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坡地土壤的降雨入渗性能对于水文过程、作物水分利用、灌溉管理、土壤侵蚀等方面的研究和实践非常重要。提出了测量坡地降雨条件下土壤入渗能力的径流/入渗方法。依据水量平衡原理,根据径流在坡面上的推进过程和有积水情况下积水深度随时间的变化过程推导得到了计算土壤入渗率(入渗能力)的数学模型。采用两种工况：雨强为20 mm/h、坡度0°和雨强60 mm/h、坡度20°,径流/入渗坡面长度比均为1∶1测量土壤入渗性能。还用双环入渗仪测量了入渗性能用于比照。用含水量10％的粘黄土进行室内试验,获取了相关的数据,并据此计算得到了两种工况的降雨入渗率曲线。结果表明,这种新方法可以很好地表征土壤入渗性能的概念,并能获得很高的初始入渗能力。分析了这种测量方法和计算模型的合理性。采用降雨量、入渗量对比方法,计算了上述两种工况的测量误差各为1．82％/1．39％和4．49％/3．529％(试验/模型),说明了该方法的测量精度。由于初始阶段供水能力的限制和土壤团聚体崩解的影响,双环入渗仪测量得到的瞬态和稳定入渗能力均远小于用该方法测量得到的结果。本方法可以克服以往降雨器和双环入渗仪方法的不足,可以用于测量坡地降雨/径流/土壤侵蚀等因素影响下的整个降雨入渗过程曲线,为相关研究提供了有力的工具。
Rainfall infiltration on sloping land is very important for the research and practice of hydrological processes, crop water use, irrigation management and soil erosion. A runoff / infiltration method for measuring soil infiltration capacity under raining conditions was proposed. According to the principle of water balance, a mathematic model for calculating soil infiltration rate (infiltration capacity) is deduced based on the process of runoff on the slope and the change of water depth with time. Two conditions were used: rainfall intensity of 20 mm / h, gradient of 0 ° and rainfall intensity of 60 mm / h, slope of 20 °, and runoff / infiltration slope length ratio of 1: 1. The infiltration performance was also measured with a double ring infiltration meter. Indoor tests were conducted on the loess with a moisture content of 10%. Relevant data were obtained and the rainfall infiltration rate curves of the two conditions were calculated. The results show that this new method can well characterize the concept of soil infiltration performance and obtain high initial infiltration capacity. The rationality of this measurement method and calculation model is analyzed. Using the method of comparison of rainfall and infiltration, the measurement errors of the above two conditions were calculated respectively as 1.82% / 1.39% and 4.49% / 3.529% (test / model) Method of measurement accuracy. Due to the limitation of initial water supply capacity and the disintegration of soil aggregates, the transient and steady infiltration capacity measured by the double ring infiltration device is far less than the results measured by this method. The method can overcome the deficiencies of the conventional rainfall detector and the double-ring infiltration device and can be used to measure the whole rainfall infiltration process curve under the influence of rainfall / runoff / soil erosion and other factors, and provides a powerful tool for the related research.