Fig. 2: Principal component analysis (PCA).

PCA was conducted with total soil P, microbial biomass P, exchangeable Ca++, total Fe oxide, net abiotic immobilization, net biotic immobilization, gross Pi mobilization, sand content (%), and clay content (%), with vectors displaying the association of these factors with principal component (PC) 1 and PC2. Individual cases are grouped by treatment, and large dots indicate the mean points of each group. Arrows represent loadings of variables. Positively correlated variables are grouped together, while negatively correlated variables are positioned on opposite sides of the plot origin. The distance between variables and the plot origin measures their importance on the respective PC.