Effect of plastic waste soil contamination on urban agriculture production in Kampala District, Uganda.

Abstract

Plastic waste pollution is one of the challenges faced by people globally; 79% is disposed of in landfills and the rest in the open field through open dumping. Plastic waste in East Africa threatens crop production, leading to low yields obtained by farmers. The aim of this study was to assess the effects of plastic waste pollution on crop yields obtained by urban farmers growing beans in Kampala in order to devise ways of reducing their impacts. This experimental study was set up at the Department of Environmental Management grounds using pots under natural field conditions. The soil was obtained from farmland at Makerere University behind Livingstone Hall in Kampala district at a depth of 0–15 cm so as to get the natural soil nutrients for bean growth. Since the soil was homogenous, five treatments were randomly distributed in a completely randomized design and replicated five times to avoid errors. The different amounts of plastic waste used were 2g, 3g, 4g, and 5 g. Five treatments were used, which included four with various plastic waste amounts and a control experiment that did not contain any plastic waste. The 1 kg of soil was mixed with the plastic waste in each pot, and water was added and left for 6 hours so the water could get well distributed for the proper moisture requirements for yellow bean growth. Each pot had four growing spots; one bean seed was sown per spot, and therefore a total of 120 bean seeds was required for the experiment. The study showed that the level of plastic contamination had a significant impact on the number of flowers (p = 0.00) and pods (p = 0.027) that emerged from the bean plants in different treatments. Based on the findings of this study, it is therefore recommended that soils meant for bean planting be kept safe from plastic contamination to promote bean growth and higher yields. The soils should also be supplemented with inorganic and organic fertilizers so as to increase the nutrient levels required for quality bean yields.