Bruns Soil Microbial Ecology Lab

Our research group investigates soil- and plant-associated microbial communities, especially populations involved in nutrient cycling and biogeochemical transformations of redox-active elements like N, Fe, and Mn.

Important functional groups include free-living, associative, and symbiotic N2 fixers, nitrifiers, denitrifiers, mycorrhizal fungi, and other taxa involved in micronutrient availability and pathogen suppression. We use cultural, metagenomic, and biochemical techniques to gain understanding of microbial responses to management in the field and to more controlled conditions in soil mesocosms. Of particular interest are soil conditions resulting from climate-adaptive agricultural practices, such as reduced tillage and cover cropping. Edaphic conditions, such as increased soil organic carbon, water-holding capacity, and sustained biological activity, may support underexplored microbial metabolisms important in nutrient cycling and delivery to plants. We want to learn how plants, soils, and their associated microorganisms can be managed to improve soil health, plant growth, and ecosystem resilience.

Ongoing projects:

• N2 fixation and modulation of inorganic N by cyanobacterial crusts on arable soils
• Effects of labile carbon and soil management (tillage, cover cropping, manure application) on nitrite ammonification and denitrification
• Cover crop diversity impacts on arbuscular mycorrhizal abundance and colonization
• Soil fertility management that promotes beneficial plant-microbe interactions
• Effects of sorghum rhizosphere populations on cold tolerance
• Identifying the most useful and informative methods to assess soil health