Soil microbial diversity in organic and non-organic pasture systems

Abstract

Understanding the effects of organic pasture management on the soil microbiome is important for sustainable forage production since soil microbiome diversity contributes to improved nutrient cycling, soil structure, plant growth, and environmental resiliency; however, the soil microbiome response to pasture management is largely unknown. This study assessed the soil microbial diversity, richness, and community structure following 10 years of pasture management (organic or non-organic) of the V4 region of the 16S rRNA using the Illumina MiSeq platform. Soil samples were collected from 0–15 cm in July and August from 2017–2018 and soil nutrient properties (nutrients, carbon, nitrogen, and pH) quantified and correlated with soil microbial diversity. Overall, greater soil bacterial species richness (P ≤ 0.05) occurred in organic relative to non-organic (conventional) systems. Management affected bacterial species richness (Chao1), with greater richness occurring in organic pasture soils and less richness occurring in non-organic systems (P ≤ 0.05). Similarly, management affected bacterial evenness (Simpson’s index), with a more diverse community occurring in organically managed soils relative to non-organic pastures (P ≤ 0.05). Linear discriminant analysis effect size analysis showed statistically significant and biologically consistent differences in bacterial taxa in organic compared with non-organic soils. Therefore, there was a shift in bacterial community structure in organic relative to non-organic soils (P ≤ 0.05). Additionally, soil nutrients (Fe, Mg, Ni, S, Al, K, Cd, and Cu), pH, C, and N were correlated with one or more dominant bacterial phyla (Gemmatimonadetes, Planctomycetes, Firmicutes, Chloroflexi, Actinobacteria, and Acidobacteria). Overall, pasture management affected soil microbial diversity, with greater diversity occurring in organic than non-organic systems, likely owing to applications of organic poultry litter in organic systems compared to non-organic management (use of inorganic-fertilizers and herbicides). Results indicate that when pastures are converted to organic production systems, soil microbial richness and diversity may increase, thereby resulting in enhanced soil microbiome diversity and overall ecosystem services.

Soil Microbial Community Responses to Different Management Strategies in Almond Crop

“…Differences in microbial communities and physical–chemical characteristics of organically versus conventionally managed soils have been reported [ 10 , 11 , 12 ]. In addition, cover crops and soil amendments alter soil bacterial and fungal communities [ 13 , 14 , 15 ].…”

High-throughput sequencing reveals rhizosphere fungal community composition and diversity at different growth stages of Populus euphratica in the lower reaches of the Tarim River

“…In the current research, it was found that there is a close correlation between rhizosphere microorganisms and plants, and their interaction mechanism was complicated ( Morgan, Bending & White, 2005 ). The composition of rhizosphere microbial community will be affected by vegetation type ( Sinha et al, 2008 ), soil type ( Lu et al, 2011 ; Acharya et al, 2021 ), human factors and other factors ( Li et al, 2015 ; Huang et al, 2021 ; Yin, Li & Du, 2021 ). For the same plant, different planting methods ( Durrer et al, 2021 ), different development stages, even genetic background and other factors will lead to the change of the rhizosphere microbial community ( Marschner et al, 2001 ; Dang et al, 2020 ).…”

One or many? Multi-species livestock grazing influences soil microbiome community structure and antibiotic resistance potential

“…Compared with cropping systems, however, little is known about how grazing management impacts soil microbial communities in pastures and rangelands (Dignam et al, 2016;Acharya et al, 2021). Multi-species rotational grazing (MSRG) is a management-intensive alternative to continuous monospecies stocking that may hold promise for improving environmental sustainability of animal agriculture (Kleppel, 2020).…”

“…Another compared long-term continuously grazed and rotational pasture management, finding that continuously grazed pastures had greater soil microbial richness (Yang et al, 2019), although more antimicrobial resistance genes (ARGs) were found under continuous grazing (Yang et al, 2020). Lastly, pastures that transitioned from conventional to organic management tended to have higher richness and diversity in soil microbial communities (Acharya et al, 2021). Notably, both of these studies only tested the impact of cattle grazing; to our knowledge, no research currently exists on the effects of MSRG on soil microbial communities.…”