Abstract:
Precise adjustments of farm management activities, such as irrigation and soil treatment
according to site-specific conditions, are crucial. With advances in smart agriculture and sensors, it is
possible to reduce the cost of water and soil treatment inputs but still realize optimal yields and highprofit returns. However, achieving precise application requirements cannot be efficiently practiced
with spatially disjointed information. This study assessed the potential of using an electromagnetic
induction device (EM38-MK) to cover this gap. An EM38-MK was used to measure soil apparent
electrical conductivity (ECa) as a covariate to determine soil salinity status and soil water content
θ post irrigation at four depth layers (Hz: 0–0.25 m; Hz: 0–0.75 m; Vz: 0.50–1 m). The inverse
distance weighting method was used to generate the spatial distribution thematic layers of electrical
conductivity. The statistical measures showed an R2 = 0.87; r > 0.7 and p ≤ 0.05 on correlation of ECa
and SWC. Based on the South African salinity class of soils, the area was not saline ECa < 200 mS/m.
The EM38-MK can be used to estimate soil salinity and SWC variability using ECa as a proxy, allowing
precise estimations with depths and in space. These findings provide key information that can aid in
irrigation scheduling and soil management.
