**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** ESCALATING CONCERNS OVER FOOD SAFETY AND ENVIRONMENTAL PROTECTION HAVE SUBSTANTIALLY INCREASED CONSUMER DEMAND FOR ORGANIC PRODUCTS. HOWEVER, THESE PRODUCTS ARE OFTEN IN SHORT SUPPLY DUE TO THE LIMITED LAND AREA UNDER ORGANIC PRODUCTION, AND ALSO BECAUSE CROP YIELDS TEND TO BE LOWER THAN FOR CONVENTIONAL AGRICULTURE. THE IMPORTANCE OF SYMBIOTIC DINITROGEN (N2) FIXATION IS READILY APPARENT FROM THE WIDESPREAD USE OF LEGUME ROTATIONS IN ORGANIC SYSTEMS, WHEREAS VERY LITTLE ATTENTION HAS BEEN GIVEN TO NON-SYMBIOTIC FIXATION BY FREE-LIVING BACTERIA. THE LATTER PROCESS WOULD BE FAVORED FOR THESE SYSTEMS BY THE ABSENCE OF SYNTHETIC NITROGEN AND BY FREQUENT COVER-CROPPING THAT IMPROVES SOIL STRUCTURE AND AUGMENTS THE INPUT OF CARBON FROM ROOTS AND RESIDUES.IN THE PRESENT PROJECT, A NOVEL APPROACH WILL BE UTILIZED TO ASSESS THE DIVERSITY (TARGETED GENE SEQUENCING) AND ABUNDANCE (QPCR ANALYSIS) OF FREE-LIVING BACTERIA, ALONG WITH THEIR FUNCTIONAL CAPACITY (15N2 FIXATION), FOR A WELL-ESTABLISHED ORGANIC ROTATION. BASED ON PREVIOUS INVESTIGATIONS DOCUMENTING THE IMPORTANCE OF A NEUTRAL TO ALKALINE SOILS WITH ADEQUATE CALCIUM AVAILABILITY, A COMPARISON WILL BE MADE OF MICROBIAL COMMUNITIES AND FREE-LIVING N2 FIXATION (FLNF) WITH AND WITHOUT CERTIFIED ORGANIC LIMESTONE AND GYPSUM AMENDMENTS. THIS PROJECT ADDRESSES ALL THREE GOALS OF THE SOIL HEALTH PROGRAM AREA, AND HAS POTENTIAL TO PROVIDE A SIMPLE AND COST-EFFECTIVE MEANS TO REDUCE NITROGEN LIMITATION IN ORGANIC PRODUCTION SYSTEMS. THERE ARE IMPLICATIONS FOR ENHANCING ECONOMIC PROFITABILITY FOR PRODUCERS, IMPROVING THE COMMERCIAL AVAILABILITY OF ORGANIC PRODUCTS, AND PROTECTING AIR, SOIL, AND WATER QUALITY.