不同土壤水分条件下松嫩草地土壤呼吸及其组分对氮添加和放牧的响应  

Effects of Nitrogen Addition and Grazing on Soil Respiration and Its Components in Songnen Grassland under Varied Soil Moisture Conditions

作　　者：付晓[1] 张睿[1] 袁艺倩 王成亮 史宝库 宋彦彦[2] 梁启[2] 孙伟[1] FU Xiao;ZHANG Rui;YUAN Yiqian;WANG Chengliang;SHI Baokui;SONG Yanyan;LIANG Qi;SUN Wei(Institute of Grassland Science,Northeast Normal University/Key Laboratory of Vegetation Ecology,Ministry of Education/Jilin Songnen Grassland Ecosystem National Observation and Research Station,Changchun 130024,China;ForestrySurvey and Design Institute of Jilin Province,Changchun 130024,China)

机构地区：[1]东北师范大学草地科学研究所/植被生态科学教育部重点实验室/吉林松嫩草地生态系统国家野外科学观测研究站,吉林长春130024 [2]吉林省林业勘察设计研究院,吉林长春130024

出　　处：《中国草地学报》2023年第11期12-23,共12页Chinese Journal of Grassland

基　　金：吉林省科技厅自然科学基金(YDZJ202201ZYTS479);国家自然科学基金项目(32071627)。

摘　　要：量化土壤呼吸的时间变化(包括热时刻)并阐明不同土壤水分条件下(“干旱”和“湿润”)氮沉降增加和放牧干扰对自养呼吸和异养呼吸的影响,有助于准确估算区域生态系统的CO_(2)通量。本研究于2016年在松嫩草甸草原进行了氮添加和放牧处理试验,于2020年6~8月对土壤呼吸及其组分进行连续测定,并同步测定了土壤理化性质、土壤微生物特征和植物生物量。研究发现,在观测期间的“湿润”时期,所有处理的土壤呼吸和自养呼吸均高于“干旱”时期。各处理对土壤呼吸的影响受土壤水分条件调控,即在“干旱”条件下,放牧处理以及氮添加和放牧共同处理显著降低了土壤呼吸,而氮添加显著增加了土壤呼吸和自养呼吸,对异养呼吸无显著影响。在“湿润”条件下,放牧以及氮添加和放牧共同处理增加了土壤呼吸,单独氮添加对土壤呼吸及其组分均无显著影响。研究结果阐明了氮沉降增加和放牧干扰对自养呼吸和异养呼吸影响的水分条件依赖性。Quantifying temporal changes,including thermal-time,in soil respiration(SR)and elucidating the effects of nitrogen addition and grazing on heterotrophic respiration(HR)and autotrophic respiration(AR)under varying water conditions(drought and wet)is crucial for accurately estimating regional scale CO_(2) fluxes.An experiment was conducted in the Songnen Leymus chinensis meadow steppe,commencing in 2016,with four treatments:control(CK),grazing(G),nitrogen addition(N),and grazing plus nitrogen addition(NG).SR,HR,and AR were measured in situ from June to August 2020.Simultaneous measurements of SR were conducted alongside assessments of soil physicochemical properties,soil microbial characteristics,and plant biomass.The results showed that both SR and AR across all the treatments were higher during“wet”periods compared to“drought”periods in Songnen grassland.In this ecosystem,the magnitudes of SR and its components were predominantly influenced by soil moisture content.During“drought”conditions,both G and NG treatments significantly reduced SR,whereas N treatment had the opposite effect,increasing SR and AR without significantly affecting on HR.Conversely,under“wet”condition,G and NG treatments led to increased SR,while N treatment had a negligible impact on SR and its components.These findings illustrated the regulatory role of soil water content in modulating the effects of nitrogen addition and grazing on SR,HR,and AR.

关 键 词：土壤呼吸 土壤水分含量 热时刻 异养呼吸 自养呼吸 放牧 氮添加 

分 类 号：S812.2[农业科学—草业科学]