2-DIMENSIONAL INFILTRATION UNDER FURROW IRRIGATION - MODELING, ITS VALIDATION AND APPLICATIONS

A model of water movement in soil during furrow irrigation using Richa rds' equation in its bidimensional form is presented. This model was d eveloped and tested for two types of soil and short closed furrows. It gives information on the position of the wetting front in the soil wi th time, thus allowing quantification of the water stored in the root zone and computing the percolation losses during a given lime interval and relative to any given soil depth. In this model, an implicit meth od is used and the resulting equation set is solved with the Gauss-Sei del method. The model considers the initial conditions of the soil bef ore irrigation and the boundary conditions defined by the water level in the furrow. Also, the model can be used to simulate infiltration in different sections, thus providing better information concerning the uniformity and efficiency of the irrigation.