Sustainable Production of Liquid Biofertilizer: Utilizing Spent Mushroom Substrate and Watermelon Peels

Abstract

Biofertilizers are natural fertilizers that contains live biomass. This study demonstrates the production of Liquid biofertilizer through the use of spent mushroom substrate (SMS), and watermelon peels by liquid state fermentation technique. This is a result of contamination and lose of soil fertility faced by the environment and agricultural farm land as a result of incessant use of inorganic fertilizers that are persistent in the soil. The two waste materials of 5379g each were obtained and placed on a 35-litre drum, 27 litre of water was poured on the mixture after washing the watermelon peel and stirred evenly, then allowed to ferment for 3 weeks under anaerobic condition, then filtration of the mixture was done after complete fermentation, and microbiological and physicochemical analysis was carried out on the mixture before and after fermentation. Reduction in the concentration of total nitrogen, phosphorous, magnesium and potassium were observed after fermentation while iron content increased after fermentation. The following bacterial species were identified using 16S rRNA gene amplicons: Pseudomonas aeruginosa, Stenotrophomonas, geniculata, Sphingobacterium daejeonense and Alcaligene faecalis. A Pot experiment was carried out with a planting bag on three set ups in duplicates, (i) seed + liquid biofertilizer application, (ii) seed + chemical fertilizer application (iii) Seed alone. Then planting of bean seed (Phasolous vulgaris L.) and groundnut seed (Arachis hypogea) on each set up after physicochemical analysis of the planting soil. Growth comparison using germination test was done by measuring the shoot length, leaf length, leave number, leaf width, stem girth and number of branches, it was observed that the treatment with liquid biofertilizer application competed favourably with that of chemical fertilizer treatment and the biofertilizer also serves as a bio-control agent as the leaves of the biofertilizer set up was not eaten by caterpillar while that of inorganic (chemical fertilizer) was eaten up.