酸雨类型转变对杉木林地土壤和细根生长的影响  

Effects of acid rain-based transformation on Cunninghamia lanceolata fine root growth and soil nutrient content

作　　者：丁咏 刘鑫[1] 张金池[1] 王宇浩 陈美玲 李涛[1] 刘孝武 周悦湘 孙连浩 廖艺 DING Yong;LIU Xin;ZHANG Jinchi;WANG Yuhao;CHEN Meiling;LI Tao;LIU Xiaowu;ZHOU Yuexiang;SUN Lianhao;LIAO Yi(Co-Innovation Center for Sustainable Forestry in Southern China,Jiangsu Provincal Key Laboratory of Soil and Water Conservation and Ecological Restoration,College of Forestry and Grassland,College of Water and Soil Conservation,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学林草学院、水土保持学院,南方现代林业协同创新中心,江苏省水土保持与生态修复重点实验室,江苏南京210037

出　　处：《南京林业大学学报（自然科学版）》2024年第3期90-98,共9页Journal of Nanjing Forestry University：Natural Sciences Edition

基　　金：江苏省自然科学基金青年基金项目(BK20200785);江苏省研究生科研与实践创新计划项目(KYCX23_1240);江苏高校优势学科建设工程资助项目(PAPD);江苏省科技计划项目(BE2022420)。

摘　　要：【目的】探究酸雨类型转变对杉木细根生长和土壤养分含量的影响,为改善酸雨胁迫地区杉木人工林土壤酸化提供依据。【方法】在江苏南京铜山林场进行了为期1 a的野外模拟酸雨试验,设置了3种酸雨酸度(pH为4.5,3.5和2.5)和3种酸雨类型[硫酸型酸雨,SO_(4)^(2-)与NO_(3)^(-)的浓度比(硫氮比)5∶1。混合型酸雨,硫氮比1∶1。硝酸型酸雨,硫氮比1∶5],并设置对照CK(pH为6.6,利用当地自然溪水),共10个试验处理。分别测定酸雨胁迫后杉木林地土壤化学性质、细根生理特性及细根元素含量,利用相关性及结构方程模型分析方法,探究酸雨类型转变对杉木细根生长的直接及间接影响。【结果】随着酸雨pH和硫氮比的降低,杉木细根生物量和根系活力均减少。所有强酸雨处理(pH 2.5)杉木根系的过氧化氢酶活性均低于其他酸雨处理,且当酸雨类型转变为硝酸型酸雨时,过氧化氢酶活性逐渐降低并低于CK;另外,细根镁、铝含量及钙铝比(含量比,下同)和镁铝比在不同的硫氮比处理之间均存在差异。与CK相比,所有酸雨处理均增加了细根钙和铝含量,钾含量随着酸雨胁迫逐渐减少。然而,土壤养分总碳、总氮、碳氮比、总硫、有效磷和速效钾在不同硫氮比和不同pH之间不存在显著差异。通过相关性分析可知:土壤pH与镁铝比、根系生物量和根系活力呈极显著正相关(P<0.01),并且根系生物量与过氧化物酶、过氧化氢酶之间均呈显著正相关(P<0.05),却与铝含量呈极显著负相关(P<0.01)。【结论】酸雨酸度对杉木细根和土壤均有较大影响,酸雨类型对细根的影响要强于土壤。其中,酸雨类型对根系活力和钙铝比均有直接影响。随着硫氮比值的降低,酸雨对杉木细根生长的抑制作用更明显。【Objective】This study explored the effects of acid rain-based changes in soil nutrient content and Chinese fir(Cunninghamia lanceolata)fine root growth,to provide a theoretical basis for improving soil acidification of C.lanceolata plantations in acid rain-stressed areas.【Method】A one-year simulated acid rain field experiment was conducted at the Tongshan Forest Farm in Nanjing,Jiangsu Province.Three acid rain acidity levels(pH=4.5,3.5,and 2.5)were applied with each of three acid rain types:sulfuric acid rain,with 5∶1 concentration ratio of sulfur(S,SO_(4)^(2-))to nitrogen(N,NO_(3)^(-));mixed acid rain,with 1∶1 S/N ratio;nitric acid rain,with 1∶5 S/N ratio;and a control(CK,pH=6.6,local river water).There were thus 10 total experimental treatments.Outcome measures of acid rain stress included soil chemical properties,fine root physiological characteristics,and fine root element contents.Correlations and structural equation model analyses were used to explore the direct and indirect effects of acid rain type on C.lanceolata fine root growth.【Result】With decreasing acid rain pH and S/N ratios,the fine root biomass and root activity of C.lanceolata decreased.The catalase activity of all strong acid rain treatments(pH=2.5)was lower than that of other acid rain treatments.Compared with nitric acid rain types,the catalase activity incrementally decreased and was lower than CK;Mg and Al content,as well as the c(Ca)/c(Al)and c(Mg)/c(Al)in fine roots also differed.Compared with CK,all acid rain treatments increased fine root Ca and Al contents,while K content decreased with acid rain stress.However,there were not significant differences in soil total C,total N,C/N ratio,total S,available P,or available K among S/N ratios or pH levels.Correlation analysis showed that soil pH was extremely significant positively correlated with c(Mg)/c(Al),root biomass,and root activity(P<0.01),and that root biomass was significantly positively correlated with peroxidase,catalase,but extremely significant negative correlate

关 键 词：杉木 酸雨 硫氮比 细根生物量 土壤养分 

分 类 号：S718[农业科学—林学]