呼伦贝尔草甸草原主要功能群植物碳、氮、磷化学计量特征对氮磷添加的响应  

Response of Carbon,Nitrogen,and Phosphorus Stoichiometric Characteristics in Dominant Plant Functional Groups of the Hulun Buir Meadow Steppe to Nitrogen and Phosphorus Addition

作　　者：肖红[1] 戎郁萍[2] 李鹏珍 刘玉玲 XIAO Hong;RONG Yuping;LI Pengzhen;LIU Yuling(College of Pratacultural Science,Gansu Agricultural University/Key Laboratory of Grassland Ecosystem,Ministry of Education,Lanzhou 730070,China;College of Grassland Science and Technology,China Agricultural University,Beijing 100193,China)

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,甘肃兰州730070 [2]中国农业大学草业科学与技术学院,北京100193

出　　处：《中国草地学报》2023年第10期1-11,共11页Chinese Journal of Grassland

基　　金：甘肃省教育厅青年博士基金项目(2022QB-072);国家重点研发计划项目(2021YFD1300503)。

摘　　要：刈割是呼伦贝尔草甸草原的主要利用方式,连年打草导致草地养分不断输出,植物生长受到氮磷养分的共同限制。碳、氮、磷是生态化学计量学关注的重点,然而,草甸草原不同功能群植物C∶N∶P化学计量特征对氮磷养分输入的响应规律尚不明确。本研究于2018~2020年在呼伦贝尔草甸草原打草场采用裂区试验设计研究了氮磷添加对土壤和植物碳氮磷含量的影响。结果表明,氮添加显著增加了禾本科植物C含量,对豆科和菊科植物C含量影响较小。氮添加显著增加了各功能群植物N含量并降低了其C∶N,磷添加显著增加各功能群植物P含量并降低其C∶P。氮添加降低了菊科植物P含量,禾本科和豆科植物P含量不受氮添加的调控。氮添加显著提高了各功能群植物N∶P,禾本科植物的响应更敏感,在低氮(N1)处理下即可表现出磷限制。豆科植物在对照处理下的N∶P大于16,生长受到磷限制。磷添加显著降低了各功能群植物N∶P,使得禾本科植物生长氮限制加剧,而豆科植物生长由磷限制转为氮限制。各功能群植物的C∶P和N∶P均与土壤全磷含量显著负相关,与土壤全碳和全氮含量无显著相关性。综上,呼伦贝尔草甸草原植物生长受到氮磷养分的共同限制,建议在打草场养分管理中,氮肥施入量高于1.55 g N/(m^(2)·a)时,应配施磷肥[<5.24 g P/(m^(2)·a)]以缓解禾本科牧草生长磷限制,维持打草场的可持续利用。Mowing is the predominant grassland utilization pattern in Hulun Buir.However,consecutive years of mowing can lead to the excessive depletion of soil nutrients in meadow steppe,resulting in limited nitrogen(N)and phosphorus(P)resources available for plant growth.Carbon(C),nitrogen and phosphorus are the focus of ecological stoichiometry,Nevertheless,the responses of plant functional groups concerning C:N∶P stoichiometry to N and P addition remain unclear.To address this,we conducted a threeyear spit plot experiment(2018~2020)in Hulun Buir meadow steppe to investigate the effects of varying levels of N and P addition on the contents of C,N and P in plants and soil.The results showed that N addition led to an increase in C content within the gramineae,while C content in leguminosae and compositae remained relatively constant.Furthermore,N addition significantly augmented N content and reduced C∶N ratio across different plant functional groups.In contrast,P addition notably raised P content and lowered C∶P ratio in these plant functional groups.It was noteworthy that N addition decreased the P content in com‑positae,whereas no significant correlation was observed between P content and N addition in gramineae and leguminosae.Moreover,N addition substantially elevated N∶P ratio in different plant functional groups,with grasses displaying a heighted sensitivity,particularly demonstrating P limitation under low level N(N1)addition treatment.Meanwhile,legumes exhibited N∶P ratio exceeding 16 in the control group,constraining their growth due to P deficiency.Conversely,P addition significantly diminished N∶P ratio in various plant functional groups,resulting in increased N limitation for gramineae plants while transitioning from P limitation to N limitation in leguminosae plants.The C∶P and N∶P ratios across different functional groups exhibited significant negative correlations with soil total P content but displayed no significant correlation with soil total C and total N content.In summary,plant growt

关 键 词：氮添加 磷添加 植物功能群 碳氮磷含量 化学计量比 

分 类 号：Q948[生物学—植物学] S812[农业科学—草业科学]