高寒草原针茅枯黄期主要限制因子分析及模型构建

Analysis and construction of a forecast model for the main limiting factors of the withering phenology of Stipa Grass on the alpine grassland

【目的】探明1999—2020年三江源区兴海县高寒草原针茅枯黄期的变化特征及其与气象因子的关系,为兴海县及类似地区牧草资源的合理利用与生态环境保护提供依据。【方法】利用三江源区兴海县气象局观测的1999—2020年高寒草原牧草物候期资料及同期气象资料,对高寒草原牧草枯黄期变化趋势进行分析,利用相关分析法对牧草枯黄期与前期气候因子进行分析,利用回归分析法构建了牧草枯黄期预报模型。【结果】(1)三江源地区兴海县高寒草原西北针茅牧草平均枯黄日期为9月4日,最早与最晚日序差值达22 d。(2)1999—2020年近22年三江源区兴海县牧草枯黄期呈明显的提前趋势。【结论】回归分析表明,牧草枯黄期变化主要受到气温的限制,所构建的枯黄期模型可较好反映针茅牧草枯黄时间早晚与相关热量因子变化的规律。

【Objective】To demonstrate the variation characteristics of natural grass yellowing period in alpine grasslands and its relationship with meteorological factors in Xinhai County,Three⁃river source area from 1999 to 2020.The aim was to provide a basis for the rational utilization and ecological environment protection of forage re⁃sources in Xinghai County and similar areas.【Metod】Utilizing phenological period data of herbage in alpine grass⁃lands and contemporaneous meteorological data observed by Xinghai County Meteorological Bureau in the Sanji⁃angyuan region from 1999 to 2020,this paper analyzed the change trend of the yellowing period of alpine grasslands.Correlation analysis was employed to examine the relationship between the yellow period of herbage and climatic fac⁃tors during the early period.Additionally a forecast model of the yellowing period was constructed using the regres⁃sion analysis method.【Result】(1)the average yellowing date of northwest stipa grass was September 4,with a dif⁃ference of 22 days between the earliest and the latest diurnal order.(2)From 1999 to 2020,the yellowing period of herbage in Xinghai county had notably advanced in the recent 22 years.(3)Regression analysis indicated that the yel⁃lowing stage of herbage was primarily limited by temperature.【Conclusion】The prediction model of the yellow pe⁃riod could reflect the rule of the yellowing time and its association with heat factors of Stipa grass.