A major issue facing the cotton industry in Australia is the potential for surface and groundwater contamination from the inefficient application of nitrogenous fertilisers. This dissertation appraises the merits of applying site-specific nitrogen management to irrigated cotton in Australia, as this system has been hypothesised as being economically and environmentally more sustainable than the traditional 'blanket' approach to the application of crop production inputs. Site-specific crop management (SSCM) utilising new technologies such as Global Positioning System (GPS), yield monitors, orbital-satellites and variable-rate crop applicators to identify within-field crop and soil variability as well as their causes. The rational behind SSCM is 'by identifying within-field variability in crop and soil attributes and their origin', it then becomes possible to optimise crop production inputs such as pesticides and fertilisers on a point- by-point basis. Implicitly, this lowers the potential for their over- and under-application.