土壤学报2025，Vol.62Issue(1)：81-91,11.DOI:10.11766/trxb202308140323
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
摘要
Abstract
[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 NO3--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 soil.Lignin,a resistant organic C source,weakly promoted microbial immobilization of fertilizer N but directly inhibited nitrification.The mentioned C sources regulated the N transformation process and increased the soil pH by approximately 0.6 pH units.Sodium benzoate,as a labile organic acid salt,reduced nitrification directly by inhibiting nitrification and indirectly by promoting microbial N immobilization,although the microbial immobilization of fertilizer N was significantly lower than that of glucose and cellulose.Decarboxylation of sodium benzoate rapidly consumed a substantial amount of H+and significantly increased the soil pH by approximately 3.0 pH units.[Conclusion]The chemical properties of organic C sources,including the complexity of their chemical structure,microbial availability,microbial C use efficiency,and microbial toxicity,are the main factors affecting the transformation process of soil C and N,and consequent soil acidification.The findings obtained in this study provide significant theoretical support for the effective and sustainable management of soil nutrients and acidity in cropland.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Key words
Organic carbon source availability/Microbial nitrogen immobilization/Nitrification/Carbon and nitrogen mineralization/Soil acidification分类
农业科技引用本文复制引用
官鹏,王如海,时仁勇,李九玉,徐仁扣..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[J].土壤学报,2025,62(1):81-91,11.基金项目
国家自然科学基金项目(41877102、U19A2046)和中国科学院战略性先导科技专项(XDA0440201)资助 Supported by the National Natural Science Foundation of China(Nos.41877102,U19A2046)and the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA0440201) （41877102、U19A2046）
