Abstract: Based on the meteorological data and grazing grass data from 1985 to 2006 in the meteorological station in Zoige County,Sichuan Province,the relationship between the temperature and precipitation,and the growing period of Kentucky Bluegrass(Poa pratensis L.) dominated in the Zoige grassland was analyzed.The starting time of all growing periods in relation to the meteorological conditions was also studied.The main results showed that the growing period of Kentucky Bluegrass ranged from 125 to 176 days,with the average by 144 days.However,the vegetative growing period which ranged from 79 to 111 days,on average by 92 days,was longer than the reproductive growth which was between 39 days and 64 days,on average by 49 days.The duration of vegetative growth,reproductive growth and the whole growing period was negatively related to accumulated temperature by 0℃,while it positively related to precipitation.The accumulated temperature was more important.The returning green stage of Kentucky Bluegrass was typically between March 26th and April 16th,the leaf-expansion period between May 2nd and May 16th,and the heading date between June 30th and July 16th.There was no significant correlation between the returning green stage of Kentucky Bluegrass and previous accumulated temperature by 0℃.The starting time of other growing periods had certain relations with previous accumulated temperature.The growing period was inclined to delay with lower previous accumulated temperature.

Key words: Zoige, Zoige, Kentucky Bluegrass, Growing period, Meteorological conditions