Quantifying response of azospirillum and phosphate solubilizing bacteria liquid inoculants seed treatment on productivity and profitability of kharif grain sorghum (Sorghum bicolor)

A field study was carried out during 2017–19 at Sorghum Research Unit, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra to assess the effect of liquid bio-fertilizers inoculation over existing powder form inoculants on kharif grain sorghum [Sorghum bicolor (L.) Moench]. The experiment comprised of 6 treatments, viz. no bio-fertilizer control i.e. with RDF alone (T1 ); RDF + Azo. (Azospirillum) + PSB @50 g each/kg seed (T2 ); RDF + Azo. + PSB @2 ml each/kg seed (T3 ); RDF + Azo. @2 ml and PSB @4 ml/kg seed (T4 ); RDF + Azo. @4 ml + PSB @2 ml/kg seed (T5 ); and RDF + Azo. + PSB @4 ml each/kg seed (T6) conducted in randomized block design (RBD) with 4 replications. Pooled data revealed that seed inoculation with Azo. + PSB @2 ml each/kg seed (T3 ) has improved the sorghum biological, grain yield and net returns 21.13, 19.83 and 17.92% over their powder form of inoculants i.e. T2 (14.71 t/ha, 3.56 t/ha and 73,116). These enhancements in biomass, grain yields and net income was owing to liquid bio-fertilizer seed treatment. Liquid-based inoculants were found to boost growth and yield parameters, which was ascribed to the concomitant increase in plant height and number of grains/panicle, respectively. Increase in quantity of liquid bio-fertilizers beyond 2 ml/kg seed proved not-rewarding from both productivity and profitability point of view. Sorghum seed inoculation with liquid bio-fertilizers @2 ml each/kg seed proved to be a potential substitute for existing powder form without any additional cost.