Geophysical surveys are now commonly used in agriculture for mapping applications. High‐throughput collection of geophysical properties such as electrical conductivity (inverse of resistivity) can be used as a proxy for soil properties of interest (e.g., moisture, texture, salinity). Most applications only rely on a single geophysical survey at a given time. However, time‐lapse geophysical surveys have greater capabilities to characterize the dynamics of the system, which is the focus of this work. Assessing the impact of agricultural practices through the growth season can reveal important information for the crop production. In this work, we demonstrate the use of time‐lapse electrical resistivity tomography (ERT) and electromagnetic induction (EMI) surveys through a series of three case studies illustrating common agricultural practices (cover crops, compaction with irrigation, and tillage with N fertilization). In the first case study, time‐lapse EMI reveals the initial effect of cover crops on soil drying and the absence of effect on the subsequent main crop. In the second case study, compaction leading to a shallower drying depth for potatoes (Solanum tuberosum L.) was imaged by time‐lapse ERT. In the third case study, larger changes in electrical conductivity over time were observed in conventional tillage compared with direct drill using time‐lapse EMI. In addition, different N application rates had a significant effect on the yield and leaf area index but only ephemeral effects on the dynamics of electrical conductivity, mainly after the first application. Overall, time‐lapse geophysical surveys show great potential for monitoring the impact of different agricultural practices that can influence crop yield.

中文翻译：

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农业实践对土壤水分动力学的时空地球物理评估

现在，地球物理勘测在农业中通常用于制图应用。高通量的地球物理特性（例如电导率（电阻率的倒数））可以用作感兴趣的土壤特性（例如水分，质地，盐分）的替代。大多数应用程序在给定时间仅依赖一次地球物理调查。但是，延时地球物理勘测具有表征系统动力学的强大功能，这是这项工作的重点。在整个生长季节评估农业做法的影响可以揭示有关作物生产的重要信息。在这项工作中 我们通过一系列三个案例研究证明了时延电阻层析成像（ERT）和电磁感应（EMI）测量的使用，这些案例研究说明了常见的农业实践（覆盖作物，灌溉压实和氮肥耕作）。在第一个案例研究中，延时EMI揭示了覆盖作物对土壤干燥的最初影响，而对随后的主要作物没有影响。在第二个案例研究中，压实导致马铃薯的干燥深度变浅（马铃薯通过延时ERT成像。在第三个案例研究中，与使用延时EMI的直接钻探相比，传统耕作中的电导率随时间变化更大。另外，主要在第一次施用后，不同的氮肥施用量对产量和叶面积指数有显着影响，而对电导率的动态影响仅短暂。总体而言，延时地球物理调查显示了监测可能影响作物产量的不同农业实践的影响的巨大潜力。