There is a gap between lab experiments where resistivity–soil moisture relations are generally very good and field studies in complex environmental settings where relations are always less good and complicated by many factors. An experiment was designed where environmental settings are more controlled, the best outside laboratory, to assess the transferability from lab to outdoor. A field experiment was carried out to evaluate the use of electric resistivity tomography (ERT) for monitoring soil moisture dynamics over a period of 67 days. A homogeneous site in the central part of The Netherlands was selected consisting of grass pasture on an aeolian sand soil profile. ERT values were correlated to gravimetric soil moisture samples for five depths at three different dates. Correlations ranged from 0.43 to 0.73 and were best for a soil depth of 90 cm. Resistivity patterns over time (time-lapse ERT) were analyzed and related to rainfall events where rainfall infiltration patterns could be identified. Duplicate ERT measurements showed that the noise level of the instrument and measurements is low and generally below 3% for the soil profile below the mixed layer but above the groundwater. Although the majority of the measured resistivity patterns could be well explained, some artefacts and dynamics were more difficult to clarify, even so in this homogeneous field situation. The presence of an oak tree with its root structure and a ditch with surface water with higher conductivity may have an impact on the resistivity pattern in the soil profile and over time. We conclude that ERT allows for detailed spatial measurement of local soil moisture dynamics resulting from precipitation although field experiments do not yield accuracies similar to laboratory experiments. ERT approaches are suitable for detailed spatial analyses where probe or sample-based methods are limited in reach or repeatability.

中文翻译：

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在均匀田间条件下使用电阻层析成像监测土壤水分动力学。

在实验室实验中，电阻率与土壤水分的关系通常非常好，而在复杂环境中的实地研究却总是差强人意，并且受许多因素的影响，两者之间存在差距。设计了一个可以更好地控制环境设置（最好是外部实验室）的实验，以评估从实验室到室外的可移植性。进行了现场实验，以评估电阻层析成像（ERT）在67天的时间内监测土壤水分动态的作用。选择了荷兰中部的一个均匀地点，包括风沙性土壤剖面上的草场。ERT值与三个不同日期的五个深度的重量土壤水分样品相关。相关性在0.43到0.73之间，最适合90 cm的土壤深度。分析了随时间变化的电阻率模式（延时ERT），并与降雨事件相关，可以确定降雨入渗模式。重复进行的ERT测量表明，仪器和测量的噪声水平较低，对于混合层以下但在地下水之上的土壤剖面，噪声水平通常低于3％。尽管可以很好地解释大多数测得的电阻率模式，但即使在这种均匀的现场情况下，也很难澄清一些伪像和动力学。橡树的根部结构和带有较高电导率的地表水的沟渠的存在可能会影响土壤剖面和时间的电阻率模式。我们得出的结论是，尽管田间试验不能产生类似于实验室试验的准确度，但ERT可以对由降水引起的局部土壤水分动力学进行详细的空间测量。ERT方法适用于详细的空间分析，在这些分析中，基于探针或样品的方法的范围或可重复性受到限制。