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| DOI：10.13522/j.cnki.ggps.2022414 |
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| Impact of Planting Practices on Nitrogen and Phosphorus Loss Via Surface Runoff in Poyang Lake Basin |
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CHEN Yu, LIU Fangping, WU Caiyun, WANG Zirong, ZHANG Fujian
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1. Jiangxi Central Station of Irrigation Experiment, Nanchang 330201, China;
2. Agricultural Technology Extension Center of Chongming District, Shanghai 202150, China
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| Abstract: |
| 【Objective】 Poyang Lake is one of the largest lakes in southern China but has experienced pollution due to agricultural activities. This paper aims to analyze the changes in nitrogen (N) and phosphorus (P) loss via surface runoff from cropped lands under different planting practices in the basin. 【Method】For each crop, we compared three planting practices: upland farming, paddy farming, and alternate upland and paddy farming. The experiment lasted two years, during which we measured precipitation, surface runoff and changes in N and P in the surface runoff. 【Result】 The peak rainfalls occurred in June and July, aligning with the highest flow rates under all three planting practices. In the three planting practices, cabbage and early rice had the highest crop runoff, while pakchoi and late rice had the least, with rape and middle rice between. The runoff coefficient was the largest for cabbage and least for late rice, consistent with the change in rainfall intensity during growth seasons of the crops. The crop runoff of the three planting practices was ranked in the order of upland farming>alternate paddy and upland farming>paddy farming. Compared with paddy farming, upland farming and alternate paddy and upland farming increased the crop runoff by 42.28% and 20.84%, respectively. In all three planting practices, nitrogen and phosphorus loss via the surface runoff occurred from May to July. Water spinach under upland farming lost most total N, total P, and nitrate, while middle rice under alternate paddy and upland farming lost most ammonium nitrogen. The losses of total N, total P, and nitrate N via surface runoff from the three planting practices were consistent with the variations in crop runoff. Nitrogen loss from upland farming is through nitrate leaching, while N loss from the rice fields was mainly ammonium. 【Conclusion】 Upland farming resulted in the highest surface runoff, and N and P losses. These findings have important implications for improving planting practices to improve fertilizer use efficiency and mitigate N and P losses in the Poyang Lake basin. |
| Key words: natural rainfall; planting patterns; farmland; runoff; nitrogen and phosphorus loss |
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