** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** HEALTH SOILS ARE CRITICAL TO SUSTAINABLE AGRICULTURE. CURRENTLY, A VARIETY OF CONSERVATIVE FARMING PRACTICES ARE APPLIED TO AGRICULTURE SOILS TO PROMOTE SOIL HELATH. COVER CROPPING IS ONE OF THE MOST COMMONLY USED APPROACH. HOWEVER, A MAJOR KNOWLEDGE GAP IS THE UNCERTAINTY OF THE BENEFITS OF IMPLEMENTING COVER CROPPING AND THE TIME THAT IT TAKES FOR POSITIVE EFFECTS TO BECOME NOTICEABLE. IN THIS PROJECT, OUR LONG-TERM GOAL IS TO BETTER UNDERSTAND HOW COVER CROPPING MODULATES SOIL HEALTH, CROP PERFORMANCE, AND MICROBIAL COMMUNITIES. BY APPLYING A SPACE-FOR-TIME APPROACH AND CONTROL-TREATMENT PAIRED DESIGN, WE WILL INVESTIGATE THE TIME SCALES AT WHICH COVER CROPPING CASCADES INTO MICROBIAL COMMUNITY STRUCTURE (MAINLY OF BACTERIA, ARCHAEA AND FUNGI), THE ASSOCIATED NUTRIENT PROCESSING INCLUDING CARBON AND NITROGEN, SOIL HEALTH, AND CROP YIELDS.THE KEY QUESTIONS WE TRY TO ANSWER HERE ARE: HOW DO COVER CROPPING ALTER MICROBIAL COMPOSITION, SOIL HEALTH, AND CROP PERFORMANCE? AND AT WHAT TIME SCALES DO THESE EFFECTS MANIFEST? ARE SOIL HEALTH INDICES REFLECTIVE OF MICROBIAL STRUCTURE AND FUNCTION, AND DO RELATIONSHIPS AMONG THESE MEASURES VARY THROUGH TIME? WE WILL PARTINER WITH 48 FARMS (24 PAIRED FIELDS EACH YEAR FOR 2 YEARS) IN PENNSYLVANIA WITH TIME SINCE IMPLEMENTATION OF CONSERVATION PRACTICE RANGING 0-15+ YEARS. WE WILL (1) CHARACTERIZE DETAILED COMPOSITIONS OF SOIL MICROORGANISMS SUCH AS BACTERIA, ARCHAEA AND FUNGI; (2) MEASURE NITROGEN AND CARBON PROCESSES AND DYNAMICS WITH COVER CROPS IMPLEMENTED IN DIFFERENT DURATION OF YEARS; AND (3) SUTDY THE HOW COVER CROPPING IMPACT SOIL HEALTH MEASUREMENTS AND CROP PERFORMANCE. THIS STUDY WILL PROVIDE ROBUST INFORMATIONON HOW COVER CROPPING CONTRIBUTES TO IMPROVEMENT OF MICROBIAL SOIL HEALTH AND SUSTAINABLE AGRICULTURE. LESSONS FROM THIS STUDY WILL BE TRANSFERABLE TO A BROADER AGRICULTURE AUDIENCE AND FARMING COMMUNITIES. THIS STUDY WILL SUPPORT THE PROFESSIONAL DEVELOPMENT AND EDUCATION OF FOUR RESEARCHERS (TWO SENIOR AND TWO JUNIOR), ONE SOIL HEALTH COORDINATOR, FIVE TECHNICIANS, AND MULTIPLE UNDERGRADUATE STUDENTS.