Estimating soil surface evaporation from fields irrigated by micro systems

点击翻译按钮获取中文摘要

To evaluate the consumptive use efficiency of irrigated water. it is interest to estimate the soil surface evaporation component separately from transpiration component. When the fields are irrigated by microirrigation systems. wetted area are formed on the soil surface. Estimating evaporation rate from the wetted spots are important to quantify the water for irrigation.Two approaches were pursued on this project. Firstly. vapor diffusion mechanism in the binary layer on the soil surface was experimentally examined. Evaporimeter made with thin plaster layer was observed to give good estimation. Secondary. the mechanism of water diffusion in the the vicinity of soil surface was examined. Using an equipment to measure soil water potential, distribution of volumetric soil water contents during the fallen rate stage of drying in the surface layer were observed. Water flow rates determined with this observation were compared with calculated results of summation model. With this technique, water diffusivity in the surface layer were precisely investigated.