高寒针茅草原土壤湿度变化特征及与降水量和牧草产量的关系

利用青海省三江源区兴海县牧业气象站1999-2012年西北针茅牧草生长季的土壤湿度、降水量及牧草产量资料，分析了西北针茅牧草生长季不同生育期土壤相对湿度的变化特征，及与降水量和牧草产量的关系。结果表明：高寒草地西北针茅牧草生长季降水量随年际呈显著增加趋势。牧草返青和枯黄期间的降水量呈减少趋势，抽穗、开花和成熟期降水量均呈增加趋势，其中开花期间的降水量增加趋势极显著。牧草生长季土壤相对湿度随年际呈显著上升趋势，且与生长季降水量之间相关极显著。牧草开花、成熟、抽穗和枯黄期土壤相对湿度的增加趋势显著。牧草开花期土壤相对湿度与气温为显著正相关，抽穗期和全生育期的土壤相对湿度与气温负相关显著。抽穗期、开花期、成熟期和全生育期土壤相对湿度与降水量正相关显著。西北针茅牧草产量与枯黄期土壤相对湿度呈极显著的相关关系。

Variation of soil moisture within alpine Stipa grassland and its relation with precipitation and pasture yield

In this paper,the relations between variation of soil moisture in different growing periods,precipitation and pasture yield in Stipa growing season are analyzed based on the data of soil moisture,precipitation and pasture yield from 1999 through 2012 in Qinghai Province.The following conclusions can be drawn:(1) Precipitation increases remarkably in Stipa growing period in the province year by year.(2) Precipitation in the grass green and yellow periods has a decreasing tendency and in heading period,flowering period and maturity period has an increasing tendency,especially,in flowering period.(3) Soil relative moisture in pasture growing period increases year after year and has significant dependence on precipitation in growing period.Soil moisture increase remarkably at flowering,maturity,heading and yellow periods.There is a significant positive correlation between soil moisture and temperature at flowering period,with a significant negative correlation between soil moisture and temperature at heading period and whole growth period.Between soil moisture and precipitation,there is a significant positive correlation at heading,flowering,maturity and whole growth period.There is a significant correlation between yield of Stipa and soil moisture in yellow period.