Managing Legume and Fertiliser N for Northern Grains Cropping

The purpose for writing this manual was twofold. First, it was to provide an update of current information on fertiliser and legume nitrogen (N) in broadacre cropping in Australia's northern grains region, with particular emphasis on the legume N. Second, the manual was written to provide instructions, underpinning technical information and background science for 'NBudget' - the web-based (CropMate™) calculator for estimating the fertiliser N requirements of cereal and oilseed crops and dinitrogen (N₂) fixation by legumes. The manual's target audience is likely to be the private and government agronomists, consultants and advisers who work with farmers to make decisions about N, rather than the farmers themselves. The manual may also provide useful material for tertiary-level education and training. Data and concepts that underpin the manual and calculator were sourced from the many published and unpublished experiments conducted primarily by the farming systems and plant nutrition programs of the NSW and Queensland government agencies during the past 30 years. I have interpreted and reported not only the data but also the knowledge and insight of the Australian and international scientists who have worked and published in the fields of soil and plant N.