Soil Water Evaporation: First Stage Drying as Influenced by Surface Residue and Evaporation Potential

Evaporation with time was measured from wetted columns of fine sandy loam treated with seven rates of surface residue in six runs with different evaporation potentials. First stage (constant rate) evaporation rate decreased with either increasing residue rates or decreasing evaporation potentials. Total water loss during first stage drying decreased as the rate of first stage evaporation increased. Conversely, water loss for the first 25 days following first stage drying increased as first stage evaporation rate increased. A linear relationship was established by log‐log plotting the duration of first stage drying versus first stage evaporation rate.