Final report to the Sugar Research and Development Corporation CTA007 A modelling framework to integrate research on nitrogen management of sugarcane

Abstract

This project used a measurement and modelling approach to explore the processes controlling nitrogen supply and losses in the crop and soil elements of sugarcane production systems. Measurements took place both in the field and laboratory. These measurements, together with data coUected from other sugarcane research projects in Australia and overseas, lead to the development of the APSIM-Sugarcane simulation model. This model captures the main elements of our understanding of sugarcane growth, yield, N uptake and utilisation and water use. APSIM is a modular modelling system, and the Sugarcane module is compatible with other APSIM modules of soil processes and crop management. Within the life of this project, APSIM-Sugarcane was used to investigate N management strategies in sugarcane production systems. A major outcome of these modelling studies was the recognition of the potential for substantial N losses via leaching in situations where N fertiliser inputs exceeded crop demands. This project drew together different threads in nitrogen research on sugarcane for the first time. Prior to this, the focus was on either empirical "rates and dates" experiments, which while underpinning current N fertiliser recommendations, were not advancing our understanding of N in the crop-soil system, and on studies of particular N processes(eg volatilisation or mineralisation), which were not integrated with one another or with the broader system performance.