Soils ain't soils: NSW DPI on the front foot with carbon sequestration potential in soils.

With the potential for carbon sequestration in Australian soils such a hot topic at the moment, NSW Department of Primary Industries (DPI) has dedicated two up-to-date and informative web pages to the issue.

The first web page (www.dpi.nsw.gov.au/research/areas/resources-research/soils-recycled-organics/scientific-outputs/2008/soil_organic) highlights a 28-page Scoping Paper: Soil Organic Carbon (SOC) Sequestration Potential for Agriculture in NSW, authored in 2008 by NSW DPI scientists Yin Chan, Annette Cowie, Georgina Kelly, Bhupinderpal Singh and Peter Slavich.

The second web page (www.dpi.nsw.gov.au/research/topics/biochar) provides a comprehensive background to biochar, a carbon-rich material produced from the slow pyrolysis of biomass, which has great capacity to sequester carbon in the soil. This page also outlines the research being conducted by NSW DPI into the potential for this material.

The web pages highlight the important work being done by NSW DPI to assess and explore the potential for holding carbon in the soil long term, and the benefit this would have in reducing greenhouse gas emissions.

The scoping paper says the highest SOC sequestration potential in NSW exists in pasture land in the higher rainfall regions (>450 mm), both as permanent pastures or as ley pasture in the cropping zone.

"Considerable increases can be achieved by pasture improvement and improved management practices," the paper says.

"Significant SOC potential also exists in the low rainfall rangelands which comprises nearly 50 per cent of NSW.

"Promotion of conservation tillage practices (particularly no-tillage) is important to halt further carbon losses from cropping soils (emission avoidance).

"In addition, SOC can be sequestered by adopting new land conversion and soil amelioration options such as bioenergy crops from perennial vegetation, recycling organics including biochars, and by ameliorating sodic and acid soils.

"As a rough estimate, total SOC sequestration potential from pasture land, cropping land and rangelands amounts to 4.9 Mt C/yr (18 Mt CO2e/yr), which is equivalent to 11 per cent of the total GHG emission from NSW in 2005.

"Many of the management practices that are effective in increasing SOC in agricultural soils also improve productivity and profitability, conserve the resource base and protect the environment."

The Paper says it is important that soil carbon management is in agricultural systems is included in the Carbon Pollution Reduction Scheme (CPRS), to provide an incentive for land managers to increase soil carbon, both for the mitigation benefits and the resulting improvements to soil health.

"Inclusion of agricultural soil carbon management in the Australian Emissions Trading Scheme (AETS), whether as an offset or within a covered sector, will require development of cost-effective methods for estimating soil carbon change under changed land management practices."

The biochar web page says biochar may be an immediate solution to reducing the global impact of farming (and in reducing the impact from all agricultural waste).

Biochar can store carbon in the ground, potentially making a significant reduction in atmospheric Greenhouse gas (GHG) levels; at the same time its presence in the earth can improve water quality, increase soil fertility, raise agricultural productivity and reduce pressure on old growth forests.

As well as characterising the qualities and benefits of biochar, the web page outlines a number of NSW DPI projects on biochar, including:

  • Land management to increase soil carbon sequestration in NSW - Annette Cowie
  • Assessment of Biochar for agronomic benefits, improved fertiliser use efficiency, greenhouse gas abatement, and reduced off-site migration of chemicals - Lukas Van Zwieten
  • Soil carbon sequestration and rehabilitation: Landholders develop, implement and assess biochar - Dr Lukas Van Zwieten
  • Benefits of papermill biochar (Agrichar TM ) - Dr Lukas Van Zwieten
  • Assessment of Biochar in Sugarcane cropping systems - Dr Lukas Van Zwieten
  • Characterisation of Biochar by analytical Py-GC-MS - Dr Lukas Van Zwieten
  • Reduction in N2O emmissions from soils ammended with Biochar - Dr Lukas Van Zwieten
  • Nitrogen dynamics of biochar in soils - Yin Chan and Simon Eldridge