Effects of burning and mowing on the soil microbiome of restored tallgrass prairie

Understanding soil microbiome responses to different land-management strategies provides insights into tallgrass prairie restoration. However, few studies have examined these interactions. We addressed this issue by surveying samples from the University of Nebraska at Omaha's Glacier Creek Preserve, where a long-term burn experiment was established in 1982, with the mow treatments incorporated in 2002. In 2015, we collected 89 soil samples and obtained ~2.3 million bacterial and archaeal 16S rRNA sequence reads and ~2.4 million fungal ITS reads. Analysis of the sequences showed that dominant phyla were Proteobacteria (~30.0%) and Acidobacteria (~22.8%) in bacteria and Ascomycota (~66.2%) in fungi. We found that burning and mowing had a distinct effect on soil bacterial and fungal diversity: soils exposed to the burn treatments possessed a relatively high bacterial diversity but a relatively low fungal diversity. We also observed that burning and mowing had different effects on different microbial groups within bacteria and fungi. The burn treatments led to a relatively high abundance of bacterial groups such as Gemmatimonadetes and Armatimonadetes that prefer dry or warmer soils and arbuscular mycorrhizal (AM) fungi, whereas the mow treatments resulted in increased abundances of Nitrospirae bacteria. Moreover, functional prediction revealed that soil samples from the burn treatments were enriched with AM and plant saprotrophic fungi, and fungal plant pathogens were enriched in the mow samples. Considering soil functional differences between burn and mow treatments and an increased plant production after burning treatments, we speculate that burning could be a better strategy in the tallgrass land restoration, with certain fungal groups as an imperative indicator. Highlights: Understanding soil microbiome responses to different land-management strategies provides insights into tallgrass prairie restoration We showed differences in the soil bacterial and fungal communities between burn and mow treatments. Soil fungi were enriched in AM fungi and plant saprotroph functions after burning, but fungi with putative plant pathogens after mowing. The burn treatment is a better strategy for tallgrass prairie land restoration in this study region.