放牧管理模式对高寒草甸生态系统有机碳、氮储量特征的影响  

Changes in organic carbon and nitrogen storage in alpine meadows under different grazing management regimes

作　　者：李文[1] 曹文侠[1] 师尚礼[1] 李小龙[1] 陈建刚[1] 徐长林[1] 

机构地区：[1]甘肃农业大学草业学院,草业生态系统教育部重点实验室,中-美草地畜牧业可持续发展研究中心,甘肃兰州730070

出　　处：《草业学报》2016年第11期25-33,共9页Acta Prataculturae Sinica

基　　金：国家自然科学基金(31360569);现代农业产业技术体系(CARS-35);甘肃省退牧还草科技支撑项目;青藏高原打草场建设项目资助

摘　　要：为探讨不同放牧管理模式高寒草甸生态系统有机碳、氮储量特征的变化,对青藏高原东缘禁牧（NG）、全生长季休牧（RG）、传统放牧（TG）和连续放牧（CG）4种放牧管理模式高寒草甸地上植被、地表凋落物、根系和土壤有机碳、氮储量进行测定和分析。结果表明,1）NG、RG和TG较CG显著提高了土壤、根系、植被和凋落物有机碳、氮储量。2）高寒草甸生态系统中,土壤有机碳储量所占比例最大（88.859%~98.242%）,其次为根系（1.563%~8.742%）,再次为植被（0.172%~1.430%）,最小为凋落物（0.022%~0.969%）;氮储量所占比例最大的是土壤（97.331%~99.633%）,其次为根系（0.316%~2.071%）,再次为植被（0.047%~0.442%）,凋落物最小（0.003%~0.157%）。3）不同放牧管理模式土壤有机碳、氮储量具有明显的垂直分布特征,随土壤深度的增加土壤有机碳、氮储量明显降低。为期4年不同放牧模式仅对0~40cm土层土壤有机碳、氮储量有影响。4）土壤有机碳、氮储量主要分布在0~40cm土层,同时,放牧有使有机碳、氮向深层转移的趋势。5）NG、RG和TG显著提高了高寒草甸生态系统总有机碳、氮储量,而CG显著降低了总有机碳、氮储量,导致有机碳、氮的流失。禁牧和季节性休牧能有效增加青藏高原东缘高寒草甸生态系统有机碳、氮储量,实现碳、氮增汇的目的,是该区和类似区域草地放牧管理的重要模式。A study has been undertaken to investigate changes in organic carbon and nitrogen storage under different grazing regimes in the alpine meadow ecosystem of the eastern margin of the Qinghai-Tibetan plateau.Organic carbon and nitrogen storage was measured in above-ground biomass,litter,roots and the 0-80 cm soil layer（divided 8layers,and each layer was 10cm）at four sites that represent different grazing management regions：non-grazing（NG）,grazing rest during the growing stage（RG）,traditional grazing（TG）and continuous grazing（CG）.The results indicated that organic carbon and nitrogen in the 0-80 cm soil layer,roots,above-ground tissue and litter were significantly higher in NG,RG and TG than in CG.In general,the proportion of organic carbon in the alpine meadow ecosystem was the largest in soils（88.859%-98.242%）,followed by roots（1.563%-8.742%）,vegetation（0.172%-1.430%）and litter（0.022%-0.969%）;similarly,the proportion of nitrogen was the largest in soils（97.331%-99.633%）,followed by roots（0.316%-2.071%）,vegetation（0.047%-0.442%）and litter（0.003%-0.157%）.There were obvious differences in the vertical distributions of soil organic carbon and nitrogen storage under the four grazing regimes,with these differences mainly affecting the 0-40 cm layer and with no significant effect on deeper layers.Organic carbon and nitrogen storage was mainly distributed in the 0-40 cm layer,with grazing tending to move this storage to deeper layers.NG,RG and TG significantly increased storage in the alpine meadow ecosystem,while CG significantly reduced storage and was associated with a loss of carbon and nitrogen.Non-grazing and seasonal rest grazing can thus contribute to achieving carbon and nitrogen sinks on the eastern margin of the Qinghai-Tibetan Plateau and are important grazing management regimes for this and similar areas.

关 键 词：高寒草甸 放牧管理 有机碳储量 氮储量 

分 类 号：S812[农业科学—草业科学]