中国农业科学 ›› 2026, Vol. 59 ›› Issue (13): 2878-2893.doi: 10.3864/j.issn.0578-1752.2026.13.010

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

氮添加对晋北赖草草地土壤微生物的影响

贾会丽1,2,3(), 朱熠辰1,2,3(), 陈思学1,2,3, 刘妙1,2,3, 董宽虎1,2,3, 赵祥1,2,3, 石永红1,2   

  1. 1 山西农业大学草业学院, 山西太谷 030801
    2 草地生态保护与乡土草种质创新山西省重点实验室, 山西太谷 030801
    3 山西右玉黄土高原草地生态系统国家定位观测研究站, 山西右玉 037200
  • 收稿日期:2025-08-18 接受日期:2025-12-10 出版日期:2026-07-01 发布日期:2026-07-01
  • 联系方式: 贾会丽,E-mail:jiahuilisxau@126.com。朱熠辰,E-mail:zhuyichen233@163.com。朱熠辰和贾会丽为同等贡献作者
  • 基金资助:
    国家自然科学基金区域创新发展联合基金重点项目(U22A20576); 现代农业产业技术体系建设专项(CARS-34)

Effect of Nitrogen Addition on Soil Microorganisms in Leymus secalinus Grassland in Northern Shanxi

JIA HuiLi1,2,3(), ZHU YiChen1,2,3(), CHEN SiXue1,2,3, LIU Miao1,2,3, DONG KuanHu1,2,3, ZHAO Xiang1,2,3, SHI YongHong1,2   

  1. 1 College of Grassland Science, Shanxi Agricultural University, Taigu 030801, Shanxi
    2 Shanxi Key Laboratory of Grassland Ecological Protection and Native Grass Germplasm Innovation, Taigu 030801, Shanxi
    3 Youyu Loess Plateau Grassland Ecosystem National Research Station, Youyu 037200, Shanxi
  • Received:2025-08-18 Accepted:2025-12-10 Published:2026-07-01 Online:2026-07-01

摘要:

【目的】探究不同水平氮添加对晋北赖草草地土壤微生物群落结构、多样性和参与氮循环功能基因的影响,明晰氮沉降背景下草地生态系统氮循环过程,深入揭示其内在变化规律,为草地养分平衡调控与生态管护提供理论支撑。【方法】依托右玉黄土高原草地生态系统国家定位观测研究站2017年建立的不同水平氮添加试验平台,设置N0、N1、N2、N4、N8、N16、N24和N32共8个处理,对应施氮量分别为0、1、2、4、8、16、24和32 g N·m-2·a-1,利用宏基因组技术,对不同水平氮添加下土壤微生物进行了研究。【结果】(1)氮添加显著影响土壤细菌和真菌的群落结构,增加了细菌群落中酸杆菌门和热脱硫杆菌门的相对丰度,降低了硝化螺旋菌门的相对丰度;增加了真菌群落中子囊菌门的相对丰度,降低了毛霉门和担子菌门的相对丰度。(2)氮添加显著影响细菌群落的丰富度,对多样性无显著影响;对真菌群落的丰富度和多样性无显著影响。(3)不同水平氮添加富集的微生物差异类群不同。(4)氮添加显著增加了硝化基因amoABChao的相对丰度;N4处理显著增加了反硝化基因nirKnirS相对丰度,N1、N24处理显著增加了norBC相对丰度;N16—N32处理显著增加异化硝酸盐还原基因nirBD和nrfAH的相对丰度,而N1、N2、N4、N16和N24处理则显著降低napABnarGHI相对丰度;N32处理显著增加固氮基因nifDKHvnfDKGH相对丰度。(5)随着氮添加水平的增加,土壤含水量(SWC)、pH显著下降,全碳(TC)、全氮(TN)呈现出先升高后降低的趋势,微生物量碳(MBC)、微生物量氮(MBN)也是先升高后降低。这些土壤因子的改变显著影响了细菌群落结构组成,其中SWC是最显著的影响因素。(6)异化硝酸盐还原为铵过程基因与SWC和pH呈显著负相关,同化硝酸盐还原为铵过程基因与MBC和MBN呈极显著正相关,固氮过程基因与SWC呈显著正相关,硝化过程基因与SWC呈显著负相关,与NO3--N呈显著正相关。【结论】氮添加显著影响土壤微生物群落结构,通过影响SWC和pH显著影响硝化过程、异化硝酸盐还原为铵过程、固氮过程和反硝化过程的基因相对丰度,从而改变了土壤氮循环过程。土壤微生物在养分循环中起着关键作用。

关键词: 土壤微生物, 氮添加, 微生物群落结构, 氮循环功能基因, 晋北赖草草地, 氮沉降

Abstract:

【Objective】This study aimed to investigate the effects of different nitrogen addition levels on soil microbial community structure, diversity and nitrogen cycling functional genes in Leymus secalinus grassland of northern Shanxi, which held the profound significance for understanding nutrient cycling in grassland ecosystems under the context of nitrogen deposition.【Method】This experiment was conducted based on the multi-level nitrogen (N) addition platform established in 2017 at the Youyu Loess Plateau Grassland Ecosystem Research Station, Shanxi Province. Eight treatments were set up: N0, N1, N2, N4, N8, N16, N24, and N32, corresponding to nitrogen application rates of 0, 1, 2, 4, 8, 16, 24, and 32 g N·m-2·a-1, respectively. Utilizing metagenomic technology, soil microorganisms were studied under different levels of nitrogen addition. 【Result】 (1) Nitrogen addition significantly altered the soil bacterial and fungal community structures. It increased the relative abundance of Acidobacteria and Thermodesulfovibrionales in the bacterial community while reducing that of Nitrospirales. In the fungal community, nitrogen addition increased the relative abundance of Ascomycota but decreased that of Mucoromycota and Basidiomycota. (2) Nitrogen addition significantly affected bacterial community structures richness, but had no significant effect on diversity, with no significant impact on the richness and diversity of fungal communities. (3) Microbial differential groups enriched with different levels of nitrogen addition were different. (4) Nitrogen addition significantly increased the relative abundances of nitrification genes amoABC and hao; the relative abundances of denitrification genes nirK and nirS significantly increased under the N4 treatment, while norBC relative abundances significantly increased under N1 and N24 treatments; the relative abundance of dissimilatory nitrate reduction genes nirBD and nrfAH increased significantly under the N16-N32 treatments, while the relative abundance of napAB and narGHI decreased significantly under the N1, N2, N4, N16 and N24 treatments; the relative abundances of nitrogen fixation genes nifDKH and vnfDKGH significantly increased under the N32 treatment (5) With the increase in nitrogen addition levels, soil water content (SWC) and pH decreased significantly, while total carbon (TC) and total nitrogen (TN) showed a trend of first increasing and then decreasing. Similarly, microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) also exhibited a trend of first increasing and then decreasing. These changes in soil factors significantly affected the composition of the bacterial community structure, among which SWC was the most significant factor. (6) The genes involved in the process of dissimilatory nitrate reduction to ammonium were significantly negatively correlated with SWC and pH. The genes involved in the process of assimilatory nitrate reduction to ammonium were significantly positively correlated with MBC and MBN, nitrogen fixation process genes were significantly positively correlated with SWC, nitrification process genes were significantly negatively correlated with soil moisture, and were significantly positively correlated with NO3--N.【Conclusion】 In summary, nitrogen addition significantly affected the structure of soil microbial communities by influencing soil water content (SWC) and pH, which notably impacted the relative abundances of genes involved in nitrification, dissimilatory nitrate reduction to ammonium, nitrogen fixation, and denitrification processes, thereby altering the progression of soil nitrogen cycling. Soil microorganisms play a pivotal role in nutrient cycling. Further investigating the effects of nitrogen addition on soil microorganisms not only provided a theoretical basis for the rational management of Leymus secalinus grasslands in northern Shanxi but also held significant implications for the restoration of ecosystem functions in these grasslands.

Key words: soil microorganism, nitrogen addition, microbial community structure, nitrogen cycling functional genes, Leymus secalinus grassland in Northern Shanxi, nitrogen deposition