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Closing Crop Yield Gaps

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farmer.jpgBY PAUL C. WEST

Several reports estimate that we need to double current crop production by 2050 in order to meet the needs of a growing population that eats more meat and uses more crops for fuel. Some strategies - like reducing waste and reducing meat consumption - would reduce pressure on our land and water resources and free up more food calories that are potentially available. But we commonly assume that increasing crop production will come at a cost of increased environmental damages to our climate, water and natural habitat.  It turns out that does not have to be the case.

In their recent article in Nature, Nathan Mueller and colleagues estimate that yields could be increased for most major crops by 45 to 70 percent, with the biggest opportunities in Eastern Europe, sub-Saharan Africa, East Asia, and South Asia (see Figure 1). The vast majority of yield variability within a particular climate is from differences in nutrient and water management. This is great news as it means that these yield gains are possible with today's seeds and management practices. Many foundations and companies emphasize the need for seeds that utilize water and nutrients more efficiently. That's a great mid- and long-term strategy, but yields can be increased a lot in the meantime through changes in management. Nutrient and water management will always be a key part of the solution in many areas where hunger is currently widespread, soils are depleted of nutrients, and the climate is arid.

West_Fig1.pngYes, in most regions it will require additional nutrients or water to boost yields. Crops are notoriously inefficient in their use of both organic and mineral fertilizers--they typically only utilize half of what's applied--so additional management practices may be needed to ensure water quality is maintained. However, fertilizer application could be greatly reduced in many areas while still maintaining high yields (see Figure 2). Mueller and colleagues estimate that current yields for maize, wheat and rice could be maintained while reducing global input of nitrogen and phosphorus by 28 and 38 percent, respectively. The biggest opportunities for these reductions are in China, United States, Western Europe, and India.

West_Fig2.pngAnalyses like this study help define what's biologically and physically possible. Ideally, lessons learned here can be used to help guide investments in markets and infrastructure through a combination or public and private capital, policy, and education.

Disclosure: Nathan Muller and the other co-authors of this study are colleagues that I work closely with on other, related research.

Paul West is an ecologist finding ways to feed the future while sustaining our planet. Through his job as chief collaboration officer at the University of Minnesota's Institute on the Environment, he works to get science out the of ivory tower and into the hands of people affecting change on the ground. Find him on twitter @coolfireconserv. Reposted with permission from Landscapes Blog for People, Food, and Nature.

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