Modelagem do movimento de água no solo sob condições de irrigação por gotejamento superficial considerando absorção radicular e evaporação de água do solo

Abstract

Drip irrigation is one of the most efficient methods for applying water to a crop, capable of delivering water at a rate close to the demand. Many efforts have been required to estimate the amount of water needed by plants. Therefore studying soil water extraction by plants linked to mathematical modeling for behavior prediction, and linked to computational resources to allow complex mathematical procedures to be realized in a short space of time, becomes a powerful and necessary alternative for the understanding and quantification of the involved processes. This work aims to simulate soil water movement under conditions of drip irrigation, including the quantification of soil evaporation and crop transpiration of soil water. The finite volumes method was used to numerically solve the Richards equation for the simulation of soil water movement. Equations from literature were used to estimate transpiration and evaporation, adjusting them for use in finite volumes and modifying them, when necessary, to adapt them to the used model. A software was developed to perform the simulations of soil water movement, formation of a wet bulb and quantification of transpiration and evaporation. Concerning mass conservation, the results of the lesser simulations presented a relative error smaller than 0.001%. The results of the simulations of water losses by evaporation and transpiration were very similar to observed data from a lysimeter experiment, making the model results satisfactory. However, more tests and comparisons with more robust models are suggested.