退耕草地演替过程中的碳储量变化  

Changes of carbon storage in vegetation and soil during different successional stages of rehabilitated grassland

作　　者：王俊明[1,2] 张兴昌[1] 

机构地区：[1]黄土高原土壤侵蚀与旱地农业国家重点实验室中国科学院水利部水土保持研究所,陕西杨凌712100 [2]中国科学院研究生院,北京100049

出　　处：《草业学报》2009年第1期1-8,共8页Acta Prataculturae Sinica

基　　金：教育部创新团队支持计划和国家科技支撑计划(2006BAD09)资助

摘　　要：退耕草地演替的研究对了解现有退耕草地的变化趋势有重要意义，也可以为退耕地的植被恢复提供科学依据。本研究采用以空间代替时间的方法，对处于不同演替时间阶段退耕草地的土壤碳储量以及植被的地上部分与根系生物碳储量变化进行了研究，结果表明，退耕草地演替过程中，地上部分生物碳储量呈阶梯式上升趋势，演替初期地上部分生物碳储量先降后升，并在演替的22-32年，保持相对平稳，之后在演替的40-60年，达到第2个相对平稳的阶段。根系生物碳储量也呈分阶段的阶梯式上升趋势，但第1个相对平稳的阶段出现在演替的第12～28年，在演替的第32～60年出现第2个相对平稳的阶段。退耕草地的土壤碳储量在退耕演替的初期下降，且在演替的第1～12年一直小于农地，在演替的第15年之后，土壤碳储量逐步上升。在o～150cm的不同土层中，土壤有机碳含量以0～15cm最高，在演替的1～12年，各土层有机碳含量均小于农地，之后在演替的第15～60年，各土层土壤有机碳含量均随演替时间的增加有所增加，且0～50cm表层土壤有机碳含量在演替第34～60年迅速积累，增幅较大。在演替初期，草地地上部分生物碳储量、根系生物碳储量和土壤碳储量较演替第1年均表现为下降趋势，表明退耕初期生态环境并没有改善，如何缩短这段时间需进一步研究。Over the last few decades the extent of land-use and vegetation composition has dramatically changed in the Loess Plateau. For a better understanding of the dynamics of rehabilitated grassland, carbon storage in vegetation and soil were studied in a space series of replaced time courses. The aboveground biomass carbon did not directly increase at the beginning stage of succession, but decreased to its lowest point in the second year following abandonment. After abandonment for 22 to 32 years, the aboveground biomass carbon increased to a steady state and after abandonment for 40 and 60 years, it approached a second steady state. The dynamics of root biomass carbon was similar to that of aboveground biomass carbon. Between abandonment ages 12 and 28 years, the root biomass carbon reached a steady state and between abandonment ages 32 and 60 years, the root biomass carbon approached a second steady state. Compared with cropland, the rehabilitated grassland had a lower soil organic carbon storage at the beginning （1-12 years） but after 15 years the soil organic carbon storcontent of the 0 to 15 cm layer was the highest. Our study indicated that in the ear bilitated grassland, the aboveground biomass carbon, root biomass carbon and so y successional stage of reha organic carbon storage did not increase, but remained at a low-level for about 10 years. Further study is required to work out how to reduce this delay.

关 键 词：退耕草地 演替 土壤碳储量 地上部分生物碳储量 根系生物碳储量 

分 类 号：S812[农业科学—草业科学]