Lukas Van Zwieten Principal Research Scientist Adjunct Professor Rural Climate Solutions University of New England and Tony Walker Richmond Landcare What is biochar and how is it made Biochar and Terra Preta ID: 591078
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Slide1
“Biochar,” a bit of myth busting
Lukas Van Zwieten
Principal Research Scientist
Adjunct Professor, Rural Climate SolutionsUniversity of New EnglandandTony WalkerRichmond LandcareSlide2
What is biochar and how is it made?Slide3
Biochar and Terra Preta
Downie, AE., Van Zwieten, L., Smernik RJ., Morris, S., Munroe, PR (2011)
Terra Preta Australis: Reassessing the carbon storage capacity of temperate soils. Agriculture Ecosystems Environment 140, 137-147. Slide4
Pyrolysis is an engineering term “energy and biochar can be produced”Slide5
BiosecurityOdour
Concentration of C and nutrientsTransport costsBeneficial agricultural reuseRenewable energy
Why pyrolyse biomassSlide6
Biochar is carbon that is going to last for hundreds of years
Diagram source: Lehmann et al., 2006,
Mitigation and Adaptation Strategies for Global ChangeSlide7
Agronomic trials Over 350 plots being managed as part of the Richmond Landcare collaborative project
Key soil constraints on ferrosolsDeclining C Immobilisation of PLow pH High Al saturation Low CECSlide8
Control corn (13t cob/ha)
1200mm
1900mm
Poultry litter biochar, 50t/Ha (35t cob/ha)
Biochar “can” significantly improve soil fertility and crop productionSlide9
Long-term field sites testing biocharSlide10
Trials in a macadamia orchard
45 trees used testing poultry litter char and greenwaste char (@10t/ha- 40kg per tree)
2 years onSlide11
Trials in coffee
3.3kg per tree, 30 trees per block, 4 treatments, 4 replicates, testing poultry biochar and rice husk biochar
2 years onSlide12
control
1% biochar
5% biochar
Sections of x-ray computed tomography scans of a vertosol soil, packed into tubes of
~
30 mm, at a resolution of 70 µm
P Quin (PhD student) and I YoungSlide13
Summary of effects of some
biochars in some soilsNutrientsStable C contentLiming effectReactive surfaces and redoxCEC and AECPorosity/ water holding capacity and bulk densityPorosity / microbial habitat
Smoke chemicals?Increases in nutrient use efficiency allowing reduced fertiliser inputs
Improved water use efficiencyReduced leaching and gaseous losses of fertiliserReduced denitrificationLowered Al toxicity Reduced heavy metal bioavailabilityIncreased P availability on P sorbing soilsImproved mycorrhizae and biological N2 fixation Long-term accumulation of soil C
Properties of biochar
Soil and crop outcomesSlide14
Myth Busting
Not all biochars will be valuableBiochars may not be beneficial in all soil typesValue of the crop will limit application of biochar- and bottom lineBiochar certification is comingSlide15
More myth busting
Understand biochar characteristics to ameliorate soil constraintsFarming system impacts the way biochar works: Possible C accumulation under permanent pasture, but tillage and biomass removal under cropping can still result in a decline in CBiochar can particularly target chemical constraints in ferrosols including low pH, high Al availability and low P availabilityBiochars with high mineral ash component are more effective at improving crop productionBiochars with high C content are more effective at accumulating additional C in soil