Simulation of Modeling of Water Ecohydrologic Dynamics in a Multilayer Root Zone under Protected Conditions in the Temperate Region of India

Abstract

The present study was conducted to simulate the moisture dynamics for a multilayer soil under protected conditions for a pea crop (Pisum sativum). A field experiment was conducted in a temperate region of the Kashmir valley, India, during the period November 2014 to June 2015. A root water uptake (RWU) model was developed for a multilayer crop root zone. The moisture uptake prediction efficiency of the model in a multilayer crop root zone was evaluated on the basis of secondary and experimental data. The nonlinear mathematical model incorporated the spatial and temporal variations of the soil and plant parameters. The quantitative values of the reference evapotranspiration for open and protected conditions were recorded at 358.8 mm and 156.5 mm, respectively, for the whole crop period. The average seasonal crop evapotranspiration inside the polyhouse was recorded at 1.91 mm/day. The crop evapotranspiration inside the polyhouse for the whole crop period was found to be 372.45 mm. The crop evapotranspiration was partitioned into transpiration and evaporation and those values were used as input parameters in the model to determine the moisture uptake by the plants. The maximum value of transpiration for the pea crop inside the polyhouse was recorded at 3.51 mm/day on May 21 (141 Julian day). Using a developed numerical model, the percentages of soil moisture extraction and soil moisture status at different depths were simulated inside the polyhouse. In the upper part of the root zone where the root density is high, moisture depletes very rapidly. The maximum moisture depletion was seen in the month of May inside the polyhouse. The results demonstrated the utility of the root water uptake model across different agro-climates and established its efficacy for nonuniform soils that vary in soil moisture properties along their depths, in predicting soil moisture in the crop root zone.