A good understanding of the soil water content (SWC) distribution at the field scale is essential to improve the management of water, soil and crops. Recent studies proved that Electrical Resistivity Tomography (ERT) opens interesting perspectives in the determination of the SWC distribution in 3 dimensions (3-D). This study was conducted (i) to check and validate how ERT is able to monitor SWC distribution in a maize field during the late growing season; and (ii) to investigate how maize plants and rainfall affect the dynamics of SWC distribution. Time Domain Reflectometry (TDR) measurements were used to validate ERT-inverted SWC values. Evolution of water mass balance was also calculated to check whether ERT was capable of giving a reliable estimate of soil water stock evolution. It is observed that ERT was able to give the same average SWC as TDR (iR/isup2/sup = 0.98). In addition, ERT gives better estimates of the water stock than TDR thanks to its higher spatial resolution. The high resolution of ERT measurements also allows for the discrimination of SWC heterogeneities. The SWC distribution showed that alternation of maize rows and inter-rows was the main influencing factor of the SWC distribution. The drying patterns were linked to the root profiles, with drier zones under the maize rows. During short periods, with negligible rainfall, the SWC decrease took place mainly in the two upper soil horizons and in the inter-row area. In contrast, rainfall increased the SWC mostly under the maize rows and in the upper soil layer. Nevertheless, the total amount of rainfall during the growing season was not sufficient to modify the SWC patterns induced by the maize rows. During the experimental time, there was hardly any SWC redistribution from maize rows to inter-rows. Yet, lateral redistribution from inter-rows to maize rows induced by potential gradient generates SWC decrease in the inter-row area and in the deeper soil horizons.
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机译：对田间规模的土壤含水量（SWC）分布有充分的了解对于改善水，土壤和农作物的管理至关重要。最近的研究证明，电阻断层扫描（ERT）为确定3维（3-D）SWC分布开辟了有趣的观点。进行了这项研究（i）检查并验证ERT如何在生长季后期监测玉米田中SWC的分布; （ii）研究玉米植物和降雨如何影响SWC分布的动态。时域反射法（TDR）测量用于验证ERT转换后的SWC值。还计算了水质平衡的演变，以检查ERT是否能够对土壤水库的演变给出可靠的估计。可以看出，ERT能够提供与TDR相同的平均SWC（ R 2 = 0.98）。此外，由于其较高的空间分辨率，ERT可以比TDR更好地估算水存量。 ERT测量的高分辨率还可以区分SWC异质性。 SWC分布表明，玉米行和行间的交替是SWC分布的主要影响因素。干燥模式与根部轮廓相关联，玉米行下方有较干燥的区域。在短时期内，降雨可忽略不计，SWC的下降主要发生在两个较高的土壤层和行间区域。相反，降雨增加了SWC，主要是玉米行下和土壤上层。然而，生长期的降雨总量不足以改变玉米行诱导的SWC模式。在实验期间，几乎没有SWC从玉米行到行间的重新分配。然而，由势梯度引起的从行间到玉米行的横向再分布在行间区域和更深的土壤层中使SWC降低。
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