But the end result is a healthier soil, which may prove vital in efforts to make it more resilient in the face of climate change as well as conserve it. Organic soils, for example, retain water better than those farms that employ conventional methods. "You use a lot more water [in irrigation] because the soil doesn't have the capacity to retrain the water you use," noted farmer Fred Kirschenmann, president of Stone Barns Center for Food and Agriculture at the "Feeding the World While the Earth Cooks" event at the New America Foundation in Washington, D.C., on April 12.
At the same time, a still-growing human population requires more food, which has led some to propose further intensifying conventional methods of applying fertilizer and pesticides to specially bred crops, enabling either a second Green Revolution or improved yields from farmlands currently under cultivation. Crops genetically modified to endure drought may also play a role as well as efforts to develop perennial versions of annual staple crops, such as wheat, which could help reduce environmental impacts and improve soil. "Increasing salt, drought or heat tolerance of our existing crops can move them a little but not a lot," said biologist Nina Fedoroff of Pennsylvania State University at the New America event. "That won't be enough."
And breeding new perennial versions of staple crops would require compressing millennia of crop improvements that resulted in the high-yielding wheat varieties of today, such as the dwarf wheat created by breeder Norman Borlaug and his colleagues in the 1950s, into a span of years while changing the fundamental character of wheat from an annual crop to a perennial one. Then there is the profit motive. "The private sector is not likely to embrace an idea like perennial crop seeds, which do not require the continued purchase of seeds and thus do not provide a very good source of profit," Seufert notes.
Regardless, the world already produces 22 trillion calories annually via agriculture, enough to provide more than 3,000 calories to every person on the planet. The food problem is one of distribution and waste—whether the latter is food spoilage during harvest, in storage or even after purchase. According to the Grocery Manufacturers Association, in the U.S. alone, 215 meals per person go to waste annually.
"Since the world already produces more than enough food to feed everyone well, there are other important considerations" besides yield, argues ecologist Catherine Badgley of the University of Michigan, who also compared yields from organic and conventional methods in a 2006 study (pdf) that found similar results. Those range from environmental impacts of various practices to the number of people employed in farming. As it stands, conventional agriculture relies on cheap energy, cheap labor and other unsustainable practices. "Anyone who thinks we will be using Roundup [a herbicide] in eight [thousand] to 10,000 years is foolish," argued organic evangelist Jeff Moyer, farm director the Rodale Institute, at the New America Foundation event.
But there is unlikely to be a simple solution. Instead the best farming practices will vary from crop to crop and place to place. Building healthier soils, however, will be key everywhere. "Current conventional agriculture is one of the major threats to the environment and degrades the very natural resources it depends on. We thus need to change the way we produce our food," Seufert argues. "Given the current precarious situation of agriculture, we should assess many alternative management systems, including conventional, organic, other agro-ecological and possibly hybrid systems to identify the best options to improve the way we produce our food."