This project was prompted by disappointingly low cotton yields at Emerald and other Central Queensland centres. The aims of the project are to provide a basis for sound irrigation management of cotton through studies of ( i) Crop response to a range of irrigation management options in terms of crop irrigation efficiency (yield per unit water applied) and plant fruiting development. (ii) Soil water balance in relation to irrigation application efficiency (infiltration per unit water applied), crop water use, ground-water accessions and model predictions of all these factors.