青藏高原芨芨草型温性草原不同土地利用方式的理论碳增汇潜力比较

Response of Potential Carbon Sequestration Capacity to Different Land Use Patterns in Achnatherum splendens Grassland in Qinghai-Tibetan Plateau

于2009年7－8月对青藏高原芨芨草（Achnatherum splendens）型温性草原主要分布区的4种土地利用类型──原生草地、退化草地、农田耕种和退耕还草区的土壤容重、土壤有机碳含量和植物地上、地下生物量进行对比研究,以探讨土地利用方式对青藏高原草地生态系统碳储垂向分布的影响.结果表明,土地利用方式显著影响着浅层（0－20 cm）土壤容重和地下生物量（P〈0.05）;农田耕种和退耕还草对土壤有机碳含量的影响程度可深达60cm;农田耕种区和退耕还草区的地上生物量极显著高于原生草地区和退化草地区（P〈0.01）;原生草地、退化草地、农田耕种区和退耕还草区的系统（植物＋0-40 cm土壤）碳储分别为122.84、108.82、130.68和108.99 t·hm^-2;以原生草地区地下系统碳储为参照,退化草地、农田耕种区和退耕还草区的增汇潜力分别为14.05、-6.38和14.88 t·hm^-2,但增汇的时间效益和经济效益区别较大.

To understand the influence on grassland ecosystem carbon stock vertical profiles and carbon services function for land use changes,we surveyed the soil bulk density,soil organic carbon,aboveground and belowground biomass under 4 different land use patterns（native grassland,degraded grassland,cultivation and plantation） in main temperate grassland region on the Qinghai-Tibetan Plateau from July to August in 2009.The results showed that soil bulk density and belowground biomass of 0~20 cm depth was remarkably influenced by land use patterns（P0.05）.Plantation and cultivation had significantly impacted soil organic carbon and been even up to 60 cm deep.Aboveground biomass of cultivation and plantation was much more enhanced than that of native and degraded grassland（P0.01）.The ecosystem carbon stock（plant＋0~40 cm soil） of native,degraded grassland,cultivation and plantation was 122.84,108.82,130.68 and 108.99 t·hm^-2,respectively.The carbon sequestration potential was defined as the difference with belowground carbon stock of native grassland and was 14.05,-6.38 and 14.88 t·hm^-2.However,there would be much more different in time-consuming and economy-investing.