Soil Water Balance Simulation of Rice using HYDRUS-2D and Mass Balance Model

This chapter considers quantifying the water balance parameters such as runoff, actual evapotranspiration, vertical percolation and lateral seepage from the effective root zone of rice field with different weir heights using HYDRUS-2D and field water balance model. The vertical boundaries were assumed to have seepage face conditions and rest of the domain was assumed no flow boundary conditions. The predicted ponding water depth was estimated by mass balance as a residual of other water balance components. HYDRUS-2D model and the water balance model have produced realistic results, which are supported by the field experiment. The models therefore, are useful for planning water management practices such as irrigation scheduling and better use of rainfall. HYDRUS-2D was used to simulate soil water content, lateral seepage and vertical percolation in the effective root zone of rice field with different weir heights under variable saturated condition.