** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THIS PROJECT AIMS TO DEVELOP NEW KNOWLEDGE THAT WILL GUIDE TARGETED MANAGEMENT APPROACHES FOR IMPROVING THE BENEFICIAL EFFECTS OF SOIL AMENDMENTS IN AGRICULTURE. ORGANIC AMENDMENTS WILL BE THE FOCAL MANAGEMENT PRACTICE. WE WILL DEVELOP BIOPHYSICAL AND BIOCHEMICAL CONCEPTUAL MODELS, HIGHLIGHTING KEY PROCESSES FOR IMPROVING SOIL HEALTH DURING ORGANIC AMENDMENT DEGRADATION. WE WILL DEFINE CRITICAL TRAITS OF SOIL AND ORGANIC AMENDMENTS THAT CAN PROMOTE SOIL HEALTH. BIOLOGICAL METRICS WILL ALSO BE DEVELOPED FOR DIAGNOSING THE CAPACITY AND THE CAUSE OF ORGANIC AMENDMENT-RELEVANT SOIL HEALTH PROCESSES. THE GOAL AND OBJECTIVES WILL BE ACHIEVED BY INTERROGATING CASCADE AND ANTAGONISTIC SOIL PROCESSES VIA A SEQUENCE OF MICROCOSM, GREENHOUSE, AND SMALL-SCALE FIELD EXPERIMENTS AND A SUITE OF CHROMATOGRAPHY-, SPECTROMETRY-, IMAGING- AND MICROBIOME-APPROACHES. THE OUTCOME OF THIS PROJECT WILL BE A KNOWLEDGE PACKAGE THAT INCLUDES MECHANICS, METRICS, AND CRITERIA FOR RELIABLE DIAGNOSIS AND EFFECTIVE MANAGEMENT OF SOIL HEALTH. THIS PROJECT IS DIRECTED TOWARDS THE CORE GOAL OF THE AFRI FOUNDATIONAL AND APPLIED SCIENCE PROGRAM - SOIL HEATH. IT IS FOCUSED ON DEVELOPING KNOWLEDGE TO BUILD RECOMMENDATIONS FOR IMPROVING SOIL HEALTH FROM AN INFORMED BASELINE. IT ADDRESSES HOW ORGANIC AMENDMENTS SHOULD BE MANAGED IN ARABLE LAND TO IMPROVE SOIL HEALTH, AND WHAT BIOLOGICAL METRICS ARE MORE FEASIBLE TO DIAGNOSE THE BENEFICIAL EFFECTS OF SOIL AMENDMENTS.