A comparison of three methods for determining vineyard evapotranspiration in the arid desert regions of northwest China

✍ Scribed by Sien Li; Shaozhong Kang; Lu Zhang; Fusheng Li; Zhilin Zhu; Baozhong Zhang

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 233 KB
• Volume: 22
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.7059

✦ Synopsis

Accurate measurement and estimation of crop evapotranspiration (ET ) plays an important role in understanding field soil water cycle and managing water-saving irrigation in the arid regions. This study compares three methods for estimating ET : field Water Balance (WB), Eddy Covariance (EC) and Bowen Ratio-Energy Balance (BREB). The experiment was conducted in a vineyard in the arid desert regions of northwest China. Results indicate that the three methods provided similar estimate of total ET. Compared to total ET measured by WB (ET WB ) during the whole growing stage, total ET estimated by EC (ET EC ) was 1Ð57% lower, and total ET estimated by BREB (ET BREB ) was 5Ð19% higher. Variations of ET EC and ET BREB are similar at hourly or daily timescale, but the values are slightly different. At sunrise or sunset, ET BREB increases or decreases more rapidly than ET EC . The difference between ET BREB and ET EC is linearly related to the residual of the energy balance for EC and the two methods yielded close estimates when the residual was small. This study showed that the three methods provided accurate estimates of ET at daily and seasonal timescales and the methods can be used to estimate ET from vineyards in arid environments.