کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2414408 | 1552091 | 2012 | 11 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: N fluxes in an agricultural catchment under monsoon climate: A budget approach at different scales N fluxes in an agricultural catchment under monsoon climate: A budget approach at different scales](/preview/png/2414408.png)
The purpose of this study was to develop options for a more sustainable catchment management, resulting in a reduction of agricultural non-point pollution of water resources in South Korean agricultural catchments. Therefore, an N budget analysis was conducted, which related N inputs into soil under intensive agriculture to N outputs at both field and catchment scale in a mountainous catchment in South Korea. The N budget of all investigated crops was positive, with total N inputs exceeding N outputs by 2.8 times. Radish showed the highest N uptake efficiency (43–45%), whereas rice showed the lowest with 24–30%. At the catchment scale, agriculture contributed over 90% to the maximum N surplus (473 Mg). Rice and radish, with over 100 Mg N surplus each, contributed the largest part. Comparing these results to the N export in the catchment outlet, it was found that N leaching and surface runoff were the dominant loss pathways, leading to a seasonal inorganic N export of 329 Mg. Because fertilizer N was the major N input (>50%) for all crop types except soybean, its reduction was identified as the major scope of action for N savings at the field and catchment scale. The currently observed trend of land use change from annual to perennial crops additionally assists the reduction of N surplus but shows only a spatially limited applicability for the future. Further measures like split applications, application timing to match crop needs and cover crops during the fallow complement the attempt.
► Agricultural N budgets were positive, with N inputs exceeding outputs by 2.8 times.
► High N inputs and high N losses resulted in low NUE for all key crops.
► Agriculture contributed >90% to the N surplus at catchment scale.
► Up to 86% of the N surplus was exported by stream flow.
► Reducing fertilizer N is the most important factor to reduce N surplus.
Journal: Agriculture, Ecosystems & Environment - Volume 161, 15 October 2012, Pages 101–111