不同土地利用方式对土壤活性有机质的影响  

Effects of Different Land-use Types on Soil Labile Organic Matter

作　　者：李君剑[1,2] 赵溪[1] 潘恬豪[1] 严俊霞[1] 李洪建[1] 

机构地区：[1]山西大学黄土高原研究所,太原山西030006 [2]城市与区域生态国家重点实验室,中国科学院生态环境研究中心,北京100085

出　　处：《水土保持学报》2011年第1期147-151,共5页Journal of Soil and Water Conservation

基　　金：国家科技支撑计划项目(2008BAD95B04);山西省农业攻关资助项目(2008-03-11075)

摘　　要：不同土地利用方式会影响土壤碳氮通量的活性有机质储量,以撂荒地、沙棘灌木林、华北落叶松人工林和华北落叶松-白桦-山杨混交林为研究对象,测定土壤容重、持水量、粒径组成、分型维数和pH值,并应用H2SO4两步酸水解法测定了土壤活性和顽固性碳氮的季节变化。结果表明:5年弃耕撂荒地土壤理化特征及不同活性有机质含量最差,而沙棘灌木林和乔木林在土壤物理、化学特征和有机质含量方面均有所提高,尤以混交林土壤质量最佳。有机碳和不同活性碳是撂荒地的2～3倍左右,总氮及不同活性氮提高幅度较小,在1.1～1.5之间。土壤活性碳氮受季节变化较大,其中活性碳季节变化幅度更为显著,同时季节效应因土地利用方式而异。土壤持水量、粘粒和分型维数与顽固性有机质含量间存在显著的相关性,活性碳氮分别与有机碳和总氮显著相关。各监测指标显示在几种不同土地利用方式中,自然次生混交林是最佳土地利用方式。Soil labile organic matter which largely dominated carbon and nitrogen flux is subject to different land-use types.In this study,soil physiochemical characteristics were investigated under 5-year abandoned land,Hippophae rhamnoides shrub,Larix principis-rupprechtii plantation and mixed forest（mainly contain of Betula platyphylla,L.principis-rupprechtii and Populus davidiana）.Soil labile and recalcitrant organic matter were measured by the two-step acid hydrolysis with 2.5 mol/L H2SO4 in the first step and 13 mol/L H2SO4 concentrations in the second step.Significant differences were found in soil bulk density,water holding capacity,pH,sand,silt,clay and dimension among four study sites.Soil water-holding capacity was low in deserted land and increased in soil under H.rhamnoides shrubs,L.principis-rupprechtii plantation and mixed forest.Soil bulk density was high in abandoned land and H.rhamnoides shrub and decreased significantly in soil under forests.Soils sampled from study sites were classified as sandy loam but the percent soil silt and clay markedly different between study sites,and the fractal dimension values also differed from each other.Mixed forest possessed of the highest mean contents of soil organic carbon（26.27 g/kg） and total nitrogen（1.79 g/kg）.The lowest soil organic carbon（8.6 g/kg） and total nitrogen（1.00 g/kg） respectively were found in abandoned land and L.principis-rupprechtii plantation.Soil labile I and II carbon,and recalcitrant carbon content and indexes from mixed forest also were significantly higher than other sites.Soil labile pool nitrogen and recalcitrant nitrogen indexes from abandoned land and plantation were significantly lower than other two sites.Season brought on different effects on soil labile carbon and nitrogen with land-use types.The highest and lowest labile I and II carbon always respectively demonstrated in August and May.Season significant influences were only brought on soil labile I nitrogen from H.rhamnoides shrub and L.principis-rupprechtii pla

关 键 词：土地利用方式 活性碳和氮 顽固性碳和氮 顽固性碳和氮指数 

分 类 号：S153.621[农业科学—土壤学]