Biochar is a type of charcoal that is created by burning organic material at high temperatures without any oxygen (a process known as pyrolysis). Biochar has the potential to bring many advantages to production industries in the NT as it has shown considerable success as a soil improver and the raw materials for biochar can be derived from woody weeds. There is also the potential for biochar to play a role in carbon sequestration as it can help reduce carbon dioxide emissions from the agricultural industry.
WHY IS IT BENFICIAL?
The production and use of biochar has many advantages, including Soil enhancement and improvement of soil functions; Reduction of agricultural waste and associated greenhouse gas emissions; Production of renewable energy: Mitigation of climate change.
EFFECTS OF BIOCHAR AND SOIL
Biochar appears to have significant potential in horticultural
applications due to the chemical, physical and biological
influence it has on soils. Accordinfg to current research, the
potential benefits include:
Improving water and nutrient retention in the soil;
Increasing cation exchange capacity;
Reducing soil acidity;
Increasing soil carbon;
Encouraging the growth of beneficial soil microbes;
Enhancing the effectiveness of fertilizers;
Reduced soil emissions.
EFFECTS OF BIOCHAR ON CROP YIELDS
In trials to date, biochar has been found to generally increase crop yield. The greatest positive effects on crop productivity were seen in acidic soils, neutral pH soils, and soils with a medium or coarse texture. These results suggest that a liming effect, improved water holding capacity and improved crop nutrient availability were key mechanisms contributing to the increased yields.
EFFECTS OF BIOCHAR ON FERTALISER EFFICIENCY
Adding biochar to acidic and nutrient poor soils, in combination with fertiliser, can produce yields greater than either fertiliser or biochar alone, although the effect of biochar on crop growth depends on application rates and the soil type to which it is applied. Evidence also suggests that addition of biochar in soils can significantly reduce the required nitrogen fertiliser application while maintaining similar yields. Alternatively, yields may increase significantly with the addition of biochar to soils and little change in established nitrogen fertiliser regimes.
BIOCHAR AND WASTE MANAGEMENT
Biochar can be produced from a variety of feedstocks which
makes it a good potential waste management tool. Biochar
feedstocks derived from invasive woody species, green waste,
plantation thinnings, sawmill offcuts and other sources of wood
waste, can potentially be used for soil remediation in degraded
soils thereby simultaneously tackling two natural resource
management issues at the same time.
Biochar is recognised for its potential to sequester atmospheric carbon and reduce greenhouse gas emissions in the following ways:
Biochar is a stable form of carbon and so can remain in the soil for up to many hundreds of years.
Avoiding the emissions for biomass decomposition at land fill sites.
N2O and CH4 emissions from soil can be reduced by biochar application.
Reducing emissions associated with fertiliser production, due to decreased fertiliser usage.
The energy produced in the pyrolysis process can be used as a substitute for fossil fuel.
Because of these emission reduction benefits, there are currently projects aimed at creating methodologies to allow for carbon credit generation from biochar, e.g. under the Carbon Farming Initiative (CFI). This could create significant financial benefits in the future.