title: Forest burning affects quality and quantity of soil organic matter.
abstract: Fire alters ecosystem carbon cycling and generates pyrogenic matter such as charcoal, which can be incorporated into soils. The incorporation and cycling of charcoal in soils is a potential carbon sink, but studies investigating charcoal and carbon dynamics in soils are still lacking. We investigated soil carbon, charcoal and nitrogen dynamics in the top 20cm of a sandy soil within a eucalypt forest in eastern Australia at three sites representing a chronosequence from 3months to 14years post-fire. In the short-term, fire removed litter, but resulted in an increase in both the charcoal and non-charcoal SOC content of the soils, which we attribute to above-ground charcoal generation and its incorporation into the soil profile, as well as below-ground root mortality. On a decadal timeframe, charcoal was preferentially retained in the sandy soil, in which other stabilisation mechanisms are limited, so that the influx of dead root carbon had no remnant effects. The incorporation and retention of charcoal in the soil profile is highly important to carbon cycling in such sandy soils with high fire frequency. It is highly likely that these effects are not limited to the upper 20cm of soil and future studies should investigate deep soil charcoal cycling.
authors.affiliation: Lehrstuhl für Bodenkunde, Department für Ökologie und Ökosystemmanagement, Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt, Technische Universität München, Freising-Weihenstephan 85354, Germany; School of Environmental and Rural Science, Ecosystems Management, University of New England, Armidale 2351, Australia. Electronic address: nellie.hobley@wzw.tum.de.
authors.forename: Eleanor U
authors.initials: EU
authors.lastname: Hobley
authors.affiliation: School of Environmental and Rural Science, Ecosystems Management, University of New England, Armidale 2351, Australia.
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Le Gay Brereton
authors.affiliation: School of Environmental and Rural Science, Ecosystems Management, University of New England, Armidale 2351, Australia; NSW Office of Environment and Heritage, Armidale 2350, Australia.
authors.forename: Brian
authors.initials: B
authors.lastname: Wilson
keywords: Charcoal; Depth distribution; Fire; Slope; Soil nitrogen; Soil organic carbon