The impact of stand age and fertilization on the soil microbiome of Miscanthus × giganteus

Yield of the perennial grass Miscanthus × giganteus has shown an inconsistent and unpredictable response to nitrogen (N) fertilizer, yet fertilization underpins the crop’s environmental and economic sustainability. The interactions among soil microbial communities, N availability, and Miscanthus × giganteus and management may explain changes in plant productivity. In this study, soil samples from different stand ages of Miscanthus × giganteus in a replicated chronosequence field trial were used to investigate the effects of stand age and N fertilizer rates on microbial community structure. We hypothesized that there is a definable Miscanthus × giganteus soil microbiome and that this community varies significantly with stand age and fertilization. Our results showed that the main phyla in soil microbial communities, regardless of plant age, are similar but microbial community structures are significantly different. The variation in observed microbial communities generally decreases with older stand ages. The amount of N fertilizer applied also affected the microbial community structure associated with different aged Miscanthus × giganteus. Specifically, the relative abundance of Proteobacteria (Alphaproteobacteria and Gammaproteobacteria) and Acidobacteria (subgroup Gp1) increased shortly after fertilization and was more associated with younger Miscanthus × giganteus. Furthermore, our results show a significant relationship between bacterial α diversity and fertilization rates and that this response is also affected by stand age. Overall, our results emphasize linkages between microbial community structure, plant age, and fertilization in Miscanthus × giganteus

The impact of stand age and fertilization on the soil microbiome of Miscanthus × giganteus

Yield of the perennial grass Miscanthus × giganteus has shown an inconsistent and unpredictable response to nitrogen (N) fertilizer, yet fertilization underpins the crop’s environmental and economic sustainability. The interactions among soil microbial communities, N availability, and Miscanthus × giganteus and management may explain changes in plant productivity. In this study, soil samples from different stand ages of Miscanthus × giganteus in a replicated chronosequence field trial were used to investigate the effects of stand age and N fertilizer rates on microbial community structure. We hypothesized that there is a definable Miscanthus × giganteus soil microbiome and that this community varies significantly with stand age and fertilization. Our results showed that the main phyla in soil microbial communities, regardless of plant age, are similar but microbial community structures are significantly different. The variation in observed microbial communities generally decreases with older stand ages. The amount of N fertilizer applied also affected the microbial community structure associated with different aged Miscanthus × giganteus. Specifically, the relative abundance of Proteobacteria (Alphaproteobacteria and Gammaproteobacteria) and Acidobacteria (subgroup Gp1) increased shortly after fertilization and was more associated with younger Miscanthus × giganteus. Furthermore, our results show a significant relationship between bacterial α diversity and fertilization rates and that this response is also affected by stand age. Overall, our results emphasize linkages between microbial community structure, plant age, and fertilization in Miscanthus × giganteus.This article is published as Ma, Lanying, Fernando Igne Rocha, Jaejin Lee, Jinlyung Choi, Mauricio Tejera, Thanwalee Sooksa-Nguan, Nicholas Neal Boersma, Andrew Vanloocke, Emily Heaton, and Adina Howe. "The impact of stand age and fertilization on the soil microbiome of Miscanthus× giganteus." Phytobiomes Journal (2021). doi: 10.1094/PBIOMES-01-20-0014-FI.</p

Litter Matters: The Importance of Decomposition Products for Soil Bacterial Diversity and abundance of key groups of the N cycle in Tropical Areas

This study investigated the contribution of soil organic layers to bacterial diversity evaluations. We used a forest in the eastern Amazon and an adjacent pasture as model systems. Distinct organic and organo-mineral layers were identified in the forest and pasture floors, including the litter, partially and wholly decomposed organic material, and the mineral and rhizospheric soils. DNA was extracted, and 16S rRNA gene sequencing and qPCR were performed to assess bacterial community structure and the abundance of critical groups of the N cycle. We observed a clear vertical gradient in bacterial community composition. Species followed a log-normal distribution, with the highest richness and diversity observed in transitional organic layers of both land uses. Generally, critical groups of the N cycle were more abundant in these transitional layers, especially in the pasture’s fragmented litter and in the forest’s partially decomposed organic material. Considering the organic layers increased diversity estimates significantly, with the highest alpha and gamma bacterial diversity observed on the pasture floor and the highest beta diversity on the forest floor. The results show that organic layers harbor significant bacterial diversity in natural and anthropized systems and suggest that they can be crucial for maintaining the N cycle in these ecosystems, highlighting the need to consider them when studying soil bacterial diversity.This is a pre-print of the article Diniz, Priscila Pereira, Beatriz Maria Ferrari Borges, Aline Pacobahyba de Oliveira, Mauricio Rizzato Coelho, Osnar Obede da Silva Aragao, Thiago Goncalves Ribeiro, Fernando Igne Rocha et al. "Litter Matters: The Importance of Decomposition Products for Soil Bacterial Diversity and abundance of key groups of the N cycle in Tropical Areas." bioRxiv (2023): 2023-03. DOI: 10.1101/2023.03.03.530969. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). Copyright 2023 The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. Posted with permission