Biggest under-crop biochar trials in NSW underway at Holbrook

The biggest under-crop biochar trial in NSW is underway at Holbrook with more than 2000 square metres being trialed under canola at Peter and Skye Trescowthick's property "Koombahla".

Biochar, the charcoal-like residue when biomass (such as agricultural or council waste) undergoes pyrolysis (by heating under low oxygen conditions at 400-900°C), has potential to sequester a stable form of carbon while enhancing soil fertility.

The Holbrook trial, initiated and supported by Holbrook Landcare, builds on a three-year project (2009-2012) researching biochar in southern NSW, and is funded by Grains Research and Development Corporation, EH Graham Centre (an alliance between Charles Sturt University and Industry & Investment NSW) and Woolworths.

Project manager, researcher David Waters from the EH Graham Centre, said the program had moved into the paddock stage with field trials also taking place at Industry & Investment's Henty Field Day site (in conjunction with Eastern Riverina Landcare Network) and Wagga Wagga Agricultural Institute to validate laboratory and glass house experiments, as well as determine large scale outcomes.

Mr Waters said the potential agronomic and environmental benefits from application of biochar to soils needs to be substantiated across different ecological and agricultural systems.

"Biochar has been associated with improved retention of nutrients in soils resulting from reduced leaching or emissions. This could increase fertiliser efficiency, while lowering input costs and environmental impacts.

"There is also some circumstantial evidence linking biochar to improvements in soil health including aggregate stability and water holding capacity," he said

The Holbrook trial involves two biochars that have been sourced from a research plant on the central coast.

Mr Waters said comparative analysis of the poultry manure and green waste biochars has indicated a diverse range of characteristics.

"Fertiliser was applied with the biochar in late April at three rates (0, 50 and 100kg MAP), while the biochar was applied at three rates (15 T, 7.5 T and zero T /ha) with four replications," he said.

His initial results from laboratory experiments will be presented at the World Soils Conference in Brisbane in August, and the International Biochar Conference in Rio de Janeiro in September, with results from the first season due at the end of the year.

A field day featuring the Holbrook trial is planned for Tuesday 17 August.

Photo of Murray CMA’s site visit on 8 June is available from