Impact of addition of biochar along with Bacillus sp on growth and yield of French beans

Use of chemical fertilizers to enhance crop yield may lead to pollution, acidification or mineral depletion in soil. Plant growth promoting rhizobacteria (PGPR) are an alternative to chemical fertilizers as they contribute towards promotion of plant growth and yield of different crops. But if added with biochar, they result not only in enhancement of crop yields, but also help in preventing fertilizer run-off, leaching, retaining moisture and helping plants through periods of drought. To the best of our knowledge this is first report to study the effect of biochar along with a potential PGPR strain, Bacillus sp. A pot experiment was done with 6 different treatments viz, pure soil, soil + biochar, soil + Bacillus sp., soil + biochar + Bacillus sp., soil + biochar + commercial biofertilizer (Biozyme), and soil + chemical fertilizer (Di-ammonium phosphate, DAP), and the length and biomass of root and shoot, seed yield and nutrient uptake were measured in French beans (Phaseolus vulgaris). Generally, all treatments showed a significant increase in growth and yield as compared to plants grown in untreated soil. It was observed that addition of biochar to soil influenced the overall growth of plants positively but the inoculation with Bacillus sp. or Biozyme enhanced this effect further. The treatment, soil + biochar + Bacillus sp. also showed the highest number of phosphate solubilizing bacteria in the rhizosphere of plants and percent N content in shoots, whereas the highest P content was observed in soil + DAP, followed by soil + biochar + Bacillus sp. combination. Hence, it can be concluded that both biochar and the bioinoculant, Bacillus sp. are good treatments for sustainable agriculture. (C) 2013 Elsevier B.V. All rights reserved.