Are you a carbon farmer?
Carbon-rich organic matter in your soil is essential for the soil's fertility and your crop's health. However, soil organic matter levels in many cotton fields have declined significantly since the fields were developed - through cultivation, excessive nitrogen application, wind and water erosion of top soil, crop stubble removal and high temperatures (particularly affecting bare fallow in summer). Addressing this decline is necessary to maintain the soil's fertility.
The major sources of energy use on an irrigated cotton farm are synthetic fertilisers (see the soil health page) as well as electricity and fossil fuels used to power irrigation pumps (see the energy efficiency page). These are also the main contributors to greenhouse gas (GHG) emissions. Healthy riparian vegetation on-farm can act to mitigate and off-set GHG emissions, while carbon sequestration and conservation of native vegetation can contribute to the long-term health and sustainability of the farm (like helping to produce beneficial pests). There are lots of benefits to farming carbon.
What do you need to know?
Off-farm: GHG emissions targets and Government policy
Greenhouse gas (GHG) emission targets
In 2008, the Australian Government made a commitment to ratify the Kyoto Protocol, signing an agreement with the United Nations Framework Convention on Climate Change (UNFCC).
Under this agreement commitments were made to:
- reduce GHG emissions by 2020, to at least 5 percent below 2000 levels
- reduce GHG emissions by 2050, to 80 percent below 2000 levels
The Emissions Reduction Fund is the centrepiece of climate action policy, and is designed to work with other incentives under the Cleaner Environment Plan to help meet the target to reduce of emissions by 5 percent below 2000 levels. Through the Emissions Reduction Fund the Government will purchase the lowest cost abatement via reverse auction in a ‘carbon buy-back’.
The Fund will provide incentives for abatement activities such as: revegetation and land management; soil carbon; forestry; energy efficiency; cleaning up power stations; cleaning up waste coal mine gas; and cleaning up landfill. For more on the Fund, see this series of fact sheets, developed specifically for the cotton industry.
The Carbon Farming Initiative
The Carbon Farming Initiative (CFI) is provides opportunities and support for agriculture to implement emissions mitigation activities and adaptive practices. It aims to reward land managers for providing abatement action, particularly activities that deliver additional practical environmental benefits. The CFI is designed to acheive agriculture's GHG abatement targets.
The CFI methodologies detail the requirements necessary for a project to earn carbon credits under the Emissions Reduction Fund.
On-farm: capturing carbon, the role of vegetation, responsible use of N fertiliser
The why and how: capturing carbon on farm
Soil carbon and organic matter supply nutrients for plant growth and soil micro organisms, stabilise soil structure, and improve soil water storage and infiltration. Carbon rich soil organic matter also increases soil cation excahange capacity, buffers soil pH, and reduces the effects of salinity and sodicity.
The soil and vegetation in non-cropped areas of the farming landscape are valuable carbon stores.
The role of vegetation
Vegetation in uncropped areas sequesters and stores large amounts of carbon. Old growth River Red Gums can store almost 400 tonnes of carbon per hectare per year (equivalent to the carbon emitted by 290 Holden Commodores in a year).
Native vegetation plantings can form part of a whole farm carbon emission reduction plan.
Responsible use of nitrogen fertiliser
Research indicates significantly more nitrogenous fertiliser (N) is being applied to cotton crops than is currently recommended as part of industry best practice. This additional N is a significant additional cost to growers that does not necessarily result in increased production, and excessive or inappropriately managed N application also contributes to GHG emissions.
N in the form of ammonia is lost to the atmosphere through the process of volatilisation, particularly when solid fertilisers are applied and are not incorporated properly or in a timely manner.
Oversupply of N frequently occurs as a result of factors such as: over-estimation of yield potential; lack of consideration of soil N that will become available (mineralisation potential); under-estimation of residual soil mineral N; overcompensation for less than optimal soil condition (compaction) and irrigation practices; and poor calibration of application equipment. An audit of current Fertiliser Nitrogen Use Efficienty (FNUE) and related farming practices can identify strategies and tactics to improve nitrogen use efficiency.
So, what should you do on your farm?
- Monitor soil carbon levels.
- Adopt minimum tillage practices where appropriate.
- Conserve crop residues and avoid prolonged bare fallows.
- Include legume crops in rotations.
- Implement management practices which preserve or improve soil organic carbon levels.
- Identify different sources of carbon sequestration and emissions across the whole farm.
- Undertake environmental plantings on farm and protect existing living and dead native vegetation to prevent carbon losses.
Where should I go for more information?
Jon Welsh – Technical Lead Energy and Climate
Ph: 0458 215 335
- Australian Cotton Production Manual
- Case study: An irrigated cotton farm emissions case study in NSW
- CottonInfo and NSW DPI fact sheets: Cotton and the Emissions Reduction Fund
- CottonInfo case study - Investigating carbon farming in the Macquarie
- CottonInfo paper for the 17th Australian Cotton Conference: Carbon neutral cotton farms
- CottonInfo paper for the 17th Australian Cotton Conference: Nitrogen fertiliser use efficiency across the regions
- Life-Cycle Energy and Carbon Footprint Assessments: Agricultural and Food Products (Encyclopedia of Energy Engineering and Technology)
- Soil carbon snapshot (Fertilizer Australia)
- Best Management Practices to reduce nitrous oxide emissions for irrigated broadacre cropping (Fertilizer Australia)
- FarmGAS Calculator Scenario Tool: a tool from the Australian Farm Institute to investigate how different farm practices might alter the greenhouse gas emissions estimates.
- Why all the fuss about greenhouse gases? (Fertilizer Australia)
- Three part webinar on nutrition and the Emissions Reduction Fund: