Abstract:Soil nitrate accumulation in North China has been reported by many researchers. The land use patterns changed markedly along with agricultural productivity in the flat parts of Weibei dryland on the Loess Plateau. The rotation system of gramineous crop/legumina grass was replaced by winter wheat or maize cropping. Furthermore, traditional crop like winter wheat decreased and apple orchard increased continuously. Nitrate accumulation in the soil profiles under the different land use patterns was studied in this area, compared with a long-term experiment nearby the studied area. The results showed that nitrates accumulated in soil profile in apple orchard and farmland, but did not in soil of artificial grassland and younger forest in which no nitrogen was applied. Generally, the soil layer with nitrate accumulation was located at 40-260 cm soil depth. Nitrogen fertilizers were heavily applied in the apple orchard, resulting in distinct nitrate accumulation. Because a majority of farmland is used for productive agriculture or apple orchard, the amount of nitrogen application should be reduced. We suggest that effects of nitrogen application on eco-environment and quality of apple should be studied in the future.