不同放牧退化程度典型草原植被—土壤系统的有机碳储量

Organic carbon storage in vegetation-soil systems of typical grazing degraded steppes

以典型草原大针茅＋羊草群落为研究目标,以1979年围封样地为参照（CK）,选择轻度（GL）、中度（GM）、重度（GH）放牧退化样地开展植被—土壤系统有机碳分布与储量的研究,结果表明,1）不同放牧退化典型草原植被地上碳储量为42.63~203.16g/m2,植被地下（0~40cm）碳储量为664.14~1 199.53g/m2,且大小顺序均为CK〉GL〉GM〉GH,植被总碳储量CK和GL显著高于GM和GH;植被地上、地下碳储量存在显著相关关系。2）不同放牧退化典型草原土壤0~100cm有机碳储量均存在显著性差异,碳储量为9.85~13.33kg/m2,且GM〉GL〉GH〉CK;土壤有机碳随土层深度增加而减少,有机碳储量与深度具有显著相关性。3）放牧退化典型草原植被—土壤系统的碳储量为11.26~14.07kg/m2,且GM〉GL〉GH〉CK,各类型间亦均存在显著性差异;有机碳主要储存于土壤当中,占比约88%~95%,土壤有机碳储量与植被无显著相关性。4）适度放牧利用有利于发挥草原生态系统的碳汇功能。

Stipa grandis-Leymus chinensis grassland was analyzed for organic carbon storage and distribution in vegetation-soil systems under four different grazing degraded plots （CK：exclosed in 1979, GL：grazed light- ly, GM.grazed moderately, GH：grazed heavily）. The carbon storage in aboveground biomass was 42.63-- 203.16 g/m2, in belowground biomass （0--40 cm） was 664.14--1 199.53 g/m2, and the order in both was CKGL2〉GMGH. The total plant carbon storage in CK and GL were significantly higher （P0.05） than in GM and GH. There was a significant positive correlation between the carbon storage in ahoveground and be- lowground biomass. The carbon storage in the 0--100 cm soil depth among the different grazing degraded grasslands was 9.85-- 13.33 kg/m and they were significantly different from each other in the order GM GL〉GHCK. The carbon storage was significantly correlated with soil depth and was reduced with an in- crease of soil depth. The total carbon storage in the vegetation-soil system was 11.26--14.07 kg/m2 and was significantly （P%0.05） different between the different grazing degraded grasslands in the order GMGL GHCK. Grassland organic carbon was mostly stored in soil, which accounted for 88--95% of the storage. There was no significant correlation between soil organic carbon and plant carbon. Moderate grazing can benefit the carbon sequestration function of grassland ecosystems.