fig4

Figure 4. Principal Component Analysis (PCA) integrating the Carbon Footprint (CFP, kg CO₂ eq ton^-1) with the main chemical, microbiological and enzymatic soil parameters under treatments with Compost, Vermicompost, Digestate, and SBO (sulfur bentonite with olive pomace). Variables included: TOC (Total Organic Carbon, %), TEC (Total Extractable Carbon, %), HA (Humic Acid carbon, %), FA (Fulvic Acid carbon, %), HA+FA (Humic + Fulvic Acid carbon, %), HA/FA (Humic to Fulvic Acid ratio, dimensionless), HR (Humification Rate, %), HD (Humification Degree, %), HI (Humification Index, %), E4/E6 (absorbance ratio at 465/665 nm, dimensionless), WSP (Water Soluble Phenols, mg TAE g^-1 d.w.), SOM (Soil Organic Matter, %), TN (Total Nitrogen, %), C/N (Carbon to Nitrogen ratio, dimensionless), pH (H₂O, 1:2.5 ratio), EC (Electrical Conductivity, dS m^-1), WC (Water Content, %), CEC [Cation Exchange Capacity, cmol(+) kg^-1], MBC (Microbial Biomass Carbon, µg C g^-1), FBC (Fungal Biomass Carbon, µg C g^-1), BBC (Bacterial Biomass Carbon, µg C g^-1), ABC (Actinomycetes Biomass Carbon, µg C g^-1), FC (Fraction of Carbon easily decomposable, %), HC (Humified Carbon, %), HC/FC (Humified Carbon to Fraction of Carbon ratio, %/%), FDA (Fluorescein Diacetate hydrolase activity, µg fluorescein g^-1 h^-1), DHA (Dehydrogenase activity, µg TPF g^-1 h^-1), ACT (Actinomycetes, % of total microbial biomass), BACT (Bacteria, % of total microbial biomass), and FUNGI (Fungi, % of total microbial biomass).