Asian Journal of Biotechnology and Bioresource Technology

Abstract

This study showed the production of liquid biofertilizer from organic wastes (cassava peels and spent mushroom substrates) using microbial inoculants (Bacillus spp., Pseudomonas spp., Lactobacillus spp. and Aspergillus spp.). The organic wastes were autoclaved and then immersed in sterile water inside plastic pots. The plastic pots were twelve in number (labelled A to L) with duplicates but one of it (L) serves as the negative control (sterile water + organic wastes). They were used as the composting reactors with different compositions of microbial inoculants. There were increase in the physicochemical parameters of the liquid compost in week one and two respectively. Generally there was slight decrease in the microbial population at week two. On the addition of Azotobacter spp. the microbial population increased substantially along with some physicochemical parameters (nitrates, carbon(iv)oxide, total organic carbon, potassium and phosphates), only the pH and Total Nitrogen concentrations showed  reduction in their concentrations. All compost reactors were then mixed together and filtered to obtain the liquid biofertilizer. The shelf life of the liquid biofertilizer was determined at monthly intervals from December to April. The highest microbial population was observed in the third week of February (3.6 x 10⁸ cfu/l). The efficacy of liquid biofertilizer produced were tested on the growth index of plant (Maize and Okra) and compared with a commercial organic liquid fertilizer and a control (no fertilizer application). The number of leaves, size of stem girth and the height of plant in maize and okra favoured the liquid biofertilizer applications compared to the commercial Organic liquid fertilizer. To determine the most efficient mode of fertilizer application, foliar applications and soil inoculation were tested on the crops using the liquid biofertilizer and the commercial organic liquid fertilizer until week five. It was discovered from this research that soil inoculation is the best method for the application of the liquid biofertilizer.