Effect of Different Tillage Methods on Soil Water Retention and Infiltration Capability of Rainfed Field

A six-year conservation tillage experiment with wheat-pea-wheat or pea-wheat-pea rotation was conducted in Dingxi City,Gansu Province.The soil moisture characteristic curves,soil bulk density,soil porosity,soil saturated hydraulic conductivity of 0-30 cm soil layer under different tillage methods were determined.Results indicate that soil water characteristic curves of 0-30 cm soil layer under the two rotation systems and different tillage methods are nearly overlapped when the soil water suction are 5 bar or 15 bar,respectively;the characteristic curves are different under 3 bar,1 bar and 0.5 bar soil water suction.The fitting result of the Gardner model suggest that,in the suction range from 0.5 bar to 15 bar,the relationships between soil water suction(S) and soil water content(θ) meet the power function of S=Aθ-B,and the correlation coefficient passes the extremely significant level.Both no-tillage with stubble mulch and no-tillage with plastic film mulch tillage methods improve the soil water-holding capacity than traditional tillage.The soil bulk density of 0-5 cm soil layer under both conventional tillage with straw incorporation and no-tillage with stubble mulch tillage methods are significantly lower than that under conventional tillage methods and the total soil porosity are increased.The method of no-tillage but with stubble mulch can significantly increase the soil saturation conductivity.