**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** SOILS SERVE AS IMPORTANT STORAGE SYSTEMS FOR ATMOSPHERIC CARBON, AND THIS IS ESPECIALLY TRUE FOR GRASSLAND SOILS. IN ADDITION TO CARBON STORGAE, GRASSLANDS SUPPORT DIVERSE ARRAYS OF POLLINATORS, SUPPORT GROUNDWATER RECHARGE, AND PROVIDE FOOD, FUEL, AND FIBER. UNFORTUNATELY, THROUGH HUMAN-DRIVEN LAND-USE CHANGES, MUCH OF THE HISTORIC GRASSLAND COVER HAS BEEN LOST, HAVING BEEN MOSTLY REPLACED BY SINGLE-SPECIES CROPPING SYSTEMS. IT IS WELL-KNOWN THAT DIVERSE GRASSLANDS WITH MANY PLANT SPECIES ARE MORE CAPABLE OF SERVING AS CARBON STORAGE SYSTEMS, BUT MANY KNOWLEDGE GAPS REMAIN. FOR EXAMPLE, CERTAIN SOIL MICROBES ARE KNOWN TO IMPROVE PLANT HEALTH STATUS AND HAVE DRAMATIC IMPACTS ON WHICH PLANT SPECIES MAY BE PRESENT OR ABSENT FROM A PARTICULAR AREA. THUS, IT IS LIKELY THAT THESE SOIL MICROBES CAN LIKELY ALSO INFLUENCE CARBON STORAGE, EITHER DIRECTLY BY IMPROVING THE ABILITY OF SOILS TO CLUMP TOGETHER, FURTHER IMPROVING CARBON STORAGE, OR INDIRECTLY BY INFLUENCING PLAT COMMUNITY COMPOSITION. CURRENTLY, IT IS NOT KNOWN HOW THE PLANTS AND SOIL MICROBES IN A GRASSLAND INDEPENDENTLY AND INTERACTIVELY AFFECT CARBON STORAGE, WHICH IS THE PRIMARY OBJECTIVE OF MY PROPOSED RESEARCH. FURTHERING THIS KNOWLEDGE WILL IMPROVE OUR ABILITY TO MAINTAIN AND ESTABLISH HEALTHY GRASSLAND PLANT COMMUNITIES THAT SUPPORT GRAZING AND POLLINATING SYSTEMS, WHILE ALSO SUPPORTING OTHERKEY FUNCTIONS OF GRASSLANDS HAPPENING BELOW THE SOIL SURFACE,WHICH WILL BECOME EVEN MORE CRITICAL IN THE FACE OF LOOMING CLIMATE CHANGE.USING PLOTS ESTABLISHED IN 2018 AT THE UNIVERSITY OF KANSAS FIELD RESEARCH STATION, I WILL TEST THE EFFECTS OF PLANT COMMUNITY STRUCTURE AND MICROBIAL COMMUNITY ASSEMBLAGES ON CARBON STORAGE AND OTHER SOIL MEASUREMENTS THAT ARE IMPORTANT FOR SOIL HEALTH (NAMELY SOIL AGGREGATESTABILITY AND MICROBIAL ABUNDANCES). TO DO THIS, I WILL VISIT FIELD PLOTS THROUGHOUT THE GROWING SEASON (APRIL-OCTOBER) AND VISUALLY ASSESS PLANT COVER (I.E. PERCENT OF PLOT COVERED BY EACH SPECIES PRESENT IN PLOT). SIMULTANEOUSLY, I WILL COLLECT SEVERAL SOIL SAMPLES, SOME OF WHICH WILL BE USED FOR MICROBIAL COMMUNITY ASSESSMENTS. FOR THIS, MICROBIAL DNA WILL BE EXTRACTED FROM THE SOIL, AFTER WHICH THE DNA WILL BE SEQUENCED AND WILL BE USED FOR IDENTIFICATION OF INDIVIDUAL MICROBIAL SPECIES PRESENT IN THE PLOTS. SOIL WILL ALSO BE SAMPLED FOR CARBON STORAGE USING EQUIPMENT AT THE KANSAS BIOLOGICAL SURVEY.SOIL AGGREGATE STABILITY, OR THE DEGREE TO WHICH SOIL PARTICLES HOLD TOGETHER, WILL ALSO BE MEASURED, AS THIS IS OFTEN ANOTHER INDICATOR OF SOIL HEALTH OR QUALITY. FINALLY, SOILS WILL ALSO BE USED TO ANALYZE FATTY ACIDS, WHICH GIVE A MEASUREMENT OF RELATIVE ABUNDANCE OF IMPORTANT SOIL MICROBIAL GROUPS. IN SHORT, THE DNA AND SEQUENCING WILL TELL US WHO IS THERE, WHILE THE FATTY ACID ANALYSES WILL TELL US HOW MUCH IS THERE. WITH ALL THESE MEASUREMENTS, WE WILL BE ABLE TO TEST THE RELATIVEIMPORTANCE OF PLANT AND SOIL MICROBIAL COMMUNITITES, AS WELL AS THEIR INTERACTIONS, TO SOIL HEALTH IN GRASSLAND SYSTEMS.