摘要：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 in 1983. This bulletin includes statistics for 1970-91 on U.s. imports and exports of selected fertilizer materials, world and U.S. imports and exports of nitrogen, phosphate, and potash, and U.S. import origins and export destinations for selected fertilizer materials.
