湘东丘陵红壤有机化合物组成对土地利用的响应  

Response of Organic Compound Composition in Hilly Red Soil to Land-use Changes in Eastern Hunan Province

作　　者：马颢榴 盛浩[1] 宋迪思[1] 张凤[2] 张亮[1] 周萍[3] MA Haoliu;SHENG Hao;SONG Disi;ZHANG Feng;ZHANG Liang;ZHOU Ping(College of Resources & Environment,Hunan Agricultural University,Changsha 410128,China;College of Science,Hunan Agricultural University,Changsha 410128,China;Key Laboratory of Agro-Ecological Processes in Subtropical Region,Institute of SubtropicalAgriculture,Chinese Academy of Sciences,Changsha 410125,China)

机构地区：[1]湖南农业大学资源环境学院,长沙410128 [2]湖南农业大学理学院,长沙410128 [3]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,长沙410125

出　　处：《亚热带资源与环境学报》2018年第4期16-24,40,共10页Journal of Subtropical Resources and Environment

基　　金：国家自然科学基金项目(41571234);湖南省教育厅优秀青年科学研究项目(15B110)

摘　　要：为了解高强度土地利用活动下土壤有机质分子组成和品质变化规律,选取中亚热带湘东丘陵区同一景观单元、利用史清晰的花岗岩红壤4种土地利用方式(天然林以及由此转变而来的人工林、板栗园和坡耕地)为研究对象,分别采集表层(0～20 cm)和底层(80～100 cm)红壤样品,应用热裂解-气相色谱/质谱(Py-GC/MS)技术检测不同土地利用方式下红壤稳定性有机质化合物组成特征。结果表明,土壤有机质以木质素类、脂肪族化合物和含氮化合物为主,表土中富含木质素类和含氮化合物,而底土则以脂肪族化合物为主。木质素类化合物结构相对简单,脂肪族化合物以植物来源为主。天然林地改为其他土地利用方式导致土壤中木质素类化合物相对含量下降25%～88%,指示土壤中相对稳定的有机化合物的损失,木质素成为土地利用变化中土壤向大气释放的碳源。相反,土壤含氮化合物大幅升高1～8倍,脂肪族化合物升高约0. 3～6倍。表土中,相对稳定的有机化合物(如木质素、脂肪族)对土地利用变化响应的敏感性高于底土。土壤有机化合物的组成变化可能与植物/人为有机物输入的数量、化学组成密切相关。为维持和提升花岗岩红壤坡地土壤有机质水平,不仅需要持续补充新鲜有机物的数量,更应注重投入有机物的化合物组成,宜采取多种管理措施丰富土壤有机质的来源。This study was to determine to what extent the loss of red soil carbon(C)pool caused by land use change(natural forest conversion to Chinese fir plantation,orchard,and sloping tillage)is reflected in soil organic compound at the molecular level.Red soil developed on granite was chosen,and samples from topsoil(0-20cm)and subsoil(80-100cm)layers were collected by self-made soil drilling.The indoor thermal pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS)technology was employed to analyze soil organic compound composition.The chromatograms revealed peaks related to compounds derived from lignin compounds,aliphatic compounds and nitrogen(N)compounds.The topsoil was rich in lignin and N compounds,while the subsoil was dominated by aliphatic compounds.After the natural forest was converted to other land-uses,lignin compounds were decreased by25%-88%,indicating a loss of relative stable organic compounds in soil.In contrast,N compounds substantially increased by1-8folds and aliphatic compounds increased by0.3-6folds.The relative stable compound(e.g.lignin and aliphatic)in topsoil was more sensitive to land-use changes than in subsoil.Changes in compound composition of soil are closely related to the quantity and quality of organic matter from plant and human inputs.In order to enhance the soil organic matter level,it needs to continuously supply the quantity and emphasize the quality(compounds)of fresh organic matter.Various managements should be adopted to enrich sources of soil organic matter.

关 键 词：土壤有机质 化学组成 Py-GC/MS 木质素 底土 农业管理 

分 类 号：X144[环境科学与工程—环境科学] S151.1[农业科学—土壤学]