Performance of single-cut forage sorghum varieties under varying fertility levels during summer season in semi-arid conditions

A field experiment was conducted during summer season of 2023 to evaluate the performance of fodder sorghum varieties under different fertility levels at Research Farm, Department of Agronomy, Chaudhary Charan Singh Haryana Agricultural University, Hisar, which is located at 29° 10′ N latitude and 75° 46′ E longitude with an elevation of 215.2 m above mean sea level in semi-arid conditions of Haryana state of India. Sixteen treatment combinations consisted of four varieties viz. CSV 53F, HJ 541, HJ 513 and HC 308 and four fertility levels viz. control, 75%, 100% (75 kg N + 30 kg P2O5 + 30 kg K2O ha-1) and 125% RDF and were laid out in factorial RBD with three replications. Results revealed that sorghum variety CSV 53F performed best in terms of growth and quality parameters and as well as in terms of yield with green fodder and dry fodder yield of 524.43 and 134.57 q ha-1, respectively, which was statistically at par with variety HJ 541. Also, the highest crude protein and digestible crude protein content (8.17% and 4.66%, respectively) at harvest and the lowest HCN content (92.78, 88.96 and 37.10 µg/g at 30, 45 and 60 DAS, respectively) were observed in CSV 53F. The maximum HUE for green fodder yield was recorded from HJ 541 (29.02 kg ha-1 °C-1 day-1) and was statistically at par with CSV 53F. The most economical variety was found to be CSV 53F, as it recorded the maximum benefit-cost ratio (2.05) being statistically at par with HJ 541. Among fertility levels, fodder sorghum responded upto 100% RDF, being at par with 125% RDF. Application of 125% RDF gave higher green and dry fodder yield (564.05 and 146.94 q ha-1, respectively) which were 2.9 and 2.3 % higher over 100% RDF, respectively. With the increase in fertility levels from control to 125% RDF, though HCN (at 30, 45 and 60 DAS) have also increased, but it was found below the critical limit (200 µg/g) at all the stages. The maximum HUE for green and dry fodder yield was recorded with 125% RDF (32.36 and 8.43 kg ha-1 °C-1 day-1) over rest of the fertility levels.