5. Conclusions
Increasing stand ages reduced the N concentrations in litter, soil,
microorganisms, and plants but increased their P concentrations, which
led to lower N:P ratios in the C. hystrix plantation ecosystem in
response to increasing stand ages. Overall, C. hystrixplantations become relatively N deficient over time, and their P
limitation may be alleviated with increasing stand age in southern
China. Based on the results of this study, the increase in potential N
mineralization with increasing stand age did not meet the plant N
demand, while the increases in total soil P and MBP facilitated the
plant uptake of P. The shift in the nutrient balance under increasing
stand age will increase the importance of N availability in subtropical
plantation forest ecosystems as well as influence the availability of P.