国際廃棄物資源ジャーナル

概要

Evaluating Methods of Composting on Date of Maturity and Quality of Compost in Assosa, Western Ethiopia

Biruk Teshome and Jabir Amza

Organic matter addition to degraded soils is one best option in reclaiming soil productivity; and in relation to this the habit of preparing organic fertilizers (composting) using the best available method, which could simplify preparation and conserve the quality of compost is necessary. Therefore this study was conducted with the objective of evaluating different methods of composting in terms of date of compost maturity and selected chemical and physical property of the compost. The treatments were rotating bin, turned heap, turned pit, bamboo layered heap and non-turned pit methods, which were replicated three times using a complete randomized design. The analysis of variance showed, there was significant (p<0.01) difference among methods in the date of maturity, organic carbon, total nitrogen, exchangeable calcium (Ca), exchangeable potassium (K) and dry bulk density. The rotating bin method showed relatively shorter period of compost maturity date (37.67 days), followed by turned pit (62.33) and turned heap (62.67 days) methods. The methods showed no significant difference in compost temperature, while showing the highest mean temperature (52.40°C) on the fourth day for all the methods. The pH (7.13), organic carbon (32.67%) and total nitrogen (2.8%) of rotating bin compost were significantly higher than all the methods, followed by bamboo layered method. The amount of Ca and potassium K were also highest for the rotating bin composting, but with the least dry bulk density. Generally, frequent turning of compost as in the case of rotating bin facilitated suitable temperature (mesophilic) for longer period until the curing phase, while reducing the loss of carbon (CO2) and nitrogen (NH3+) through reducing anaerobic decomposition, it also conserved leaching of nutrients (Ca+2, K+) and reduced the date of maturity with a least cost of preparation.