Assessing hydrus-2D to simulate soil water content (SWC) and salt accumulation under an SDI system: Application to a potato crop in a semi-arid area of Central Tunisia

Abstract

In this paper the suitability of the HYDRUS-2D model to simulate volumetric soil water content in the root zone of a potato crop under subsurface drip irrigation (SDI) is initially assessed on the basis of a field study. Then, considering that the crop is moderately sensitive to soil salinity, the model is tested to predict the salt distribution around a buried emitter, when two different water qualities (i.e.electrical conductivity of 1.0 and 4.0 dS m-1) are used during the growing season (treatments T1 and T2). Finally, the soil volume in which salt accumulates is distinguished by the model for the two treatments, for which the respective yields are not significantly different. The results showed that in the root zone, simulated and measured soil water content (SWC) are fairly close. HYDRUS-2D well enough predicts the average salt concentration in the soil and evaluates the dynamic of mass-conservative solutes around buried emitters. In both treatments, the salt concentration resulted in an increase in the wetting bulb, with a maximum located towards the edge of the wetting bulb and near the soil surface.