Abstract

A field experiment was conducted at the Main Agricultural Research Station, University of Agricultural Sciences, Dharwad to study the effect of spentwash and tillage on juice quality and economics of sweet sorghum under rainfed condition. Results revealed that deep tillage recorded significantly higher ethanol yield (769.6 l/ha), juice yield (9644.0 l/ha), extractability (269.73 ml/kg), extraction per cent (31.84%), brix0 (18.250) and pol per cent (12.76%) of sweet sorghum as compared to shallow tillage. Among the different spentwash levels, 150 kg N per ha through spentwash recorded significantly higher ethanol yield (750.2 l/ha), juice yield (9567.3 l/ha), extractability (273.95 ml/kg), extraction per cent (32.30%), brix0 (17.990 ) and pol per cent (12.71%) as compared to 75 kg N per ha through spentwash and control, but was on par with 100 kg N per ha through spentwash recommended dose of fertility and 125 kg N per ha through spentwash. The study indicated that a treatment combination of deep tillage with 100 kg N per ha through spentwash was found to be suitable for juice quality of sweet sorghum over other treatment combinations. Based on economics, this treatment was found to be suitable for higher gross returns (Rs. 35486.9/ha), net returns (Rs. 21644.9/ha) and B C ratio (2.56) with minimum cost of cultivation (Rs. 13842.0/ha) as compared to other treatment combinations. The enormous quantities of plant nutrients present in spentwash offers an excellent opportunity to use it as a liquid fertilizer along with irrigation water, thus enabling the farmers to save cost incurred on fertilizers and at the same time achieve higher yields of crops.

Keywords: Distillery effluent, Spentwash, Sweet sorghum, Ethanol, Tillage