Portal de Periódicos da CAPES

SOIL WATER MOVEMENT DURING THE FIRST STAGE OF DRYING OF A MOIST SANDY SOIL UNDER A VERY LOW DRYING RATE

1977; Lippincott Williams & Wilkins; Volume: 124; Issue: 2 Linguagem: Inglês

10.1097/00010694-197708000-00001

1538-9243

M Nakano,

Heat Transfer and Optimization

First, here are reported some interesting data of cumulative evaporation observed in the drying process of soil columns without a water table and under a very low drying rate. It is a fact that there is a stage in which the drying rate is remarkably low, after the first stage of drying has finished, i.e., early in the second stage of drying. Second, approximate solutions of the unsaturated liquid water flow equation for the first stage of drying of moist soil have been derived under a constant rate of drying assuming that water movement during the first stage occurs under a total hydraulic head gradient which is not far from zero. Solutions are presented for finite soil columns under the isothermal conditions applying an empirical expression relating water content to tension for limited ranges of water content. The domain of validity of theoretical analysis is characterized by the ratio of drying rate to the unsaturated hydraulic conductivity at the soil surface. When this condition is met, the theoretical water content profiles are in good agreement with the experimental water content distributions.