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

JI Baoyi; ZHAO Yali; GUO Haibin; MU Xinyuan; XUE Zhiwei; LI Chaohai

doi:10.15933/j.cnki.1004-3268.2015.03.016

Abstract：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.