Geoelectric method applied in correlation between physical characteristics and electrical properties of the soil

Abstract

This paper presents the study of the relationship between electrical properties and physical characteristics of the soil. Measures of apparent electrical resistivity of the soil were made for different types of soil, varying moisture content gradually while maintaining a constant compaction, and then varying the compaction and relating it to a constant humidity. Development of a correlation surface is proposed in order to identify granulometry of the soil from moisture and compaction measurements. For the study of spatial variability, two areas were chosen to allow the change of moisture content and compaction in order to verify the measurement capacity of apparent electrical resistivity of the soil as methodology to identify change in soil dynamics. Results obtained show correlations among apparent electrical resistivity of the soil, moisture, soil compaction and clay content.

Root System Analysis and Influence of Moisture on Soil Electrical Properties

“…Both moisture and soil compaction are positively correlated with the apparent electrical conductivity of the soil σ a . However, σ a increases more with increasing moisture than with increasing compaction [3,18,19].…”

“…Figure 2 illustrates the method applied in Column 1 in A1, B1, C1 and D1. Horizontal mapping is obtained by tracing the other columns (Column 2, Column 3 and Column 4) [3,27]. The red circumference shown in Figure 2 indicates the measurement/stratification location.…”

“…The apparent conductivity of the soil σ a varies according to physico-chemical properties contained in soil under study. Mapping σ a is, therefore, an efficient tool in the investigation of soil behavior and spatial variability, allowing the identification of areas with similar properties and delimiting differentiated management units [2,3].…”

Application of the Horizontal Soil Stratification and Lateral Profiling Methods for 3D Mapping of the Soil Electrical Resistivity

“…Figure 1, adapted from Silva Filho et al [32], illustrates the lateral profiling method of soil investigation, in which the measurement process of apparent electrical resistivity ρ a is performed for the measuring spots given by the intersection between the Column 1 and the Row A, Row B, Row C and Row D. The Wenner's method is applied in Figure 1, where the current and voltage electrodes are represented by dots in the blue color while the dots in the red color are the measuring spots of ρ a . By performing the lateral profiling method along Column 1, Column 2, Column 3 and Column 4, the mapping of the apparent electrical resistivity over the surface of the soil being studied is obtained [33,34]. Soil mapping is used in many areas from civil engineering to precision agriculture.…”

“…In geoprospecting, the conductor is the soil, in which the electrical current circulates due to the presence of free salts in the soil solution (liquid phase) and also due to the exchangeable ions on the surface of the particles (solid phase). However, unlike the conductive wire, the electrical current in the ground may go through several paths, as illustrated in Figure 3, adapted from Silva Filho et al [36]. In sufficiently moist soils, the conduction of current occurs due mainly to the salt content in the water of the soil that occupies some pores (pores with water).…”