DINITROGEN FIXING MICROBES ARE CRITICAL MEMBERS OF THE PLANT MICROBIOME REGULATING KEY ASPECTS OF PLANT GROWTH, NUTRIENT CYCLING AND SOIL HEALTH. IN MANAGED PASTURES, THE RHIZOSPHERE PROCESSES AND MECHANISMS INVOLVED WITH MIXED PLANTINGS ARE NOT WELL UNDERSTOOD. THIS STUDY WILL INTEGRATE CUTTING-EDGE MOLECULAR AND BIOCHEMICAL TECHNIQUES TO ASSESS SOIL COMMUNITY AND FUNCTIONAL DYNAMICS BETWEEN TWO FORAGE SPECIES (BAHIAGRASS: PASPALUM NOTATUM FLÜGGÉ; RHIZOMA PEANUT: ARACHIS GLABRATA BENTH) AND THEIR NITROGEN (N)-FIXING MICROBES, AS AFFECTED BY PLANT COMBINATION, GRAZING, TIME, AND ENVIRONMENTAL VARIABLES; AND TO DETERMINE THESE CONSEQUENCES ON N UPTAKE EFFICIENCY OF PASTURE PLANTS AND SOIL N/CARBON (C) RETENTION. BAHIAGRASS IS DISTRIBUTED OVER 6 MILLION ACRES OF IMPROVED BAHIAGRASS PASTURE ACROSS SOUTHEASTERN UNITED STATES. IN THE SOUTHEASTERN STATES, THESE PASTURES FACE DECREASING SOIL C/N. WE HYPOTHESIZE THAT SPECIFIC N-MICROBES SELECTED THROUGH SCREENING GRASS-LEGUME GENOTYPE COMBINATIONS AND INTEGRATED PRACTICES (I.E., GRAZING) CAN BE USED TO IMPROVE PASTURE PRODUCTIVITY VIA GREATER SOIL N UTILIZATION AND C SEQUESTRATION. IMPROVING PLANT-SOIL-MICROBE FUNCTIONS WILL RESULT IN MORE RESILIENT AND ENVIRONMENTALLY SOUND PRODUCTION SYSTEMS. OUR AIM IS TO PROVIDE THE FIRST EVER ASSESSMENT OF THE FUNCTIONAL DYNAMICS FOR THESE MICROBES THROUGH SELECTION AND TESTING OF THE MOST COMPATIBLE FORAGE GENOTYPES, BASED UPON MICROBIAL FUNCTIONS RELATED TO GRASS AND LEGUME N REQUIREMENTS, SOIL C SEQUESTRATION AND MULTI-PRACTICE ADAPTATION. OUR LONG-TERM GOAL IS TO IMPROVE PRODUCTION EFFICIENCY AND PERSISTENCE BY HARNESSING PLANTS AND THEIR MICROBIOMES TO INCREASE PASTURE BIODIVERSITY, N-FIXATION AND SOIL C SEQUESTRATION, WHILE REDUCING ABIOTIC N INPUTS.

University Of Florida, Gainesville FL

Investigators