Rice paddies need to be constantly flooded, and, because they are often located on steep slopes, this leads to significant runoff of fertilizers and sediment. Shifting to corn not only reduces water consumption; it also cuts the amount of pollution that reaches city residents downstream.
某些地方已经出台了上述举措。比方说北京附近的农民已经得到补偿，让他们从水稻改种玉米。稻田需要不断进行漫灌，而且因为多数座落在陡峭的山坡上，将会导致化肥和土壤显著流失。改种玉米不仅能降低水资源消耗；还能减轻下游城市居民所受的污染。该项目的执行成本约合每公顷1，330美元，却能产生每公顷2，020美元的经济效益。