An assessment of greenhouse gas emissions from the Australian vegetables industry.

Recently, partly due to the increasing carbon consciousness in the electorates and partly due to the imminent introduction of the Australian Government's Carbon Pollution Reduction Scheme (CPRS), estimating carbon footprints is becoming increasingly necessary in agriculture. By taking data from several sources, this study estimates the national greenhouse gas (GHG) emissions from a variety of farm inputs, for the 23 key vegetables crops grown in Australia. For the 121,122 ha of land occupied by vegetable farms, there are 1.1 MtCO(2)e GHG emissions or 9.2 tCO(2)e ha(-1). In total, 65% of total GHG emissions from the vegetable industry are due to electricity use for irrigation and post-harvest on-farm activities, 17% from soil N(2)O emissions due to N fertiliser use, 10% from agrochemicals, 7% through fossils fuels and 1% from on-farm machinery. The top four vegetables (by area), potatoes, lettuce, tomatoes and broccoli account for 29.1%, 7.9%, 5.9% and 7.2% of total GHG emissions from vegetables, respectively. However, the ratio of GHG emissions between the highest and lowest-emitting crops per hectare and per tonne, are different. Therefore, care must be exercised in carbon footprint labelling vegetable products to ensure that the labels reflect carbon emissions on a per tonnage basis.

Piggery: from environmental pollution to a climate change solution.

Pig farms are a vital component of rural economies in Australia. However, disposal of effluent leads to many environmental problems. This case study of the Berrybank Farm piggery waste management system in Victoria estimates greenhouse gas (GHG) benefits from three different activities. Analysis reveals that the capturing and combusting of methane from piggery effluent could save between 4859 and 5840 tCO2e yr(-1) of GHG emissions. Similarly, using methane for replacing fuels for electricity generation could save another 800 tCO2e yr(-1)of GHGs. Likewise, by utilizing the biogas wastes to replace inorganic fertilizers there could be a further saving of 1193 to 1375 tCO2e yr(-1) of GHG, depending on the type of fertilizers the waste replaces. Therefore, a well-managed piggery farm with 15,000 pigs could save 6,852 to 8,015 tCO2e yr(-1), which equates to the carbon sequestrated from 6,800 to 8,000 spotted gum trees (age=35 year) in their above plus below-ground biomass. Implementation of similar project in suitable areas in Australia could have significant environmental and financial benefits.

A comparison of greenhouse gas emissions from inputs into farm enterprises in southeast Queensland, Australia.

One of the assumptions underlying efforts to convert cropping land, especially marginal crop land, to plantations is that there will be a net reduction in greenhouse gas emissions, with a gas "sink" replacing a high energy system in which the breakdown of biomass is routinely accelerated to prepare for new crops. This research, based on case studies in Kingaroy in southeast Queensland, compares the amount of greenhouse gas (GHGs) emissions from a peanut/maize crop rotation, a pasture system for beef production and a spotted gum (Corymbia citriodora) timber plantation. Three production inputs, fuel, farm machinery and agrochemicals (fertilizer, pesticides and herbicides) are considered. The study extends beyond the farm gate to include packing and transportation and the time period is 30 years. The results suggest that replacing the crops with plantations would indeed reduce emissions but that a pasture system would have even lower net emissions. These findings cast some doubt on the case for farm forestry as a relatively effective means of ameliorating greenhouse gas emissions.