Step-Frequency Ground Penetrating Radar for Agricultural Soil Morphology Characterisation

Abstract

Soil morphology plays a fundamental role in the vertical and lateral movements of solutes and water transport, providing knowledge regarding spatial distribution of its textural properties and subsurface dynamics. In this framework, the measured values of electrical conductivity are able to reveal the heterogeneity of soil that is present in a particular agricultural field and they are affected by more than one important physical characteristic: soil texture, organic matter, moisture content, and the depth of the clay pan. In the microwave region, these dynamics are known to exhibit a frequency dependent behaviour. This study explores the application of a Step Frequency Continuous Wave Ground Penetrating Radar (SFCW GPR) to shed light on the practical impact that these dependencies have on the imaging results, not only regarding the electrical characterisation of the subsurface morphology, but also in its correct interpretation. This information is of notable importance for determining water-use efficiency and planning precision-agriculture programs. The results clearly show visible and significant fluctuations of the amplitude levels, depending on the considered central frequency, demonstrating that the frequency dependence of electromagnetic properties of heterogeneous soil are significant and cannot be ignored if the aim is to properly define the subsurface attributes. The measurements also suggest that correlating the delineated variations might help in the identification of extended features and the classification of areas that possess similar properties in order to increase the confidence in monitoring soil resources.

A Bibliometric Network Analysis of Recent Publications on Digital Agriculture to Depict Strategic Themes and Evolution Structure

“…Therefore, this cluster is linked with increasing efficiency and crop productivity. The analysis of spatial variability is, indeed, a key factor for increasing food production [ 112 ] and farmers’ economic revenues [ 113 ]. The mapping of soil heterogeneity has contributed to enhance soil data and to make geostatistics become a fundamental tool in agricultural management [ 114 ].…”

From Its Core to the Niche: Insights from GPR Applications

“…Information on water content, porosity, and soil moisture is also critical within the domain of agriculture and precision farming, where such features have an immediate impact on crop yield, irrigation management, and the environmental effects of farming activities [190][191][192][193]. The use of GPR in the agricultural discipline, therefore, has been extensively researched with aims spanning from estimating the limited soil depth restricted by bedrock, hardpan, or water table; determining the root biomass; and mapping local soil attributes affecting agricultural performance, to the characterization of movements of agrochemicals and vadose zones, local soil texture, and layering [194,195].…”

Agriculture 4.0 and Smart Sensors. The Scientific Evolution of Digital Agriculture: Challenges and Opportunities

“…The information obtained through 'MANAGEMENT ZONES', for instance, contributes for monitoring soil properties at agricultural sites. This is a key factor for increase food production [100] and farmers' economic returns [101]. The mapping of soil heterogeneity have been contributing for the use of 'MANAGEMENT ZONES' and 'GEOSTATISTICS' as tools in agricultural management [102].…”