SOIL APPLICATION OF ORGANIC AMENDMENTS TO PROTECT AND ENHANCE THE BIODIVERSITY OF URBAN ECOSYSTEMS: EVALUATION OF CARBON SEQUESTRATION DYNAMICS BASED ON BOTH SOIL PROPERTIES AND IMPACT ON HERBACEOUS AND TREE SPECIES

URBANIZATION DURING THE PAST DECADES HAS PROFOUNDLY ALTERED THE STRUCTURE AND FUNCTIONALITY OF URBAN SOILS, REDUCING FERTILITY, COMPROMISING BIODIVERSITY, AND LIMITING CARBON SEQUESTRATION CAPACITY. IN THIS CONTEXT, THE APPLICATION OF ORGANIC AMENDMENTS REPRESENTS A PROMISING STRATEGY TO REGENERATE URBAN ECOSYSTEMS AND SUPPORT PLANT BIODIVERSITY; HOWEVER, THE SCIENTIFIC LITERATURE REMAINS FRAGMENTED, AND STUDIES CONDUCTED UNDER TRULY URBAN CONDITIONS ARE LIMITED. IN ADDITION, THE APPLICATION OF ORGANIC AMENDMENTS LIKE COMPOST AND BIOCHAR ON EXISTING URBAN GREEN AREAS AS TURF ARE NOT POSSIBLE. AMONG THE ORGANIC AMENDMENTS, NO DATA IS AVAILABLE ON THE USE OF MICRONIZED ONES IN URBAN SOILS. CONSIDERING THESE ASPECTS, THE PRESENT WORK INVESTIGATED THE APPLICATION OF MICRONIZED AMENDMENTS IN URBAN SOILS, TOGETHER WITH THEIR ASSESSMENT USING HIGH-RESOLUTION DIGITAL MONITORING SYSTEMS. THE EXPERIMENTAL WORK ASSESSED FOUR URBAN SITES WITH CONTRASTING MANAGEMENT CHARACTERISTICS, EVALUATING THE EFFECTS OF MICRONIZED VERMICOMPOST, MICRONIZED BIOCHAR AND THEIR COMBINATIONS ON SOIL CHEMICAL PROPERTIES, WATER AVAILABILITY, SPONTANEOUS VEGETATION PHYSIOLOGY, PRODUCTIVITY, AND POTENTIAL CARBON SEQUESTRATION, OVER THREE YEARS. THE RESULTS SHOW THAT MICRONIZED AMENDMENTS, PARTICULARLY WHEN APPLIED IN COMBINATION, ENHANCE SOIL FERTILITY, INCREASE NUTRIENT AVAILABILITY, STIMULATE MICROBIAL BIOMASS, AND IMPROVE WATER-HOLDING CAPACITY. IN ADDITION, INCREASED CHLOROPHYLL CONTENT, NITROGEN USE EFFICIENCY, AND PHOTOCHEMICAL EFFICIENCY AND ENHANCING ABOVEGROUND BIOMASS. DIGITAL SENSORS PROVED TO BE EXTREMELY SENSITIVE TOOLS FOR DETECTING DIFFERENCES AMONG THE INVESTIGATED TREATMENTS, REVEALING INTERESTING PHYSIOLOGICAL DIFFERENCES. THE MOST PRONOUNCED RESPONSES WERE OBSERVED IN SOILS HAVING A LOW CHEMICAL FERTILITY, HIGHLIGHTING THE IMPORTANCE OF THE ECOLOGICAL CONTEXT. THIS THESIS DIRECTLY ADDRESSES MAJOR GAPS IN LITERATURE BY DEMONSTRATING THAT STUDIES CONDUCTED UNDER REAL CONDITIONS, USING MULTIDISCIPLINARY APPROACHES ARE ESSENTIAL FOR A CORRECT ASSESSMENT ON THE USE OF INNOVATIVE AMENDMENTS IN URBAN SOIL. THE RESULTS PROVIDE A SOLID EMPIRICAL FOUNDATION FOR FUTURE RESEARCH ON CARBON STABILIZATION, MICROBIAL DYNAMICS, LONG-TERM EFFECTS, AND INTERACTIONS BETWEEN MICRONIZED AMENDMENTS AND ANTHROPOGENIC SOILS. OVERALL, THIS THESIS CONTRIBUTES TO ESTABLISHING A MORE ROBUST AND REALISTIC SCIENTIFIC FRAMEWORK FOR THE USE OF INNOVATIVE ORGANIC AMENDMENTS IN URBAN ENVIRONMENTS, OFFERING PRACTICAL GUIDANCE FOR ECOLOGICAL PLANNING AND THE SUSTAINABLE MANAGEMENT OF URBAN GREEN SPACES.