Abstract

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Water hyacinth is an aquatic weed that is difficult to manage due to its rapid and extensive growth rate. Composting is a promising technique widely used for the management of organic wastes. This study evaluated the application of water hyacinth and cow dung composts as bio-fertiliser on tomato plant. Water hyacinth and cow dung were composted for 20 days in five different proportions of cow dung, water hyacinth, cow dung and water hyacinth (CW) at ratio (1:1, 1:2, 2:1) respectively. Physicochemical properties and microbial load of the composts were determined. Bacterial and fungi isolates were isolated and identified using standard methods. Composts were applied to sterile soil after which tomatoes were transplanted. Agronomic parameters such as plant height, number of leaves, stem girth and leaf area were determined after eight weeks of transplanting. Results showed that cow dung only had the highest total bacterial count of 27.2 x 106 cfu/g while water hyacinth only had the least bacterial count of 5.0 x 106 cfu/g. Cowdung and water hyacinth (1:1) and cowdung only recorded had the highest and lowest total fungal count of 12.8 x 106 cfu/g and 2.0 x 106, respectively. pH ranged from 5.8 – 7.8 while temperature ranged from 25.67-40.5°C. The isolated and identified bacteria were Bacillus subtilis, Campylobacter jejuni, Citrobacter koseri, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa and Staphylococcus saprophyticus. The identified fungal isolates include: Aspergillus flavus, A. fumigatus, A. niger, Candida albicans, Penicillium sp. and Saccharomyces sp.Cowdung: water hyacinth at ratio 1 to 2and water hyacinth only showed the highest and least support for tomato plants, respectively. All the agronomic parameters analysed were significantly higher(P≤ 0.05)in all the treatments than the control. This study revealed that compost of cow dung and water hyacinth could be used to improve the growth of tomato.

Keywords: Compost, Cow dung, Tomato, Water hyacinth, Microbial load