Abstract Spatially representative estimates of saturated hydraulic conductivity, Ks, are needed for simulating catchment scale surface runoff and infiltration. Classical methods for measuring Ks are time-consuming so sampling campaigns need to be designed economically. Important insights can be obtained by experiments directed to understand the controls of Ks in an agricultural setting and identify the minimum number of samples required for estimating representative plot scale Ks. In this study, a total of 131 double-ring infiltrometer measurements were made on 12 plots in a small Austrian catchment. A statistical analysis of Ks across the catchment suggests Ks to be only slightly influenced by physical and topographical soil characteristics while land use is the main control. The highest values of Ks were observed in arable fields, with a median of about 3 times and a coefficient of variation (CV) of about 75% of those in grassland areas. An uncertainty analysis aimed at determining the minimum number of Ks measurements necessary for estimating the geometric mean of Ks over a given area with a specified accuracy suggests that, beyond a specific and plot-size dependent number of measurements, the benefit of any extra measurement is small. The confidence interval of the geometric mean of Ks decreases with the number of measurements and increases with the size of the plot sampled. Applications of these findings for designing field campaigns are discussed.

中文翻译：

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农业环境中空间代表性样地尺度饱和导水率的估计

摘要 模拟集水区地表径流和入渗需要饱和导水率 Ks 的空间代表性估计值。测量 Ks 的经典方法非常耗时，因此需要经济地设计抽样活动。通过旨在了解农业环境中 Ks 的控制并确定估计代表性地块规模 Ks 所需的最小样本数量的实验，可以获得重要的见解。在这项研究中，在奥地利一个小集水区的 12 个地块上总共进行了 131 次双环渗透计测量。对整个流域内 Ks 的统计分析表明，Ks 仅受物理和地形土壤特征的轻微影响，而土地利用是主要控制因素。在可耕地中观察到 Ks 的最高值，中位数约为草原地区的 3 倍，变异系数（CV）约为 75%。不确定性分析旨在确定以指定精度估计给定区域内 Ks 几何平均值所需的最小 Ks 测量数表明，除了特定的和图大小相关的测量数外，任何额外测量的好处是小的。Ks 几何平均值的置信区间随着测量次数的增加而减小，并随着采样图的大小而增加。讨论了这些发现在设计实地活动中的应用。不确定性分析旨在确定以指定精度估计给定区域内 Ks 几何平均值所需的最小 Ks 测量数表明，除了特定的和图大小相关的测量数外，任何额外测量的好处是小的。Ks 几何平均值的置信区间随着测量次数的增加而减小，并随着采样图的大小而增加。讨论了这些发现在设计实地活动中的应用。不确定性分析旨在确定以指定精度估计给定区域内 Ks 几何平均值所需的最小 Ks 测量数表明，除了特定的和图大小相关的测量数外，任何额外测量的好处是小的。Ks 几何平均值的置信区间随着测量次数的增加而减小，并随着采样图的大小而增加。讨论了这些发现在设计实地活动中的应用。