BMC Plant Biology (Apr 2024)

Impact of nitrogen fertilizer sustainability on corn crop yield: the role of beneficial microbial inoculation interactions

  • Fernando Shintate Galindo,
  • Paulo Humberto Pagliari,
  • Edson Cabral da Silva,
  • Bruno Horschut de Lima,
  • Guilherme Carlos Fernandes,
  • Cassio Carlette Thiengo,
  • João Victor Silva Bernardes,
  • Arshad Jalal,
  • Carlos Eduardo Silva Oliveira,
  • Lucila de Sousa Vilela,
  • Enes Furlani Junior,
  • Thiago Assis Rodrigues Nogueira,
  • Vagner do Nascimento,
  • Marcelo Carvalho Minhoto Teixeira Filho,
  • José Lavres

DOI
https://doi.org/10.1186/s12870-024-04971-3
Journal volume & issue
Vol. 24, no. 1
pp. 1 – 20

Abstract

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Abstract Background Considering the challenges posed by nitrogen (N) pollution and its impact on food security and sustainability, it is crucial to develop management techniques that optimize N fertilization in croplands. Our research intended to explore the potential benefits of co-inoculation with Azospirillum brasilense and Bacillus subtilis combined with N application rates on corn plants. The study focused on evaluating corn photosynthesis-related parameters, oxidative stress assay, and physiological nutrient use parameters. Focus was placed on the eventual improved capacity of plants to recover N from applied fertilizers (AFR) and enhance N use efficiency (NUE) during photosynthesis. The two-year field trial involved four seed inoculation treatments (control, A. brasilense, B. subtilis, and A. brasilense + B. subtilis) and five N application rates (0 to 240 kg N ha−1, applied as side-dress). Results Our results suggested that the combined effects of microbial consortia and adequate N-application rates played a crucial role in N-recovery; enhanced NUE; increased N accumulation, leaf chlorophyll index (LCI), and shoot and root growth; consequently improving corn grain yield. The integration of inoculation and adequate N rates upregulated CO2 uptake and assimilation, transpiration, and water use efficiency, while downregulated oxidative stress. Conclusions The results indicated that the optimum N application rate could be reduced from 240 to 175 kg N ha−1 while increasing corn yield by 5.2%. Furthermore, our findings suggest that replacing 240 by 175 kg N ha−1 of N fertilizer (-65 kg N ha−1) with microbial consortia would reduce CO2 emission by 682.5 kg CO2 −e ha−1. Excessive N application, mainly with the presence of beneficial bacteria, can disrupt N-balance in the plant, alter soil and bacteria levels, and ultimately affect plant growth and yield. Hence, highlighting the importance of adequate N management to maximize the benefits of inoculation in agriculture and to counteract N loss from agricultural systems intensification.

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