Relative Significance of N Nutrition on Yield, Quality and Ethanol in Sugarcane (Saccharum species hybrid) Plant: Ratoon System

Abstract

Field experiments were conducted at Sugarcane Breeding Institute, Coimbatore during 2005–2006 and 2006–2007 crop seasons as plant and ratoon crop to find the effect of N nutrition on yield, quality and ethanol production from direct fermentation of juice in sugarcane. Treatments involving four nitrogen levels viz., 280, 350, 420 and 490 kg N/ha were laid out in the main plots while the subplot treatments included its split application at different days after planting (DAP) (3 splits on 45, 90, 135 DAP, 4 splits on 45, 90, 135 and 180 DAP, 5 splits on 45, 90, 135, 180 and 225 DAP, 6 splits on 45, 90, 135, 180, 225 and 270 DAP). High yields of 140.7 t/ha and 118.6 t/ha were recorded with the application of recommended dose of nitrogen (280 kg N/ha) in the plant and ratoon crop, respectively. Yields with N application at 45, 90 and 135 DAP exceeded those recorded over other splits. Juice quality and ethanol production per 100 ml of juice did not show a significant variation due to the treatments imposed. However, the variation in cane yields ultimately caused a variation in the amount of ethanol produced per hectare with respect to rates of N (8,544 and 7,566 l/ha in the plant and ratoon crop, respectively, at 280 kg N/ha) and split application (8,617 and 7,617 l/ha in the plant and ratoon crop, respectively, at 3 splits). Application of N at 280 kg/ha at 3 splits at 45, 90 and 135 DAP produced the highest ethanol yield.