上海郊区菜田地表径流氮磷流失特征分析

Nitrogen and phosphorus losses via surface runoff from vegetable field in Shanghai

采用径流池收集地表径流的方法,研究了上海郊区菜田不同施肥处理下地表径流导致的氮(N)、磷(P)养分流失规律。结果表明:2016年试验区降水量1 153.2 mm,总径流量391.1 mm,产流系数33.9%;减施N肥可降低N流失量;与对照相比,减N 25%的径流中N的流失量减少7.8%,减N 25%+有机无机配合使用径流中N的流失量减少13.4%—17.0%;减N 25%的缓释肥料N流失量减少12.8%;可溶性总N是径流中N流失的主要形态,其中NO_3-N占60%以上。施用P肥处理和径流中P的流失量无显著的差异性,径流中可溶性总P占径流中总P流失量的9.2%—12.2%,可溶性总P不是菜田土壤P流失的主要形态。

This paper studied the nitrogen and phosphorus losses via surface runoff from vegetable fields which were treated with different fertilization. The surface runoff was collected by establishing runoff pool. The results showed that in 2016,the precipitation was 1 153.2 mm,and the total runoff was 391.1 mm with a runoff coefficient amounting to 33.9%. Nitrogen losses could be reduced by deceasing nitrogenous fertilizer. Compared with the conventional fertilization, the use of fertilizer with a 25% decrease in nitrogen reduced the loss of it by7. 8%,and the use of fertilizer（with a 25% decrease in nitrogen） mixed with organic fertilizer reduced nitrogen loss by 13.4% —17.0%. Decreasing 25% of nitrogen in slow release fertilizer reduced nitrogen loss by 12. 8%.The dissoluble total nitrogen was the main form of nitrogen losses,in which the NO_3-N accounted for more than60%. There was no significant difference between phosphate fertilizer and phosphorus losses via runoff. The dissoluble total phosphorus of runoff accounted for 9.2% —12. 2%. The dissoluble phosphorus was not the main form of phosphorus losses in vegetable fields.