Physical and chemical properties of the biochar varied as a function of feedstock selection and pyrolysis temperatures. Biochar additions to acidic soils have the potential to improve soil fertility and crop yield. Biochar materials were produced from coffee husk and corn cob at temperatures of 350 and 500°C and characterized by their physical and chemical properties. These were mixed with acidic soil at the rates of 0, 5, 10 and 15 t haG 1 and were laboratory incubated for 2 months at ambient temperature to examine changes in soil properties. Types of feedstock used at two different pyrolysis temperatures and application rate had no significant effects on soil textural classes but showed highly significant effects (p<0.01) on soil pH, Electrical Conductivity (EC), Cation Exchange Capacity (CEC), Organic Carbon (OC), Organic Matter (OM), Total Nitrogen (TN), exchangeable cations and available phosphorous. Application of coffee husk biochar showed relatively better improvement in soil chemical properties (pH, EC, CEC, OC, OM, TN, exchangeable cations and available phosphorous) than corn cob biochar at all application rates. The highest values of chemical properties were recorded when coffee husk biochar produced at 500°C temperature was applied at a rate of 15 t haG 1 . Therefore, we generated an evidence that application of biochar is very important to improve physical and chemical properties of acidic soil.

No abstract

No abstract

A B S T R A C T Field experiment was conducted to identify the most promising and adaptable sweet potato (Ipomoea batatas L.) variety. Five Orange Fleshed Sweet Potato (OFSP) varieties: variety Beletech (192026 II), Birtukanie (Saluboro), Kulfo (Lo-323), Tulla (CIP 420027) and one local variety were used as experimental treatments and arranged in randomized block design with three replications. Data collected on growth parameters were analyzed using the GLM procedure of SAS Version 9.2. Variety had highly significantly affected the growth parameters; number of branches per plant, number of leaves per plant and vine length and also significantly affected fresh weight and dry matter content of sweet potato roots. For the majority of growth parameters variety, Tulla was preferably the best variety compared to the other three improved OFSP varieties as, well as the local variety and significantly the highest number of branches per plant (41.41), vine length (99 cm), fresh weight (1.56 kg) and dry matter content (54.40%) were recorded from variety Tulla. The result of the correlation analysis also indicated that fresh weight and dry matter content of sweet potato roots were negatively and significantly correlated with number of branches per plant. This indicated that sweet potato producers targeting above ground biomass production should use number of branches and leaves per plant as selection criteria, where as those targeting sweet potato root tubers production, should use the fresh weight and dry matter content of sweep potato roots as selection criteria. Likewise, these growth parameters are important factors for selection of sweet potato and can serve as indicators of adaptability of the crop to the growing conditions of the study area. Therefore, OFSP variety Tulla (CIP 420027) can be used as the most promising and adaptable variety for optimum growth and productivity at the study area, Jimma in the Southwestern part of Ethiopia and combat VAD at community level.

No abstract