Australian net (1950s-1990) soil organic carbon erosion: implications for CO2 emission and land-atmosphere modelling

TitleAustralian net (1950s-1990) soil organic carbon erosion: implications for CO2 emission and land-atmosphere modelling
Publication TypeJournal Article
Year of Publication2014
AuthorsChappell A, Webb N, Rossel RV, Bui E
JournalBiogeosciences
Volume11
Start Page5235
Pagination5235-5244
Date Published09/2014
ARIS Log Number310889
Abstract

The debate remains unresolved about soil erosion substantially offsetting fossil fuel emissions and acting as an important source or sink of CO2. There is little historical land use and management context to this debate, which is central to Australia's recent past of European settlement, agricultural expansion and agriculturally induced soil erosion. We use "catchmen" scale (25 km2) estimates of 137Cs-derived net (1950s–1990) soil redistribution of all processes (wind, water and tillage) to calculate the net soil organic carbon (SOC) redistribution across Australia.  We approximate the selective removal of SOC at net eroding locations and SOC enrichment of transported sediment and net depositional locations. We map net (1950s–1990) SOC redistribution across Australia and estimate erosion by all processes to be 4 Tg SOC yr-1, which represents a loss of 2% of the total carbon stock (0–10 cm) of Australia. Assuming this net SOC loss is mineralised, the flux (15 TgCO2-equivalents yr-1) represents an omitted 12% of CO2-equivalent emissions from all carbon pools in Australia. Although a small source of uncertainty in the Australian carbon budget, the mass flux interacts with energy and water fluxes, and its omission from land surface models likely creates more uncertainty than has been previously recognized.

URL/files/bibliography/14-030.pdf
DOI10.5194/bg-11-5235-2014