Abstract:

Based on the phenological data of Stip sareptana var. krylovii flowering stage on alpine grassland and contemporaneous meteorological data observed by Xinghai County Meteorological Bureau in Sanjiangyuan region from 1999 to 2021, this paper analyzed the change trend of the Stip sareptana var. krylovii flowering stage on alpine grassland, to find out the main meteorological factors influencing the flowering time and build the forecast model by using the regression analysis method. The results showed that: (1) the average temperature was stable during flowering stage of Stip sareptana var. krylovii on alpine grassland of Xinghai County from 1999 to 2021, but precipitation increased significantly; (2) the flowering stage of Stip sareptana var. krylovii showed no significant delay trend from 1999 to 2021, and the flowering time of herbage varied greatly from year to year, the difference between the earliest and the latest was 26 days; (3) correlation analysis showed that, the average temperature and average maximum temperature in the first ten days and the last ten days of April were significantly negatively correlated with the flowering time, the average maximum temperature and sunshine duration in the first ten days of May were significantly positively correlated with the flowering time, and the average minimum temperature in late April was very significantly negatively correlated with the flowering time of herbage; (4) the regression analysis showed that for every 1.0℃ increase (or decrease) of the average minimum temperature in late April, the flowering time of herbage was correspondingly earlier (or delayed) by 2.1 days.

Key words: alpine grassland, phenological period, variation characteristics, influencing factors, regression analysis, Sanjiangyuan region