QU Yan-ping 1, 2, KANG Shao-zhong 3, WANG Su-fen 3

1. China Institute of Water Resources and Hydropower Research, Beijing 100038, China
2. Research Center on Flood and Drought Disaster Reduction, Beijing 100038, China
3. Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China

Abstract: The water consumption of irrigated Populus alba var. Pyramidalis was studied in Shiyang River Basin. The results indicated that the daily sap flux in the trunk of Populus alba var. Pyramidalis showed obvious seasonal pattern, and correlated quadratic parabolic curve with the days after bud burst (DAB), with a determination coefficient of 0.765. The multiple linear regression of the daily sap flux (SF) of Populus alba var. Pyramidalis with mean daily air tempreature (T a), mean daily vapour pressure deficit (VPD), mean daily solar radiation (R s) and mean daily wind speed (V w) was programmed by SPSS using the stepwise regression method, with a high determination coefficient of 0.807. The partial coefficients between SF and T a, VPD, R s were 0.637, 0.188 and 0.373, respectively, indicating T a was the prime meteorological factors. The combination method of Sap flow and Micro-lysimeter was used to measure the evapotranspiration of irrigated Populus alba var. Pyramidalis., and its applicability was analyzed. In the growing season (from May to October), the overall evapotranspiration was 508.26 mm, with the proportion of 37.1 % and 62.9 % for evaporation and transpiration, respectively. The water balance method was used to estimate the evapotranspiration of Populus alba var. Pyramidali., with the relative error within ±15 %, validating the applicability of combination method of Sap flow and Micro-lysimeter.

Key words: Populus alba var. Pyramidalis, daily sap flux, meteorological factors, combination method of Sap flow and Micro-lysimeter, water balance method

Published in: Journal of China Institute of Water Resources and Hydropower Research (Vol. 12 No. 1, 2014)