Quantifying nitrogen use efficiency in tropical mango production systems

Figure 1. The leaves on this mango plant are being labelled via infusions of 15N fertiliser in solution into branch xylem tissue. After drying, the labelled leaf litter will be placed on soil under mango trees to decompose while soil N gas emissions and mineralisation are measured.

Dr Joanne Tilbrook and Dr Tony Asis (Department of Primary Industry and Resources)

Improving nitrogen use efficiency in tropically grown mangoes is part of a five-year collaboration under the umbrella of the More Profit from Nitrogen Program across the horticulture, cotton, dairy and sugar industries.

To quantify mango nitrogen (N) demand and cycling through the soil-plant-atmosphere system in local orchards, Dr Jo Tilbrook and Dr Tony Asis have developed a xylem (woody tissue) infusion method to label mango trees with a stable isotope of nitrogen, 15N. Once the trees are labelled with 15N, the amount of soil or foliar applied fertiliser taken up by the tree or lost to the environment can be quantified. Jo and Tony demonstrated the method during the Territory Natural Resource Management Field Day at Coastal Plains Research Station in November 2017 (Figure 1).

Recently they labelled leaf litter for an experiment planned by Raj Pandeya, a Queensland University of Technology PhD candidate and collaborator. The labelled leaves will be placed directly over soil in mango orchards and as they decompose during the wet season, nitrogen movement, mineralisation and gas emissions will be analysed.

Building knowledge of where and when nitrogen is lost to the environment rather than cycled or used by a crop is needed to establish how to minimise nitrogen losses and potential negative environmental impacts.

For information on resource management including nitrogen visit the Northern Territory Government website.

For information on our research projects visit the Department of Primary Industry and Resources website.

YouTube video on Measuring N2O Emissions.

This project is supported through funding from the Australian Government Department of Agriculture and Water Resources as part of its Rural R&D for Profit program, the Northern Territory Government Department of Primary Industry and Resources, Queensland University of Technology’s Institute for Future Environments and Hort Innovation Limited. In-kind support is also provided by the Australian Mango Industry Association Inc.

Last updated: 19 December 2017