冻融期膜下滴灌棉田水盐时空动态特征研究

利用经典统计学方法,分析了冻融期北疆地区常年滴灌棉田土壤水分、盐分时空动态变化特征。结果表明:在整个冻融期,裸地处理的含水率随时间变异性较覆膜处理大;在最大冻土深度(90 cm土层)附近,土壤盐分随时间变异剧烈,属于强变异性,变异系数高达1.1左右;在深度方向上,土壤含水率呈中等变异性,而土壤含盐率则呈强变异性;在整个冻融过程中,冻结带中盐分随时间和深度的变化幅度较小;冻融期土壤存在稳定盐分累积层,该累积层的深度在120 cm土层,且不受地表覆盖的干扰。覆膜对120 cm土层以下土壤盐分运移影响较小。

Study on spatial and temporal variabilities of soil moisture and salt during freeze-thawing period in cotton field with drip irrigation

The coefficient of variation of the classical statistics was used to analyze the spatial-temporal dynamic variability characteristics of soil moisture and salinity content in the cotton field of Shihezi district in Xinjiang Uygur Au -tonomous Region ,China .The results indicated that during the whole freezing and thawing period ,for all soil layers ,the coefficient of variation in soil moisture with bare land treatment (L) was higher than that with the mulching treatment (M) .At the maximal depth of frozen soil layer around 90 cm ,soil salinity exhibited strong variability with a coefficient of variation up to 1 .1 .Soil content demonstrated moderate variability in the vertical profile ,and salinity content present-ed strong variability .During the whole freezing and thawing period ,changes of salinity in frozen zone varied little with both bare land and mulching treatment ,the 120 cm soil layer was stable for salinity accumulation ,indicating that mulching had no significant effect on the layer beneath 120 cm .The results in this paper could be considered as a theo-retical basis for prevention of the secondary salinization in soil ,which would be conducive to the sustainable and safety use of the local farmland .