Effects of multi-species rotational grazing on soil microbial communities

View the project final report

Commodities

• Animals: bovine, sheep, swine

Practices

• Animal Production: grazing - multispecies
• Education and Training: on-farm/ranch research
• Soil Management: soil microbiology

Small-scale livestock farmers are looking for innovative ways to manage their lands for environmental sustainability and economic profitability, while ensuring animal well-being. Multi-species rotational grazing (MSRG) has been suggested as a promising approach, since it allows high grazing intensity and stocking density without negatively impacting pasture quality or animal health. However, the potential effects of MSRG on soil microbial communities are poorly understood. To address this knowledge gap, we will collect soil microbial samples before, during, and after one season of MSRG by cattle, sheep, and swine. Nine paddocks experiencing MSRG, as well as three paddocks experiencing monospecies grazing (one paddock per species) and one with no grazing, will be sampled. Soil samples will be sent to the University of Oregon Genomics & Cell Characterization Core Facility for shotgun metagenomic analysis to identify taxonomic, phylogenetic, and functional characteristics of the microbial communities from each paddock. We expect that MSRG paddocks will have higher microbial taxonomic, phylogenetic and functional diversity, as well as distinct taxonomic composition, in comparison to monospecies grazing or no livestock. In addition to posting results on the farm website and social media, we will share the outcomes of our study with other farmers and agricultural professionals at the Oregon State University Extension Small Farms Conference in February, 2021, and host a Farm Field Day to conclude the project in May, 2021. This project will substantially improve our understanding of soil microbial communities under MSRG and provide information for other farmers following sustainable agriculture practices.

Objective 1: Measure the impact of MSRG on soil microbial diversity, composition, and function.
We will collect soil samples before, during, and after MSRG and use shotgun metagenomics to identify taxonomic, phylogenetic, and functional characteristics of soil microbial communities (bacteria, fungi, and archaea). We hypothesize that each livestock species has a different effect on soil microbial communities (due to distinct foraging/grazing strategies and unique manure composition), and that MSRG will lead to higher microbial taxonomic and functional diversity, as well as different taxonomic composition, in comparison to monospecies grazing or no livestock.

Objective 2: Assess changes in livestock health and pasture forage quality following MSRG.
Since MSRG can effectively break livestock parasite cycles, we hypothesize that animal health will improve following MSRG. Additionally, we hypothesize that pasture productivity and plant diversity will increase after MSRG, due to changes in manure deposition and grazing patterns.

Objective 3: Share study outcomes with other farmers, agricultural professionals, and the general public.
We will disseminate our project methods and results by presenting at the Oregon State University Extension Small Farms Conference in February, 2021, and hosting a Farm Field Day to conclude the project in May, 2021.