The impact of N fertilizer on the soil microbiome with grasses

  • Letusa Momesso Marques (Creator)
  • Carlos A. C. Crusciol (Owner)
  • João William Bossolani (Contributor)
  • Luiz Moretti de Souza (Data Collector)
  • Marcio Fernandes Alves Leite (Contributor)
  • George Kowalchuk (Institute of Environmental Biology, Utrecht University) (Contributor)
  • Eiko Kuramae (Creator)



Forage grasses used in cropping no-till systems in tropical regions alter soil chemical properties, but their long-term impact on soil microbial processes of the nitrogen (N) cycle and microbial community abundance, composition and structure are unknown. Here, microbial functions related to nitrogen fixation, nitrification and denitrification as well as bacterial, archaeal and fungal populations were evaluated in a long-term field experiment in which tropical forage grasses (palisade grass and ruzigrass) were cultivated with or without N fertilization. Uncultivated soil was used as a control. Forage grasses, especially palisade grass, increased soil bacterial and fungal abundances, whereas the archaeal population was highest in uncultivated soil. In soils cultivated with forage grasses, N fertilization favored N-cycle-related genes; however, cultivation of palisade grass enhanced the abundances of amoA bacteria (AOB) and amoA archaea (AOA) associated with soil nitrification and decreased the abundances of the denitrification-related genes nirS, nirK and nosZ regardless of N input. In addition, in soils cultivated with forage grasses, total bacteria and fungi were associated with the N cycle and organic matter decomposition. Compared with uncultivated soil, forage cultivation clearly benefitted the soil environment (S-SO42-, Mg2+, total-C and -N, N-NO3- and N-NH4+) and microbiome (bacteria and fungi). In soil cultivated with palisade grass, the microbial community composition was unresponsive to N addition. The high N uptake by palisade grass supports the competitive advantage of this plant species over microorganisms for N sources. However, when soil was cultivated with ruzigrass, the composition of the microbial communities and abundances of N-cycle-related genes suggested the potential for N losses such as NO3- leaching and N2O emissions. Our results suggest that palisade grass has advantages over ruzigrass for use in intercropping systems, regardless of N input.
Date made available30 Sept 2022
PublisherEuropean Nucleotide Archive (ENA)

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