适宜施氮量提高东北黑土非共生固氮速率和固氮菌丰度  

Optimal nitrogen application rate enhances the asymbiotic nitrogen fixation rate and nitrogen-fixing bacteria abundance in black soil of Northeast China

作　　者：黄丹丹[1] 高越 陈文博 刘志华 陈学文[1] 张延[1] 张旸 梁爱珍[1] HUANG Dan-dan;GAO Yue;CHEN Wen-bo;LIU Zhi-hua;CHEN Xue-wen;ZHANG Yan;ZHANG Yang;LIANG Ai-zhen(Key Laboratory of Mollisols Agroecology/Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Changchun,Jilin 130102,China;Nong’an Agricultural Technology Extension Center,Nong’an,Jilin 130200,China;Jilin Longyuan Agricultural Service Company,Nong’an,Jilin 130200,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院东北地理与农业生态研究所/黑土区农业生态重点实验室,吉林长春130102 [2]农安县农业技术推广中心,吉林农安130200 [3]吉林隆源农业服务有限公司,吉林农安130200 [4]中国科学院大学,北京100049

出　　处：《植物营养与肥料学报》2024年第12期2258-2266,共9页Journal of Plant Nutrition and Fertilizers

基　　金：国家重点研发计划项目(2023YFD1501103);中国科学院“黑土粮仓”战略性先导科技专项(XDA28080200);中国科学院黑土区农业生态重点实验室开放基金项目(2020ZKHT-06);国家自然科学基金(42371063);吉林省自然科学基金(20230101085JC);吉林省科技发展计划项目(20240602008RC);“黑土粮仓”科技会战人才专项基金(HTRC202213)。

摘　　要：【目的】非共生固氮是农田生态系统中氮素输入的重要途径之一,探明非共生固氮速率、固氮微生物丰度及其群落结构对施肥量的响应,为农业可持续生产提供施肥参考。【方法】试验地点位于东北黑土区,该地块自2012年起一直实行免耕及秸秆还田。田间试验设置6个施氮量处理:0、120、150、180、210、240 kg/hm^(2),分别记作N0、N120、N150、N180、N210、N240。玉米收获后,采集0—5、5—20 cm土层土壤样品,测定土壤pH和速效氮、磷、钾含量;采用乙炔还原法、定量PCR和高通量测序技术,分析土壤非共生固氮速率、固氮微生物丰度、群落结构多样性。【结果】不同施氮量下,土壤非共生固氮速率为C_(2)H_(4)0.26~0.63 nmol/(g·d),N150处理0—5和5—20 cm土层土壤非共生固氮速率均最高,分别为C_(2)H_(4) 0.53和0.63 nmol/(g·d);固氮酶基因nifH丰度范围为5.34×10^(6)~15.64×10^(6) copies/g,0—5和5—20 cm土层土壤nifH基因丰度的最大值也为N150处理,分别为15.64×10^(6)和8.74×10^(6) copies/g。主成分分析(PCoA)结果显示,不同施氮量之间固氮微生物群落结构存在显著差异。各施氮量处理土壤固氮菌群属水平以unclassified_o_Burkholderiales、unclassified_k_norank_d_Bacteria、Skermanella、Methylocystis为优势菌属。Spearman相关性分析结果表明,非共生固氮速率与土壤速效钾含量呈显著正相关,与pH呈负相关;nifH基因拷贝数与土壤速效钾含量呈显著正相关,与施氮量呈负相关。冗余分析显示,nifH群落结构与土壤pH及NH_(4)^(+)-N、NO_(3)^(-)-N、有机碳、全氮、有效磷、速效钾含量呈显著相关。【结论】在长期免耕和秸秆全量还田条件下,施用N150 kg/hm^(2)有利于增加土壤非共生固氮速率和固氮微生物丰度,丰富群落结构多样性,是该地区较为适宜的施氮量。【Objectives】Asymbiotic nitrogen fixation is one of the important sources of nitrogen input in farmland ecosystems.Investigating the responses of asymbiotic nitrogen fixation rate,abundance of nitrogen-fixing microorganisms and diversity of community structure to nitrogen fertilizer application rates will provide fertilization reference for sustainable agricultural production.【Methods】The experiment was conducted in black soil area of Northeast China,the test field was under conservation tillage and straw return since 2012.Six N application rate treatments were setup,0(N0),120(N120),150(N150),180(N180),210(N210),and 240(N240)kg/hm^(2).At harvest of maize,0-5 cm and 5-20 cm soil samples were collected,conventional chemical methods were used to determine soil pH and available N,P and K contents,and acetylene reduction method,quantitative PCR,and high-throughput sequencing technology were used to analyze the soil asymbiotic nitrogen fixation rate,diazotroph community abundance and structure diversity.【Results】Under the six N rate treatments,the asymbiotic nitrogen fixation rate ranged from C_(2)H_(4)0.26-0.63 nmol/(g·d)in both 0-5 cm and 5-20 cm soil layers,and N150 treatment exhibited the maximum asymbiotic nitrogen fixation rate,C_(2)H_(4)0.53 nmol/(g·d)in 0-5 cm layer and C_(2)H_(4)0.63 nmol/(g·d)in 5-10 cm layer.The nifH gene abundance ranged from 5.34×10^(6) to 15.64×10^(6) copies/g,and N150 treatment was recorded the maximum nifH gene abundance as well,they were 15.64×10^(6) and 8.74×10^(6) copies/g in the two aforementioned layers.Principal component analysis(PCoA)revealed notable differences among fertilization rates regarding the composition of soil diazotroph community.The dominant bacterial genera at species level were unclassified_o_Burkholderiales,unclassified_k_norank_d_Bacteria,Skermanella,and Methylocystis in all the six treatments.Spearman correlation analysis between environmental factors and indicators for soil diazotroph community showed that asymbiotic nitrogen fixation was pos

关 键 词：免耕 施肥量 非共生固氮速率 土壤固氮微生物群落 NIFH 

分 类 号：S154.3[农业科学—土壤学]