Abstract: The stem sap flow in different diameter classes of pear trees in a pear orchard in Yangling of Shaanxi Province was monitored by heat pulse method, and scaling -transformed into the sap flow in the orchard. In the meantime, a comparison wa s made between the sap flow in the orchard and the orchard transpiration obtaine d from the transformation of leaf transpiration rate measured by CIRAS-1 infrared gas analyzer. On the whole, the result of heat pulse method was consis tent with that of infrared gas analyzer. The pear orchard water consumption, bas ed on the stem sap flow of single tree and the leaf transpiration rate, was calc ulated as 52351 and 49805 mm, respectively. Basal diameter was the optimal s calar from individual tree up to pear orchard.

Key words: Intersubspecific hybrid rice, Fertilization, Temperature, Model