Microbial valorization of water hyacinth (Eichhornia crassipes) into compost as a cost-effective biofertilizer

Abstract

Water Hyacinth (Eichhornia crassipes) is an invasive aquatic weed whose management presents a challenge in water bodies. This study sought to evaluate eco-friendly and cost-effective products from water hyacinth. The efficacy of water hyacinth compost (WHC) product was tested on 3 different plants namely Abelmoschus esculentus, Zea mays and Cucurbita pepo for 60days. Their seeds were planted in 2kg of Agricultural soil mixed with 100g and 200g WHC and controls (without WHC). The microbial counts and physicochemical parameters of the dry water hyacinth compost were assessed using standard methods. The growth of the three plant species was measured at 5 days interval. Results of the microbial count ranged from 2.50 ±1.50×10³ to 1.58±0.43×10⁸ CFU/g for Total Heterotrophic Bacteria (THB), Total Heterotrophic fungi (THF), Total Hydrocarbon Utilizing Bacteria (THUB) and Total Hydrocarbon Utilizing fungi (THUF). The nitrate, phosphate, potassium and trace metal concentrations in the water hyacinth compost (WHC) were 8.38, 0.4, 6.75 and 0.003mg/kg respectively. The nitrate, phosphate, potassium and heavy metal concentrations in the soil before planting were 10.56, 2.70, 1.30 and 0.01-0.03 mg/kg respectively. After planting, the microbial count of the treated soil ranged from 3.23 ±2.70x10³ to 2.97 ±1.54×10⁸ CFU/g, representing 56.07% increase; nitrate was 14.04, phosphate 5.30, potassium was 5.00 and heavy metals 0.01mg/kg. There was an overall increase in the growth of the plant. This study has demonstrated that Eichhornia crassipes compost is an appropriate organic amendment for soil conditioning and the potential to benefit the environment and economy from water hyacinth.