RESULTS
Impact of soil microbial diversity loss on soil functions
The consequences of microbial diversity loss had a profound impact on the observed soil functions (pools + processes) including soil N and P pools, particularly on ammonium (F(2,195) = 65.2, p <0.001) and nitrate (F(2,195) = 35.9, p<0.001) concentrations. In soils with reduced microbial diversity (D6), ammonium concentrations were approximately 40 times higher compared to those in high (D0) and intermediate (D2) diversity soils, which exhibited similar levels of ammonium (~1.8 mg kg-1) and nitrate (~80 mg kg-1) (Figure S4-i, and S4-ii). Consequently, ammonium had a significant negative correlation with microbial richness (bacterial; ρ = -0.61, p < 0.001 and fungal; ρ = -0.62, p < 0.001) (Table S2), while nitrate displayed a strong positive correlation (bacterial; ρ = 0.77, p < 0.001 and fungal; ρ = 0.74, p< 0.001). Although phosphate levels did not significantly differ among soil dilutions (Figure S4(iii)), they exhibited a significant negative correlation with microbial richness (bacterial; ρ = -0.43, p < 0.001 and fungal; ρ = -0.48, p< 0.001) (Table S2). We also observed that low-diversity soils (D6) had increased the rates of N mineralization, although this difference was not statistically significant (F(2,195) = 0.34, p =0.711; Figure S4(iv)), resulting in a negative correlation with microbial richness (bacterial; ρ = -0.42, p< 0.001 and fungal; ρ = -0.38, p < 0.001). Similarly, while no significant differences were found in Phosphatase activity among soil diversity levels (Figure S4(v)), it showed a positive relationship with microbial richness (bacterial; ρ = 0.27,p < 0.001 and fungal; ρ = 0.28, p < 0.001) (Table S2).