微生物利用性不同的有机碳源阻控尿素诱导红壤酸化的作用机制  

Inhibition Mechanisms of Acidification Induced by Urea Application Using Organic Carbon Sources with Different Availability for Microorganisms in Ultisol

作　　者：官鹏 王如海[1] 时仁勇 李九玉[1,2,3] 徐仁扣 GUAN Peng;WANG Ruhai;SHI Renyong;LI Jiuyu;XU Renkou(State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China;University of Chinese Academy of Sciences,Nanjing,Nanjing 211135,China)

机构地区：[1]土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所),南京210008 [2]中国科学院大学,北京100049 [3]中国科学院大学南京学院,南京211135

出　　处：《土壤学报》2025年第1期81-91,共11页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41877102、U19A2046);中国科学院战略性先导科技专项(XDA0440201)资助。

摘　　要：为研究有机物料中不同类型碳源对肥料氮转化及其引起土壤酸化的调控作用,选择葡萄糖、苯甲酸钠、纤维素、木质素四种微生物利用程度不同的碳源,在外加碳源和尿素的C/N=40的条件下进行45 d的室内培养,分析有机碳源与尿素配合施用对红壤氮素形态转化和酸度的影响。结果表明,在红壤中单施尿素会发生强烈的硝化作用,培养结束时土壤pH降低1.17个单位。与单施尿素处理相比,有机碳源与尿素配施处理土壤呼吸作用显著增强,土壤无机氮和NO_(3)^(–)-N分别减少了17.1%~99.4%和46.1%~99.9%,土壤微生物生物量氮和固相有机氮共增加了3.0%~14.8%,土壤pH提高0.67~3.11个单位。有机碳源与氮肥配施促进了土壤微生物对肥料氮的同化作用和土壤固持,显著降低硝化作用及其诱导的土壤酸化。其中微生物易利用的葡萄糖有利于促进前期肥料氮被微生物快速同化和后期有机氮的矿化作用,对肥料氮可起暂存和缓释作用;较难利用的纤维素促进肥料氮微生物同化的作用较葡萄糖滞后,但同化作用强、效率高,有利于肥料氮在土壤中较长时间的固持;难利用的木质素促进肥料氮的微生物同化作用弱,但直接抑制了硝化作用,以上有机碳源调控氮素转化过程可提升土壤pH约0.6个单位。而苯甲酸钠作为易利用有机酸盐,虽然促进肥料氮的微生物同化作用显著低于葡萄糖和纤维素,但其具有直接抑制硝化作用的能力,而且苯甲酸钠的脱羧作用可以快速消耗H^(+),可大幅提升土壤pH约3.0个单位。综上,有机碳源本身的化学性质,如化学结构的复杂程度、微生物碳利用效率、有机物本身的毒性效应等是影响土壤碳、氮转化过程及其耦合的土壤酸化过程的重要因素,研究结果为农田土壤养分和酸度调控的高效管理提供重要理论依据。【Objective】This study investigated the mechanism of different organic carbon(C)sources to control fertilizer nitrogen(N)transformation and its induced soil acidification.【Method】Four types of organic C sources(glucose,sodium benzoate,cellulose,and lignin)with different availability for microorganisms were selected for a 45-day indoor incubation experiment.It was conducted under the condition that the C/N ratio of C source and fertilizer(urea)was 40.The effects were analyzed for the combined application of organic C source and urea on N transformation and soil acidity in Ultisol.【Result】The results showed that intensive nitrification occurred when urea was used solely in Ultisol,resulting in a soil pH decrease of 1.17 pH units at the end of the incubation.Compared with the sole application of urea,the combined application of organic C sources and urea significantly enhanced soil respiration,and decreased soil inorganic N by 17.1%–99.4%and soil NO_(3)^(–)-N by 46.1%–99.9%.However,these organic treatments increased soil microbial biomass N and solid organic N(non-extractable N)by 3.0%–14.8%,and increased soil pH by 0.67–3.11 pH units.These findings suggest that the combined application of organic C sources and N fertilizer promoted the immobilization of fertilizer N by soil microorganisms and soil N sequestration,thereby significantly reducing nitrification and soil acidification induced by N fertilizer.Specifically,as a labile organic C source,glucose facilitated the rapid immobilization of fertilizer N by microorganisms in the early stage and the mineralization of organic N in the later stage.It indicated that glucose could play a role in temporary storage and slow release of fertilizer N in the soil.Cellulose was less easily utilized by microorganisms and also promoted microbial immobilization of fertilizer N.Although cellulose was not as fast as glucose,it had strong immobilization capacity and high C use efficiency,which was conducive to the long-term immobilization of fertilizer N in the

关 键 词：有机碳源的可利用性 微生物氮同化 硝化作用 碳氮矿化 土壤酸化 

分 类 号：S153[农业科学—土壤学]