Land use impact on nitrogen discharge by stream: a case study in subtropical hilly region of China
- 105 Downloads
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 2.5–3.0 times 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.
KeywordsWatershed Land use Nitrogen Stream water Nutrient discharge
Unable to display preview. Download preview PDF.
This study was supported by the International Foundation of Science C 2661/1), Natural Science Foundation of China (40235054) and the INCO-DC program of the European Commission (EROCHINUT: No. ERBIC18CT98037). We greatly appreciate the intensive suggestions and opinions of two anonymous reviewers, which helped us improve our manuscript substantially.
- Barisas SG, Baker JL, Johnson HP, Laflen JM (1978) Effect of tillage systems on runoff losses of nutrients, a rainfall simulation study. Trans ASAE 75:893–897Google Scholar
- Castillo MM, Allan JD, Brunzell S (2000) Nutrient concentrations and discharges in a midwestern agricultural catchment. J Environ Qual 29(4):1142–1151Google Scholar
- Chen JS, Gao XM, Xia XH, He DW (1999) Nitrogen contamination in the Yangtse River system, China. Environ Chem 18(4):289–293Google Scholar
- Cooper CM (1993) Biological effects of agriculturally derived surface water pollutants on aquatic systems—a review. J Environ Qual 22(3):402–408Google Scholar
- Cooperative Research Group of Chinese Soil Taxonomy (CRG-CST) (2001) Chinese soil taxonomy. Science Press, Beijing, New YorkGoogle Scholar
- Editing Office of China Agricultural Yearbook (2005) China agricultural yearbook. China Agricultural Press, BeijingGoogle Scholar
- Harenz H, Köster W, Merkel D (1992) Stickstoff, Phosphor und Kaliumbilanzen der Landwirtschaft der Bundesrepublik Deutschland und der ehemaligen DDR von 1950 bis 1988. Agrobiol Res 45:285–293Google Scholar
- Institute of Soil Science, Chinese Academy of Sciences (1961) Soil environment of paddy high output. Science Press, BeijingGoogle Scholar
- Lebo ME, Herrmann RB (1998) Harvest impacts on forest outflow in coastal north Carolina. J Environ Qual 27(6):1382–1395Google Scholar
- Ma LS, Wang ZQ, Zhang SM, Ma XF, Zhang GY (1997) Pollution from agricultural non-point sources and its control in river system of Taihu Lake, Jiangsu. Acta Sci Circum 17(1):39–47Google Scholar
- Payraudeau S, Cernesson F, Tournoud MG, Beven KJ (2004) Modelling nitrogen loads at the catchment scale under the influence of land use. Phys Chem Earth 29:811–819Google Scholar
- Rayment GE, Higginson FR (1992) Australian laboratory handbook of soil and water chemical methods. Inkata Press, SydneyGoogle Scholar
- Shen SM (2002) Contribution of nitrogen fertilizer to the development of agriculture and its loss in China. Acta Pedol Sin 39:12–25Google Scholar
- Xuanzhou Soil Survey Office (1985) Xuanzhou soil. Xuanzhou Soil Survey Office and Xuanzhou Soil Fertilizer Station, Xuancheng, AnhuiGoogle Scholar
- Yang JL, Zhang GL (2003) Quantitative relationship between land use and phosphorus discharge in subtropical hilly regions of China. Pedosphere 13(1):67–74Google Scholar
- Yang JL, Zhang GL, Zhou RR (2001) Dynamic change of runoff nitrogen discharge of a small watershed of south Anhui hilly area. Rural Eco Environ 17(3): 1–4Google Scholar
- Yuan SF, Lu J, Yu JY (2004) Methods of prevention and cure to agricultural non-point source pollution caused by nitrogen and phosphorous. J Soil Water Conserv 18(1):122–125Google Scholar