不同利用程度高寒干旱草地碳储量的变化特征分析

Analysis of the change of carbon storage in alpine arid grassland

本研究对处于青海湖北部不同退化梯度草地的土壤碳储量以及植被的根系生物碳储量变化进行了研究。调查草地样本包括7个样地和4个土层,样地依次分别为严重退化草场、重度退化草场、中度退化草场、轻度退化草场、正常草场、封育3年草场和人工草场,土层分别为0-10,10-20,20-30与30-40 cm 4个土层。结果表明,在不同退化梯度上,土壤碳储量随着退化程度的减轻依次增大,总体上各样地之间的变化趋势为,在5-7月为轻度退化草地〉无退化草地〉中度退化草地〉重度退化草地〉人工草地草地〉封育草地〉严重退化草地;在8-10月为无退化草地〉轻度退化草地〉中度退化草地〉重度退化草地〉封育草地〉人工草地〉严重退化草地,严重退化草地土壤碳储量最低,其次为封育草地;封育草地和人工草地的碳储量显著的低于轻度退化和无退化草地（P〈0.05）,但在封育草地和人工草地之间无显著差异（P〉0.05）。在不同的土层,土壤碳储量从上至下依次降低,且各层之间表现出显著差异（P〈0.05）。在不同的月份,各土层深度的土壤碳储量,总体上均表现为5-6月份降低,6-10月份呈递增的变化趋势,而且不同退化草地都表现出了较为一致的变化趋势。

The different change of organic carbon contents of the 0-10,10-20,20-30,30-40 cm soil layers were studied on based on seven different alpine meadow-use types,which were serious degraded（SD）,heavy degraded（HD）,moderate degraded（MD）,light degraded（LD）,non-degraded（ND）,fenced-ungrazed（FUG） and artificial-pasture（AP）,in the northeastern of Qinghai Lake Region.The storage of soil organic carbon per unit area varied in the order of LDNDMDHDAPFUGSD in the May to July,in the order of NDLDMDHDFUGAPSD in the August to October,the soil organic carbon in the fenced-ungrazed and artificial-pasture was significantly（P0.05） lower than that in lightly degraded and non-degraded,no significant difference was found between in the fenced-ungrazed and artificial-pasturer（P0.05）.From 0-10 to 30-40 cm soil layers,the storage of soil organic carbon per unit area varied in the order of 0-1010-2020-3030-40 cm and was significantly（P0.05）.In different months,the carbon storage decreased dramatically from May to June and increased from July to October.