Differetial Increase in Efficacy of Azotobacter Chroococcum and Bacillus Subtilis Co-Immobilized with Different Organic Manuares in Relation to Plant Growth, Nutritional Status and Grain Yield of Wheat (Triticum aestivum L.)

Abstract

Present study indicates that the growth, productivity and grain yield of wheat can be enhanced significantly by amending higher dose of Azotobacter chroococcum and Bacillus subtilis co-immobilized in 45mm diameter granules composed of different organic materials. The biofertilizers were co-immobilized in cow dung/ Farm Yard Manure (FYM) or vermicompost using acacia gum as binder, neem leaf powder and clay soil and applied to the earthen pots in forms of granules of 4-5 mm diameter. The vermicompost containing granules provided higher plant biomass (e.g. shoot height, root length, number of leaves, number of roots, tiller numbers, fresh weight and dry weight of shoot and root than others. FYM and cow dung based granules also enhanced the plant growth with a lower magnitude. The granules released NH4+, NO3-, NO2- and PO43- in the plant's rhizosphere and enhanced availability of essential nutrients to the plants. The co-immobilized form of biofertilizers with vermicompost also increased yield of wheat (Triticum aestivum L. cv 502) in terms of grain weight per plant by 13.79%, with FYM by 11.65% and that with cow dung by 10.15% over free form of the chemical fertilizers (Recommended dose of urea; 150 kg/ha and DAP; 75 kg/ha). The studies indicate that the vermicompost is a better carrier for co-immobilization of the microbial biofertilizers A. chroococcum and B. subtilis to provide the better shelter and nutrient to the microbes and for higher nutrient availability during their application in the earthen pots.