不同强度放牧对贝加尔针茅草原群落和土壤理化性质的影响

在一个生长季内,比较分析了贝加尔针茅草甸草原不同放牧强度地段(非牧段,轻牧段,中牧段和重牧段,以放牛为主)植物群落的总地上现存量、总投影盖度、平均高度和土壤理化性质的变异。结果表明,不同强度放牧条件下各项指标均呈规律性变化,表现为植被的生长状况和土壤状况随着放牧强度的增加而劣化,且群落总地上现存量、总投影盖度、群落高度之间具有显著的相关性。土壤的pH值和电导率与地面凋落物的量之间存在显著负相关。考虑各项指标对放牧反应的敏感性、变化的稳定性和测定的方便性,可以把群落盖度、土壤化学性质的变化作为草地健康评价的关键指标。

Effects of Different Grazing Intensities on Community and Soil Physical and Chemical Characteristics in Stipa baicalensis Steppe

During a growing season,the total standing crops,total coverage and average heights of plant community,as well as soil physical and chemical characteristics in different grazing units ofstipa baicalensissteppe,Hulunbeir,were compared and analyzed.These data came from four grazing gradient units that represented four grazing intensities,non-grazing,light-grazing,moderate-grazing and heavy-grazing(grazed by cattle).The results showed that the above mentioned items under different grazing intensities varied regularly,which presented that the vegetation growing and soil condition deteriorated along with the increase of grazing pressure.The total standing crops,total coverage and community heights were notably correlated positively.Soil pH value,electrical conductivity and litterfall were significantlycorrelated negatively.Considering the sensitive response for grazing,varying stability and determining convenience,the community total coverage and soil chemical characteristics could be used as the critical index of grassland health evaluation.