The nitrogen content of the soils in the Loess Region has a obvious range. The average of the nitrogen content is from 0.01% to 0.094%. Estimating the snnual loss of soil nitrogen is about 5.775—40.65kg/ha.According to totae nitrogen and its loss amonnt, the Loess Region is divided into six zones. Th1 ways increasing the nitrogen content of soils are to grow leguminous crop, to edvelop animal husbandry and to add chemical fertilizers.