青海湖地区天然草地土壤水分动态变化及对牧草生物量的影响

Soil moisture dynamic of natural meadow and its impacts on forage biomass in Qinghai Lake region

分析了青海湖地区天然草地土壤水分动态变化及其牧草生物量与土壤水分的关系。结果表明：青海湖地区年内土壤水分的变化可分为春季缓慢失墒期、春末夏初墒情缓慢恢复期、夏季快速失墒期、秋季快速增墒期4个时段;不同年份土壤水分的垂直变化不同,0-30 cm土层土壤含水率受天气、牧草生长等因素影响干湿变化明显,30-50 cm土层土壤含水率的变化相对较稳定。牧草生长季（5-9月）各月末的生物量与前期土壤水分的关系密切,上一年度土壤水分对牧草生物量的影响在牧草生长前期较为明显,后期逐渐减弱。

The dynamic changes of soil moisture on natural grassland and the relations between forage biomass and the soil moisture in Qinghai Lake region were analyzed. Results indicated that changes of the soil humidity in the Qinghai Lake region can be divided into four periods, such as the slowly lost period in spring, the slow-moving convalescent period in the end of spring and early summer, the fastly lost period in summer and the fast increment and imbursement period in autumn. The perpendicular variety of the soil moisture differed among different years. 0--30 cm depth of soil moisture levels effected by factors such as weather and pasture growth, and the impact of wet and dry changed significantly, the changes in 30--50 cm depth of soil moisture levels were relatively stable. The forage biomass at the end of each month during the growth season （from May to September） was closely related to the soil humidity in its front period. The influence of the soil humidity in previous year on forage biomass was more obvious in the early period of forage grass growth, and it worn off gradually in late period.