EFFECTS OF GRAZING ON SOIL MICROBIAL COMMUNITIES IN CALIFORNIAN PASTURES

Abstract

In Californian rangelands and across the globe, the livestock grazing industry is challenged to meet rising livestock product demands without degrading the land. Research on the impacts of grazing on ecosystems is growing, but the microbial community response to grazing is still uncertain. Soil samples were taken from grazed and ungrazed plots of Californian pastures. The soil microbial communities were studied using 16S rRNA (bacteria and archaea) and ITS (fungi) amplicon sequencing. Microbial diversity and community composition were not affected by grazing status, and community composition was instead associated with pasture region. Some trends were present among microbial groups in response to grazing status, but none of the impacts were statistically significant. These results support a growing body of evidence that soil microorganisms are variably influenced by livestock grazing, and suggest that microbial communities are driven most by regional factors such as vegetation and soil characteristics.