Farming Better

How do we feed a growing population while minimizing environmental impacts? Contrary to popular belief, making the switch from conventional to organic farming is not the answer, or so find Michael Clark and David Tilman in a recent study published in Environmental Research Letters. Rather, the authors emphasize, we should be prioritizing research and adoption of practices that increase agricultural input efficiency—the amount of food produced per unit of agricultural input.

With world population expected to exceed nine billion people by 2050, global food production needs to increase dramatically. One of the central challenges of this century will be to feed this growing population without degrading the natural environment. Producing food already emits over 25 percent of anthropogenic greenhouse gases, takes up more land than any other human use, is a primary cause of habitat loss, and contributes to several types of water and air pollution that harm humans and ecosystems.

Some advocates and academics have proposed that low-input production such as organic agriculture could feed the world. Many assume that growing food with less synthetic fertilizer, energy, and other inputs would leave a smaller environmental footprint. But a growing body of research suggests that the reality is more complex.

For their study, Clark and Tilman analyzed over 700 food production systems, assessing greenhouse gas emissions, land use, energy use, and contributions to water and air pollution in order to compare the relative merits of different systems, including conventional farms, which often use synthetic inputs such as chemical fertilizer and pesticides, and organic farms, which abide by organic certification standards and forgo these synthetic inputs.

Notably, they found that organic agriculture requires more land, contributes to greater eutrophication (a harmful type of water pollution), and generates similar greenhouse gas emissions per unit of food as conventional agriculture. This is because most organic farms are less productive and use a lot of manure to fertilize their crops. Lower productivity means that organic farms need more land to produce the same amount of food as conventional farms. And while using manure is a resourceful way to recycle waste, it has its downsides. Manure provides nutrients to crops less efficiently than conventional fertilizer, and thus a greater portion of it seeps into waterways and is emitted as nitrous oxide, a potent greenhouse gas.

Clark and Tilman’s work therefore suggests that a dramatic and widespread shift from conventional to organic agriculture and other low-input systems will not reduce many of agriculture’s environmental impacts. This is not to argue, however, for the status quo. Conventional farming has its share of problems; Clark and Tilman find that conventional farms use more energy and fossil fuels than organic farms and note that they tend to apply high amounts of pesticides that harm humans and ecosystems.

This underscores the importance of accelerating sustainable intensification. We need to help all types of farmers—organic and conventional alike—to adopt practices and inputs that improve their productivity while minimizing their environmental impacts. Some of these practices are already common among organic farms, as others are among conventional ones. Cover cropping and multi-cropping, for example, common in organic agriculture, can increase productivity and reduce land use and nutrient loss. Likewise, emerging precision agriculture technologies that many people associate with large-scale conventional agriculture, such as fertigation and variable-rate fertilization, have already begun to reduce agriculture’s environmental footprint while boosting yields.

Existing research indicates that developing and spreading such best practices will require greater investment in research and efforts to provide farmers with the information and inputs they need. Where this is not enough, Clark and Tilman point to reducing food waste and meat consumption. “It’s essential we take action,” Tilman says, “to increase public adoption of low-impact and healthy food, as well as the adoption of low-impact, high-efficiency agricultural production systems.” In order to do so, it will be critical to think beyond the dichotomy of conventional versus organic, and focus instead on the uptake and development of better ways to farm.