Investigating the role of different land uses in nitrate changes in groundwater (Case study: Sirjan plain, Kerman, Iran)

Groundwater pollution is severely affected by different land uses, so that it is created widespread contamination in different areas in groundwater and endangers the health of human, livestock and other living organisms. In this study, the nitrate content of 55 water sources in Sirjan plain aquifer was investigated. Then, 5 types of land use were identified in Sirjan plain. Then, the polygon of Sirjan plain was mapped based on 5 types of land use to determine the role of each land use in the amount of groundwater nitrate in Sirjan plain. Then the amount of area and nitrate of different land uses were divided into 7 classes. The results showed that range land use in Sirjan plain has the highest level in aquifer and the lowest level of planting forests in Sirjan plain aquifer. Considering the minimum and maximum nitrate distance in Sirjan plain, the results showed that range land use has a lot of nitrate spatial variability compared to other land uses, and industrial land use has the least spatial variation in nitrate compared to other uses. In general, according to the mean amount of nitrate in Sirjan plain aquifer, the results showed that the minimum nitrate mean in different land uses of Sirjan plain is related to agricultural land use with 7.53 ppm and the maximum nitrate mean in different land uses of Sirjan plain is related to industrial land use with 10.24 ppm and the average nitrate level in planted forests, range and residential land uses with small changes is between agricultural and industrial land uses. In general, among all nitrate classes in Sirjan plain, the results showed that range land use has the highest percentage of land area, and industrial and planted forests land uses have the lowest percentage of land area.