Evaluation of Nutrient Content of Vermicompost Made from Different Substrates at Mechara Agricultural Research Center on Station, West Hararghe Zone, Oromia, Ethiopia

摘要

The study was conducted at Mechara Agricultural Research Centre during 2016-2018 to evaluate nutrient content of vermicompost made from different substrates. The treatments were sorghum straw, maize straw, teff straw, haricot bean straw, grass straw and mixture of all straws. A red worm (Eisenia fetida) was selected to digest the substrates. The substrates was chopped and added to the worm bin volume calculated using spherical frustum formula 1/6h (3a~2+3b~2+h~2 in a ration 2.5:1 ration of cattle manure to crop residue in weight basis. Water was sprayed to maintain optimum moisture for worms as it needed. The vermi composting process was started by releasing 100 worms in to the substrates. Matured composite vermicompost samples were prepared and collected for laboratory analysis. The laboratory result showed that, the pH and EC values of all type of vermicompost are found in suitable range for survival of earthworms and also for plant growth. Data with regards to %OC, C: N ratio and CEC of vermicompost made from all material is excellent and promise for improvement of soil properties. Relatively the highest (4.26%) and lowest (3.04%) TN content was recorded from vermicompost made from grasses and haricot bean substrates respectively. The highest value of available P and K was also registered from vermicompost prepared from all materials. Even if the values of recorded exchangeable Ca, Mg, K and extractable micro nutrients were different, the vermicompost obtained from all substrates were rich in exchangeable cations and micro nutrients. Therefore, the nutrient content of vermicompost prepared from all substrates showed the highest values for all macro and 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.