不同耕作措施对旱地农田土壤水分保持及入渗性能的影响研究

 通过定西市安定区的中长期保护性耕作试验,对连续6 a不同耕作措施后0～30 cm土层土壤的水分特征曲线、土壤容重、孔隙度、土壤饱和导水率进行了测定。结果表明,两种轮作序列下,不同耕作措施0～30 cm土壤水分特征曲线在水吸力为5 bar和15 bar时几近重合,在3 bar、1 bar和0.5 bar时出现差异;Gardner模型拟合的结果显示在0.5~15 bar吸力范围内,其水吸力与含水量之间的关系符合幂函数式S=Aθ-B这一关系式,且相关系数均达极显著水平。免耕秸秆覆盖和免耕地膜覆盖的两个处理较传统耕作改善了土壤持水性能;传统耕作秸秆还田和免耕秸秆覆盖处理较传统耕作处理显著降低了0～5 cm土层容重,增加了土壤总孔度;免耕秸秆覆盖可以显著提高土壤饱和导水率。

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.