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Nitrogen and carbon leaching losses from northern Australian mango soils

Study level

Honours

Vacation research experience scheme

Faculty/Lead unit

Topic status

We're looking for students to study this topic.

Supervisors

Dr Johannes Friedl
Position
Research Fellow
Division / Faculty
Science and Engineering Faculty
Associate Professor David Rowlings
Position
Associate Professor
Division / Faculty
Science and Engineering Faculty

Overview

Mangoes are a significant tree crop in tropical climates of Australia with an annual value $140M and a rapidly developing export market.

There is a major push at all levels of government for the economic development of northern Australia by expanding these agricultural industries. However, northern soils are vastly different and more difficult to manage compared to the well-established agricultural regions in southern Australia.

A better understanding of these unique soil properties, and how they response to agricultural management practices, is therefore required to ensure sustainable development in the north.

Nitrogen (N) is an essential nutrient for plant growth and development but is also a major environmental pollutant. It can also bring inefficiences from overuse or inaccurate time of application, such as:

  • tree vegetative growth and the incidences of post-harvest diseases
  • reduction in fruit quality
  • pollution of the environment through groundwater leaching or denitrification to nitrous oxide (N2O).

This is exasperated in northern Australia due to the poor, freely-draining soils and extreme rainfall events associated with these growing regions. There is currently little information regarding the fate of applied fertiliser under these conditions and the contribution that recycling of leaf litter has on nutrient supply and losses.

Finding the balance between food production and environmental sustainability is one of the critical global challenges of our time.

Research activities

Using previously collected cores from five different mango orchards in the Northern Territory, carefully extracted to ensure soil structure and porosity remain intact students will use isotopically labelled (nitrogen tracer) mango leaf litter to determine the decomposition rate, amount and the fate of nutrients of this important source of nutrients in northern soils.

In a series of laboratory incubation and leaching trials, we will look to uncover how much and when nitrogen and carbon is released from synthetic fertiliser and leaf litter and either:

  • washed out of the soil profile
  • lost as a greenhouse gas (CO2, CH4 and N2O)
  • immobilised by microbes in the soil.

Outcomes

You will gain firsthand experience in working on the frontier of environmental science in Australia and in working with tropical soils.

You will learn about a variety of laboratory techniques, such as:

  • ion colorimetry
  • gas chromotrography
  • mass spectrometry.

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.