ABSTRACT
The deficit irrigation is commonly used in regions of reduced water and energy availability for irrigation with a view to increase water use efficiency. This technology can be a strategy to increase sorghum production under the conditions of limited soil water availability. The objectives of this study were to: (i) evaluate the effects of different deficit irrigation management on leaf area index, plant height and grain yield of sorghum, and (ii) identify the critical level of deficit irrigation for optimum irrigated water productivity and economic return. The experiment was conducted in a Rainout Shelter during the 2012/13 cropping season. The deficit irrigation management consisted of water replacement in the crop root zone by: 100, 75, 50 and 25% of crop evapotranspiration (ETc). A 25% reduction in the replacement of ETc resulted in about 7% decrease in plant height, 5% in leaf area index and 17% in sorghum grain yield . The highest net revenue of the culture was achieved using ETc replacement of 75%. The water productivity and economic return of water application showed a positive linear response in relation to the reduction in ETc replacement.
crop evapotranspiration; irrigation water productivity; Sorghum bicolor
