Evaluation and Characterization of Nutrient Content of Vermicompost Made from Different Locally Available Substrates at Haro Sabu Onstation, Kellem Wollega Zone, Oromia, Ethiopia

Locally available materials could be used to address soil fertility constraints. Vermicomposting is a promising technology where various organic materials are converted into processed compost by earthworms. This study was conducted at the Haro sabu Agricultural Research Center on-station during the consecutive two years (2021 - 2022 years) with the aim to evaluate the quality of vermicompost made from different locally available waste materials to explore the possibility of using organic fertilizers for sustainable agriculture and minimize the use of chemical fertilizers in the crop production and reduce soil pollution. The experiment consisted of ten different treatments in the ratio of 1:1 cattle manure to crop residues on a weight basis viz., T1: Cow manure + maize straw, T2: Cow manure + haricot bean straw, T3: Cow manure + coffee husk/pulp, T4: Cow manure + green leaf, T5: Cow manure + haricot bean straw + maize straw, T6: Cow manure + coffee husk/pulp + maize straw, T7: Cow manure + green leaf + maize straw, T8: Cow manure + haricot bean straw + coffee husk/pulp, T9: Cow manure + haricot bean straw + green leaf, and T10: Cow manure + maize straw + haricot bean straw + coffee husk/pulp + green leaf. Water was sprayed to maintain optimum moisture for worms as it needed. The substrates were chopped and added to the worm bin. A red worm (Eisenia fetida) was used for the preparation of vermicompost. Matured composite vermicompost samples were prepared and collected for laboratory analysis. The laboratory result showed that the pH values of all feeding substrates are found in a suitable range for the survival of earthworms and also for plant growth. The OC, TN, available P, C:N ratio, and CEC of vermicompost made from all material were excellent and promise improvement of soil properties. The highest value of available P and K was also registered from vermicompost prepared from all materials. Even if the values of recorded nutrients were different, the vermicompost obtained from all substrates was rich in selected micronutrients. Therefore, the nutrient content of vermicompost prepared from all substrates showed the highest values for all selected micro plant nutrients. Thus, the vermicompost made from all materials could correct the plant nutrient imbalance and could be used for vermicompost preparation based on the accessibility of materials. Also utilizing the vermicompost for crop production and enhancing soil fertility.