Abstract
A field trial was conducted in medium-black soil under rainfed conditions to study the effect of combined inoculation of Azospirillum brasilense and Pseudomonas striata or Bacillus polymyxa (with and without fertilizer nitrogen and rock phosphate) on the yield and nutrient uptake of sorghum. The results showed a significant increase in grain and dry matter yields and N and P uptake of sorghum from the combined inoculation over single inoculation of individual organisms. A further increase in yields was observed from application of 40 kg N and 60 kg P2O5 ha-1, as urea and rock phosphate, respectively, together with inoculation treatments over the unfertilized inoculation treatments or uninoculated fertilizer treatments. The population counts of Azospirillum and phosphate-solubilizing bacteria in the rhizosphere of sorghum were higher in the respective inoculation treatments than in uninoculated treatments.
