Sub sections:
Christine Walela - Profile dynamics of soil carbon storage and resilience under three paired land uses on a duplex soil in NSW, Australia.
Terrestrial ecosystems have been identified as having the potential to offset greenhouse gas emissions through carbon sequestration. Though various authors have estimated the terrestrial sink to absorb approximately 2-4 Pg C yr-1, there is still a considerable debate in literature regarding the most effective land use practice that might achieve increased soil carbon storage. In particular, knowledge of the relative quantities of soil carbon that might be stored by different land uses is lacking in Australia and particularly in NSW. Further, most work to date in Australia has been focussed on the surface layers and our knowledge of the subsurface carbon distribution and resilience is still limited. The importance of carbon (C) sequestration in subsoil is steadily growing, with increasing evidence of low turnover rate and occurrence of subsoil soil organic carbon in relatively stable form.
The objective of this research is to quantify profile (up to 1m) carbon stocks in three paired land uses which include; native woodland, native pastures and forage cropping on a duplex soil in NSW, Australia. The choice of conducting this study on a duplex was to assess the association of soil texture and C storage with increasing depth. In order to understand the resilience/stability of soil carbon stored in these systems, the size and turnover of carbon pools (active, slow and resistant) will be determined through mineralization studies and carbon dating techniques. Further, the stability of these pools will not have been fully understood without understanding the interactions between how both above (plant) and below ground (root) litter quality affects transformations of residues into stable soil organic matter. Therefore, Christine will determine biochemical characteristics of plant and root litter and conduct litter mineralization studies in order to provide insights on how litter quality may influence C storage and resilience within a given management system.
Activities conducted so far include, completion of the first phase of field work. Christine has successfully sampled all the sites which were located around the township of Uralla on the Northern Tablelands of NSW. An extended laboratory incubation study which will last for six months has also been set up. Extended laboratory incubation utilizes the degradative enzymes of the soil biota to provide an analytical estimate of the soil C pools and fluxes. Laboratory analyses are now underway.
During this calendar year, Christine received AUD $2000 funding from PIIC to attend and present a paper and a poster at the European Geosciences Union International Conference which was held in Vienna, Austria.