Abstract: Basing on the fruit trees’ phonological observation data from 1998 to 2010 and meteorological data from 1981 to 2010 in main planting regions in the dryland area of southeast Gansu, the model of water suitability for fruit trees growing was set up with the FAO Penman-Monteith formula (1998 edition) and crop coefficient, the water requirement of fruit trees in different growth periods from 1981 to 2010 was calculated. The results showed that the drought in spring appeared more and more severe compared with other seasons during the period of fruit growing since 1980s.The water suitability of whole growth periods decreased with the time under the background of climate warming, the water supply to apple and grape was under good conditions, which annual mean water suitability was above 0.50; the water supply to big cherry and peach was under bad conditions, which annual mean water suitability was 0.41 and 0.47, respectively. The water suitability for 4 kinds of fruit trees decreased at the initial growth stage. The grape was with an optimal moisture condition, followed by apple. The water suitability of big cherry and peach was less than 0.40 since 2010s, and the contradiction was marked between supply and demand of water during initial growing of big cherry. The water suitability of grape and apple increased at the vigorous growth stage since 2010s. The amount of water requirement for peach and big cherry in fruit trees growing was lacking, and the water suitability of big cherry was only 0.31, with increased water stress because of the spring drought. The water suitability increased basically at the last growth stage, and the precipitation was more than the amount of water requirement for grape with the water suitability of above 1.0, 1.0 for apple. The precipitation was suitable for apple; it was above 0.5 for big cherry and peach. The precipitation could also satisfy requirement. The established model can assess the environmental climate of fruit trees and provide scientific suggestion for planting regions of fruit trees in the dryland area of southeast Gansu.

Key words: special fruit trees, water suitability, assessment, southeast Gansu