Water Use Efficiency of Irrigated Sugarcane as Affected by Row Spacing and Variety

To meet the challenge of a limited and costly water supply, South African sugarcane growers will have to find ways of increasing the efficiency of irrigation to maintain high cane and sucrose yields. The term ‘water use efficiency’ (WUE) is generally used as a measure of the overall effectiveness of water (either rainfall or irrigation, or both) for crop production. WUE can be defined as cane yield per unit of crop water use (evapotranspiration). Irrigation water use efficiency (IWUE) is another term commonly associated with WUE, and can be defined as the cane yield response per unit of irrigation water applied. More efficient irrigation systems, accurate irrigation scheduling and agronomic practices such as mulching, variety choice and row spacing are potential means of increasing water use efficiency. WUE and IWUE values are required for water resource planning and for the assessment of irrigation management practices. Improved water use efficiency would also reduce negative environmental impacts by reducing runoff, erosion, drainage and leaching of agricultural chemicals.