Draft Reduction on Tillage Tools by Electro-osmotic Lubrication (Part 1)

Electrical Conductivity of Unsaturated Soil

Abstract

This paper is the first report of three series researches related to the application of electro-osmosis to reduce the draft of tillage tools. The present paper describes the characteristics of electrical conductivity of unsaturated soils under the influence of normal pressure, soil bulk density, soil moisture and applied voltage. Measurement of electrical conductivity was done by measuring electrical resistance of soil blocks at constant voltage. Sandy loam and silt loam soils were used in this experiment. Unsaturated test soils showed constant values for electrical conductivity (EC) when the electrical voltage and current applied were changed. Electrical conductivity of unsaturated soil had linear relationship with pressure acting on electrode. Soil moisture content had a quadratic relationship with electrical conductivity on silt loam soil, but it had a linear relationship with electrical conductivity on sandy loam soil. At low moisture, the effect of bulk density was in quadratic relationship, and became linear at moisture content higher than 31.5%db.