caa a22 4500 463208730 CHVBK 20180405153133.0 cr unu---uuuuu 170326e20070101xx s 000 0 eng 10.1007/s10705-006-9022-1 doi (NATIONALLICENCE)springer-10.1007/s10705-006-9022-1 Land use impact on nitrogen discharge by stream:a case study in subtropical hilly region of China [Elektronische Daten] [Jin-Ling Yang, Gan-Lin Zhang, Yu-Guo Zhao] As a crucial factor of water eutrophication, nitrogen (N) discharge by agricultural non-point sources (NPS) has become a worldwide concern, and so has its relationship to land use. This study was aimed at the quantitative relationships between N discharge by stream and land use. It was conducted in the Meicun watershed of Xuancheng County, Anhui Province, in the subtropical low hilly area of China. The study integrated dynamic monitoring of nutrient discharge by stream water and Geographic Information Systems (GIS) analysis of land use of the watershed. Results showed that NO 3 − -N discharge ranged between 50 and 60% of the total nitrogen (T-N) and was 2.5-3.0times as much as NH 4 + -N. There was a significant difference between forested and mixed sub-watersheds for NH 4 + -N, NO 3 − -N and T-N concentrations. Significant correlations existed between NH 4 + -N, NO 3 − -N and T-N concentrations in stream water and the area percentages of forest and paddy fields. The study found that the discharges of NH 4 + -N, NO 3 − -N and T-N decreased exponentially with forest area increase, but a steep decline for NO 3 − -N and T-N seemed to occur when the forest percentage surpassed 70% and then there was almost no change. Similarly, the discharges of NH 4 + -N, NO 3 − -N and T-N increased exponentially with the paddy fields increase, but a steep augmentation occurred for NO 3 − -N and T-N when the paddy percentage surpassed 20% and then it remained at a plateau. The study showed that in the subtropical hilly region, paddy fields could increase N discharge due to farming management practices. Thus, primary measures to reduce N in the receiving water body would include a change in farming management and building an ecological interception system for paddy fields. Springer Science+Business Media B.V., 2006 Watershed nationallicence Land use nationallicence Nitrogen nationallicence Stream water nationallicence Nutrient discharge nationallicence Yang Jin-Ling State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, 210008, Nanjing, China aut Zhang Gan-Lin State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, 210008, Nanjing, China aut Zhao Yu-Guo State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, 210008, Nanjing, China aut Nutrient Cycling in Agroecosystems Springer Netherlands 77/1(2007-01-01), 29-38 1385-1314 77:1<29 2007 77 10705 https://doi.org/10.1007/s10705-006-9022-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10705-006-9022-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yang Jin-Ling State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, 210008, Nanjing, China aut NATIONALLICENCE 700 1- Zhang Gan-Lin State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, 210008, Nanjing, China aut NATIONALLICENCE 700 1- Zhao Yu-Guo State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, 210008, Nanjing, China aut NATIONALLICENCE 773 0- Nutrient Cycling in Agroecosystems Springer Netherlands 77/1(2007-01-01), 29-38 1385-1314 77:1<29 2007 77 10705 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer