放牧对草地生态系统磷循环调控机制的研究进展与展望  

Grazing regulation of phosphorus cycling in grassland ecosystems:Advances and prospects

作　　者：乌力吉 李响 赵萌莉 白永飞[2,3] Liji Wu;Xiang Li;Mengli Zhao;Yongfei Bai(College of Grassland,Resources and Environment,Inner Mongolia Agricultural University,Huhhot 010011,China;State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]内蒙古农业大学草原与资源环境学院,呼和浩特010011 [2]中国科学院植物研究所植被与环境变化国家重点实验室,北京100093 [3]中国科学院大学资源与环境学院,北京100049

出　　处：《科学通报》2020年第23期2469-2482,共14页Chinese Science Bulletin

基　　金：国家自然科学基金(31630010)资助。

摘　　要：放牧是全球范围内草地生态系统最主要和最直接的利用方式.磷(P)是植物生长所必需的大量元素,同时也是草地初级生产力的关键限制性养分元素,广泛参与植物的光合、呼吸等重要代谢过程.放牧通过直接和间接作用影响草地植物和土壤各组分的P含量和P库,进而通过正负两种反馈影响生态系统的P循环.目前,国内外有关放牧对草地P循环的影响机制,特别是P循环的生物学过程和机制尚不十分清楚.本文总结了有关放牧对植物和土壤各组分P含量及P库的影响及其机制,并对该领域的几个重要研究方向和亟待回答的科学问题进行了展望.未来研究中需要重点关注的问题包括:(1)土壤微生物量P组成沿不同放牧强度的变化,以及放牧对土壤微生物P源和汇的影响机制;(2)放牧如何影响土壤磷酸酶的活性(磷酸单酯酶、磷酸二酯酶、三磷酸单酯水解酶等)进而调控土壤中P的矿化过程;(3)放牧如何调控P在植物-土壤-微生物系统中的转化过程;(4)采用分子生物学和组学的手段,揭示土壤微生物在P循环及生态系统功能中的作用,以及放牧如何影响植物和根际微生物,进而调控生态系统P循环;(5)不同放牧强度如何影响植物多样性、菌根真菌多样性及两者之间的关系,进而影响植物对P的吸收和利用,以及地上和地下生物量P库;(6)不同家畜种类的食性差异及其对磷循环的影响机制;(7)其他植食动物(野生食草动物、植食昆虫、啮齿动物、蚯蚓、植食性线虫等)在草地生态系统P循环中的作用;(8)不同放牧强度如何调控生态系统各营养级组分的N:P化学计量关系,进而影响N、P循环之间的耦合关系.Grassland ecosystems,which cover a total area of 52.5 million square kilometers and account for 40.5%of the global land surface,are the largest biomes in the world.Grazing is the most dominant and direct land use type in grasslands and a predominant driver regulating multiple ecosystem functions and services,such as primary production,nitrogen(N)and phosphorus(P)cycling,carbon sequestration,forage and food production,and water and soil erosion control etc.Many studies have demonstrated that primary production of grasslands is often limited by water,N and P availability,which interact with grazing to influence the maintenance of ecosystem functions and services.However,compared with numerous studies on the effects of grazing on N cycling and plant water use,fewer studies have explored how grazing influence P cycling of grasslands,particularly the internal cycling of P among main pools within ecosystems.Here we reviewed the advances in grazing effects on soil and plant P pools and biological processes of P cycling.Our review is mainly focused on:(1)Grazing effects on internal and external cycles of P in grassland ecosystems;(2)grazing effects on soil P vertical distribution,and P inputs and outputs mediated by soil erosion and spatial heterogeneity;and(3)mechanisms underlying grazing-induced changes in plant P content and P pools across different levels of organization(individual,species,functional group and community).Finally,we proposed a unified framework synthesizing the influence of grazing on P pools and key biological processes of P cycling in grassland ecosystems.We also proposed eight key questions that need to be addressed in future studies:(1)How do the dominant P forms(e.g.,nucleic acids,phospholipids,cytoplasmic inorganic P,cytoplasmic organic P,and polyphosphate)and concentration within soil microbial biomass vary with grazing intensity?How does the role of microorganisms as sink and source of P change with increasing grazing intensity?(2)How does grazing affect enzyme activities,including phosphomono

关 键 词：放牧生态系统 磷循环 磷含量 磷库 N:P比 磷限制 

分 类 号：S812[农业科学—草业科学]