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Potential of grazing management to impact soil methane consumption in rangelands

Study level

Honours

Vacation research experience scheme

Faculty/Lead unit

Topic status

We're looking for students to study this topic.

Supervisors

Professor Peter Grace
Position
Professor of Global Change and Theme Leader
Division / Faculty
Science and Engineering Faculty
Associate Professor David Rowlings
Position
Associate Professor
Division / Faculty
Science and Engineering Faculty

Overview

The Australian beef industry has committed to becoming carbon neutral by 2030. This mammoth task will require all sinks and sources of greenhouse gas emissions associated with the industry, including:

  • carbon dioxide (CO2) sequestration in soils and plant biomass
  • reduced nitrous oxide from fertiliser and urine sources
  • increasing microbial methane (CH4) consumption (uptake) in soils.

The large extent of rangelands across western Queensland, NSW and the Northern Territory offers massive potential for carbon abatement, assuming we can get the management right. However, current knowledge of the basic processes and potential of these mitigation strategies in these often remote and vast areas is extremely lacking.

Methane is a short-lived greenhouse gas 21 times more potent than CO2. In Agriculture, it’s produced through enteric fermentation in ruminants, and through anaerobic methanogenesis in flooded systems like rice.  However, it is also consumed for energy by a group of soil microbes called methanotrophs, which globally represent a major sink for CH4 removal from the atmosphere. The rate of consumption in soils is principally driven by soil texture and water content, which determine the diffusivity of the soil (i.e. how fast atmospheric CH4 can get to where the microbes live), though microbial activity is also limited when soils are very dry.

The potential for improved grazing management to increase soil CH4 consumption is therefore based on two things:

  1. the baseline potential of current practices
  2. the maximum potential of methanotrophic activity under a given climate and soil type.

Research activities

For this project we will collect soils from contrasting grazing management, soil types and climatic regions and incubate them in a QUT lab to determine CH4 consumption potentials and drivers.

We will then repack the soils at different bulk densities to simulate the effect of different grazing intensities and water contents to determine maximum potentials in arid zones.

Soil microcosms will then be placed in air-tight vessels and the change in CH4 concentration of the headspace will be monitored over a 21-day period.

Outcomes

We expect to uncover the methane uptake potential of different agro-ecosystems with the potential for farm management to increase carbon abatement.

Skills and experience

We assume you are knowledgeable in unit basic chemistry, physics and chemistry. Knowledge in soil science is preferred for this project.

This project will suit you if you have some knowledge of environmental science and biochemistry.

Experience in a laboratory is desirable as this project will involve laboratory work.

Keywords

Contact

Contact the supervisor for more information.