自然降雨条件下秸秆还田对巢湖流域旱地氮磷流失的影响

本文通过野外径流小区观测试验,开展了自然降雨条件下秸秆覆盖对巢湖流域旱地地表径流、泥沙和氮磷流失影响的研究。试验结果表明,秸秆覆盖能有效减少地表径流量、侵蚀产沙量以及因地表径流引起的土壤氮磷流失。在整个玉米生长期间,秸秆覆盖小区的总产流量与产沙量比传统耕作小区分别减少30.47%和22.88%,表现出显著的水土保持作用。与传统耕作小区相比,秸秆覆盖小区随地表径流迁移的氮、磷流失总量分别降低27.42%和32.29%,但秸秆覆盖对径流中氮磷浓度的影响却不明显。溶解态氮是氮素流失的主要形态,颗粒态磷是磷素流失的主要形态。秸秆覆盖可以作为源头控制农业面源污染的较好措施之一加以推广。

Effect of straw mulch on nitrogen and phosphorus loss from farmlands in Chaohu Lake Region under natural rainfall condition

A field experiment was conducted in the Chaohu Lake Region to analyze the characteristics of nitrogen and phosphorus loss via runoff from farmlands under natural rainfall conditions. Two treatments of conventional tillage (CK) and straw mulch (TS) were set up in 3 replications. The results show that straw mulch effectively reduces surface runoff, and sediment and nutrient loss from farmlands under natural rainfall conditions. During maize growth period, the amounts of runoff and sediments in TS decrease by 30.47% and 22.88%, respectively compared with CK. This implies that straw mulch has a significant effect on soil and water conservation. Straw mulch respectively reduces total nitrogen (TN) and total phosphorus (TP) loss via surface runoff by 27.42% and 32.29%. However, straw mulch has an insignificant influence on TN and TP concentration of runoff. While dissolved nitrogen (DN) is predominant form of nitrogen loss, particle phosphorous (PP) is the main form of phosphorus loss. In order to control agriculture non-point source pollution, straw mulch should be strongly promoted in the study area.