Soil‐Based Irrigation and Salinity Management Model: I. Plant Water Uptake Calculations

Abstract

AbstractA new soil‐based model for irrigation and soil salinity management has been formulated to rectify deficiencies in existing soil‐based models with respect to mass balance, numerical stability, and the treatment of plant growth and water uptake dynamics. The advantages of the new model are: (i) the treatment of temporal variation in potential transpiration (TP) and rooting depth and distribution, (ii) the adjustment of TP based on feedback from simulated crop water uptake, (iii) the provision for treating growth‐stage‐specific crop tolerance to salinity and water stress, and (iv) the provision for multiseasonal simulation through the treatment of noncropped periods. A sensitivity test and a comparison of model calculations to experimental data were conducted. The model tended to overpredict relative crop yield from a field experiment based on relative crop water uptake calculations. The mean simulated relative yield was 7% higher than observed with a root squared error (RMSE) of 8.8% relative yield. Willmott's d index (a statistical index of agreement between measured and observed data) result was high 0.79 (perfect agreement = 1.0).