Effects of Precipitation Change and Nitrogen Addition on Organic CarbonMineralization and Soil Microbial Carbon of the Forest Soils in Dinghushan,Southeastern China

Abstract

Soil organic carbon(SOC) mineralization and soil microbial carbon(SMBC) play an important role in global C cycle.With method of incubation and chloroform fumigation extraction,the effects of precipitation change and nitrogen(N) addition on the SOC mineralization and SMBC were studied along a forest succession series including pine forest(PF),mixed pine and broadleaved forest(MF) and monsoon evergreen broadleaved forest(MEBF) at Dinghushan,Southestern China.The results showed that:(1) Increased precipitation could improve the mineralization of SOC in the late-successional forest plots,but the effect in the early-successional forest plots were not significant(P0.05).(2) Less precipitation(drought) resulted in lower content of SMBC in the monsoon forest soil(0～10 cm),while the doubled precipitation treatment had no significant effect on the SMBC content.(3) N deposition did not affect SMBC mineralization and SMBC in all of the three forests.It is important to take the quality of organic matter,C/N ratio,exogenous nitrogen and many other combined effects into consideration in the future studies on the responses of SOC mineralization and SMBC to climate change.Fig 4,Tab 2,Ref 37