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Southern Cross GeoScience

Long-term terrestrial carbon sequestration using phytolith occluded carbon

Funding / collaborators:

  • Australian Research Council
  • Australian Institute of Nuclear Science and Engineering
  • Department of Primary Industries
  • Fujian Academy of Forestry Science, China

Project description:

Atmospheric CO2 concentrations are considered to underlie dangerous climate change. This project is aimed at providing practical low-cost and natural solutions to this global problem. We are doing this by exploring the potential of plants to securely sequester carbon within the microscopic silica particles that form in plants called plantstons (these are also known as phytoliths or plant opal). Both these plantstones and the carbon enclosed within are highly resistant to decomposition and endure in soil for thousands of years. The current project involves determining the potential of grass crops, and other plants for their phytolith carbon storage capacity. The research to date has indicated that this technology can reduce CO2 emissions by ~1.5 billion tonnes of CO2 per annum, equivalent to > 10% of the current rate of global CO2 increase in the atmosphere, at low cost by the adoption of simple and practical changes to present farming practices. (Parr, Sullivan et al. In press: see Global Change Biology paper in Publications list below).


Team members:

  • Jeff Parr
  • Leigh Sullivan

Outcomes / key findings:

  • The potential size of the contribution that this technology can make to reducing CO2 emission sis ~1.5 billion tonnes of CO2 per annum simply by farmers choosing to grow the high-plantstone carbon yielding cultivars of the grass crops they already grow (Parr, Sullivan et al 2010.
  • By radiocarbon dating the carbon protected in the phytoliths themselves we have demonstrated that phytoliths can resist decomposition in a range of soils for 8,000 years.
  • Some agricultural crops produce phytolith carbon at rates 40 times greater than natural vegetation.
  • By the selection of existing species and varieties there is a potential to significantly increase the amount of long-term carbon stored by phytoliths produced in agricultural grass crops such as barley, maize, sorghum, sugarcane and wheat, as well as other plant species such as bamboos and native grasses.
  • Results also show large variation in the phytolith carbon yields between different cultivars of crops. For example, the soil carbon sequestration rate for high phytolith carbon yielding wheat varieties was over 10 times times that of the lowest phytolith carbon yielding wheat varieties.
  • Our trials with wheat and sorghum clearly indicate that there is no trade off between high Plantstone carbon yielding cultivars and crop yield.

Relevant publications:

Parr, J.F., Sullivan, L.A., Chen, B., Ye, G. and Zheng, W., 2010. Carbon bio-sequestration within the Phytoliths of economic bamboo species. Global Change Biol, 16(10): 2661-2667.

Parr, J.F., Sullivan, L.A. and Quirk, R., 2009. Sugarcane Phytoliths: Encapsulation of a Long-Lived Carbon Fraction. Sugar Tech, 11(1): 17-21

Parr, J.F., and Sullivan, L.A. 2007. Deposition of plant silica, a long-lived soil fraction containing easily quantifiable carbon. International Symposium on Organic Matter Dynamics in Agro-Ecosystems. 16th - 19th July, Poitiers, France (INRA).

Sullivan, L.A., and Parr, J.F. 2007. Management of silica biomineralisation in crops to enhance soil carbon sequestration in agro-ecosystems International Symposium on Organic Matter Dynamics in Agro-Ecosystems. 16th - 19th July, Poitiers, France (INRA).

Sullivan, L.A. and Parr, J.F., 2007. Green' geosequestration: Secure carbon sequestration via plant silica biomineralisation. Geochimica et Cosmochimica Acta, 71(15): A985-A985.

Parr, J.F., 2006. Effect of Fire on Phytolith Coloration. Geoarchaeology, 21(2): 171-185.

Parr, J. F. and Sullivan, L. A. (2005). 'Soil carbon sequestration in Phytoliths.' Soil Biology and Biochemistry. 37(1): 117-124.