Productivity, nutrient-use efficiency and economics of rainy-season grain sorghum (Sorghum bicolor) as influenced by fertility levels and cultivars

Field experiments were conducted under All India Coordinated Sorghum Improvement Project (AICSIP) at 6 locations during rainy seasons of 2009 and 2010 in a split plot design having 3 fertility levels, viz., control (0:0:0 kg/ha of N: P₂O₅: K₂O), recommended dose of nutrients-RDF (80:40:40 kg/ha of N: P₂O₅: K₂O) and 150% of RDF (120:60:60 kg/ha of N: P₂O₅: K₂O) in main-plots, while 8 sorghum cultivars including 3 hybrids (‘CSH 14’, ‘CSH 16’, ‘CSH 23’) and 5 varieties (‘SPV 462’, ‘CSV 15’, ‘CSV 17’, ‘CSV 23’, ‘SPV 1616’) constituted the sub-plot to find out their effects on productivity and nutrient-use efficiency in rainy-season grain sorghum [Sorghum bicolor (L.) Moench]. Results revealed that increasing levels of fertility up to 150% RDF significantly increased the grain yield (3.28 t/ha), nutrient uptake, net returns (25.97 ×10³/ha) and benefit: cost ratio (1.79) as compared to control. Hybrids produced 20.6% higher grain yield over varieties. Among hybrids ‘CSH 16’ (3.07 t/ha) and among varieties ‘SPV 462’ (2.56 t/ha) produced the maximum grain yields. The nutrient-use efficiency (NUE) was higher in hybrids (6.66 kg grain/kg NPK) than the varieties (5.54 kg grain/kg NPK). Increasing fertility levels from 100% RDF to 150% RDF increased the NUE of all the test hybrids, but decreased the efficiency of varieties except ‘CSV 17’.