高寒草甸不同海拔梯度土壤有机质氮磷的分布和生产力变化及其与环境因子的关系

Distribution of organic matternitrogen and phosphorus along an altitude gradient and productivity change and their relationships with environmental factors in the Alpine meadow

以高寒草甸6个不同海拔(从低到高依次为3840,3856,3927,3988,4232,4435m)梯度内的野外观测和土壤实测数据,分析了土壤有机质、氮、磷的分布特征及其与土壤含水量和土壤温度之间的关系。结果表明,土壤有机质、土壤全氮、土壤速效氮、土壤全磷含量均在第一梯度(3840m)和第六梯度(4435m)较高,中间梯度较低,但土壤速效磷变化有波动;土壤含水量对土壤有机质、氮、磷作用强度依次为土壤全氮、土壤有机质、土壤全磷、土壤速效氮、土壤速效磷;土壤温度对土壤有机质、氮、磷作用强度依次为土壤速效氮、土壤有机质、土壤全氮、土壤全磷、土壤速效磷;温度对高寒草甸植物群落初级生产力(地上生物量)的作用最大,是决定不同海拔梯度植物群落初级生产力的主要环境因子,其回归方程为:Ya=-92.982+13.832X3(F=13.355,P<0.05)。

The distribution gradient of soil organic matter, nitrogen and phosphorus, productivity changes, and their responses to environmental factors were analyzed in this study. The data analyzed in this study was collected from sites at 6 different altitudes （3 840,3 856,3 927,3 988,4 232,4 435 m）, in the alpine meadow. The results indicated that the amount of soil organic matter, soil total nitrogen, soil available nitrogen and soil total phosphorus were higher at the altitudes of 3 840 m and 4 435 m and lower at the mid--altitude gradients. Soil available phosphorus fluctuated. The effect of precipitation on soil organic matter, nitrogen and phosphorus decreased with soil total nitrogen, soil organic matter, soil total phosphorus, soil available nitrogen and soil available phosphorus. The effect of temperature on soil organic matter, nitrogen and phosphorus decreased with soil available nitrogen, soil organic matter, soil total nitrogen, soil total phosphorus, and soil available phosphorus. Based on the results from the study it was concluded that temperature was the major environmental factor that affected the primary productivity of the plant community in the alpine meadow. The stepwise regression equation with environmental factors was： Ya=-92. 982＋13. 832X3 （F= 13. 355 ,P〈0.05）.