Abstract: The amount of crop water requirement is the key to determine irrigation efficiency and quality in agricultural irrigation. Therefore, studying crop evapotranspiration is of great significance for water-saving irrigation. In this paper, the Penman-Monteith equation is used as the main research object. The meteorological data from March 10, 2018 to April 10, 2018 and the monthly average data from 2018 are used to compare the PM modified equation with the tea tree-based transpiration evaporation model. The analysis proves that the ET₀ calculated based on the transpiration evaporation model of tea tree is more accurate and agrees well with the measured value, which can theoretically serve as the basis for tea garden irrigation.

Key words: crop water requirement, irrigation, tea tree, evapotranspiration