Effect of feeding black soldier fly larvae (BSFL) on urban market and brewery waste on quality of larvae and compost from the wastes
Abstract
This study was conducted to examine the effect of feeding black soldier fly larvae (BSFL) on urban wastes (market and brewery waste) on quality of compost from the wastes. The wastes were collected from Kalerwe market and Uganda Breweries in Central Uganda and transported to the Animal Science Laboratory in Makerere University Agricultural Research Institute, Kabanyolo (MUARIK), Central Uganda. Prior to establishment of the experiment, market waste, was chopped to a maximum length of 3 cm. Two sets of three levels of 5 kg subsamples each of fresh urban waste: market waste, brewery waste and a combination of market and urban waste (50:50%) were weighed into plastic boxes each of length 60 cm, width 30 cm and depth 40 cm in six replicates. One set of each level of waste was inoculated with 10,000 BSFL and other not inoculated, giving a total of 36 experimental units (3 levels of waste * 2 levels of inoculation * 6 replicates) in a randomized complete design (CRD). The experiment was conducted for two weeks during which, the waste was carefully turned twice everyday (morning and evening) using a tea spoon to avoid injuring the BSFL. Subsamples of approximately 0.5 kg of compost and all the BSFL retrieved from the inoculated treatments were collected and transported to the Soil, Water and plant Analytical Laboratory of Makerere University. The samples were analysed for: pH, organic carbon, Nitrogen, Phosphorous, Potassium, Electronic conductivity, and crude protein. The data were subjected to ANOVA using Genstat Statistical Package 14th Edition. There was a strongly significant (P˂0.001) effect of BSFL on all the chemical properties investigated except E.C that showed no significant (P˃0.05) effect. The highest pH (9.63±0.12) was from market waste inoculated with BSFL whereas the lowest (3.73±0.12) was from un-inoculated brewery waste. Total N was highest in larvae fed on a combination of waste (7.56±0.21%) and lowest in un-inoculated market waste material (1.50±0.15%). Total P was highest in inoculated brewery waste (0.87±0.09%) and lowest in un-inoculated market waste (0.35±0.09%). Total K was highest in inoculated market waste (45.05±1.20%) and lowest in inoculated brewery waste (0.55±1.20%). Percentage crude protein was highest in larvae that fed on a combination of waste (45.51±1.24) and lowest in un inoculated market waste (9.05±0.88). Basing on the results obtained in this study, it is recommended that urban waste materials be inoculated using the Black Soldier Fly Larvae before being used as an organic fertiliser in soils. A combination of market and brewery waste is also recommended to be fed on by larvae for high crude protein to cater for feeds in poultry and fish farming. Alternatively brewers waste can solely be fed larvae in absence of market waste since larvae fed on brewery waste gave a relatively high crude protein. Inoculated brewery waste can also be used as feed for livestock. In this study inoculated brewery waste had a percentage crude protein recommended for a feed source in livestock (poultry and fish farming).