关键词: 柽柳, 蒸散速率, 日变化, 波文比, 额济纳旗

Abstract: This article makes use of the Bowen Ratio-equilibrium Energy Method to measure evapotranspiration of Tamarix ramosissima in Ejina oasis. The results showed that the diurnal variation of evapotranspiration rate were obvious and single-peak curve under the clear and cloudless term. Evapotranspiration begins at 6:30 in the morning and the rising rate of evapotranspiration is smooth in the morning, attains the peak by noon, later evapotranspiration rate quick decreases and to the least at 16:00. No evapotranspiration happens in evening, while the evapotranspiration rate often appears negative and has a coagulation process. The net radiation plays critical role in plant evapotranspiration. The trend of net radiation change is similar to evapotranspiration rate; the diurnal variation has the same peak type. Evapotranspiration of Tamarix ramosissima increases with the wind velocity. Soil temperature has minor influence on the evapotranspiration of Tamarix ramosissima, but variety of soil temperature has basic consistence with change of evapotranspiration rate. Evident relation existed between the variations and the soil moisture, the evapotranspiration went down while the soil moisture decreased, the evapotranspiration went up quickly when the soil moisture increased. The correlation analysis showed that the order of fitness degree between evapotranspiration rate and single environment factor was: variety of soil temperature > net radiation > wind speed > soil moisture > air temperature and humidity.

Key words: Tamarix ramosissima, evapotranspiration, diurnal variation, Bowen ratio, Ejina Banner