灌区绿肥面积,1966年曾达到33万多亩,其中稻田绿肥26万多亩,旱田绿肥6万多亩。由于小麦的高产栽培,水稻采用生长期长的品种以及复种指数的提高等原因,原有的种植制度发生了较大的变化,1976年全区绿肥面积下降到4.2万亩,其中旱田绿肥约2000亩。1980年回升到20万亩,约为1966年的2/3左右。1981年又略有下降,共约14万亩。为了恢复和发展、利用绿肥,1981年在灌区进行了调查。 Irrigated area of ​​green manure, 1966 has reached 330,000 mu, of which more than 260,000 mu of paddy green manure, dry land green fertilizer more than 60,000 mu. Due to the high-yielding cultivation of wheat and the long-growing varieties of rice and the improvement of multiple-cropping index, the original planting system has undergone great changes. In 1976, the area of ​​green manure in the whole area dropped to 42,000 mu, of which green manure in dry land was about 2,000 mu. In 1980 it rose to 200,000 mu, about 2/3 of 1966. In 1981 it dropped slightly, a total of about 140000 acres. In order to restore and develop, using green manure, a survey was conducted in the irrigation area in 1981.