长兴县低产白土有28万亩,常年平均粮食亩产不到400斤,中心问题是土瘦肥缺。以城郊公社三星(土斗)大队来说,历年来对于可以改土供肥的绿肥作物紫云英很少种植,1964年仅有22亩,且产量极低,每亩只有500～1,000斤。1965年全大队实种934亩,占耕地面积的42％;并由于采取了综合丰产栽培措施,平均鲜草亩 Changxing County, low-yield white clay has 28 million mu, perennial average grain yield of less than 400 pounds, the center of the problem is lean manure. In suburban commune Samsung (soil bucket) brigade, over the years for the soil can be fertilized green manure Astragalus rarely planted in 1964, only 22 acres, and the yield is very low, only 500 to 1,000 pounds per mu. In 1965, the entire brigade was 934 mu in total, accounting for 42% of the cultivated land area. Due to the comprehensive high-yielding cultivation measures, the average fresh grass mu