Better irrigation can dramatically improve crop yield and about 40% of the world's food supply is currently derived from irrigated land.
更好的灌溉可以显著提高作物产量;目前,全球约40%的粮食供应都来自于灌溉地。
2
As water tables have fallen and irrigation wells have gone dry, China's wheat crop, the world's largest, has declined by 8% since it peaked at 123 million tons in 1997.