Most variables or categories examined in this study were correlated with one another, making this data set appropriate for SEM analysis (Table S2). SEM analyses indicated that soil acidification directly altered soil N status and soil base cations. The soil acidification pathway directly explained 65% of the total variance in soil N status and 74% of total variance in soil base cation concentrations (Fig. 4). The increases in contents of H+ were associated with decreases in the net N mineralization rate and soil NO3−−N and increases in soil NH4+−N. Similarly, the increases in H+ were associated with soil base cations. Observed changes in N status and soil base cations explained about 51% of the total variance in plants (increases in BB, BB/AB, and PR/PB and decrease in AB). Most of the total variance (82%) in the soil microbes (increases in fungal FAs and fungi/bacteria ratio and decreases in bacterial FAs and PC1 score of EEA) were apparently explained by both soil acidification and soil base mineral cations pathways (Fig. 4)