渭北旱原粮食产量低而不稳,严重缺肥是主要原因。该地区人均耕地多,农家肥有限,一般有机肥的施用面积只能占耕地的30％左右。因而利用豆科作物、牧草肥地就成了恢复地力的主要手段。旱原小麦传统的倒茬方式多为豌豆→小麦→小麦+晚秋,三年四熟。这种方式,种豌豆一般不施肥,豌豆后茬小麦也多不施肥,加上部分苜宿茬,大体上豆类作物倒茬肥地的面积占耕地的50％左右。由此可见,生物养田占有极 Weibei drylands low and unstable grain yield, a serious lack of fertilizer is the main reason. The per capita arable land in this area is limited, and the manure is limited. Generally, the area covered by organic fertilizer accounts for only about 30% of the cultivated land. Thus the use of leguminous crops, forage grass has become the main means of restoring fertility. The traditional method of upside down dry wheat wheat is peas → wheat → wheat + late autumn, three years four cooked. This way, the kind of peas generally do not fertilize, peas are not fertilized after the wheat crop, with some alfalfa stubble, in general the stubble crop area of ​​beans account for about 50% of arable land. This shows that bio-farmland occupies a very large area