Optimization of biodegradation and nutrient release in food waste and goat manure vermicompost amended with seaweed-biochar
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
University of Namibia
Abstract
Vermicomposting has been gaining momentum as a technology capable of generating a nutrient rich organic fertilizer. However, for effective nutrient release, there is need for the optimization of this biological process to allow repeatable production of organic nutrient sources. This study aimed to generate an optimized vermicompost produced from food waste, goat manure and seaweed biochar. This study was guided by the following specific objectives, (i) to characterise biochar produced from two seaweed species at different pyrolysis temperatures (ii) to optimize different combination of Food Waste (FW) and Goat Manure (GM) vermicompost (iii) to optimise the seaweed biochar incorporation into food waste-goat manure mixtures for enhanced biodegradation and nutrient mineralization. Biochar from G. funicularis had the highest macro elements with a total of C 38.3%; N 4.3% and P 6.3 g/kg contents, whilst L. pallida had the highest cations. A pyrolysis temperature of 400°C resulted in the best quality biochar in terms of macro elements, pH, and total C. G. funicularis biochar had significantly higher nutrient concentrations with a great potential for soil quality improvement. The 75 FW: 25 GM and 50 FW: 50 GM vermicompost combinations had significantly ( P ≤ 0.05) the highest final concentration of Olsen phosphorus of 0.98 and 0.96 g per kg of compost, respectively. Biochar incorporation of 4% may be the most optimal, as it enhanced biodegradation and nutrient release than all other treatments with biochar incorporation. Our study clearly indicated that local Namibian waste biomass can be used to develop nutrient rich organic fertilizer. However, the study was done under laboratory conditions further studies will need to evaluate the actual amount of beach cast biomass harvested as well as food waste produced in various industries in order to assess the actual feasibility of producing such fertilizers in practical terms.
Description
A dissertation submitted in partial fulfilment of the requirements for the degree of
Master Science in Agriculture (Crop Science)
Keywords
Seaweed biochar, Nutrient release, Biodegradation, Humification parameters, Macro-nutrients