highly significantP < 0.001
Soil pH emerged as a master regulator, exhibiting highly significant negative correlations with all measured soil nutrients (SOM, TN, TP, TK, AN, AP, AK) and most hydrolase enzymes (URE, ALP, SUC, PRO) ( P < 0.001), while showing a unique positive correlation with polyphenol oxidase (PPO) activity ( P < 0.01).