Multi-channel GPR to assess the influence of shallow structural heterogeneity on spatio-temporal variations of near-surface soil water content

Abstract

Structural heterogeneity in the vadose zone can significantly influence the dynamics of surface and subsurface distribution of water. It is one important reason for the patterned crops in fields. GPR as a non-invasive tool facilitates the quick investigation of subsurface structures and associated soil water contents of agricultural lands. A field study site with patterned wheat was surveyed at 1.5 m line spacing using 400 MHz multichannel GPR. Through time-lapse snapshots of the ground with multi-channel GPR and surface TDR measurements after a heavy rainfall event, we (i) determine the subsurface 3D architecture, (ii) simultaneously measure the depth-averaged soil water content, and (iii) assess the influence of the structural heterogeneity on the surface and subsurface soil water redistribution. Through investigating the field-scale soil water dynamics, we discuss the relationship between soil architecture and the patterned crops in hydrological perspective. Results demonstrate that multi-channel GPR allows the collection of valuable information about the subsurface structure and soil water dynamics at site-specific land.