A study of soil water flow in olton loam soil under field conditions

A field of study of soil water flow was conducted in Olton soil at Lubbock, Texas. Four 8x8 meter square plots, having four replications of one access tube, eight tensiometers and eight thermocouples in each plot, were used in this study. The tensiometers and the thermocouples were placed randomly at 15-, 30-, 45-, 60-, 75-, 90-, 120- and 150-cm depths and the access tube to 200-cm depth. Three access tubes were placed outside each plot, 50-cm apart, to study the lateral flow of water. Three of the plots were kept under a shelter to protect them from rain. Rates of infiltration were measured following first irrigation with 7.62-cm of water to plots I, II and III, respectively. The infiltration period varied depending on initial amount of water present in each plot. The infiltration period was longer with high initial water content. The rates of infiltration were very fast at the beginning and continuously decreased with time until they attained a nearly constant value. The infiltration rates were lower during the second irrigation than the first because of high initial moisture content in the former case. At the cessation of infiltration plots I, II, and III were covered with clear plastic, black plastic and crude oil plus clear plastic, respectively. The plot IV remained uncovered and its evaporation loss was obtained from nearby lysimeters.