Soybeans in a field in Springfield, Neb., on Wednesday. The nation's corn and soybean farmers will bring in by far the largest harvest ever this year, driving down the price of the commodities, according to the U.S. Department of Agriculture. Nati Harnik/AP hide caption

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Tractors sit on a sugarcane plantation on the land of a Guarani-Kaiowá indigenous community in Brazil, where Oxfam has alleged "land grabs" unfairly take land from the poor. The United Nations is drafting voluntary guidelines for "responsible investment in agriculture and food systems" in response to such concerns. Tatiana Cardeal/Courtesy of Oxfam hide caption

toggle caption Tatiana Cardeal/Courtesy of Oxfam