The tolerance of sugarcane to water stress during its main development phases

Abstract

Sugarcane's annual growth is divided into the three development phases of germination and tillering, stalk growth and maturation. An experiment conducted in Swaziland compared conventional irrigation scheduling and a revised conservative regime in ratoon cane. Within each growth stage two disparate irrigation schedules were adopted. In the germination phase the cane was irrigated after harvest and then either regularly according to Et/Eo ratios based on development of cane canopy or not again until the commencement of rapid stalk elongation. During the period of stalk growth irrigations were scheduled assuming Et/Eo ratios of either 1,0 or 0,8. The cane was dried off in the maturation phase when the predicted accumulated evaporation prior to harvest was expected to be either 1 1 2 or 3 times the total available moisture (TAM). Results showed that there was no reduction in cane yield with the drier irrigation regimes. Withdrawal of irrigation in the tillering phase tended to increase cane and sucrose yield and the longer drying off period marginally improved cane quality in terms of sucrose %. Pest and disease susceptibility was not increased with the dry regimes. Important savings in water applied were achieved.