[Effects of different carbon addition modes on the soil priming effect of a subtropical Phyllostachys edulis forest under nitrogen deposition]. / æ°®æ²‰é™ä¸‹ä¸åŒç¢³æ·»åŠ æ¨¡å¼å¯¹äºšçƒ­å¸¦æ¯›ç«¹æž—åœŸå£¤æ¿€å‘æ•ˆåº”çš„å½±å“.

ABSTRACT

Priming effect (PE) plays an important role in regulating terrestrial soil carbon (C) cycling, but the impact of different C addition modes on the PE in subtropical forest ecosystems with increasing nitrogen (N) deposition is unclear. In this study, we investigated the effects of C addition patterns (single or repeated C addition) on soil PE by adding 13C-labeled glucose for 90 d in an incubation experiment with different levels of N application (0, 20, and 80 kg N·hm-2·a-1). The different patterns of glucose addition significantly increased soil organic C (SOC) mineralization and produced positive PE. Single glucose addition resulted in stronger PE than repeated addition. PE was significantly weakened with increasing N application levels, indicating that N deposition inhibited soil excitation in Phyllostachys edulis forests. The cumulative PE was significantly negatively correlated with ß-N-acetylaminoglucosidase (NAG) and peroxidase (PEO) activities, and was significantly positively correlated with microbial biomass P (MBP) and potential of hydrogen (pH). Our findings indicated that, when acting together on soil, N application and C addition could strongly affect soil C stocks by stimulating the mineralization of native soil organic matter in subtropical forests. The findings further indicated that single C addition model might overestimate the effect of exogenous readily decomposable organic C on PE and ignore the effect of N deposition on PE, which in turn would overestimate the mineralization loss of forest SOC.