Effect of biofertilizer application on rainfed sorghum in calcareous soil

The influence of biofertilizers like Azospirillum, phosphobacteria, azophos (50:50 combinations of Azospirillum and phosphobacteria) and mycorrhiza, individually and in combination was investigated in pre-monsoon sowing with sorghum APK 1 variety in randomized replicated field trial at the Regional Research Station, Aruppukottai, Virudhunagar, Tamil Nadu. The adherence of the inoculated bacteria was recorded under all treatments. The results showed the feasibility of biofertilizer treatment to seeds in pre-monsoon sowing as the bacterial inoculants survived on seeds up to 21 days even though they were sown in dry soil and colonized until the receipt of showers. Treatment azophos + mycorrhiza with 75 per cent recommended N and P treatment was found most effective in enhancing fresh stover weight (70 tonnes/ha) and grain yield (3,536 kg/ha). This treatment also resulted in higher earhead yield (13.00 kg/plot) alongwith phosphobacteria + mycorrhiza treatment (12.80 kg/plot).