中文摘要：

为阐明早稻与晚稻生长期土壤水稳性团聚体分布及其稳定性对秸秆还田的响应,以福州平原红壤水稻田为研究对象,对秸秆还田后早稻田和晚稻田土壤水稳性团聚体分布特征及其稳定性,包括粒径〉0.25 mm团聚体的百分含量R0.25、平均质量直径（MWD）、平均几何直径（GMD）和分型维数（D）进行测定与分析.研究结果表明,秸秆还田和对照样地,0～40 cm土层中早稻与晚稻生长期土壤均表现为水稳性团聚体组成以微团聚体（〈0.25 mm粒级团聚体）为主,团聚体粒级越大,含量越少;秸秆还田对0～40 cm土层中早稻田土壤水稳性大团聚体和微团聚体总含量的影响均不显著,但秸秆还田显著增加了晚稻田土壤水稳性大团聚体（粒径〉0.25 mm）含量（p〈0.05）,并显著减少了土壤水稳性微团聚体含量（p〈0.05）;秸秆还田对早稻田土壤水稳性团聚体MWD、GMD和D值影响均不显著,但显著增加了晚稻田土壤水稳性团聚体MWD和GMD值,显著降低了土壤水稳性团聚体D值（p〈0.05）;秸秆还田对早稻田土壤水稳性团聚体稳定性影响不显著,但显著增加了晚稻田土壤水稳性团聚体稳定性（p〈0.05）.

英文摘要：

In order to clarify the response of the soil water-stable aggregate distribution and stability to the straw returning in the early and late paddy field, the paddy field of Fuzhou plain was chosen as the study object, and the soil water-stable aggregate distribution and stability, including the percentage of aggregates particle size bigger than 0.25 mm R0.25, mean weight diameter （MWD）, geometric mean diameter（GMD） and fractal dimension（D） were determined and analyzed in the early and late paddy field after straw retuning. The results showed：Micro-aggregate（ 〈0.25 mm aggregate） was the main composition of water-stable aggregate for the 0 ～ 40 cm soil in the early and late paddy field, and the aggregate concentration decreased as the grain size increment. Water-stable macro-aggregate and micro-aggregate concentration were not significantly influenced by straw returning in the early paddy field. However, water-stable macro-aggregate concentration significantly increased （p〈0.05） and micro-aggregate concentration significantly decreased （p〈0.05） for the 0～40 cm soils in the late paddy field after straw returning.MWD, GMD and D did not significantly change in early paddy field after straw returning. However, MWD and GMD significantly increased （p〈0.05） and D significantly decreased（p〈0.05） for the soils in the late paddy field after straw returning. Straw retuning did not significantly influence soil water-stable aggregate stability in the early paddy, but significantly promoted soil water-stable aggregate stability（p〈O.05） in the late paddy.