南方型杨树人工林土壤呼吸及其组分分析  

Partitioning of autotrophic and heterotrophic soil respiration in southern type poplar plantations

作　　者：唐罗忠[1] 葛晓敏[1] 吴麟[1] 田野[1] 魏勇[1] 

机构地区：[1]南京林业大学森林资源与环境学院,南京210037

出　　处：《生态学报》2012年第22期7000-7008,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30872013)

摘　　要：采用开沟隔离法,利用LI-8100型土壤呼吸测定系统,对15年生的南方型杨树(Populus deltoides)人工林土壤呼吸进行了研究,并试图区分根系呼吸和土壤微生物呼吸。结果表明,开沟隔离处理后的10个月内,由于土壤中被截断根系具有自养呼吸和分解作用,土壤呼吸中的根系呼吸与微生物呼吸尚难以区分。尽管如此,研究表明15年生杨树人工林的土壤总呼吸通量为9.74 tC.hm-.2a-1,其中,枯枝落叶等土壤表层凋落物分解所释放的碳通量是2.63 tC.hm-.2a-1,占总量的27.0%;林木根系呼吸与土壤微生物呼吸通量的和为7.11 tC.hm-.2a-1,占总量的73.0%。土壤各组分呼吸速率与10 cm深处的土壤温度之间存在着显著的指数函数关系。不同直径的杨树根系被截断后的活力变化有所不同,根系越粗,存活时间越长。Soil respiration in forests is an important part of the carbon cycle in terrestrial ecosystems.It primarily includes respiration occurring in plant roots（autotrophic respiration） and in soil microbes（heterotrophic respiration）.The carbon sources for autotrophic and heterotrophic respiration are different,and their contributions to total soil respiration may also be different.Understanding the mechanisms of soil respiration require separating its component.Many studies have focused on developing methods to separate the components of soil respiration,such as the root exclusion method,isotopic method,and in situ root techniques although each method has some defects.The trenching method is generally considered effective and can separate root and microbial contributions from total soil respiration in forested ecosystems.Poplar,one of the most important timber species,also provides important ecological services.Currently,China has about seven million hectares of poplar plantations,and it plays an important role in a supplying the country′s timber demand.However,few published reports can be found related to the characteristics of soil respiration.The contributions of root and microbial respiration to the total soil respiration in poplar plantations remain unclear.In this paper,the components of soil respiration were partitioned in a poplar（Populus deltoides Bartr.cv.＇Lux＇） plantation using the trenching method with a LI-8100 automated CO2 flux system（LI-COR,Inc.,Lincoln,NE,USA）.The study was conducted at a 15-year-old poplar plantation located at Siyang Farm,Siyang County,Jiangsu Province,China（33°42′N,118°09′E）.The trees averaged 30 cm diameter at breast height and 26 m tall. In early January,2009,experiments with three treatments and four repetitions were set up in this poplar plantation.The three treatments were designed as litter removal with trenching（treatment A）,litter removal without trenching（treatment B）,and a control（treatment C）.Based on the trenching method theory

关 键 词：杨树 人工林 土壤呼吸 根系呼吸 

分 类 号：S792.11[农业科学—林木遗传育种]