牧压梯度下高寒草甸植被生物量与土壤理化性质变化特征及相互关系  

Characteristics and interrelationship of vegetation biomass and soil properties in alpine meadow under grazing gradients

作　　者：祝景彬 张志成 李红琴 吴启华 贺慧丹 张法伟[2,5] 李英年[2,5] ZHU JingBin;ZHANG ZhiCheng;LI HongQin;WU QiHua;HE HuiDan;ZHANG FaWei;LI YingNian(College of Tourism,Resources and Environment,Zaozhuang University,Zaozhuang 277160,China;Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001,China;College of Life Sciences,Luoyang Normal University,Luoyang 471934,China;Institute of Nanfan&Seed Industry,Guangdong Academy of Sciences,Guangzhou 510316,China;Key Laboratory of Adaptation and Evolution of Plateau Biota,Chinese Academy of Sciences,Xining 810001,China)

机构地区：[1]枣庄学院旅游与资源环境学院,枣庄277160 [2]中国科学院西北高原生物研究所,西宁810001 [3]洛阳师范学院生命科学学院,洛阳471934 [4]广东省科学院南繁种业研究所,广州510316 [5]中国科学院高原生物适应与进化重点实验室,西宁810001

出　　处：《中国科学：生命科学》2023年第8期1166-1175,共10页Scientia Sinica(Vitae)

基　　金：国家自然科学基金(批准号:32001185);山东省自然科学基金(批准号:ZR2021QC222);山东省高等学校青创科技计划创新团队项目(批准号:2022KJ278);中国科学院和青海省人民政府三江源国家公园联合专项(批准号:LHZX-2020-07);国家林业和草原局经济发展研究中心业务委托项目(批准号:JYFL-2021-00020);枣庄学院“青檀学者”人才项目资助。

摘　　要：高寒草地是青藏高原主要的植被类型之一,然而其生物量及土壤性状变化特征与放牧管理的耦合研究仍相对薄弱,不利于高寒草地的可持续利用.本文以青藏高原东北部高寒矮嵩草草甸为研究对象,设置封育禁牧(control check,CK)、轻牧(light grazing,LG)、中牧(medium grazing,MG)和重牧(heavy grazing,HG)放牧梯度实验样地,分析了不同放牧梯度下高寒草甸生物量与土壤性状变化特征及相互关系.结果表明,生长季中不同牧压梯度下地上生物量均表现为LG>MG>CK>HG,0~40 cm地下生物量表现为MG>LG>HG>CK,说明适度放牧(LG,MG)有助于提高高寒草甸地上、地下生物量.0~10 cm地下生物量分配比表现为LG>MG>CK>HG,暗示过度放牧压力下会使高寒草甸根系更多集中于深层土壤.根冠比基本表现为HG>MG>LG>CK,表明放牧会使高寒草甸生物量更倾向于往地下分配.放牧减少了高寒草甸有机碳(soil organic carbon,SOC)的含量,提高了土壤pH.适度放牧降低了土壤C/N和土壤容重(bulk density,BD),增加了高寒草甸的土壤速效氮(soil available nitrogen,SAN)和土壤含水量(soil water content,SWC).不同牧压梯度下,高寒草甸地上、地下生物量及其分配的主要驱动因子分别为BD,SAN和pH.结果表明,过度放牧降低了生物量并增大了根冠比,适度放牧是维持高寒草甸可持续发展的必要措施.研究结果可为准确评估高寒草甸碳循环过程提供参考,并为寒草甸的适应性管理提供理论依据.Alpine meadow is an important part of the alpine ecosystem on the Qinghai-Tibet Plateau,and is sensitive to climate change and human activities.Grazing was the main utilization mode of alpine meadow,and overgrazing caused the degradation of alpine meadow.Biomass is the most important quantitative characteristic of the ecosystem and the main embodiment of the ecosystem’s ability to obtain energy.The distribution pattern of plant biomass is not only very important for the study of plant growth,but also crucial for the carbon,nitrogen and water cycle process of grassland ecosystem.However,the dynamics of aboveground and belowground biomass allocation and its influencing mechanism under different grazing gradients in alpine meadow are still relatively weak.In this paper,the alpine meadow in the northeast of Qinghai-Tibet Plateau was selected as the research object,and the experimental plots with grazing gradients of forbidden grazing(control check,CK),light grazing(LG),medium grazing(MG)and heavy grazing(HG)were set up.The characteristics and driving mechanism of biomass allocation in the alpine meadow under different grazing gradients were analyzed.The results showed that the aboveground biomass of alpine meadow showed a unimodal trend under different grazing gradients,and reached the peak in August.The average aboveground biomass of alpine meadow in the growing season was LG>MG>CK>HG under different grazing gradients.The variation trend of belowground biomass(0–40 cm)in the growing season was basically the same,showing that the belowground biomass increased at the beginning of the growing season,decreased at the flourishing stage(July and August),and then increased again at the end of the growing season(September).The mean value of belowground biomass in the whole growing season was MG>LG>HG>CK.These results indicated that moderate grazing was helpful to improve the aboveground and belowground biomass of alpine meadow,while grazing prohibition and overgrazing were not conducive to the improvement of biomass.Und

关 键 词：青藏高原 高寒草甸 放牧 生物量 根冠比 

分 类 号：S812[农业科学—草业科学]