GEO-4 noted that established, though incomplete, evidence suggests that two thirds of the necessary increase in production needed from rain-fed farming can be achieved through better rain-use efficiency.
全球环境展望（四）指出，确立的证据（尽管不完全）表明，有三分之二必须靠雨水灌溉才能得到的必要增产，可通过更有效地利用雨水来实现。