Life Cycle Assessment Greenhouse Emissions from Maize Supply Chain Mr Tim Grant, Life Cycle Strategies P/L Dr Tom Beer, CSIRO, Div of Atmospheric Research Dr Mick Meyer, Div of Atmospheric Research
Aims of the Project To determine the greenhouse gas emission along the maize products supply chain. To examine value generation along the maize supply chain and compare with greenhouse emissions. To develop primary data on Nitrous oxide emissions from irrigated maize including effects on Nitrogen additions, stubble treatment and other farm practice variables.
Supply chains examined Corn chip production via Rosita's Australasia Pty Ltd, Bendigo Victoria Corn Starch production via Penford Australia Ltd in Sydney NSW
Inventory data collection Surveying and workshop with local farmers. Fertiliser emission from local data and ecoinvent database Corn chip and starch data collected directly from companies.
N 2 O flux measurement in fallow maize field at Griffith, NSW
Emissions monitoring through to harvest
Griffith Experiment Outline 7 8 B 11 12 B 12 Months continuous flux measurement on long-term stubble incorporation experiment. 3 treatments: 1N Rate 12 6 5 A 13 10 9 A No fertilizer N, stubble burned 300 kg N/ha, stubble burned 300 kg N/ha, stubble incorporated To test for N effect, and stubble incorporation effect 0N Rate 3 4 11 B Greenhouse Gas Experiment Plan 2 1 A Burn Bed 5 Incorporate Bed 11
Preliminary results for corn chips Pre farm 5% On farm 27% Post farm 68%
Pre-farm emissions 0.014 Carbon dioxide equivalents kg CO2 0.012 0.010 0.008 0.006 0.004 0.002 0.000 Fertiliser Pesticide Herbicide Fuel production
On farm emissions 0.090 Carbon dioxide equivalents kg CO2 0.080 0.070 0.060 0.050 0.040 0.030 0.020 0.010 0.000 water pumping N2O from fert. applic. N2O from land disturbance Tractor emissions Pesticide and herbicide degradation Drying maize
Greenhouse emissions by gas up to harvest with uncertainty 0.35 Carbon dioxide equivalents kg CO2 0.3 0.25 0.2 0.15 0.1 0.05 0 CO2 Methane N2O Other
Post farm impacts 0.20 0.18 Carbon dioxide equivalents kg CO2 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 Transport farm to corn chips Corn chip production Box Transport to market Bag Waste managemen
0.20 0.18 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 Greenhouse impacts along supply chain Pesticide Herbicide Fuel production water pumping N2O from fert. applic. N2O from land disturbance Tractor emissions Pesticide and herbicide degradation Drying maize Transport farm to corn chips Corn chip production Box Transport to market Bag Waste management Fertiliser Carbon dioxide equivalents kg CO2
Maize starch and corn chip production 1.4 1.2 1 Post farm On farm Pre farm 0.8 0.6 0.4 0.2 0 Corn chips Starch Carbon dioxide equivalents kg CO2 per kg maize utilised
Maize starch production Pre farm 9% Post farm 40% On farm 51%
Post farm impact for Starch 8 7 Carbon dioxide equivalents kg CO2 6 5 4 3 2 1 0 Transport to market Electricity in starch production Gas usage in starch production Water supply for starch production Packaging
Greenhouse emission per kg of maize utilised with uncertainty (95% confidence interval) 1.6 1.4 Carbon dioxide equivalents kg CO2 1.2 1 0.8 0.6 0.4 0.2 0 Corn starch Corn chips
Alternative water sources for maize Carbon dioxide equivalents kg CO2 0.400 0.350 0.300 0.250 0.200 0.150 0.100 0.050 N2O Methane CO2 0.000 Maize growing, irrigated from deep bore Maize growing, irrigated from surface waters
Preliminary data on stubble treatment Carbon dioxide equivalents kg CO2 0.450 0.400 0.350 0.300 0.250 0.200 0.150 0.100 0.050 0.000 Maize harvested, average Maize harvested, stubble burned Nitrous oxide Methane Carbon dioxide Maize harvested, stubble incorporation
Conclusions so far The on farm and post farm impacts dominate the supply chain emissions from maize products. The default emission factors for nitrous oxide emission from nitrogen application are close to measured emissions Stubble incorporation appears to significantly reduce these emissions Water pumping is a significant determinate of greenhouse emissions from irrigated farming
Still to come Harvest over next few weeks finalisation of emission monitoring. Nitrogen balances for crop Finalisation of life cycle data on corn and starch production Comparison of greenhouse emission along value chain.