水短缺

• Several trends are converging to reduce the grain area , including the loss of irrigation water , desert expansion , the conversion of cropland to nonfarm uses , the shift to higher - value crops , and a decline in double - cropping due to the loss of farm labor in the more prosperous coastal provinces
  粮田面积萎缩是多种趋势汇合共同作用的后果，包括灌溉用水短缺、沙漠扩大、粮田转为非农用地、改种高价值作物，以及在比较富裕的沿海省份由于农业劳动力缺失致使一年两作的萎缩。