The relationship between apparent soil electrical conductivity and particle size distribution of light-textured soils

Abstract

Measurement of apparent soil electrical conductivity (ECa) is considered to be one of the most promising and widely used methods of research in precision agriculture. Several authors have shown strong correlations between ECa and the clay content in soil. In case of heavier soils high in clay content, ECa sensors are mainly used to set soil sampling locations. The relationship between soil ECa and particle-size distribution of light-textured soils was poorly investigated. The aim of this study was to determine the soil texture impact on ECa in light-textured soils. The ECa has been investigated at two soil layers: shallow (0-30 cm measurement depth) and deep (0-90 cm measurement depth). Firstly, research was undertaken to validate optimal technological parameters of the unit Veris 3150 MSP, that have been further used to find out relationships between sizes of individual soil particles and ECa. Using the device Mastersizer Hydro 2000MU, investigation of soil particle size distribution has been accomplished showing that increase in clay (< 2 μm) and silt (2-50 μm) contents in soil causes its electrical conductivity to increase. Particles of highly fine silt (50-100 μm) were found to have no effect on ECa. Increasing proportion of even larger particles of silt (> 100 μm) contained in soil results in decreased ECa.