Effect of nitrogen, phosphorus and potassium levels on sugarcane (Saccharum spp. hybrid complex) varieties under upland rainfed conditions of Bihar

A field experiment was conducted during the spring season of 2015–16 on sandy-loam soil, to evaluate the effect of NPK levels (50, 75 and 100% of the recommended dose) on productivity and profitability of sugarcane (Saccharum spp. hybrid complex) varieties (‘BO 130’, ‘BO 139’, ‘BO 153’, ‘CoP 9301’ and ‘CoLk 94184’) under sub-humid, sub-tropical upland rainfed conditions of Pusa, Bihar (25^o 59 ’N, 85^o 40 ’E). Among the varieties, ‘BO 139’ showed the highest cane diameter (2.44 cm) and single cane weight (812 g). Variety ‘BO 153’, being equally efficient in producing millable canes and cane yield with ‘CoLk 94184’ and ‘BO 130’, were significantly found superior to ‘CoP 9301’ and ‘BO 139’. The sucrose content (18.34%) obtained with ‘CoP 9301’ was on a par with that of ‘BO 139’ (18.00%) and significantly higher over rest of the varieties, whereas ‘BO 153’ recorded the highest net returns ( 94, 000/ha) and benefit: cost ratio (1.26), followed by ‘BO 130’, ‘CoLk 94184’, ‘BO 139’ and ‘CoP 9301’. Among the fertility levels, 100% recommended dose of NPK, being at par with 75% recommended dose of NPK, recorded the significantly highest millable canes (93, 400/ha), cane diameter (2.27 cm) and cane: top ratio (4.0) over 50% recommended dose of NPK. Application of 100% recommended dose of NPK also resulted in significantly higher cane yield (64.1 t/ha), sucrose content (18.15%), gross returns ( 163, 400/ha), net returns ( 86, 700/ha) and benefit: cost ratio (1.13). However, the differences between 75 and 100% recommended dose of NPK were non-significant. Sugarcane ‘BO 153’ can be grown for higher yield and economic returns with application of 75% recommended dose of NPK under upland rainfed conditions.