湿地松人工林土壤呼吸及其组分对模拟酸雨的响应  

Responses of Soil Respiration and Its Components to Simulated Acid Rain in Pinus elliottii Plantation

作　　者：房焕英[1,2] 肖胜生 余小芳 熊永[5] 欧阳勋志 秦晓蕾[2] Fang Huanying;Xiao Shengsheng;Yu Xiaofang;Xiong Yong;Ouyang Xunzhi;Qin Xiaolei(College of Forestry, Jiangxi Agricultural University Nanchang 330045;Jiangxi Institute of Soil and Water Conservation,Nanchang 330029;Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention,Nanchang 330029;Jiangxi Normal University,Nanchang 330022;Jiangxi Provincial Water Conservancy Planning Design and Research Institute,Nanchang 330029)

机构地区：[1]江西农业大学林学院,南昌330045 [2]江西省水土保持科学研究院,南昌330029 [3]江西省土壤侵蚀与防治重点实验室,南昌330029 [4]江西师范大学,南昌330022 [5]江西省水利规划设计研究院,南昌330029

出　　处：《林业科学》2021年第7期20-31,共12页Scientia Silvae Sinicae

基　　金：国家自然科学基金项目(41303064,41761063);江西省水利科技重大研究项目(KT201716)。

摘　　要：【目的】分析不同强度酸雨对湿地松人工林土壤总呼吸速率(R_(s))及其组分(微生物异养呼吸速率R_(h)和根系自养呼吸速率R_(a))的影响规律,进一步了解森林土壤呼吸过程,为酸沉降胁迫下的森林管理提供科学依据。【方法】以亚热带湿地松人工林为对象,采用壕沟法分离土壤呼吸组分,设置3种酸沉降水平(CK:pH 6.5、低酸LA:pH 4.5,强酸HA:pH 2.5),参照研究区降雨比例分次喷洒,运用LI-8100A土壤碳通量自动测量系统原位测定土壤呼吸速率,同时测定土壤温湿度和土壤生化性质等指标。【结果】不同酸处理下,R_(s)、R_(a)和R_(h)均呈夏季高、冬季低的单峰模式,土壤温度是导致土壤呼吸季节变化的主要驱动因素;酸雨可显著降低R_(s)(P<0.05),LA和HA处理后分别降低25.83%和30.95%,其中,R_(h)分别降低29.60%和35.20%,R_(a)分别降低19.15%和23.40%,但这种抑制效应仅体现在生长季,非生长季LA可显著促进R_(a)(P<0.05);CK样地R_(h)在R_(s)中占比63.94%,LA和HA处理后该比例显著降低(P<0.05),同时R_(a)响应强度随酸雨增强而增加;R_(s)、R_(h)、R_(a)与土壤温度均呈极显著指数关系(P<0.01),酸处理后其温度敏感系数(Q10)均降低;土壤湿度与R_(s)、R_(h)、R_(a)在HA处理下极显著相关(P<0.01),土壤温湿度的协同作用极显著影响土壤呼吸速率(P<0.01);R_(h)变异主要与土壤脲酶、蔗糖酶、表层土壤总有机碳(TOC)含量和土壤pH有关,而R_(a)变异则主要与土壤脲酶、土壤温度和TOC有关,以上因素可共同解释R_(s)变异的83.9%。【结论】土壤总呼吸速率及各组分呼吸速率的季节变化特征相似,主要受土壤温度控制;酸雨造成土壤酸化,引发土壤酶、土壤有机碳含量显著变化或呈一定变化趋势,其共同作用导致R_(h)和R_(a)被抑制,进而显著降低R_(s),土壤水热因子促使这种抑制效应在生长季更显著;R_(h)在R_(s)中的占比随酸雨强度增加而逐渐降低,但短期�【Objective】The study was aimed to investigate the patterns of impacts of acid rain at different intensities on total soil respiration rate(R_(s))and its components of soil heterotrophic respiration rate(R_(h))and soil autotrophic respiration rate(R_(a))in Pinus elliottii plantation,in order to improve our understandings of the process of soil respiration and further to provide a scientific basis for forest management under environmental stresses such as acid deposition.【Method】We conducted a one-way factorial acid rain addition(CK:pH 6.5;low acid addition level(LA):pH 4.5;high acid addition(HA):pH 2.5,with 3 replicates)field experiment in a subtropical P.elliottii plantation in China.The trenching method was used to separate the heterotrophic and autotrophic soil respiration.From January to December of 2015,the R_(s),R_(a),R_(h) effluxes were measured twice a month using a LI-8100A automated soil CO_(2) flux system.Soil temperatures and soil volumetric water content and soil biochemical properties adjacent to each soil respiration points were simultaneously detected.【Result】R_(s),R_(a),R_(h) showed clear seasonal dynamics with similar single peak curves in all treatments,and were mainly driven by the surface soil temperature.Compared to the R_(s) under CK,the R_(s) under LA and HA were significantly reduced by 25.83%and 30.95%(P<0.05).Also,LA and HA treatments inhibited the R_(h) effluxes by 29.60%and 35.20%(P<0.05),reduced the R_(a) effluxes by 19.15% and 23.40%(P<0.05).The inhibitory effect of simulated acid addition on soil respiration rates only showed in the growing season.R_(a) even being promoted in non-growth season(P<0.05).In the CK plots,R_(h) accounted for 63.94%in R_(s),and the proportion was significantly reduced(P<0.05)in the LA and HA treatments.The intensity of R_(a) increased with the enhancement of acid rain.There were significant exponential correlations between R_(s),R_(h),R_(a) and soil temperature(P<0.01),and both addition levels of the simulated acid rain could reduce the temper

关 键 词：土壤呼吸 模拟酸雨 影响机制 呼吸组分 湿地松人工林 

分 类 号：S718.5[农业科学—林学]