IRRIGATED MEADOWS ABOVE 2000-M ELEVATION ARE CRUCIAL BUT UNDER-PERFORMING COMPONENTS OF LIVESTOCK OPERATIONS IN RANGELAND AGROECOSYSTEMS. NUTRIENT AVAILABILITY IS KEY TO SUSTAINABLE AGRICULTURE, BUT IRRIGATED MEADOWS CONCENTRATE ORGANIC MATERIALS ABOVE THE SOIL, CONSTRAINING MICROBIAL-MEDIATED NITROGEN (N) CYCLING, BINDING NUTRIENTS, AND LIMITING PRODUCTIVITY AND BIODIVERSITY. IMPROVED UNDERSTANDING OF LINKAGES AMONG SOIL ORGANIC MATTER (SOM) PROCESSES, MANAGEMENT, AND ECOSYSTEM SERVICES IS NECESSARY FOR LONG-TERM RESILIENCE. OUR GOAL IS TO DEVELOP PROCESS-LEVEL UNDERSTANDING IN SUPPORT OF MANAGEMENT THAT IMPROVES SOIL HEALTH, BIODIVERSITY, AND PRODUCTIVITY OF IRRIGATED MEADOWS. WE WILL SAMPLE FOUR AREAS IN WYOMING AND COLORADO, EACH WITH THREE LONG-TERM MANAGEMENT SCENARIOS: FERTILIZED IRRIGATED MEADOWS, UNFERTILIZED IRRIGATED MEADOWS, AND UNIRRIGATED RANGELAND. OBJECTIVES AND RESEARCH ACTIVITIES INCLUDE: 1) DESCRIBE SOIL AND VEGETATION PROPERTIES AND SOM PROCESSES THAT AFFECT N AVAILABILITY WITH INTEGRATED QUANTIFICATION OF LABILE CARBON (C) AND N COMPONENTS, OM C AND N SPECIATION (C AND N K-EDGE XANES SPECTROSCOPY AND FOURIER-TRANSFORM ION CYCLOTRON RESONANCE MASS SPECTROMETRY), MICROBIAL COMMUNITY COMPOSITION AND FUNCTION USING PHOSPHOLIPID FATTY ACID ANALYSIS, EXTRACELLULAR ENZYME ACTIVITY, AND C-SUBSTRATE UTILIZATION, AND SOIL GREENHOUSE GAS EMISSIONS. DATA WILL BE INTEGRATED WITH STRUCTURAL EQUATION MODELING TO BETTER UNDERSTAND CAUSAL LINKAGES IN PROCESSES THAT RESULT IN LIMITED N AVAILABILITY; 2) DEFINE A MINIMUM DATA SET FOR EVALUATING MEADOW HEALTH AND PRODUCTIVITY USING PRIMARY COMPONENT ANALYSIS AND EXPERT KNOWLEDGE TO IDENTIFY KEY INDICATORS FROM A 40-PROPERTY TOTAL DATA SET; 3) EVALUATE LIGHT MECHANICAL AND LIVESTOCK DISTURBANCE AND INTERSEEDING PRACTICES; AND 4) TECHNOLOGICAL EXCHANGE AMONG RESEARCHERS, COOPERATORS, AND OTHER STAKEHOLDERS VIA A COINNOVATION FRAMEWORK FOR STRUCTURED ENGAGEMENT.