Opportunities for improving the efficency of use of nitrogen fertiliser in the Australian sugar industry

The recent implementation of controls by the Queensland Government regulating the amount of nitrogen (N) and phosphorus (P) fertiliser that can be applied to sugarcane crops in north Queensland are aimed at protecting the Great Barrier Reef from excess nutrients derived from agricultural activities. It is timely to review recent improvements in the efficiency of nitrogen (N) fertiliser use and evaluate what opportunities exist for making further improvements. Nitrogen fertiliser application rates in the Australian sugar industry have shown a decreasing trend since the mid 1990s and when compared with cane yields have shown a steady improvement in fertiliser N use efficiency, expressed as tonnes cane/kg N. This paper discusses possible reasons for this trend including the adoption of a comprehensive program (Six Easy Steps) for supporting best practice nutrient management. Opportunities for further improvements in fertiliser N use efficiency are also reviewed. These can be divided into three main groups: more efficient plant uptake, more efficient N fertilisers and improved management practices.