Evapotranspiration in Pumica granatum stand in Lower Taihang Mountain

Based on energy balance method, the daily and monthly variations of evapotranspiration are measured in Pumica granatum stand in Lower Taihang Mountain. The evapotranspiration in different phenophase is also calculated. The results indicated that Pumica granatum trees close their stoma to decrease physiological transpiration at noon when the radiation is very intense. In Pumica granatum stand, the evapotranspiration was highly linearly correlated with net radiation. The regression equation was Y = 0.0029 X--0.1449, and regression coefficient can reach 0.9. The total evapotranspiration was 424.08 mm, 64.59% of which was consumed from flowering phase to fruit maturing phase. Two essential supplementary irrigation, one in germination phase and the another before flowering phase, should be implemented to ensure the healthy growth of Pumica granatum trees.