火干扰对兴安落叶松林土壤氮组分及土壤中氮循环功能基因的影响  

Effects of Fire Disturbance on Soil Nitrogen Fractions and Functional Genes of Nitrogen Cycling in Soil of Larix gmelinii Forests

作　　者：李航 陈金平 丁兆华 舒洋 魏江生 赵鹏武 周梅[3,4] 王宇轩 梁驰昊[1,2] 张轶超 LI Hang;CHEN Jinping;DING Zhaohua;SHU Yang;WEI Jiangsheng;ZHAO Pengwu;ZHOU Mei;WANG Yuxuan;LIANG Chihao;ZHANG Yichao(College of Grassland,Resources and Environment,Inner Mongolia Agricultural University,Hohhot 010020,P.R.China;Inner Mongolia Key Laboratory of Soil Quality and Nutrient Resource,Hohhot 010020,P.R.China;Forestry College of Inner Mongolia Agricultural University,Hohhot 010020,P.R.China;Saihanwla Forest Ecosystem National Station,Chifeng 024000,P.R.China;Inner Mongolia Genhe Forest Industry Co.LTD,Genhe 022350,P.R.China)

机构地区：[1]内蒙古农业大学草原与资源环境学院,内蒙古呼和浩特010011 [2]内蒙古自治区土壤质量与养分资源重点实验室,内蒙古呼和浩特010011 [3]内蒙古赛罕乌拉森林生态系统国家定位观测研究站,内蒙古赤峰025150 [4]内蒙古农业大学林学院,内蒙古呼和浩特010019 [5]内蒙古根河森林工业有限公司,内蒙古根河022350

出　　处：《生态环境学报》2023年第9期1563-1573,共11页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目(32001325);内蒙古自治区科技成果转换项目(2021CG0002)。

摘　　要：森林火灾通过影响土壤生物和非生物部分对土壤氮循环产生长期影响。在全球林火频发背景下,为探讨火灾与土壤氮循环之间的长期响应关系,选择火后1、6、11年兴安落叶松林(Larix gmelinii)重度火烧迹地为研究对象,通过测定土壤氮组分、氮循环功能基因和土壤基本理化性质,分析火后土壤氮组分和氮循环功能基因丰度随恢复年限的变化趋势,以及主要影响因子。结果表明,(1)土壤全氮、铵态氮和微生物量氮(MBN)含量随恢复年限呈现先降低后增加的趋势,其中MBN恢复较慢。火干扰导致土壤硝态氮含量在火后1年显著增加(P<0.05),火后6、11年均低于对照样地。(2)固氮nifH功能基因在火后11年恢复到火烧前的水平,而反硝化nirS、nirK和nosZ功能基因在火后6年显著高于对照样地,火干扰显著提高了硝化amoA-AOA和amoA-AOB功能基因丰度。(3)相关性分析表明固氮nifH功能基因与土壤全氮、铵态氮和MBN呈显著的正相关关系(P<0.05);硝化amoA-AOA功能基因与硝态氮呈极显著的正相关关系(P<0.01);反硝化nirS、nirK功能基因与硝态氮呈显著负相关关系(P<0.05)。(4)冗余分析结果表明土壤有机质、含水率、速效钾是影响火后土壤氮循环功能基因的主要因子,解释度分别为63.8%、18.4%、85.8%。可见,森林火灾对兴安落叶松土壤氮组分和土壤中的氮循环功能基因有着长期的影响,并且火后土壤理化环境的改变也会间接对土壤氮循环的恢复产生影响,研究结果可为北方地区森林火灾对土壤氮循环影响机制提供数据支撑。Forest fires have long-lasting effects on soil nitrogen(N)cycling by affecting both biotic and abiotic soil fractions.Given the prevalence of global forest fires,this study aims to explore the long-term relationship between fire and soil nitrogen cycle.The heavy fire sites of Larix gmelinii were selected as the research object,1 year,6 years and 11 years after the fire,to analyze the abundance of soil nitrogen fractions and functional nitrogen cycle genes.The analysis involved measuring soil nitrogen fraction,nitrogen cycle functional genes,and basic physical and chemical properties of the soil,and determining the main influencing factors.The results showed that(1)soil total nitrogen,ammonium nitrogen and microbial nitrogen(MBN)contents showed a decreasing and then increasing trend with the number of years of restoration,with MBN recovering more slowly.The soil nitrate nitrogen content significantly increased(P<0.05)1 year after fire disturbance and remained lower than that of the control samples 6 and 11 years after fire.(2)Nitrogen-fixing nifH functional genes recovered to pre-fire levels 11 years after fire,while denitrification nirS,nirK and nosZ functional genes were significantly higher than those in control samples 6 years after fire.Fire disturbances significantly increased nitrification amoA-AOA and amoA-AOB functional gene abundance.(3)Correlation analysis showed significant positive correlations between nitrogen-fixing nifH functional genes and soil total nitrogen,ammonium nitrogen and MBN(P<0.05);nitrification amoA-AOA functional genes showed highly significant positive correlations with nitrate nitrogen(P<0.01);and denitrification nirS and nirK functional genes showed significant negative correlations with nitrate nitrogen(P<0.05).(4)The results of redundancy analysis showed that soil organic matter,water content,and quick-acting potassium were the main factors affecting the functional genes of soil nitrogen cycling in post-fire soils,explaining of 63.8%,18.4%,and 85.8%of the variance,respectively.In

关 键 词：火干扰 恢复时间 土壤微生物 氮循环功能基因 兴安落叶松 氮库重建 

分 类 号：S718.5[农业科学—林学] X171.1[环境科学与工程—环境科学]