Effect of Salinity on Moisture Flow and Root Water Uptake in Sandy Loam Soil

Abstract

The present study analyzes the effect of salinity on crop growth and root zone soil moisture dynamics. A newly developed root water uptake (RWU) model was used for simulation of soil moisture and RWU for irrigation field experiments where paddy was grown with irrigation water with varying salinity concentrations (0.5, 7.9, 14.7, and 21.2 dS/m). The growth of the crop was monitored regularly, and crop parameters such as leaf area index (LAI) and root depth along with the soil moisture profile were measured during the crop growth period. The nonlinear parameter for the RWU model was estimated using an empirical relation in terms of observed crop variables (LAI and root depth) for each saline irrigation condition. Root zone soil moisture and RWU for the prevailing hydrometeorological conditions during the crop period and soil-crop parameters were simulated for the analysis. The irrigation experiments show that the growth of the crop is significantly affected by the salt concentration in soil-water, resulting in a decrease in the crop canopy (LAI) and root depth decreases with an increase in the salt concentration. The model simulation results show that an increase in salt concentration in irrigation water results in reduced root water extraction and reduced moisture content in the soil profile.