The N nutrition of cotton crops was investigated with respect to the effectiveness with which rotation crops improve the supply of N to cotton and reduce the amount of N fertilizer required. The CRC farming systems experiments were examined to demonstrate these principles by monitoring the N status of each system. This has helped to identify the more N efficient cropping systems and allow for more effective N nutrition of cotton. Summer and winter growing rotation crops (including grain, green-manure and forage legumes) were compared in field experiments at ACRI and the benefit of these legume systems and savings in N fertilizer for cotton was assessed. Both back-to-back and rotational cotton systems were investigated. The biofumigatory effect of Brassica species will also be determined through lint yield and VAM assessment. The value of other rotation crops was evaluated in terms of improved N nutrition, soil structure, weed and insect management, VAM and cotton pathogen survival. Improvements to soil and crop nitrate tests for predicting N fertilizer requirement and crop N status will enhance grower confidence and adoption of this technology by allowing on-farm determination of soil nitrate levels. These results will be incorporated into the Nutripak /Nutrilogic program