高寒草甸植物根系生物量及有机碳含量与土壤机械组成的关系

Relationship between root biomass,soil organic carbon and soil mechanical composition in alpine meadow

研究了青藏高原藏嵩草沼泽化草甸、矮嵩草草甸、小嵩草草甸和金露梅灌丛植物根系分布、土壤有机碳含量的变化特征,并探讨了这四种草甸类型植被根系、土壤有机碳含量与土壤机械组成的关系.结果表明,四种高寒草甸植被根系生物量分别为13.39kgm-2、2.03 kg m-2、1.32 kg m-2和2.35 kg m-2,其中藏嵩草沼泽化草甸根系生物量显著高于其它三种高寒草甸,且均随土壤层次的加深而显著降低;四种高寒草甸土壤有机碳含量分别为1.51gkg-1、0.60g kg-1、0.51gkg-1和0.61gkg-1,也随土层的加深而显著降低,其中藏嵩草沼泽化草甸的有机碳含量显著高于其它三种草甸类型.植被根系和土壤有机碳分布格局及含量对土壤机械组成有显著影响,但土壤有机碳对土壤机械组成的影响弱于土壤根系.土壤质地与植被根系、土壤有机碳含量显著相关,三者相互影响共同作用,维持着高寒草甸生态系统的稳定性.

The characteristics of plant roots and soil organic carbon were studied at the Kobresia tibetica swamp meadow,K. humilismeadow,K. pygmaea meadow,and Potentilla fruoticosa shrub in alpine meadow,and the relationship between root biomass,soil organic carbon and soil mechanical composition in different grassland types were analyzed. The results showed that the root biomass were 13. 39 kg m^- 2,2. 03 kg m^- 2,1. 32 kg m^- 2and 2. 35 kg m^- 2,respectively,with the highest root biomass in the Kobresia tibetica swamp meadow. The root biomass significantly decreased with soil depth. The content of soil organic carbon in the Kobresia tibetica swamp meadow,K. humilis meadow,K. pygmaea meadow,and Potentilla fruticosa shrub were 1. 51 g kg^- 1,0. 60 g kg^- 1,0. 51 g kg^-1 and 0. 61 g kg^- 1,respectively. The soil organic carbon content also showed a significant decrease with soil depth. The root biomass and soil organic carbon had significant effects on the soil mechanical composition,while effect of root biomass was more than soil organic carbon. There is a close linear relationship among soil texture,root biomass and soil organic carbon. They interate with each other,and maintain the stability of alpine meadow ecosystem together.