to figure out how to meet growing demand for food on the same amount of land that farmers are using today.
“You don’t focus on whether organic is better or conventional is better,” Cassman said. “You simply focus on the outcome.”
One outcome, of course, is the economic payoff. A study out of Iowa State University last year found that organic grain crops bring in about $200 more per acre than their conventional counterparts. In contrast to the study detailed in Nature, Iowa State's study— which compared 44 organic and conventional plots over 13 years — also found organic crops yielded as much grain or more per acre than conventional plots. Click here to read the Harvest story.