长期生物炭添加对稻田土壤细菌和真菌反硝化N_(2)O排放的影响  

Effects of Long-term Biochar Addition on Denitrification N_(2)O Emissions from Bacteria and Fungi in Paddy Soil

作　　者：王梦洁 蒋文婷 徐有祥 刘玉学[2] 吕豪豪[2] 汪玉瑛[2] 杨生茂[2] 何莉莉 蔡延江 WANG Meng-jie;JIANG Wen-ting;XU You-xiang;LIU Yu-xue;LÜHao-hao;WANG Yu-ying;YANG Sheng-mao;HE Li-li;CAI Yan-jiang(State Key Laboratory of Subtropical Silviculture,College of Environment and Resources,College of Carbon Neutrality,Zhejiang A&F University,Hangzhou 311300,China;Zhejiang Engineering Research Center of Biochar,Institute of Environment Resources and Soi Fertilizer,Zhejiang Academy of Agricultural Sciences,Hangzhou 310021,China;Longyou County Agriculture and Rural Affairs Bureau,Quzhou 324400,China)

机构地区：[1]浙江农林大学环境与资源学院,碳中和学院,省部共建亚热带森林培育国家重点实验室,杭州311300 [2]浙江省农业科学院环境资源与土壤肥料研究所,浙江省生物炭工程技术研究中心,杭州310021 [3]龙游县农业农村局,衢州324400

出　　处：《环境科学》2024年第8期4923-4931,共9页Environmental Science

基　　金：杭州市重点科技研发计划项目(202204T05);国家重点研发计划政府间国际科技创新合作重点专项(2022YFE0127800);国家自然科学基金项目(42077090)。

摘　　要：由细菌和真菌驱动的反硝化作用是稻田土壤氧化亚氮(N_(2)O)排放的主要来源,一般认为生物炭通过影响细菌反硝化过程来减少N_(2)O排放,而对真菌反硝化的相关影响机制尚不清楚.以中国科学院常熟农业生态实验基地长期秸秆炭化还田试验田为对象,通过室内厌氧培养和分子生物学技术研究了长期不同生物炭施加量下(空白、2.25 t·hm^(-2)和22.5 t·hm^(-2),分别用BC0、BC1和BC10表示)稻田土壤细菌和真菌反硝化产生N_(2)O的相对贡献及相关微生物的作用机制.结果表明,与BC0相比,生物炭处理显著降低了N_(2)O排放速率、反硝化势以及N_(2)O累积排放量,且3个处理中细菌反硝化贡献均大于真菌反硝化;其中,BC10的细菌反硝化相对贡献率(62.9%)相较于BC0(50.8%)显著增加,BC10的真菌反硝化相对贡献率(37.1%)显著低于BC0(49.2%).生物炭施加显著增加了细菌反硝化功能基因(nirK、nirS和nosZ)的丰度,减低了fungal nirK基因的丰度.相关分析结果表明真菌反硝化贡献率与N_(2)O排放速率显著正相关,与土壤pH、TN、SOM和DOC显著负相关.生物炭可能通过提高pH和碳氮含量等来抑制反硝化真菌的生长,降低相关功能基因丰度,从而减弱了真菌反硝化过程NO还原为N_(2)O的能力,使真菌反硝化过程产生N_(2)O的贡献率显著下降,从而减少了稻田土壤反硝化N_(2)O排放.本研究有助于拓宽对稻田土壤反硝化过程的认知,并为生物炭施用调控真菌反硝化N_(2)O排放提供理论基础.Denitrification driven by bacteria and fungi is the main source of nitrous oxide(N_(2)O)emissions from paddy soil.It is generally believed that biochar reduces N_(2)O emissions by influencing the bacterial denitrification process,but the relevant mechanism of its impact on fungal denitrification is still unclear.In this study,the long-term straw carbonization returning experimental field in Changshu Agricultural Ecological Experimental Base of the Chinese Academy of Sciences was taken as the object.Through indoor anaerobic culture and molecular biology technology,the relative contributions of bacteria and fungi to denitrifying N_(2)O production in paddy soil and the related microorganism mechanism were studied under different long-term biochar application amounts(blank,2.25 t·hm^(-2),and 22.5 t·hm^(-2),respectively,expressed by BC0,BC1,and BC10).The results showed that compared with that in BC0,biochar treatment significantly reduced N_(2)O emission rate,denitrification potential,and cumulative N_(2)O emissions,and the contribution of bacterial denitrification was greater than that of fungal denitrification in all three treatments.Among them,the relative contribution rate of bacterial denitrification in BC10(62.9%)was significantly increased compared to BC0(50.8%),whereas the relative contribution rate of fungal denitrification in BC10(37.1%)was significantly lower than that in BC0(49.2%).The application of biochar significantly increased the abundance of bacterial denitrification functional genes(nirK,nirS,and nosZ)but reduced the abundance of fungal nirK genes.The contribution rate of fungal denitrification was significantly positively correlated with the N_(2)O emission rate and negatively correlated with soil pH,TN,SOM,and DOC.Biochar may have inhibited the growth of denitrifying fungi by increasing pH and carbon and nitrogen content,reducing the abundance of related functional genes,thereby weakening the reduction ability of NO to N_(2)O during fungal denitrification process.This significantly reduces the

关 键 词：生物炭 水稻土 氧化亚氮(N_(2)O) 真菌反硝化 反硝化 

分 类 号：X16[环境科学与工程—环境科学]