Test of a simple model for estimating evaporation from bare soils in different environments

A simplified model originally proposed by Aydin [Aydin, M., 1998a. A new model for predicting evaporation from bare field soil. In: Proceedings of the International Symposium and second Chinese National Conference on Rainwater Utilization, Xuzhou-Jiangsu, China, pp. 283-287] for estimating actual evaporation from bare soils was tested under different environmental conditions. Field experiments were carried out on clay soils in a semi-arid region of Turkey. A sandy soil column-experiment in a drying chamber and a study with the same sand media in a greenhouse were conducted at Arid Land Research Center, Tottori University, Japan, in order to test the performance of the model. The model is based on the relations among potential and actual soil evaporation and soil-water potential at the top surface layer of the soil, with some simplifying assumptions. Input parameters of the model are simple and relatively obtainable viz. climatic parameters for the calculations of potential soil evaporation and matric potential measured near the soil surface. Despite some differences between calculated and measured soil evaporation, the agreement was reasonable at all sites. This agreement seems to support the model assumptions, and the model is potentially valuable, but the objective measurement of soil-water potential near the surface of the profile is difficult, especially for a drier upper layer. (C) 2004 Elsevier B.V. All rights reserved.