**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** ADDING COVER CROPS TO ROTATION BENEFITS SOIL ORGANIC C (SOC). EVEN WITH LOW ABOVEGROUND BIOMASS AND HEAVY TILLAGE DISTURBANCE, THE TWO KNOWN IMPEDIMENTS TO SOC GAINS, SOC CONCENTRATIONS IN SYSTEMS WITH COVER CROPS OFTEN BECOME COMPARABLE TO THOSE OF HIGH YIELDING NO-TILLS. THIS ENIGMATIC OBSERVATION POINTS TO A KNOWLEDGE GAP IN UNDERSTANDING THE MECHANISMS DRIVING SOC GAINS IN AGRICULTURAL SYSTEMS WITH CONTINUOUS DIVERSE GREEN COVER. WE POSIT THAT ONE OF SUCH PREVIOUSLY OVERLOOKED MECHANISMS IS CREATION OF MICRO-SCALE SOIL ENVIRONMENTS OPTIMAL FOR MICROBIAL FUNCTIONING AND TRANSFER OF MICROBIAL PRODUCTS AND NECROMASS INTO SOIL MATRIX WHERE THEY CAN BE ENTOMBED AWAY FROM FURTHER DECOMPOSITION. OUR GOAL IS TO IDENTIFY FEATURES OF INDIVIDUAL COVER CROP SPECIES AND MULTI-SPECIES MIXTURES THAT WILL MAXIMIZE SUCH MICRO-ENVIRONMENTS - A STEP IMPERATIVE FOR SCIENCE-BASED DESIGNS OF PLANT SYSTEMS CAPABLE OF RAPID ACCELERATION IN SOC GAINS. WE WILL EMPLOY A TWO-PRONG APPROACH OF (I) INTERROGATION OF MICRO-SCALE SOIL CHARACTERISTICS IN TWO LONG-TERM (>25 YR) LTER AND LTAR SITES WITH DEMONSTRATED SOC GAINS IN COVER CROP-BASED ORGANIC SYSTEMS; AND (II) AN EXPLORATION OF HOW THE POSITIVE CHANGES LEADING TO SOC GAINS ORIGINATE IN MONO- VS. POLYCULTURE COVER CROPPING. WE WILL JOINTLY ASSESS SEVERAL PHYSICAL, CHEMICAL, AND BIOLOGICAL CHARACTERISTICS IN STRUCTURALLY INTACT SOIL, USING A COMBINATION OF NOVEL AND ESTABLISHED TOOLS, INCLUDING X-RAY MCT, ISOTOPE LABELING, HYDROLYTIC AND OXIDATIVE ZYMOGRAPHY, MXRF IMAGING, AND XANES SPECTROSCOPY. THE PROJECT WILL ADDRESS THE SOIL HEALTH PROGRAM'S PRIORITY OF IMPROVING OUR UNDERSTANDING OF THE PHYSICAL AND BIOGEOCHEMICAL INTERACTIONS AND PROCESSES WITHIN THE SOIL.

Michigan State University, East Lansing MI

Investigators