Abstract:

The groundwater nitrate concentration and their influence factors under different cropping systems are studied in this paper, the quality of groundwater in Ningxia is evaluated. The result indicates that there are obvious differences in the content of nitrate in the groundwater under different cropping systems. Among them, Orchard>Greenhouse Vegetable>Grape>Forest land>Wheat-corn>Paddy rice>Saline and alkali land. The average content of nitrate in the groundwater is all lower than 20mg?L-1, which all meet the groundwater quality standard Ⅲ. The content of nitrate corresponding orchard in the groundwater is the highest, the average is 7.94mg?L-1, the lowest of the content of nitrate in the groundwater corresponds saline and alkali land, the average is 0.74 mg?L-1. As we've seen, the quality situation of groundwater in Ningxia is optimistic, but individual areas approach to pollution level. If not take the measures to prevent and control, the situation will deteriorate. The nitrate contents of the groundwater have no obvious regularity along with the burying depth, which may be affected by textures of local soil or recharge ways of groundwater. It also may be associated with places and numbers of sampling points.