Evapotranspiration of Kiwifruit Orchards and Its Sensitivity to Meteorological Factors in Southwest China

Abstract

【Objective】 Evapotranspiration (ET) is an important hydrological component and parameter for agricultural management. It varies with both plantations and meteorological factors. In this paper, we studied the effect of climate change and leaf area index (LAI) on ET, as well as the seasonal variation in crop coefficient of kiwifruit orchards in southwest China. 【Method】 The study was based on field experiments. The Penman-Monteith model using data measured in 2018 and 2019 was used to calculate the potential ET, from which we analyzed the mechanisms underlying the near-surface water vapor flux. The sensitivity of ET to various meteorological factors was also calculated, and the real ET was calculated using a single crop coefficient (Kc) and dual crop coefficient (Kcb), respectively. 【Result】 ①In 2018 and 2019, the average daily ET was 2.71 mm/d and 2.23 mm/d respectively, the aerodynamic term in ET was1.87 mm/d and 1.71 mm/d, respectively, accounting for 0.69 and 0.74 of the total ET. ②During the growth period of the kiwifruit in both 2018 and 2019, ET was most sensitive to VPD, followed by rc、Rn-G、ra. ③In both 2018 to 2019, Kc increased first followed by a fall as the plant grew, while the Kcb increased in the late growth stage. The average Kc in 2018 and 2019 was 0.93 and 0.85, and its associated average Kcb was 0.43 and 0.41, respectively. 【Conclusion】 Our results show that the aerodynamic term was the main factor affecting ET in the kiwifruit orchard, while the ET was most sensitive to VPD.

Keywords

• kiwifruit orchard
• et
• penman-monteith model
• sensitivity
• crop coefficient