Vol16 No.9: 2048-2062
【Title】Assessing effects of "source-sink" landscape on non-point source pollution based on cell units of a small agricultural catchment
【Author】WANG Jin-liang1,2; CHEN Cheng-long3; NI Jiu-pai2*; XIE De-ti2; GUO Xi1; LUO Zhi-jun1; ZHAO Yue1
【Addresses】1 School of Land Resources and Environment, Jiangxi Agriculture University, Nanchang 330045, China; 2 School of Resources and Environment, Southwest University, Chongqing 400715, China; 3 Research Center for Development and Utility of Unique Resources in the Wulingshan Region, Yangtze Normal University, Fuling 408100, China
【Corresponding author】NI Jiu-pai
【Citation】Wang JL, Chen CL, Ni JP, et al. (2019) Assessing effects of "source-sink" landscape on non-point source pollution based on cell units of a small agricultural catchment. Journal of Mountain Science 16(9). https://doi.org/10.1007/s11629-018-5268-8
【Abstract】Ascertaining the relationship between "source-sink" landscape and non-point source (NPS) pollution is crucial for reducing NPS pollution, however, it is not easy to realize this target on cell unit scale. To reveal the relationships between "source-sink" landscape and NPS pollution based on cell units of a small catchment in the Three Gorges Reservoir Region (TGRR), the runoff and nutrient yields were simulated first by rainfall events on a cell unit scale based on the Annualized AGricultural Non-Point Source Pollution Model (AnnAGNPS). Landscape structure and pattern were quantified with "source-sink" landscape indicators based on cell units including landscape area indices and location-weighted landscape indices. The results showed that: the study case of small Wangjiagou catchment highlighted a good prediction capability of runoff and nutrient export by the AnnAGNPS model. Throughout the catchment, the spatial distribution trends of four location-weighted landscape indices were similar to the trends of simulated total nitrogen (TN) and total phosphorus (TP), which highlighted the importance of spatial arrangement of "source" and "sink"landscape types in a catchment when estimating pollutant loads. Results by Pearson correlation analysisindicated that the location-weighted landscape index provided a more comprehensive account of multiple factors, and can better reflect NPS-related nutrient loss than other landscape indices applied in single-factor analysis. This study provides new findings for applying the "source-sink" landscape indices based on cell units in small catchments to explain the effect of "source-sink" landscape on nutrient export based on cell unit, and helps improve the understanding of the correlation between "source-sink" landscape and NPS pollution.
【Keywords】Nutrient load; Non-point source pollution; Source sink; Landscape index; Small catchment.