干旱区生态环境知识资源中心

This paper proposes to evaluate the performances of the TDR (Time Domain Reflectometry) technique in a semi-arid region. To achieve this objective a comparison was made on a daily scale for sorghum and maize crops. Their actual evapotranspiration (ET) was measured by two independent methods: soil water balance budget, using soil water content measured by gravimetric and TDR methods and energy balance equation (Bowen ratio). The daily ET values derived from soil water balance budget agreed with the values of ET determined by the Bowen ratio. Results show that in soils without vertical cracks daily ET can be estimated in field by using the TDR technique over a wide range of soil water content. (C) 1998 Elsevier Science B.V.