【作者】 胡向敏；

【导师】 侯向阳；

【作者基本信息】 中国农业科学院 ， 草地资源利用与保护， 2014， 博士

【摘要】 内蒙古短花针茅荒漠草原是草原向荒漠区过渡的生态系统，生态环境严酷，稳定性差，对气候和环境变化反应十分敏感。研究不同放牧制度下短花针茅荒漠草原碳储量变化规律对于深入揭示草原生态系统及全球碳储量循环过程和机制具有重要意义。本论文利用于1999年在内蒙古苏尼特右旗建立的短花针茅荒漠草原放牧试验平台，选取自由放牧样地、划区轮牧样地和围栏禁牧三类样地为研究对象，通过2012年和2013年生长季内对土壤、根系、地上植物和枯落物有机碳储量变化规律的连续观测，探讨短花针茅荒漠草原土壤-植物生态系统有机碳储量对不同放牧制度的响应过程，从碳储量角度为草原合理利用提供理论参考。主要结论如下：1、植物有机碳储量月变化和季节变化明显，根系和地上植物有机碳储量变化表现单峰曲线，8月份出现峰值；枯落物有机碳储量变化表现“V”型，8月份出现最低值。2、不同放牧制度明显改变土壤有机碳储量月变化过程，不同年份下土壤有机碳储量季节变化趋势不同，根系、地上植物和枯落物有机碳储量年际变化明显。3、划区轮牧中早期放牧（5月份初）有利于根系有机碳积累，中期放牧（5月份中旬和6月份初）有利于土壤、地上植物和枯落物有机储量积累。4、生态系统各组分有机碳储量贡献存在明显差别，表现为土壤>根系>地上植物>枯落物，生态系统有机碳储量变化主要由土壤碳储量变化引起，草原地下部分是最主要碳库。5、综合分析表明，有利于生态系统有机碳储量积累放牧制度排序为围栏禁牧>划区轮牧>自由放牧，在划区轮牧中延迟放牧较早期放牧更有利于生态系统有机碳储量积累。更多还原

【Abstract】 The Stipa breviflora desert steppe of Inner Mongolia is a transitional ecosystem from grassland todesert, its ecological environment is harsh, its stability is poor, and the response of ecosystem to climateand environment change is sensitive. Study on the change characteristics of its organic carbon storage ofunder different grazing systems, it is of great significance for further revealing the cycle process andmechanism of grassland ecosystem and global carbon storage.The change characteristics of soil, root,aboveground plant and litter organic carbon storage were studied under different grazing systems ingrowing season from2012to2013, which were continuous grazing (CG), rotational grazing(RG) andnon-grazing(NG) based on grassland grazing experiment platform in Stipa breviflora desert steppeestablished in Sonid Right Banner of Inner Mongolia in1999.Discussing the response of soil-plantecosystem organic carbon storage to different grazing systems, in order to provide theoretical referencefor grassland reasonable use from the perspective of carbon storage.The main conclusions were asfollows:1. The monthly change and seasonal change of plant organic carbon storage were obvious, theorganic carbon storage change of root and above ground plant were a single peak curve, reached thepeak in August, and the litter organic carbon storage change showed the principle of V type, theminimum value appeared in August.2. Grazing systems could change the monthly change course of soil organic carbon storageobviously. The seasonal change of soil organic carbon storage had different trends among different years,and interannual change of root, aboveground plant and litter organic carbon storage were obvious.3. Early grazing at the beginning of May was benefit for root organic carbon storage accumulationunder rotational grazing, while mid-grazing in mid of May and early June was good for soil,aboveground plant and litter organic carbon storage accumulation.4. The components contributions to ecosystem organic carbon storage existed an obviousdifference, that was soil>root>aboveground plant>litter, soil organic carbon storage could lead toecosystem organic carbon storage change, underground part organic carbon storage was the main carbonpool.5. The comprehensive analysis suggested that reasonable grazing systems contributed to ecosystemorganic carbon storage accumulation, the order was NG>RG>CG under different grazing systems,deferred grazing was better than early grazing under rotational grazing.更多还原