Agricultural pollution, which has a direct impact on the water, soil and air quality, is a common but increasingly
serious environmental problem nowadays. The misusage of fertilizer, high application fertilizer and low utilization rate,
are the major factors of the pollution. Therefore, the pollution caused by nitrate nitrogen has posed a very serious
problem to the ecological environment. Combined with the GIS technology, this paper takes Majiang County in Guizhou
province that is at southwest of China as a case, to carry out the research on the calculation of the nitrogen surplus in
paddy field and the dry land based on the farmland nutrient balance model using the fertilizer amount. This paper reveals
the spatial distribution characteristic of the nitrogen pollution, which can help to find a reasonable crop cultivation and
fertilization methods to increase the effective utilization fertilization and therefore reduce the pollution.