GROWTH AND YIELD RESPONSE OF FOUR SUGARCANE CULTIVARS TO DIFFERENT SOIL MOISTURE REGIMES AT KENANA SUGAR SCHEME

Field experiments were conducted for two years (2012 - 13 and 2013 - 14) ) on heavy clay soils, with 65 % clay, 24% silt, 11% sand and a pH of 7.5–8.5 in Kenana Sugar Scheme, Sudan (latitude 13°10` N and longitude 32°40` E) to investigate the response of sugarcane growth and yield of four sugarcane cultivars; namely; Co 6806, Co 997, R 579 and TUC 75-3 to irrigation regimes applied at the depletion levels of 25-30%, 55-60% and 75-80% of available soil moisture. In both seasons, the irrigation treatments were applied three months after sowing and continued till the crop was 13 months old. The reference evapotranspiration for Kenana Sugar Scheme was computed using Penman-Monteith approach. The amount of water required for irrigating sugarcane plants was calculated. The results revealed that irrigation based on the depletion of 75-80% of available soil moisture led to a decreased yield and yield components, whereas the best yield and yield components resulted when irrigating at 55-60% depletion of available soil moisture followed by 25-30% depletion. Regarding the effect of irrigation at different soil moisture levels on cane and sugar yields results showed that irrigation based on the depletion of 55-60% had out-yielded those of 25-30% and 75-80% depletion of available soil moisture. With respect to the performance of the cultivars the highest cane and sugar yield was obtained from the cultivar Co 6806 followed by cultivars Co 997, R 579 and TUC 75- 3. The present study also stated that a further increase in irrigation amount resulting from irrigating at 25-30% depletion of the available soil moisture did not increase the marketable yield of the sugarcane crop but significantly (P ≤0.05) reduced the irrigation production efficiency.