Abstract:
Objective To study the soil organic carbon pool of different plantations of Castanopsis hystrix mixed forest and its stability in order to provide reference for the evaluation of carbon balance process and the selection of mixed models of C. hystrix mixed plantations in subtropics of south China.
Method The C. hystrix pure forest (HC), C. hystrix + Pinus elliottii mixed forest (HS), C. hystrix + Michelia macclurei mixed forest (HH), C. hystrix + Mytilaria laosensis mixed forest (HM) were used as trial objects in this study, and the changes of soil organic carbon (SOC), easily oxidizable carbon (EOC), particle organic carbon (POC), dissolved organic carbon (DOC), microbial biomass carbon (MBC)and carbon pool management index (CMI) of different mixed plantations were analyzed.
Result The contents of SOC, EOC, POC, DOC, and MBC decreased with the increase of soil depth in the four kinds of mixed plantations. SOC had a significant positive correlation with EOC, POC, and MBC (P<0.01), and the correlation coefficient between SOC and POC was the largest. The order of SOC content was HM>HH> HS>HC among different stands, and the change of 0-20 cm soil layer was consistent with that of the whole stand (0-40 cm soil layer). The change of CMI in 20-40 cm soil layer was consistent with that of the whole stand, and the order was HM>HH>HC>HS.
Conclusion The contents of SOC, EOC, POC, DOC and MBC are mainly affected by the surface soil, CMI is mainly affected by the subsoil, and the POC content is most closely related with SOC in the four mixed plantations. The C. hystrix broadleaved mixed forests can improve soil fertility and soil quality, and the broadleaved mixed model of HM has the highest soil carbon pool quality, with the increase of organic carbon and activated carbon, it also contributes to the accumulation of inert carbon and the stability of carbon pool.