我省旱地约占总耕地面积的三分之二。而主产粮、棉的渭北地区,旱地面积更大,如白水、澄城、合阳旱地分别占总耕地的80%、91%、96%,基本上是旱地耕作。该区主要作物为小麦、玉米、棉花、谷糜和红苕等,多为一年一熟或两年三熟制,复种指数较低。渭北旱原农业生产水平较低,粮食一般亩产200～300斤,皮棉20～30斤,主要原因是干旱缺肥,据分析,土壤含有机质1%左右(低的只有0.5～0.6%),全氮0.06～0.07%。全磷0.14～0.15%。近年来化肥用量虽不断增加,因利用率不高,仍不能解决根本问题。所以发展绿肥,就成了提高渭北旱原 Dryland in our province accounts for about two-thirds of the total cultivated area. The Weibei area where the main grain and cotton are produced has a larger dry land area. For example, Baishui, Chengcheng and Heyang drylands account for 80%, 91% and 96% of the total arable land, respectively, which is basically dry farming. The main crops in this area are wheat, corn, cotton, glutinous rice and red croaker, mostly in the form of one-year or two-year three-cropping system and the lower multiple cropping index. Weibei drylands of agricultural production is low, the general grain yield of 200 to 300 pounds, cotton lint 20 to 30 pounds, mainly due to lack of drought, according to analysis, soil organic matter content of about 1% (only 0.5 to 0.6% low) , Total nitrogen 0.06 ~ 0.07%. Total phosphorus 0.14 ~ 0.15%. In recent years, although the amount of fertilizer has been increasing, due to the low utilization rate, it still can not solve the fundamental problem. Therefore, the development of green manure, it has become to improve the Weibei drylands