不同下垫面的土壤水分时间稳定性分析

Temporal stability of soil water under different soil coverages

时间稳定性是分析土壤水分时空变异性的重要因素,对土壤水分时间稳定性的分析可为区域土壤墒情的预测及水资源量的评估、以及水文模型的发展等提供依据。在2m2坡面尺度上,采用EC-5土壤水分传感器对四种土地利用类型(玉米、小麦、草地和裸地)在两种坡度(5°、15°)下浅层土壤水分的时间稳定性进行分析。基于相对差分法和Spearman秩相关系数分析法研究得出:不同植被类型、坡度下浅层土壤水分具有一定的时间稳定性,其不同深度的平均相对偏差(MRD)及其标准差均很小;不同坡度间的土壤水分时间稳定性差异不显著,而植被类型对土壤水分时间稳定性影响较大,相比而言,玉米和草地的土壤水分标准差相对较大,土壤水分时间稳定性明显低于小麦和裸地。

Temporal stability is an im portant factor to analyze the spatial and temporal variability of soil water, so its study can provide reference for the prediction of local soil moisture, evaluation of water resources, and development of hydrology model-ling. According to the real-time monitoring of soil moisture data collected by EC-5 sensors in the hillslope scale of 2 m2 , the tem-poral stability of shallow soil water under four different vegetation covers ( spring maize, wheat, ryegrass, and bare land) were analyzed using the relative difference method and Spearman rand correlation coeff icient method. Result s show ed that the tempo-ral stability occurs in t he shallow soil water under different vegetable types and slopes w ith small MRD and standard deviation values at various soil depths. There w as no signif icant difference for the t em poral stability of soil w ater under different slopes, but obvious difference under different veget ation types. The temporal stability of soil w ater for maize and ryegrass w as obviously low er t han that of w heat and bare land wit h smaller MRD and standard deviat ion values.