Vroomen, Harry; Taylor, Harold - Economic Research Service, Department of Agriculture - 1993
The United States is the world's largest phosphate exporter and the world's largest potash importer. The U.s. nitrogen … trade balance, relatively stable before 1983, has shifted as the United States became a net importer of nitrogen beginning …, world and U.S. imports and exports of nitrogen, phosphate, and potash, and U.S. import origins and export destinations for …
