Greg Constable and I have previously shown that in the Namoi Valley an irrigation water supply of 8 ML per ha is needed to obtain maximum yields in the driest years. In most years however, because there is more rain, less water is needed. The question therefore arises: with a fixed volumetric allocation of irrigation water is the best strategy to allow 8 Ml per ha or is it better to use less water per ha and to grow more hectares with the water saved? Only in the driest years would yields be reduced and even then the larger area could compensate for the reduced returns per ha.