Livestock assemblies grazing influences the abundance of genes associated with carbon decomposition and fermentation within the soil carbon cycle

Background and aims

The influence of assembled livestock grazing on rhizosphere soil microbial communities and the functional genes related to carbon cycling in natural grasslands remains uncertain, as grazing activities have the capacity to modify plant community compositions and soil structures, which consequently leads to shifts in the microbial community compositions and their functional distributions.

Methods

This study utilized metagenomic sequencing to conduct grazing experiments in plots with Yak grazing (YG), Tibetan sheep grazing (SG), Yak-Tibetan sheep mixed grazing (MG), and No grazing (CK).

Results

(1) Our findings reveal that rhizosphere soil, in contrast to bulk soil, possesses the capability to recruit beneficial microorganisms via interactions with plant roots. Under mixed grazing conditions involving yaks and Tibetan sheep, the microbial diversity within rhizosphere soil exhibits a marked increase compared to ungrazed conditions. The symbiotic network between carbon cycling genes and microorganisms is modularized, and assembled grazing of livestock primarily regulates Carbon decomposition and Fermentation genes by impacting the abundance of Acidobacteriota and Pseudomonadota. Additionally, we observed that soil microbial diversity is directly governed by soil properties, rather than being influenced by microbial biomass or the relative abundance of carbon cycling genes.

Conclusions

In conclusion, mixed grazing with yaks and Tibetan sheep proves more advantageous for sustaining soil microbial diversity, with soil properties playing a predominant role in regulating this diversity.