Comparative assessment of biofertilizer potentials of fungal and rhizobacterial isolates

Abstract

Pollution and degradation of soil due to continuous use of chemical fertilizers has led to the screening of microorganisms for use as bio-fertilizer by reason of their cost effectiveness and eco friendliness. This work investigated the ability of microorganisms to enhance crop growth using Zea mays as a case study. Pantoea eucaria, Bacillus wiadmanii and Aspergillus flavus isolated from rhizosphere of maize and identified molecularly were tested. Soil samples were obtained from Institute of Agricultural Research and Training, Moor plantation, Ibadan. Ability of the isolates to produce growth promoting factors were assessed using pikovskaya, Alecksandrouv and glucose nitrogen free media before inoculated into the seed of the maize. Three pots in replicates, each contained 5 kg of soil were seeded. Isolates were applied separately and in combination with two controls. They were allowed to stand for six weeks under green house conditions, agronomic parameters were measured at interval. Result showed ability of the isolates to solubilized Phosphorus, potassium and fix nitrogen. Pantoea eucaria and Aspergillus flavus had P-solubilization index of 1.02 and 0.551 respectively. Indole acetic acid and gibberellic acid production was observed for Bacillus wiadmanii (2.6 mg/l) and Aspergillus flavus (F1) (0.56mg/l) respectively. Height (260 cm) was observed in seeds with NPK fertilizer, (206 cm) for seeds treated with the two bacteria, seeds with Bacillus wiadmannii had the least. The leaf area was not significantly different (P≤0.05) at different treatment. Plant biomass for NPK fertilizer seeds (118.91g) while the control was 35.32g. The isolates tested can be useful in the formulation of fertilizers, their utilization would help to reduce loss of soil fertility and pollution resulting from continuous use of chemical fertilizers.