FOLIAR SPRAY OF GROWTH REGULATORS AND MINERAL NUTRIENTS FOR ENHANCED PRODUCTIVITY AND PROFITABILITY OF SINGLE CUT FORAGE SORGHUM IN SEMI-ARID REGIONS OF INDIA.

A field experiment was conducted at Forage Section Research Farm, CCS Haryana Agricultural University, Hisar, during kharif season of 2019 and 2020 on single-cut forage sorghum to quantify the impact of plant bio-regulators on forage productivity and quality of sorghum grown as rainfed crop. Eight treatments including foliar application of plant bio-regulators included 2% urea, 2% NPK (18-18-18), 2% potassium nitrate (KNO₃), 1 ppm silicic acid, 2 ppm silicic acid and 100 ppm salicylic acid at panicle initiation and flag leaf emergence stage were compared with no spray as well as water spray in randomized block design in three replicates. The application of PBRs increased green fodder yield by 13.75-19.73 per cent over control. On pooled mean basis, the highest green and dry fodder yield of 52.31 and 13.74 t/ha, respectively was recorded with application of 2% NPK (18-18-18). Among treatments, the crude protein content in dry fodder was not affected significantly, however, maximum crude protein yield was estimated with the application of 2% water soluble fertilizer NPK (18-18-18) which was on a par with urea @ 2%, KNO₃@ 2%, silicic acid 2 ppm and 100 ppm salicylic acid. Beside this, there was a substantial reduction in the HCN content due to foliar application of 2% KNO₃. On pooled mean basis, foliar application of PBRs /nutrients improved the BC ratio which ranged from 1.62 to 1.70 with KNO₃, 2% NPK (18-18-18), 2% urea, 1 and 2 ppm silicic acid and 100 ppm salicylic acid spray. The BC ratio with the foliar application of 2% KNO₃, 2% NPK (18-18-18), 2% urea, 2 ppm silicic acid and 100 ppm salicylic acid was 7.28, 9.27, 12.58, 11.26 and 11.92 per cent higher over control (no foliar spray, only recommended dose of fertilizer @ 75 kg N+30 kg P₂O₅+ 30 kg K₂O/ha), respectively on pooled mean basis. Foliar application of KNO₃ presents a viable option for improving sorghum fodder productivity and its quality under rainfed/ moisture stress situation. [ABSTRACT FROM AUTHOR]