吉林西部草地生态系统不同退化演替阶段土壤有机碳变化研究

草地盐碱化是吉林西部典型的生态环境问题。针对吉林西部具有＂羊草群落（Leymus chinense）→羊草-虎尾草群落（Carex duiuscula）→羊草-碱茅群落（Puccinellia distans）→碱蓬群落（Suaeda glauca）＂直至退化为盐碱地的逆向演替规律,本文选取大安市姜家甸草场为典型区进行野外样地调查,收集不同演替阶段植物样品30份,土壤剖面样品100份,表土样品40份,监测群落生态特征、土壤理化性质,计算土壤有机碳储量。分析结果表明：随着退化演替的进行,羊草-虎尾草群落的多样性指数、植被生物量、土壤有机质最高,土壤含水率及全N指数逐渐降低,土壤的pH值及土壤容重升高,土壤有机碳含量在0～100cm各土层呈现出先升高再降低的趋势,其中0～40cm内变化显著,50～100cm内相差不大,1m土壤有机碳密度从羊草群落的75.37t·hm-2升高到羊草-虎尾草群落的76.11t·hm-2,至盐碱地减少到52.21t·hm-2,约减少30%。研究结果对吉林省合理放牧、草地固碳量的增加和土壤碳储量的提高都有指导意义。

Changes of soil organic carbon in different succession stages of degradation grassland of western Jilin province

Grassland degradation and salinization are the typical ecological problems in western Jilin province.In the process of degradation and salinization,Leymus chinense→Carex duiuscula→Puccinellia tenuiflora→Suaeda glauca,and became saline-alkali land gradually.In this paper,the grassland of Jiangjiadian in Da’an city is selected to investigate.The sampling numbers of vegetation,soil profile,surface soil are respectively 30,100 and 40,which are taken to laboratory for testing community characteristics and soil properties,then calculate soil organic carbon storage.The results show that the diversity index,vegetation biomass, soil organic matter are highest in Carex duiuscula community with the ongoing degradation of succession.Soil moisture and total N are decreased while pH,soil bulk density are increased.The soil organic carbon goes up first and then declines in 0～100 cm soil layer. It is obvious in 0～40 cm.It has little difference in 50～100 cm.The results benefit reasonable grazing in Jilin province,grassland carbon increasing and soil carbon stocks growth.