Effect of ZnSO4 on Cane Quality of the Variety SL 96 128, under Alfisols at Uda Walawe, Sri Lanka

Abstract

Low sugar recovery experienced during the last few years has become a challenging issue for the Sri Lankan sugarcane industry. Enhancement of cane quality is one of the solutions to overcome this problem. The application of Zinc sulphate (ZnSO4) as a soil amendment is practiced in some countries to enhance the quality of the cane. Therefore, this study was conducted to evaluate the effect of ZnSO4 application on cane quality of commercial sugarcane variety SL 96 128 which is widely grown in Alfisols in Sri Lanka. A field experiment was conducted at the research farm of the Sugarcane Research Institute, Uda Walawe under irrigated conditions using RCBD with Five replicates. In addition to the recommended amounts of fertilizers (Urea-325 kg/ha, Triple Super Phosphate-50 kg/ha, Muriate of Potash-225 kg/ha), 7.5 kg/ha of ZnSO4 (Zn - 22%) was applied to treated plots (T1) at 3 months of the crop age and untreated plots (T2) were maintained without ZnSO4. The cane quality parameters: i.e., Brix%, Pol% (Sucrose content), Purity%, Fiber% and POCS% (Pure obtainable cane sugar) were measured at 10, 11 and 12 months of crop ages and cane and sugar yields (t/ha) were estimated after harvesting the crop at 12 months. ANOVA was performed by using SAS statistical software to identify the effect of ZnSO4 on cane quality. The temporal variation of quality parameters was assessed by carrying out two separate regression analyses for T1 and T2. The untreated plots (T2) showed a significant (P<0.001) declining trend for Brix%, Pol%, Purity%, and POCS% during 10 to 12 months period. At harvest, T1 recorded significantly high Pol % (14.73, 13.04), Purity % (91.60, 85.97), POCS % (11.35, 9.68) and sugar yields (10.60, 8.73) compared to T2 (at P<0.05). However, cane yields of T1 (93.67) and T2 (90.42) were not significantly different.This preliminary study revealed that there is a significant positive effect from soil micronutrient, Zn on cane quality parameters of the variety SL 96 128.