- SOC Soil organic carbon, TN Soil total nitrogen, NH4+-N Ammonium nitrogen, NO3—N Nitrate nitrogen, PN Plant nitrogen content, MBC Microbial biomass carbon, MBN Microbial biomass nitrogen, LAP Leucine aminopeptidase, NAG β-1,4-N-acetylglucosaminidase. The values in the yellow area are in the wet-hot season and in the blue areas are in the dry-cool season. ns, * and ** = F-value not significant, significant at p > 0.05 and p < 0.05 and p < 0.01, respectively