Positive priming effect occurs under nutrient-limited conditions owing to the stimulation of microbial biomass production after low amount of exogenousnutrient input. In contrast, high levels of nutrient addition decreased microbial biomass and net N mineraliza-tion. This high N, P, K, Ca, and S addition could satisfy the needs of microbial growth, thereby decreasing thedependency of the organisms on the original nutrients from SOM decomposition.