中文摘要：

为探明不同耕作措施对土壤团聚体稳定性和有机碳、全氮、全磷的影响,依托布设于黄土高原陇中雨养农田下豆麦双序列轮作系统的不同耕作措施长期定位试验,共设4种耕作措施：传统耕作（T）、免耕不覆盖（NT）、传统耕作＋秸秆还田（TS）、免耕＋秸秆覆盖（NTS）。结果表明：较传统耕作,免耕、传统耕作＋秸秆还田、免耕＋秸秆覆盖均可提升机械稳定性和水稳性大团聚体含量和稳定性,免耕＋秸秆覆盖效果最好;同时,〉0.25mm机械稳定性团聚体含量和团聚体稳定性随土层的增加而增加,水稳性团聚体含量和稳定性反之;免耕＋秸秆覆盖处理各粒级团聚体有机碳、全氮、全磷含量最高,传统耕作处理的最低。各处理团聚体中有机碳、全氮、全磷分布呈（〈0.25mm）〉（0.25～2mm）〉（2～5mm）〉（〉5mm）;全氮、全磷对水稳性团聚体含量和稳定性的提升有促进作用,而有机碳对机械稳定性和水稳性团聚体的含量和稳定性均有正激发效应。因此,长期秸秆还田不仅可以提升团聚体含量、稳定性,还可增加团聚体中养分含量,有利于该区农业可持续发展。

英文摘要：

For researching the effects of different tillage methods on soil aggregates and the content of SOC,TN and TP,conducted four types of tillage practices[T（conventional tillage with no straw）,NT（no-tillage with no straw mulching）,TS（conventional tillage with straw incorporation）,NTS（no-tillage with straw mulching）]in a phased rotation system with spring wheat and field pea at rain-fed field of the Loess Plateau in Central of Gansu province.The results showed that：Compared to T method,NT,TS and NTS methods could increase soil aggregates（mechanical stable aggregates and water stable aggregates）content and enhance the stability of aggregates,NTS was the best one.The content of〉0.25 mm macroaggregates and stability of mechanical stable aggregates increased with layer increasing,but in contrast to water stable aggregates.Compared to T method,NT,TS,NTS methods could improve the content of SOC,TN and TP of soil aggregates,NTS method was the highest.The distribution of nutrients in soil aggregates was（〈0.25mm）〉（0.25～2mm）〉（2～5mm）〉（〉5mm）.TN and TP could increase water stable aggregates content and enhance the stability of aggregates,but SOC could increase both mechanical stable aggregates and water stable aggregates content and enhanced the stability.In consequence,long-term straw returning couldimprove the content and stability of soil aggregates,and increase the nutrients in different size soil aggregates.