深耕和秸秆还田对不同质地土壤团聚体组成及稳定性的影响

Effects of Deep Tillage and Straw Returning on Different Texture Soils Aggregate Composition and Stability

在壤土和黏土中分别设置了常规耕作＋秸秆还田（ CT）、深耕＋秸秆还田（ DT）、深耕＋秸秆不还田（ DNT）3个处理，探讨了深耕和秸秆还田对土壤团聚体组成及稳定性的影响。结果表明，深耕和秸秆还田对土壤团聚体组成的影响受土壤质地和土层深度影响，两者均显著影响壤土和黏土0~10 cm土层粒径大于10 mm和粒径介于1~5 mm机械稳定性团聚体的含量，对10~20 cm土层无显著影响；两者对壤土中水稳定性团聚体组成的影响较黏土大，两者均增加壤土和黏土0~10 cm土层粒径介于3~5 mm水稳定性团聚体的含量，降低粒径小于0.25 mm水稳定性团聚体的含量，对10~20 cm土层无显著影响。总体上，深耕能增加壤土耕层下部和黏土机械稳定性和水稳定性团聚体平均质量直径，秸秆还田能增加壤土和黏土机械稳定性和水稳定性团聚体平均质量直径，进而增加土壤团聚体的稳定性。

To study the effects of deep tillage and straw retained on aggregate composition and stability, three treatments,including conventional tillage with straw returning（ CT） ,deep tillage with straw returning （ DT） and deep tillage without straw retaining（ DNT） ,were carried out in clay and loam soil. The results showed that soil aggregate composition was influenced by deep tillage and straw returning which were af-fected by soil texture and soil layer depth. Deep tillage and straw returning significantly affect the content of mechanical stable aggregates whose diameter was greater than 10 mm and between 1 mm and 5 mm in 0—10 cm soil layer in clay soil and loam soil,however,both treatments had no significant influence on the content of mechanical stable aggregates in 10—20 cm soil layer. Deep tillage and straw returning had more influence on water stable aggregates composition in loam than that in clay soil. Deep tillage and straw returning could increase the content of water stable aggregates whose diameter was between 3 and 5 mm,decrease the content of water stable aggregates whose diameter was smaller than 0. 25 mm in 0—10 cm soil layer in clay soil and loam soil;however,both treatments had no significant influence on the content of water stable aggregates in 10—20 cm soil layer. Overall, deep tillage could increase the mean weight diameter of mechanical stable aggregates and water stable aggregates in the deep layer of loam soil and clay soil, while straw returning could increase the mean weight diameter of mechanical sta-ble aggregates and water stable aggregates in loam and clay soil, thereby the stability of soil aggregates could be improved by deep tillage and straw returning.