Effect of pre-sowing seed inoculation with liquid biofertilizers on fodder yield and quality of sorghum (Sorghum bicolor)

Abstract

An experiment was carried out during the rainy (kharif) seasons of 2016 and 2017 at 2 locations of Punjab (Ludhiana and Bathinda), to study the effect of N-fixer (Azotobacter species) and P-solubilizers (Sphingobacterium species, Burkholderia species and Streptomyces badius) inoculations and their interactions, in the presence of recommended dose of fertilizer (RDF) on SL 44 single-cut forage sorghum [Sorghum bicolour (L.) Moench]. A to- tal of 9 liquid microbial inoculant combinations were used as seed treatment before sowing. All the microbial treat- ments along with chemical fertilization resulted in non-significant numeric increase in yield and growth of sorghum at both the locations in 2 consecutive years. The dual inoculation, i.e. Azotobacter species + Burkholderia species along with RDF resulted in 21.5% and 16.8% percent increase in crude protein (CP) and in-vitro dry-matter digest- ibility (IVDMD) over the control, observed from 2 locations pooled mean respectively. Similar combination of biofertilizer with recommended dose of fertilizer resulted in lower acid detergent fibre (ADF) and neutral detergent fibre (NDF) content of 40.40% and 53.53% respectively. The hydrocyanic acid (HCN) production was also noticed to be lowered down with the use of liquid dual inoculum of Azotobacter species + Burkholderia species. Green fod- der yield (GFY) had positive significant correlation with all yield, growth and quality parameters, whereas negative correlation with HCN (0.09), ADF (0.34) and NDF (0.18). Dry-fodder yield (DFY) exhibited the highest signifi- cant correlation coefficient with IVDMD (0.92) followed by CP (0.71). The results of correlation also indicated that the plant height should be given due importance as it showed significant correlation with dry-fodder yield. There- fore, there was synergetic effect of nitrogen-fixing and phosphate-solubilizing microbial inoculants on fodder qual- ity improvement of sorghum.