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Variation in vineyard evapotranspiration in an arid region of northwest China

Zhang, Baozhong, Kang, Shaozhong, Li, Fusheng, Tong, Ling, Du, Taisheng
Agricultural water management 2010 v.97 no.11 pp. 1898-1904
Vitis vinifera, grapes, vineyards, evapotranspiration, arid zones, diurnal variation, seasonal variation, energy balance, measurement, irrigated farming, rain, frost, developmental stages, fruiting, transpiration, crop coefficient, China
Grapevines are extensively grown in the arid region of China, but little information is available on the diurnal, seasonal and interannual variability of vineyard evapotranspiration (ET). To address this question, two vineyards in the arid region of northwest China were taken as an example to study the variation of ET using Bowen ratio-energy balance method in 2005-2008. Results indicate that the Bowen ratio method provided accurate estimate of vineyard ET as the instrument was correctly installed. Irrigation and rainfall increased daily ET by 38 and 175%, respectively, but frost decreased it by 32%. Daily ET had a maximum value of 1.6-3.5mm/d at the berry development stage, and a minimum value of 0.8-1.7mm/d at the early and later stages. The total ET was 226-399mm over the growing season. The ratio of transpiration to evapotranspiration was 0.52 and the modified crop coefficient (K cm ) was 0.71-0.88 (except 2005) over the whole growing stage. Larger interannual difference of ET and K cm mainly resulted from the difference of irrigation and rainfall between different years.