刈割时间对典型草原建群植物大针茅种群特征的影响

Effect of Cutting Time on the Population Characteristics of Stipa grandis

通过测定不同刈割时间处理(不刈割、8月1日刈割、8月16日刈割、8月31日刈割)下锡林郭勒盟典型草原大针茅(Stipa grandis)种群地上生物量和高度、密度、盖度、分枝数、每枝叶片数等5种个体性状以及大针茅种群粗蛋白含量、中性洗涤纤维、酸性洗涤纤维等营养物质含量之间的差异性及各项指标之间的相关性,为探究不同的刈割时间对锡林郭勒盟典型草原建群植物大针茅种群特征的影响提供理论依据,也为草地生态系统的合理利用提供技术支持。结果表明:不同时间刈割对典型草原大针茅种群特征有显著的影响。与不刈割对照相比,8月16日刈割处理大针茅种群的密度和盖度均达到最大值,分别为45.28%和16.64%;8月1日刈割处理大针茅种群的株高、分枝数、每枝叶片数等个体性状,生物量及营养物质含量均达到最大值;大针茅种群的生物量与植株高度、分枝数之间存在极显著的正相关关系(r^2=0.5130、P<0.0001;r^2=0.9075、P<0.0001),与盖度之间存在显著的正相关关系(r^2=0.3498、P<0.05);大针茅的高度、分枝数、密度、盖度之间具有相互影响的内在关联性(P<0.05)。

In this paper,the differences and relationships of S.grandis’five phenotypic traits,including the height,density,coverage,number of branches and each branch leaf of,as well as its’aboveground biomass protein content(CP),neutral detergent fiber(NDF)and acid detergent fiber(ADF)in the different cutting times(no cutting,Aug.1cutting,Aug.16cutting,Aug.31cutting)were studiedin typical steppe,Xilingol Region,Inner Mongolia to explore the effect of different cutting time of S.grandis characteristics,and toprovide a feasible theory basis for the development of the grassland ecosystem.The results were as follow,different cutting time onS.grandis coverage,branch number and biomass were significantly different(P<0.05).Compared with no cutting,the populationdensity and cover reached the maximum in Aug.16cutting treatment with45.28%and16.64%,respectively,while other threephenotypic traits such as plant height,branch number and number of leaves per branch of S.grandis,including biomass and threekinds of nutritional value in Aug.1cutting treatment.S.grandis’aboveground biomass was influenced by the height and number ofbranches,and there were positively relationship with each other(r2=0.5130,P<0.0001;r2=0.9075,P<0.0001).S.grandis’aboveground biomass was significantly correlated with individual cover(r2=0.3498,P<0.05).The height,coverage,density andbranch number of S.grandis were closely related to each other(P<0.05).