Temporal and operation-induced instability of apparent soil electrical conductivity measurements

Abstract

Measuring apparent soil electrical conductivity (ECa), using galvanic contact resistivity (GCR) and electromagnetic induction (EMI) techniques, is frequently conducted to reveal spatial soil heterogeneity. Various studies have demonstrated the possibilities for significant changes in the measured quantities over time with relatively stable spatial structure representations. The objective of this study was to quantify the effects of temporal drift and operational noise for three popular ECa mapping instruments. They were placed in stationary positions approximately 8 m apart in an area with relatively low ECa. Temporal drift was assessed using a series of 4.5-h data logs recorded under different weather conditions (from extremely hot to near freezing temperatures). The two EMI instruments were also used to quantify the effect of minor changes in the height, pitch and roll of the sensor with respect to the ground. These operational noise tests were replicated over several days. Our results reveal the GCR measurements of ECa, along with perpendicular coplanar EMI measurements, have shown relatively strong stability over time. Each operational effect introduced measurement uncertainties comparable to the impact of a change in temperature and soil water content.

Temporal Stability of Management Zone Patterns: Case Study with Contact and Non-Contact Soil Electrical Conductivity Sensors in Dryland Pastures

“…By using an EMI device four times (Dualem 1S), Serrano et al [ 2 ] found temporally stable spatial EC a patterns in a Mediterranean pasture over a period of 7 years despite changing environmental and management conditions. Various studies have demonstrated the possibilities for significant changes in the measured EC a over time, nevertheless, with relatively stable spatial structure representations [ 7 ].…”

“…However, relatively little is known about the degree of within-field spatial variation in soils used for livestock production, which leads to the common practice of uniform field 2 of 18 management [2]. Site-specific crop management aims to increase profitability and reduce the negative environmental impact of modern farming [7].…”

Exploring the Synergy between Humic Acid Substances, Dehydrogenase Activity and Soil Fertility

“…Soil EC is an important physicochemical parameter in the cultivation of agricultural plants because it reflects the content of minerals and salts dissolved in the soil, which in turn determines the ability of plants to absorb water. According to Mat Su and Adamchuk [40], the EC of soils is closely related to their salinity, texture and the CEC parameter. Optimal EC values for soil depend on the type of soil and crops grown, but are usually in the range of 500 to 3000 µS/cm.…”