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Best management practices for agricultural non‐point source pollution in a small watershed based on the Ann AGNPS model
Author(s) -
Zhang Tong,
Yang Yuheng,
Ni Jiupai,
Xie Deti
Publication year - 2020
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/sum.12535
Subject(s) - nonpoint source pollution , tillage , environmental science , particulates , pollution , watershed , fertilizer , hydrology (agriculture) , environmental engineering , arid , agriculture , agronomy , ecology , engineering , computer science , biology , geotechnical engineering , machine learning
Best management practices ( BMP s) are implemented to reduce non‐point source pollution ( NPSP ) worldwide. In this study, the Ann AGNPS model was adapted and used to evaluate the effectiveness of BMP s for NPSP control in the Three Gorges Reservoir Area in China. Through field investigation and experimental observation, the Ann AGNPS model database was constructed. The model best simulated run‐off and its simulation of total nitrogen ( TN ) was better than for total phosphorus ( TP ). Simulation of the spatial distribution of different pollutant loads showed that the annual outputs of TN and TP per unit area were the highest, with an average of 63 and 6 kg hm −2 per year, respectively. An optimal scenario was developed based on adjustments to the existing land structure which were most effective at reducing N and P loads. The reduction rates of TN and TP loads were 54% and 63%, respectively, while the reduction rates of dissolved and particulate N and P loads were between 47% and 68%. After 27% of arid slope fields were converted into terraces in the study area, the modelled particulate N and P outputs were reduced by 44% and 46%, respectively, showing that terracing sloping land could be effective at reducing particulate N and P losses. These findings indicated that slope‐shifting technology is the most important method for NPSP control in the TGRA . In addition, reduced fertilizer use and conservation tillage measures should also be adopted to effectively reduce TN and TP losses.