Soil organic carbon dust emission: a synthesis of recent Australian research

TitleSoil organic carbon dust emission: a synthesis of recent Australian research
Publication TypeConference Proceedings
Year of Publication2014
AuthorsWebb N, Chappell A, Strong C, Butler H, Marx S, Leys J, McTainsh G, Viscarra-Rossell R
Conference NameEighth International Conference on Aeolian Research (ICAR VIII)
Paginationp. 196
Date Published07/2014
PublisherInternational Society of Aeolian Research (ISAR)
Conference LocationLanzhou, China
ARIS Log NumberN/A
Abstract

Soil erosion is an important component of the global carbon cycle. Recent research has revealed the importance of aeolian processes for soil organic carbon (SOC) flux and its impacts on carbon dynamics and ecosystem function. Here we review progress in research on the mechanisms and magnitude of SOC dust emissions in Australia. We describe how field measurements of entrainment and enrichment of SOC in dust led to a new physically-based parameterisation of SOC dust enrichment for the Computational Environmental Management System (CEMSYS) national wind erosion model. Our modelling results suggest that from 2000-2011 the total dust emission for Australia was 118 Mt yr-1 with SOC dust emissions (<22 µm) ~1.59 Mt yr-1. Rangelands produced ~84% of Australia’s SOC dust emissions (1.34 Mt yr-1). Agricultural lands produced ~0.11 Mt yr-1, but emissions were larger per unit area than rangelands. The rapid and often long-distance aeolian transport of SOC may result in the depletion of SOC at source, enrichment of downwind soils, or incorporation into aquatic and marine systems. SOC loss was likely greater in the past (since 1870s) during post-colonial agricultural expansion and reduced since the 1980s with conservation agriculture. This impacted soil function and productivity of rangelands and cropping lands. The impact on land surface–atmosphere interactions is likely also considerable, but large uncertainty remains over mineralisation rates of SOC and its fate in the atmosphere. Our results demonstrate the need for aeolian processes to be given greater significance in terrestrial carbon cycling, and for the inclusion of dust emission schemes in Earth systems models and carbon accounting systems.