Links of microbial and vegetation communities with soil physical and chemical factors for a broad range of management of tallgrass prairie

Abstract

Identifying ecological indicators and management factors that influence sustainability and resilience, both ecologically and economically, is key to restoring grassland landscapes' ecological function. We examine soil and vegetation responses to different combinations of adaptive multi-paddock grazing (AMP) managed to improve soil and ecological function as the foundation to improve the provision of ecosystem services and economic benefits, relative to heavy continuous grazing (HCG) and moderate continuous grazing (MCG).We used multidimensional scaling (MDS) and analysis of similarities (ANOSIM) to indicate associations among soil, soil biota and vegetation parameters to indicate associations in response to the different grazing management strategies. AMP grazing improved total herbaceous biomass, C4 tallgrasses, native perennial summer growing forbs, and vegetation cover while decreasing bare ground cover and less productive or invasive herbaceous species. AMP also had higher biomass of total soil microbes, actinomycetes, and gram-positive and gram-negative bacteria associated with improved soil aggregation and nutrient cycling than HCG, with MCG having intermediate responses. Arbuscular mycorrhizal fungi crucial for enhanced water and nutrient acquisition by plants were higher with AMP and were lower with HCG, with MCG intermediate between the two. AMP also outperformed HCG and usually MCG in the critical soil physical elements such as soil aggregation fostering improved ecological function. These are substantive improvements, achieved despite AMP having double the stocking rate of MCG. These positive outcomes were generally not compromised with the BURN and HAY treatments as both were managed with AMP grazing. The exception was HAY, which showed increased soil penetration resistance compared to AMP but less than with HCG or MCG. AMP grazing also compared favorably with the grazing Exclosures for most parameters measured. The presence of low densities of trees had predominantly positive results relative to treeless AMP and MCG, particular for soil temperature, soil organic matter and cation exchange capacity. These findings provide evidence that AMP grazing is a powerful management strategy to positively alter plant composition and soil physical, chemical, and microbial properties relative to season-long continuous grazing to enhance the provision of ecosystem services and economic benefits in Southern Tallgrass prairie.