Development of a Soil Water Sensor using Gypsum Block and a Multimeter

Abstract

Gypsum block soil water sensors were cast and the calibration for a sandy loam alfisol was carried out using an ordinary multimeter (VOM Multimeter, Model MT 120). A temperature correction chart was also developed for the sensors. The observed stable resistances at corresponding water contents were considerably higher than the resistances that have been reported elsewhere for soils in identical textural class using a special type of meter. The approach adopted in this study however yielded consistent results as demonstrated by the similarity of the shape of the calibration curve to that of the water retention curve of the experimental soil. This suggests that the approach may be useful in at least qualitative monitoring of soil water status

JARD Vol. 2 2003: pp. 87-92