title: Long-term frequent prescribed fire decreases surface soil carbon and nitrogen pools in a wet sclerophyll forest of Southeast Queensland, Australia.
abstract: Prescribed fire is one of the most widely-used management tools for reducing fuel loads in managed forests. However the long-term effects of repeated prescribed fires on soil carbon (C) and nitrogen (N) pools are poorly understood. This study aimed to investigate how different fire frequency regimes influence C and N pools in the surface soils (0-10 cm). A prescribed fire field experiment in a wet sclerophyll forest established in 1972 in southeast Queensland was used in this study. The fire frequency regimes included long unburnt (NB), burnt every 2 years (2yrB) and burnt every 4 years (4yrB), with four replications. Compared with the NB treatment, the 2yrB treatment lowered soil total C by 44%, total N by 54%, HCl hydrolysable C and N by 48% and 59%, KMnO4 oxidizable C by 81%, microbial biomass C and N by 42% and 33%, cumulative CO2-C by 28%, NaOCl-non-oxidizable C and N by 41% and 51%, and charcoal-C by 17%, respectively. The 4yrB and NB treatments showed no significant differences for these soil C and N pools. All soil labile, biologically active and recalcitrant and total C and N pools were correlated positively with each other and with soil moisture content, but negatively correlated with soil pH. The C:N ratios of different C and N pools were greater in the burned treatments than in the NB treatments. This study has highlighted that the prescribed burning at four year interval is a more sustainable management practice for this subtropical forest ecosystem.
authors.affiliation: Griffith School of Environment and Environmental Futures Research Institute, Griffith University, Nathan 4111, Australia.
authors.forename: Bushra
authors.initials: B
authors.lastname: Muqaddas
authors.affiliation: Griffith School of Environment and Environmental Futures Research Institute, Griffith University, Nathan 4111, Australia.
authors.forename: Xiaoqi
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Agriculture, Fisheries and Forestry University of the Sunshine Coast, Sippy Downs Drive, Sippy Downs, QLD 4556, Australia.
authors.forename: Tom
authors.initials: T
authors.lastname: Lewis
authors.affiliation: Griffith School of Environment and Environmental Futures Research Institute, Griffith University, Nathan 4111, Australia.
authors.forename: Clyde
authors.initials: C
authors.lastname: Wild
authors.affiliation: Griffith School of Environment and Environmental Futures Research Institute, Griffith University, Nathan 4111, Australia. Electronic address: c.chen@griffith.edu.au.
authors.forename: Chengrong
authors.initials: C
authors.lastname: Chen
mesh_terms: D002244:Carbon / Q000032:analysis*; D057965:Carbon Sequestration; D003247:Conservation of Natural Resources / Q000379:methods*; D017753:Ecosystem; D005390:Fires; D065928:Forests; D009584:Nitrogen / Q000032:analysis*; D011793:Queensland
chemical_list: D002244:Carbon; D009584:Nitrogen
keywords: Burning frequencies; Charcoal; HCl hydrolysis; KMnO(4) oxidation