Dissolved Organic Carbon – Rubeca Fancy

Title: The significance of dissolved organic carbon (DOC) to deep soil carbon storage.

Project Description

The storage of carbon in soils has recently become the focus of considerable international research attention. Carbon accumulation in surface soils is well documented but very little is known about the mechanisms and processes that result in carbon accumulation and long-term storage in the deeper soil profile (Wilson and Lonergan, 2013). Some recent international research work related to dissolved organic carbon (DOC) dynamics reported that the leaching of DOC is the key mechanism to transport carbon to deeper soil layers and the movement of DOC potentially contributes significantly to the carbon balance of terrestrial ecosystems (Sanderman et al. 2008; Sanderman and Amundson 2009; Rumpel and Kögel-Knabner 2011). But it is still unknown the importance of DOC to vertical distribution of OC pool through the soil profile in different land-use system, management practices and conditions prevalent in Australia.

Some work has been undertaken by Soil Carbon Research Programme in Australia and reported only on SOC content and the effects of land-use and management practices on SOC storage but these research works was done only on top soils (0-30 cm depth) instead of deep soil. The principal questions of this research therefore is: what is the relative significance of DOC to carbon input in deep soil layers and how the quantities of carbon differ on different land-use systems in NSW, Australia?

Approach

Soil samples will be collected from three different land-use systems (woodland, pasture and cropland) at 0-1.0 m depth from northern NSW selected from the Statewide soil monitoring program network of sites. The work will be undertaken using a range of techniques including SOC quantification and analysis, δ¹³C and ¹⁴C isotope analysis.

Outcome

investigation of DOC in different land-use systems will gain new insight into the mechanisms and importance of DOC in the soil carbon cycle in Australian soils. The work will therefore significantly extend our knowledge of soil carbon dynamics and the potential for soils to be managed to store additional, long-lasting stocks of carbon as a response to climate change. Results will contribute much to the currently limited quantitative understanding of C fluxes resulting from C input, transport and stabilization processes in Australia.

Users

Researchers, Policy makers, Farming community.