秸秆还田对稻田磷素径流损失的影响

[目的]通过研究秸秆还田对稻田磷素径流损失及其对环境的影响,探索减少径流损失、提高巢湖水质的有效耕作措施。[方法]以巢湖流域稻田为研究对象,采用野外定位观测试验结合室内分析的研究方法。[结果]径流液TP含量为0.087～0.495 mg/L。PP是稻田P素随径流迁移的主要形态,约占TP的40%～70%。秸秆还田能够降低水稻生育前期径流液TP、DP和PP的浓度,减少P素径流流失风险。在当地常规耕作条件下(CT),2008和2009年稻季P素径流流失负荷分别为222.76和297.17 g/hm2,P肥表观流失率分别为0.68%和0.91%,平均为0.79%。与CT相比,秸秆还田处理(CTS)P素径流流失负荷分别减少了5.13%和18.98%,平均为12.05%。[结论]秸秆还田作为源头控制稻田磷素流失的较好措施可以在巢湖流域使用。

Effects of Straw Return on Phosphorous Losses via Surface Runoff from Paddy Field

[ Objective ] The characteristics of phosphorous runoff losses from paddy field were studied to explore the ways of reducing runoff losses and improve the water quality of Chaohu Lake by effective tillage. [ Method] Based on field-orientation observation and laboratory analy- sis, field experiments were carried out in paddy field in Chaohu Lake region for two consecutive years. [ Result] The results of rice seasons in 2008 and 2009 showed that, the total phosphorous （TP） concentration in runoff was 0. 087 -O. 495 rag/L, in which the particulate phosphor- ous （PP） , as the predominant form of P loss by runoff, accounted for 40% -70%. Straw return could effectively decrease the higher phos- phorous concentration in runoff water during the earlier stage, and thus lower the risk of P loss via runoff TP loss loads of CT during the rice seasons were 222.76 and 297.17 g,/hm2 , accounting for O, 68% and 0.91% of the applied P fertilizer respectively, with a mean of 0.79%. Compared with CT, TP loss loads of conventional tillage with straw returning （CTS） declined by 5.13% and 18.98% ,respectively , with a mean of 12.05%. [ Conclusion ] Straw return could be an effective measure for the source control of the phosphorous loss via runoff from paddy field in Chaohu Lake region.