Sub sections:
Gillian Burke - Biochar Project
Undergraduate student Gillian Burke starts her Biochar project.
Gillian was awarded the PIIC honours scholarship for 2008 to assess the potential of chicken manure biochar for soil amelioration. Gillian’s project combines some local tillage research history with the latest developments in soil improvement.
Gillian’s parents, Bede and Narelle, own and lease 1,214 hectares of land, including their home property “Glendon”, which is 20 kilometres west of Tamworth. Their holding is made up of displaced blocks within a 12 kilometre radius of their home. The Burkes are involved in egg production, pullet rearing, cropping and feed milling as well as sheep and cattle grazing. They have about 520 hectares of red soils suitable only for winter cropping and 590 hectares of darker soils which are used for summer and winter cropping.
During the 1980s, NSW Agriculture conducted a long-term tillage experiment on one of Bede’s red soils. It took a long time for this soil to show any response to no-tillage because of its hard-setting nature, low organic matter and high bulk density. Bede spreads chicken manure from their layer and pullet sheds and is able to cover 150 hectares per year and it takes five or six years to manure all of the cropping country. The chicken manure has made a big improvement in soil fertility.
Gillian’s project will investigate whether there are any advantages in converting the chicken manure to biochar. Biochar is a highly biologically resistant form of carbon resulting from carbonisation or pyrolysis of plant or animal material in the absence of air at a temperature above 300°C. This process also produces biofuels that can substitute for fossil fuels. Bio-char can provide long term storage of a significant proportion (25-40%) of biomass carbon that would otherwise cycle back to the atmosphere over time scales of decades. It has also been recognised that introducing bio-char into agricultural systems could provide a range of other environmental benefits. Biochars applied to the soil can provide soil carbon pools which are stable, quantifiable and accountable with respect to carbon trading. The properties of bio-chars vary with the type of organic material from which they are made (eg wood, green waste, manures, factory wastes) and production conditions (eg temperature, degree of activation). Research to date has found that biochars can improve the productivity of crops in low fertility soils through four main mechanisms, they can:
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modify soil pH, mainly using alkaline bio-chars in acidic soils, and hence affect the plant availability of nutrients and toxic elements such as aluminium
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enhance the formation of symbiotic relationships between plant roots and mycorrhiza and rhizobia. This can increase access of plants to unavailable pools of soil phosphorous and nitrogen and decrease use of fertilisers
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increase the retention of ionic forms of nutrients, particularly in soils with low cation exchange capacity. Bio-chars have the potential to increase the efficiency of uptake of nutrients released from organic amendments and inorganic fertilisers.
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increase water holding capacity of sandy or poorly structured soils and hence efficiency of use of rainfall/irrigation. Gillian will conduct a glasshouse experiment using red-brown earth (chromosol) soli collected from the family property. Data to be collected will include: physical and chemical characteristics of the soil and biochar; changes in soil physical and hydrological properties; changes in soil biological activity and effect on plant biomass.