Purdue improved crop storage bag for kocho fermentation; Ethiopian traditional fermented food from Enset (Ensete ventricosum).

Enset (Ensete ventricosm) is a multipurpose crop serving millions of Ethiopians as an alternative food source. However, the traditional kocho preparation is labor-intensive and results in poor quality. This study evaluated Purdue improved crop storage (PICS) bag as an alternative to an underground pit for kocho fermentation. The experiment was arranged in a factorial design with two fermentation systems (underground pit and PICS bag) and three fermentation times (30, 45 & 60 days) with 5 replications. Physico-chemical, proximate composition, microbial, and sensory evaluations of kocho were conducted following standard procedures. The results have revealed that protein and moisture contents were increased with fermentation time while crude fiber, carbohydrate, and total energy were decreased regardless of fermentation systems. The microbial results have demonstrated a reduction with extended fermentation but no significant difference between PICS and the underground pit. The sensory results have shown that PICS bag-fermented kocho has better overall sensory acceptability regardless of fermentation time. Generally, PICS bag-fermented kocho for 60 days has shown overall better kocho quality. The finding revealed that PICS bags could be used as an alternative to the traditional underground pit for better kocho quality. Further validation of the PICS bag as a fermentation container with various enset varieties and seasons with extended fermentation time is needed.

Nitrous oxide and methane emissions from coffee agroforestry systems with different intensities of canopy closure.

Agroforestry-based coffee production systems (AFs) contribute to climate change mitigation through carbon sequestration. However, it is unclear whether AFs produce lower nitrous oxide (N2O) and methane (CH4) emissions than the open-shade coffee production system. In addition, little to no evidence is available to explain the relationship between canopy cover levels and greenhouse gas (GHG) emissions in AFs. The aim of this study was to investigate N2O, CH4 and yield-scaled emissions in AFs with differing shade-tree canopy levels. Three canopy cover levels were identified: (i) dense shade (80 % canopy closure), (ii) medium shade (49 % canopy closure), and (iii) open-shade (full sun) production. To determine the effect of canopy cover on GHG emissions under varying soil fertility management practices, three soil fertilization strategies were included: (i) mineral fertilizer, (ii) compost, and (iii) control (i.e., without soil amendment). The results showed that N2O emissions were two-to-three times greater when there was dense canopy cover than from open-shade production. The effect of canopy cover on N2O emission was more pronounced under the mineral fertilizer treatment. CH4 emissions were 44-64 % greater under the open-shade production system than under AFs. The yield-scaled global warming potential of 1 kg of fresh coffee cherries was 0.72 kg CO2eq for open-shade production, 0.58 kg CO2eq for medium canopy cover and 0.52 kg CO2eq for dense canopy cover. This study provides the first evidence of the importance of considering canopy cover intensity when determining the spatial-temporal variations in GHG emissions from agroforestry systems.

Effect of microbial inoculation on nutrient turnover and lignocellulose degradation during composting: A meta-analysis.

Although microbial inoculants are promoted as a strategy for improving compost quality, there is no consensus in the published literature about their efficacy. A quantitative meta-analysis was performed to estimate the overall effect size of microbial inoculants on nutrient content, humification and lignocellulosic degradation. A meta-regression and moderator analyses were conducted to elucidate abiotic and biotic factors controlling the efficacy of microbial inoculants. These analyses demonstrated the beneficial effects of microbial inoculants on total nitrogen (+30%), total phosphorus (+46%), compost maturity index (C:N ratio (-31%), humification (+60%) and the germination index (+28%). The mean effect size was -46%, -65% and -40% for cellulose, hemicellulose, and lignin respectively. However, the effect size was marginal for bioavailable nutrient concentrations of phosphate, nitrate, and ammonium. The effectiveness of microbial inoculants depends on inoculant form, inoculation time, composting method, and experimental duration. The microbial inoculant effect size was consistent under different feedstock types and experimental scales. These findings imply that microbial inoculants are important for accelerating lignocellulose degradation. Higher mean effect sizes have tended to be published in journals with higher impact factors, thus researchers should be encouraged to publish non-significant findings in order to provide a more reliable estimation of effect size and clarify doubts about the benefits of microbial inoculants for composting.