This study has shown the comparative insensitivity of end-of-season sugarcane yield to early-season water de®cit. On the other hand, water de®cit imposed when the canopy is well-established will have more deleterious impacts on ®nal yield of total biomass, stalk biomass, and stalk sucrose. Signi®cant impacts on the stalk sucrose concentration or dry matter content at harvest will not occur until stalk biomass levels fall to ca. 50% of that of the well-watered control.