A framework for efficient soil architecture mapping using ground-penetrating radar

Ground-penetrating radar (GPR) is more and more prevailing in soil survey as a geophysical method due to its non-invasive and high efficiency. For subsurface soil architecture mapping, its quality relies not upon only the accuracy of GPR evaluation itself but also on often overlooked survey strategy. This study focuses on the latter one and proposed a new survey strategy to promote the commonly-used survey strategy that subjectively employing multiple parallel two-dimensional GPR acquisition lines. A preliminary survey roughly capturing the spatial variability of soil architecture is suggested to provide two key parameters, the spacing and the direction of the parallel survey lines, for the subsequent commonly-used survey design. Thus, the final survey can not only take advantage of the dense space sampling rate of GPR itself along the survey direction with the highest variability of the subsurface soil architecture, but also well controls the mapping quality and efficiency. Field experiments and numerical tests demonstrate that the new survey strategy could effectively reduce mapping uncertainties originating from unmatching sampling rate and interpolation algorithm selection. Besides, a suitable mapping quality and efficiency can be guaranteed but preventing unnecessary too dense sampling rate, namely low mapping efficiency. This indicates the proposed strategy would be useful for relevant soil surveys using geophysical methods.