Overview

Agriculture is a significant emitter of greenhouse gases (GHGs). Changing land use from native vegetation to agriculture also influences GHGs. Consequently, agriculture provides a large-scale, relatively inexpensive and easy-to-implement opportunity for mitigation.

Researching potential mitigation techniques requires the monitoring and study of cropland and pastoral GHGs. Manual and automatic sampling to monitor GHGs for a range of sites in southern Queensland will help our researchers determine the baseline (original) emissions within those regions.

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Research leader
Research team
QUT External collaborators
  • Dr Henrike Mielenz (CSIRO)
Organisational unit
Lead unit Institute for Future Environments Other units
Research areas
Keywords
greenhouse gases, GHG, agriculture, carbon , nitrous oxide, carbon dioxide, emissions, soil, land use, cotton, grain, cattle, livestock, horticulture, climate change, farming

Contact

For more information about this research program, contact Professor Peter Grace.

For more information about greenhouse gas analysis, contact the greenhouse gas analysis team.

 

Details

Nitrous oxide emissions research in Australia

Experiments

GHG chamber in wheat field

A greenhouse gas chamber used to monitor emissions in a wheat field at Kingsthorpe, Queensland.

GHG chamber attached to trailer in field

A chamber measuring emissions on a freshly ploughed field in Kingaroy, Queensland, is connected to a trailer that houses equipment and computers to collect the data.

GHG sampling unit

Inside the greenhouse gas sampling unit used for testing soil and crop emissions at Narrabri, New South Wales.

Nitrous oxide (N2O) is a soil-borne greenhouse gas, 300 times as potent as carbon dioxide (CO2). Our field experiments investigate the impact of agronomic management, nitrogen (N) use and other farming practices on soil greenhouse gas emissions. Emissions from N additions vary depending on climate, soil conditions, crop and fertiliser type and management.

In this research:

  • field experiments using automated chambers continuously compare greenhouse gas emissions from different treatments
  • plots are replicated to minimise the effects of spatial variation and ensure that the data is representative of the local region
  • similar experiments are conducted at field sites around Australia to replicate the various conditions that occur across the continent.

Each gas sample is analysed for N2O, CO2 and methane (CH4). The N2O emission rate (or flux) is the amount of N2O released from the soil over time. It is calculated as a function of the change in concentration of N2O in the chamber over time and the air temperature in the chamber.

Our automated equipment allows high frequency sampling 24 hours a day and 365 days a year for capturing short-term responses in emissions to rapid changes in the soil environment. This provides more accurate estimates of N2O and CO2 budgets from individual land-management practices.

We have automated sites at the following Queensland locations:

  • Kingsthorpe: irrigated and dryland cotton and grain cropping systems
  • Kingaroy: irrigated grain cropping systems
  • Gatton: irrigated horticultural systems
  • Gympie: irrigated and dryland dairy systems
  • Gatton: compost and manure amendments in horticulture
  • Samford: peri-urban soils.

We currently coordinate the National Agricultural Nitrous Oxide Research Program (NANORP) (2012-2015) and previously the Nitrous Oxide Research Program (NORP) (2009-2012). These federally funded (Department of Agriculture Fisheries and Forestry) programs seek to develop best management practice strategies to reduce greenhouse gas emissions from agricultural soils. The research is a multi-step process using a specific experimental design for investigating management strategies to reduce emissions. The findings will ultimately influence regional farming practices and inform government policy regarding climate change.

Sharing the data

NANORP's N2O Network makes the data available to the wider scientific community. Data sets contain enough information to fully describe the contextual information, the experimental setup and the parameters of the experiment.

The N2O Network has published a guide on how to prepare and format N2O soils emissions data for use in analysis and model development. Scientists can then examine the data firsthand; they can verify the results and validate the methods used to obtain them. The data can also be used as a benchmark for future experiments.

Measuring flux

Soil emissions of N2O are estimated by trapping air samples just above the soil inside a closed chamber. Chambers are automatically controlled and close at regular intervals. This allows the gas to accumulate. Samples of the gas are removed during the closure period and analysed using a gas chromatograph.

Plotting the emissions data as a line graph (over time) enables researchers to quickly identify trends in response to the environment and management. Data from the various sites of the network can be compared and made available to other researchers, growers, policy and extension personnel who can determine best management practices to reduce emissions.

Equipment

Our greenhouse gas field measuring equipment is comprised of three main parts:

  • gas chromatograph unit (GC-Unit)
  • control unit (C-Unit)
  • measurement chambers.

The GC-Unit includes a SRI 8610C gas chromatograph for measuring N2O and CH4. The GC has an EPC control zone (without injector) as carrier #2. Packed columns (60/80) are Hayesep Q and N for N2O and CH4 respectively. The GC is fixed inside a robust metal transport box to avoid damage and is sealed to reduce any contamination.

The C-Unit includes actuators (pump, sample valves, GC inject valves), a flow meter, a lubricator unit, particle filter, Licor 820 CO2 analyser and the PLC (programmable logic controller), which controls all actuators and processes the sensor signals. The PLC is serial connected to a computer where the user can start/stop the measurement via a graphical user interface (GUI).

Each chamber has three sections. The base is a square frame with sharp edges for easy insertion into the soil. On top of the base sits the removable chamber with lids that open/close with pneumatically controlled cylinders. During closure, pneumatic clamps are also used to ensure a tight seal. All parts of the chamber are connected with clip locks and sealed with padding. Extensions can also be inserted between the frame and the chambers to accommodate growing plants.

Quality control

Data is checked for any outlier measurements caused by mechanical failure of the sampling systems or errors of the analytical instruments.

Gaps and errors in the data are corrected using gap-filling estimates if appropriate. These are formulated by extrapolating from more reliable data acquired before the gap or from the emission patterns of the previous days, seasons or cropping cycles.

Generally, the large amount of raw data collected at high temporal frequency (eight flux measurements per day per treatment) is converted into daily averages that are easier to interpret and which smooth out the inherent variability of individual measurements.

Outcomes

Aside from the scientific importance of understanding soil N2O emissions and reducing global warming, this research is relevant to farmers, agronomists and extension agents. The scientific evidence can motivate a change in agricultural practices to minimise greenhouse gas emissions and maximise nitrogen-use efficiency. The research will ensure that growers sustain long-term productivity and profitability and understand the key role that they play in today's changing world.

Our research also has implications for government policy and for funding future systemic changes in farming practice as an adaptation strategy to climate change. The research will:

  • provide guidelines for optimal sowing dates, fertiliser use, irrigation levels and crop rotation to maintain production, while reducing emissions
  • inform the development of an evidence-based national accounting system for carbon emissions
  • help accurately reflect the contribution of farming practices to greenhouse gas emissions in Australia
  • assist in setting realistic targets for N2O emissions reduction while sustaining productivity and profitability.

Projects

Current research projects

  • Australian Flux Network (OzFlux) as part of the Terrestrial Ecosystem Research Network (TERN)
  • South East Queensland Peri-Urban Supersite node as part of the Australian Supersite Network (ASN), part of the TERN
  • Assessing the trend in greenhouse gas intensity of Australian beef production
  • Validating the cost/benefits of improved fertiliser practices in the dairy industry
  • A data transformation and model calibration system for carbon and nitrogen dynamics in Australian ecosystems
  • An integrated assessment of management practices for reducing N2O emission and improving N use efficiency for subtropical dairy systems
  • National coordination of an integrated, data synthesis and modelling network for reducing N2O emissions from Australian soils (NANORP)
  • Advanced process level understanding of factors controlling gaseous nitrogen partitioning to reduce N2O losses from Australian agricultural soils
  • The fate of above-ground carbon inputs: A key process that is poorly understood
  • Quantifying greenhouse gas emissions from dryland farming in Patancheru, India
  • Establishment of automated greenhouse gas sampling system for Kansas State University (USA)
  • Establishment of automated greenhouse gas measurement system for EMBRAPA (Brazil)

Completed research projects

  • Australian Centre for Ecological Analysis and Synthesis (ACEAS) node at QUT as part of the Terrestrial Ecosystem Research Network (TERN)
  • Enhancing soil carbon and reducing greenhouse gas emissions for improved productivity and rural incomes (with ICRISAT)
  • Monitoring terrestrial and aquatic GHG emissions - Wyaralong Dam
  • Primary Industries Adaptation Research Network (PIARN)
  • Establishment of automated greenhouse gas measurement system for Department of Primary Industries NSW (Wagga Wagga, Tamworth, Wollongbar, Camden)
  • Establishment of automated greenhouse gas measurement system for Cotton Research and Development Corporation (Narrabri)
  • Establishment of automated greenhouse gas sampling system for CSIRO (Griffith)
  • Establishment of automated greenhouse gas measurement system for Australian Department of Agriculture Fisheries (International) in Chile

Partnerships

Our collaboration with external organisations is critical to our capacity to build Australia's greenhouse gas research capabilities.

Government

  • Department of Agriculture, Fisheries and Forestry (Australian Federal Government)
  • Department of Primary Industries (New South Wales)
  • Department of Environment and Primary Industries (Victoria)
  • Commonwealth Scientific and Industrial Research Organisation (CSIRO)

Industry

  • Dairy Australia Limited
  • Grains Research and Development Corporation (GRDC)
  • Cotton Research and Development Corporation (CRDC)
  • Meat and Livestock Australia Ltd
  • SEQWater

Universities

  • James Cook University
  • Monash University
  • Queensland Cyber Infrastructure Foundation Ltd (QCIF)
  • The University of Melbourne
  • The University of Queensland

International

  • International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)
  • Michigan State University
  • Kansas State University
  • Colorado State University
  • Columbia University

Publications and output

Cotton Greenhouse Gas Calculator

broccoli field and GHG chambers being sprayed

A crop of broccoli is sprayed in Gatton, Queensland. The greenhouse gas monitoring chambers are suited to most non-severe outdoor weather conditions.

The Farming Enterprise Greenhouse Gas Emissions Calculator has been especially developed for use by cotton farmers.

The calculator estimates the annual farm-based emissions from a representative grains-cotton farming enterprise of 1000 ha to exceed 2000 tonnes of CO2-equivalent.

Farming Enterprise Greenhouse Gas Emissions Calculator

Farming enterprises contribute about 20% of Australia's total greenhouse gas account. The greenhouse gas calculator has been developed to provide an estimate of farm-based emissions in Queensland.

While the calculator is based on best available information, it is not definitive. It should be used for information only, as there is an element of uncertainty associated with estimating greenhouse gas emissions from agricultural enterprises and ecosystems.