Variation of soil fertility in Eucalyptus robusta plantations after controlled burning in red soil region and its ecological evaluation

Controlled burning is a traditional forest-clearing method used in Southern China. We analyzed the variability of soil fertility between controlled burning and non-burnt areas in a Eucalyptus robusta plantation forest of the red soil region, located in Hengxian County in Guangxi Zhuang Autonomous Region, China. Traditional incubation and culture-independent methods, such as the dilution-plate method, the polymerase chain reaction, and denaturing gradient gel electrophoresis (PCR-DGGE) were used. Possible effects on the soil ecological system were also evaluated. Soil organic matter (SOM), total and available nitrogen, phosphorus and potassium contents in the 0-3 cm soil layer only one week after burning were all higher than those in a non-burnt Eucalyptus forest. Thus, based on the above results, controlled burning is not helpful for improving the soil fertility and maintaining the development of a sustainable surface soil ecosystem in Eucalyptus plantations in the red soil region of southern China.