Abstract
Soil subsurface moisture content, especially in the root zone, is important for evaluation the influence of soil moisture to agricultural crops. Conservative monitoring by point-measurement methods is time-consuming and expensive. In this paper we represent an active remote-sensing tool for subsurface spatial imaging and analysis of electromagnetic physical properties, mostly water content, by ground-penetrating radar (GPR) reflection. Combined with laboratory methods, this technique enables real-time and highly accurate evaluations of soils' physical qualities in the field. To calculate subsurface moisture content, a model based on the soil texture, porosity, saturation, organic matter and effective electrical conductivity is required. We developed an innovative method that make it possible measures spatial subsurface moisture content up to a depth of 1.5 m in agricultural soils and applied it to two different unsaturated soil types from agricultural fields in Israel: loess soil type (Calcic haploxeralf), common in rural areas of southern Israel with about 30% clay, 30% silt and 40% sand, and hamra soil type (Typic rhodoxeralf), common in rural areas of central Israel with about 10% clay, 5% silt and 85% sand. Combined field and laboratory measurements and model development gave efficient determinations of spatial moisture content in these fields. The environmentally friendly GPR system enabled non-destructive testing. The developed method for measuring moisture content in the laboratory enabled highly accurate interpretation and physical computing. Spatial soil moisture content to 1.5 m depth was determined with 1–5% accuracy, making our method useful for the design of irrigation plans for different interfaces.
Highlights
Soil subsurface moisture content down to the root zone is significant for the development of agricultural crops, affecting their quality and quantity; unbalanced moisture content can influence their quality and damage them
The use of active remote sensing has shown great advances: e.g., ground penetrating radar (GPR) subsurface imaging and frequency domain electromagnetic (FDEM) to measure the subsurface electrical conductivity and magnetic susceptibility combine with passive tools (Spectrometer – ASD)
GPR measurement of the subsurface spatial moisture content was based on a method originally developed for sand dunes, where moisture content of an unsaturated medium was determined at a resolution of a few percent (Basson et al, 1992)
Summary
Soil subsurface moisture content down to the root zone is significant for the development of agricultural crops, affecting their quality and quantity; unbalanced moisture content can influence their quality and damage them. Soil moisture and salinity are currently monitored by conservative local sampling and testing methods in the field and in the laboratory, using neutron gauges, various types of tensiometers and time-domain reflectometry (Ben-Dor et al, 2009, Goldshleger et al, 2012). This study integrates active remote sensing by GPR with laboratory measurements verification and field tests to determine soil moisture content. GPR measurement of the subsurface spatial moisture content was based on a method originally developed for sand dunes, where moisture content of an unsaturated medium was determined at a resolution of a few percent (Basson et al, 1992)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
