Over-use of nitrogen-based fertilizer in the sugar cane industry is one of the key health pressures facing the Great Barrier Reef, but a Tropical Water Quality Hub project aims to help the cane industry reduce this wastage – without sacrificing sugar yield.
Dissolved inorganic nitrogen (DIN) is linked to Crown-of-Thorns Starfish and other reef health impacts, but providing a generous supply of affordable and widely-available nitrogen-based fertilizers is a way for famers to reduce the risk of low sugar yields resulting from large environmental nitrogen losses.
Project 2.1.8, led by Professor Mike Bell from the University of Queensland, will trial ‘enhanced efficiency fertilizers’ (EEFs) on sugarcane plots where N rates are determined on the basis of the productivity of that cane block – a system called Production Unit Yield Potential (PUYP).
The EEFs, which include technologies to either slow the release of nitrogen or temporarily prevent it transforming into the nitrate form which is vulnerable to environmental loss, should allow farmers to maintain yield at lower fertilizer N rates while also reducing the high levels of excess DIN entering the water system and therefore the Great Barrier Reef.
“Right now, offsite losses of applied nitrogen are unfortunately a feature of some cane growing districts, and the most reliable way of preventing a loss of cane yield due to those environmental losses has been to apply lots of extra nitrogen,” Prof Bell said.
“The lost nitrogen contributes nothing to crop yields and can end up in the water system.”
“Hopefully through this project we can demonstrate that EEFs can minimize those nitrogen losses, therefore eliminating the need to apply those high nitrogen rates without sacrificing crop yield.”
The results from the trials of EEFs from the first cropping season will be released in mid-late 2017.