Irrigated land is more than twice as productive as rainfed cropland.
Today, only 16 percent of the world's croplands are irrigated, but those lands yield some 36 percent of the global harvest. In the developing countries, irrigation increases yields for most crops by 100 to 400 percent. Irrigation also allows farmers to reap the economic benefits of growing higher-value cash crops. Half or even two-thirds of future gains in crop production are expected to come from irrigated land. In the developing world, where about 20 percent of arable land is irrigated, the prevalence of irrigation varies widely within and among countries and crops.