Microbiological and Physico-chemical Analysis of Compost and its Effect on the Yield of Kale (<i>Brassica oleracea</i>) in Bahir Dar, Ethiopia

Abstract

The efficiency of the composting is dependent on factors such as, number of microorganisms, nutrient balance, temperature, pH, electrical conductivity and moisture content. However there is paucity of data on these parameters and the influence of compost on the yield of kale. The aims of this study were to investigate the microbial counts, the physico-chemical parameters of compost and to assess the influence of compost on the growth yield of kale (Brassica oleracea) plants. The number of bacteria decreased from 1.2x106 cfu/g at the initial stage of composting to 1.3x104 cfu/g at the end of the process. Likewise, the number of fungi decreased from 6.05x106 cfu/g to 1.05x104 cfu/g. On the other hand the number of actinomycetes increased from 5.2x105 cfu/g to 7.4x106 cfu/g towards the end of the composting period. The electrical conductivity and pH increased through out the composting period. Mean monthly moisture content, organic matter, carbon content, nitrogen content and carbon-nitrogen ratio decreased from the initial stage to the final stage of composting. Statistically significant difference in growth parameters of kale plant was observed between compost and inorganic fertilizer (p < 0.05). Electrical conductivity and pH are the parameters that influenced growth of bacteria and fungi negatively while the organic matter content, C: N ration were the parameters that influenced the growth of actinomycetes. The mature compost improved the plant growth parameters better than inorganic fertilizer Addition of compost gave a better growth of kale compared to that of inorganic fertilizers. Compost

Keywords: actinomycetes, bacteria, compost, fungi, kale, physico-chemical