An irrigated cotton farm emissions case study in NSW, Australia
Introduction
Identifying management strategies that deliver favourable environmental outcomes while maintaining profitable farming businesses is a challenge. Furthering this challenge is the instability in government carbon and energy policy initiatives aiming to reduce greenhouse gas (GHG) emissions.
Emissions in the agriculture sector include methane and nitrous oxide, which are generated by biological processes. The cropping sector in Australia contributes 2.5% to national GHG emissions and overall, agricultural emissions are expected to grow by 23% from 2012 to 123 M tonnes (Mt) CO2e by 2030 (Department of the Environment, 2013). The Australian Government reports on emissions across different industry sectors in the National Greenhouse Gas Inventory (NGGI) accounts (Australian Government, 2013). Currently, a key component of Australia's emissions reduction efforts is the Federal Government's Emissions Reduction Fund (ERF), a market-based mechanism designed to encourage lowest cost GHG abatement through participation in a reverse auction selling Australian Carbon Credit Units (ACCU) to government as sole purchaser. Although broadacre agriculture currently has little financial incentive and few available offset methods to enable participation in the ERF (Welsh et al., 2015), policy makers continue to encourage industry sectors within agriculture to work towards participation. In doing so, the agricultural sector can formally contribute to the national effort of meeting agreed reduction targets by 2030, as outlined in the COP21 Paris Agreement (UNFCCC, 2015).
Since the Carbon Farming Initiative Act was legislated in 2011 (ComLaw, 2011) a number of industry emission accounting tools have been developed to assist agricultural producers and farm advisors to understand the drivers of emissions by designing production scenarios within each industry model and recording changes from a baseline (Australian Carbon Traders, 2015). This paper aims to outline four emission reduction strategies appropriate for cotton production systems and considers changes in farm emissions and gross margin.
Section snippets
Methods
In this paper, cropping and emissions scenarios (cropping rotations, changes in fertiliser management, land-use changes) have been analysed for a case study farm using the FarmGas Calculator Scenario Tool (ST) developed by the Australian Farm Institute (Australian Farm Institute, 2016). Separate gross margin budget analysis was conducted indicating the change in farm gross margin and the marginal cost of abatement.
Results
The three year rotational cropping summary for the case study farm baseline scenario was summarised on an annual basis in Table 3. Table 4, Table 5, Table 6, Table 7 outline the cropping summary for each of the modelled emission reduction scenarios.
Table 8 summarises the GHG emissions and gross margin results of each scenario. Gross margin calculations consider the impact on variable costs of each land use change.
The economic analysis of each scenario provides a useful guide to risk assessment
Discussion/conclusion
This study has shown that trade-offs exists between GHG and profitability of an irrigated cotton farm in some abatement scenarios. Using the FarmGas ST, estimated on-farm emissions for a large broadacre cropping enterprise can be reduced by changing land use, cropping enterprises and fertiliser programs. A combination of these strategies, if successful, can lead to substantial reductions in whole-farm emissions and emissions intensity per cotton bale by as much as 33%, while maintaining farm
Acknowledgements
Bill Back from AusCott Ltd. generously provided valuable time and information from Togo Station operations to run the emissions and economic analysis.
This project has also been supported by the Australian Governments' extension and outreach grant EO12-01-0118 and the Cotton Research Development Corporation.
References (41)
- et al.
Influence of different nitrogen rates and DMPP nitrification inhibitor on annual N2O emissions from a subtropical wheat–maize cropping system
Agric. Ecosyst. Environ.
(2014) Sensitivity Analysis of normative economic models: theoretical framework and practical strategies
Agric. Econ.
(1997)- et al.
Estimation of the N fertiliser requirement of cotton grown after legume crops
Field Crop Res.
(2001) Agvantage Weekly Market Report, Edition of 2nd July 2015
(2015)Climate Statistics for Australian Locations
(2016)Resources, australian carbon traders
Carbon Farming Initiative Case Study - Environmental Plantings of Native Tree Species: 13.6
(2013)FarmGAS Calculator Scenario Tool (ST) User Guide (Version 3.0)
(2014)FarmGas Calculator ST
(2016)National Inventory Report
(2013)