基于冗余分析的高寒草原土壤与草地退化关系

在高寒草原退化草地设置研究样地,观测植物群落特征、采集土壤样品、分析土壤物理化学性质,依据数量生态学基本原理,探讨高寒草原退化草地与土壤因子间关系。结果表明:不同退化程度样地沿冗余分析排序图第一排序轴分布,第一排序轴反映草地退化程度的变化;草地植物群落中与第一排序轴负相关且按相关程度大小排序的指标为盖度>地上生物量>地下生物量;第一、第二排序轴能够解释97.1%的土壤因子与草地退化关系;土壤沙砾、p H与第一排序轴正相关,土壤有机碳、土壤含水量、容重、全氮、有效氮与第一排序轴负相关;第一排序轴及所有排序轴所反映的土壤因子均与草地退化之间呈极显著相关关系(P<0.01);不同土壤因子与草地退化之间相关程度不同,土壤有机碳(r=-0.890)、土壤含水量(r=-0.864)、容重(r=-0.847)、全氮(r=-0.836)、有效氮(r=-0.821)等与高寒草原退化相关程度更高且相关关系极显著(P<0.01)。利用退化草地群落特征和土壤因子数据矩阵进行冗余分析能够较好地综合反映土壤因子与草地退化之间的关系及相关程度,土壤有机碳、土壤含水量、容重、全氮、有效氮是反映高寒草原退化的重要土壤指标。

Relationships between soil factors and grassland degradation on an alpine grassland based on redundancy analysis

Based on research sample plots on a degraded alpine grassland,we observed plant community characteristics,collected soil samples,and analyzed soil physical and chemical properties according to the basic principles of quantitative ecology,the relationships between a degraded grassland and soil factors in an alpine grassland were discussed.The first sorting axis of the redundancy analysis ordination diagram showed the distribution of the degree of degradation in the grassland.The grassland plant community was negatively correlated with the first sorting axis,followed by vegetation coverage,aboveground biomass,and underground biomass.The first and second sorting axes explained 97.1％ of the relationships between grassland degradation and soil factors.Sand and pH were positively correlated with the first sorting axis.Soil organic carbon,soil water content,bulk density,total nitrogen,and available nitrogen were negatively correlated with the first sorting axis.The relationship between soil factors and grassland degradation varied and was highly significant in all sorting axes (P＜0.01).The relationship between soil organic carbon (r=-0.890),soil water content (r=-0.864),bulk density (r=-0.847),total nitrogen (r=-0.836),and available nitrogen (r=-0.821) with alpine meadow degradation were highly significantly correlated (P ＜0.01).Redundancy analysis of degraded grassland community characteristics and the soil factor data matrix reflected the relationship between soil factors and grassland degradation and the degree of correlation between soil organic carbon,soil water content,bulk density,total nitrogen,and available nitrogen were the main factors affecting grassland degradation of the alpine grassland.