秸秆还田对农田周年地表径流氮、磷、钾流失的影响

2009—2010年在大田试验条件下,小麦季和水稻季分别以扬麦16和运2645为供试材料,两季均设置常规处理（A）、秸秆还田（B）、秸秆还田减肥（C）、肥料运筹（D）和少免耕（E）5个处理组合。研究不同处理对稻麦两熟制农田周年地表径流氮、磷、钾流失的影响。结果表明：（1）稻麦两季农田共发生地表径流20次,总地表径流水量为6.4×106kg·hm-2;（2）秸秆还田能够显著降低稻麦两熟制农田周年地表径流氮、磷、钾流失量,不同处理周年地表径流总氮和钾的流失量由高到低均依次为少免耕、常规处理、肥料运筹、秸秆还田和秸秆还田减肥,不同处理周年地表径流总磷流失量由高到低依次为少免耕、肥料运筹、常规处理、秸秆还田和秸秆还田减肥,秸秆还田使稻麦两熟制农田地表径流氮、磷、钾流失量分别比常规处理下降7.7%、8.0%、6.8%;（3）水稻季农田地表径流总氮、总磷、钾流失量分别占稻麦两熟制周年总氮、总磷、钾流失量的61.5%、44.0%、73.3%;（4）秸秆还田使稻麦两熟制农田周年地表径流氮、磷、钾流失率显著降低;（5）秸秆还田使水稻成熟期土壤速效养分质量分数显著提高;（6）秸秆还田使稻麦两熟制农田周年作物产量比常规处理略有增加。

Effects of straw-returning on annual overland runoff NPK loss in farmland

A field experiment was conducted to investigate the effects of straw return on annual total nitrogen（N）,total phosphorus（P）,kalium（K） loss quantity with overland runoff in wheat-rice double cropping system in 2009-2010.The wheat cultivar of Yangmai 16 and rice cultivar of Yun 2645 was field-grown.Five treatments such as conventional measurement（A）,wheat straw return（B）,wheat straw return with reducing fertilizer（C）,fertilizer application（D）,rotational tillage system（E） were conducted.The results showed that：（1） Total overland runoff of farmland was 6.4 × 106 kg.hm-2in this wheat-rice season,with twenty times.（2） Straw return significantly reduced annual overland runoff NPK loss.In different treatments condition,both the order of total N and K loss were E〉 A〉 D〉 B〉 C,and the order of total P loss was D〉 E〉 A〉 B〉 C.Compared with conventional measurement（A）,straw return decreased overland runoff N,P,K loss averaging 7.7%,8.0%,6.8%.（3） The proportion of rice season overland runoff NPK loss was 61.5%,44.0%,73.3% to the total NPK loss over the wheat-rice season.（4） Straw return reduced annual overland runoff NPK loss rate.（5） Soil available nutrient content was increased under straw return at rice maturity stage.（6） Straw return increased annual crop yield in wheat-rice double cropping system a little.