[The impact of land uses on watershed runoff nitrogen discharge in hilly regions].
Nitrogen is a crucial factor in causing the eutrophication of water body. Land use has an important impact on agricultural non-point sources (NPS) nitrogen discharge. This study on quantitative relationship of runoff nitrogen discharge and land use was conducted in Meicun watershed of Xuancheng County, Anhui Province, in the subtropical low hill area, by the dynamic monitoring of stream water and nutrient discharge, integrating interpretation of aerial image and GIS analysis. The results showed that, land use significantly affect nitrogen concentration and discharge in which nitrate nitrogen was the main component. There was a significant linear relationship between nitrate and total nitrogen concentration in the given land use system. However, statistically significant relationship between ammonium and total nitrogen concentration was found only in forest-pond system. Moreover, positive linear relationship existed between different forms of nitrogen discharge. It was found that there were exponential relationship between the discharge of nitrate, ammonium and total nitrogen and the area percentages of forest, pond, paddy and village. Forest and pond had a negative impact on nitrogen discharge while the paddy and village had positive effect. At the same time, land use types had important effect on nitrogen concentration.
Yang
Jinling
J
Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Zhang
Ganlin
G
Zhang
Hua
H
Zhao
Yuguo
Y
D000383:Agriculture; D003247:Conservation of Natural Resources; D005618:Fresh Water / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014874:Water Pollutants, Chemical; D009584:Nitrogen