STUDIES ON WATER MOVEMENT IN SOME SOILS IN FAYOUM DEPRESSION

Abstract

Soil water IS one of the most important soil dynamics in which content and movement can change rapidly. One very important factor which influences this dynamic is water movement. Soil water movement includes upward, downward, infiltration, saturated hydraulic conductivity and evaporation. The water movement either saturated or unsaturated in a ce1tain soil may affected by different •soil factors such as: texture, structure, porosities, densities, presence of entrapped air, !,'fOund water table levels, mechanical properties, sodicity, salinity, ionic composition of the water and temperature. Measuring soil water movement has an utmost important in irrigation and drainage practices, crop water requirements and hydrological studies. In field experimentations, the \ ability of the soil to conduct water has been drastically affected by

variations of some soil properties, ground water table levels, ESP and ECe contents in addition to soil texture. Pore geometry, total porosity, pore size distribution, continuity and tortuosity of soil pores have an associated interconnection with the hydraulic conductivity values. Moreover, as soil suction increased, the macropores are emptied, which greatly reduce the cross-sectional area for the flow and hence reduce the hydraulic conductivity values. Increasing the soil water content and retention increased the water movement and transmission through the soils. The water movement into (infiltration) and out of(evaporation and drainage), as well as within (conductivity) a soil may considerably have an associated interrelation with the different plant growth, yield and quality of the t,rrown sunflower and sugar beet crops, in addition to some soil properties.