Background: The use of chemical fertilizers to solve the problem of nutrient deficiency in soil has been associated with a number of environmental problems. In search of an eco-friendly means of enhancing P availability in soil, this study was conducted to evaluate phosphofungi for use as biofertilizer using Okra (Abelmoschus esculentus) as a test crop. Methods: Fungi isolated from agricultural soils were screened for P solublizing ability on National Botanical Research Institute Phosphate (NBRIP) medium. Two isolates with highest potential for P solubilization were selected for further studies. Fungal inoculants were prepared on compost, production conditions optimized and the shelf lives of the developed biofertilizers determined. A pot experiment was conducted using a completely randomised experimental design made up of seven treatments in triplicates. The treatments applied to sterilize soils were compost only, two levels each of the two fungal biofertilizers developed in combination with inorganic fertilizers at reduced levels, Inorganic fertilizer only and Soil only (Control). Some growth characteristics of okra plants grown in the pots were recorded weekly for eight weeks. Results: The two selected fungi were identified asAspergillus niger and Penicillium citrinum. Optimum P solubilisation was obtained at pH 5 for A. niger and at pH 6 for P. citrinum. Maltose and Ammonium chloride were the best carbon and nitrogen sources respectively for cultivating the fungi. The shelf life of the biofertilizer from A. niger at room temperature was eight weeks while that of P. citrinum was four weeks. The application of either of the two P biofertilizers along with reduced levels of inorganic fertilizer significantly increased okra growth & yield. However, the highest dry weight of okra pods obtained was with treatments that contained A.niger biofertilizer and this was significantly higher (P<0.05.) than values obtained for both control set up (unfertilized) and sole inorganic fertilizer application. Conclusion:Biofertilizers from native phosphofungi could be used alongside reduced levels of inorganic fertilizers to enhance soil available P.
Full conference title:
- ASM 115th (2015)