中文摘要：

通过野外控制实验,研究了刈割（留茬3cm、留茬1cm及不刈割）、施肥（施肥、不施肥）和浇水（浇水、不浇水）处理对高寒草甸矮嵩草（Kobresia humilis）和垂穗披碱草（Ely-mus nutans）补偿高度、株高相对生长率、比叶面积、叶片净光合速率和地上总生物量的影响。结果表明：2物种的株高和地上总生物量在刈割后均为低补偿响应,但其株高相对生长率显著提高,并均随年份而增加;垂穗披碱草比叶面积、叶片净光合速率和地上总生物量对刈割损伤更加敏感;尽管施肥能显著提高2物种上述各项指标,但在不同处理条件下矮嵩草的耐牧性指数均小于垂穗披碱草;浇水的作用不显著。说明2物种的耐牧性依赖于土壤养分资源获得性,矮嵩草的耐牧性强于垂穗披碱草。

英文摘要：

A field manipulation experiment was conducted to study the effects of clipping （stubbled 3 cm,stubbled 1 cm,and unclipped）,fertilizing （fertilized and non-fertilized）,and watering （watered and non-watered） on the compensatory height （CH）,relative height growth rate （RGR）,specific leaf area （SLA）,net photosynthesis rate （NPR）,and total aboveground biomass per ramet （TAB） of two major plant species （Kobresia humilis and Elymus nutans） in an alpine K.humilis meadow,aimed to compare the grazing-tolerance of the two species,and to analyze the relationships between the tolerance and the resource availability of soil.The CH and TAB of the two species had an under-compensatory response to clipping,while the RGR increased significantly with clipped intensity and the clipped effect was accumulative over time.The responses of SLA,NPR,and TAB to clipping were more sensitive for E.nutans than for K.humilis.Though fertilization greatly improved the test indices of the two species,the grazing-tolerance index of K.humilis under fertilized and non-fertilized conditions was smaller than that of E.nutans.Watering had little effects on the tolerance index of the two species.It was suggested that the grazing-tolerance of the two species depended on the resource availability of soil to some extent,and K.humilis had a higher tolerance ability than E.nutans.