SIMPLE WATER-BALANCE MODELS FOR SIMULATING MOISTURE, SALINITY AND SODICITY PROFILES IN SOILS UNDER WHEAT

Experiments were conducted in wheat planted in microplots at Hisar and Sirsa in Haryana state, India, to observe and simulate the depth distribution of moisture content, electrical conductivity in 1:2 soil-water extract (EC 1:2), and exchangeable sodium percentage (ESP) of soils after irrigation with water of high electrical conductivity (12–19 dS/m) and sodium adsorption ratio (20–80 (mmol/l)0.5). The three simulation models used differed in the procedure of estimation of evapotranspiration (models I and II, Reddy 1983; model III, Arora et al. 1987). In general, the means of the experimental moisture content profiles decreased and those of EC 1:2 and ESP increased with irrigation at both locations. Statistical analysis showed an overall good agreement between the experimental and simulated values of moisture content, EC 1:2 and ESP; the accuracy of simulation of the models followed the order model II = model III > model I, for moisture content and EC 1:2, but was identical for ESP. © 1990, Cambridge University Press. All rights reserved.