Faculty of Natural Resources

Methane emissions from ruminant livestock in Ethiopia: Promising forage species to reduce CH4 emissions

Tue, 01 Jan 2019 00:00:00 GMT

Methane emissions from ruminant livestock in Ethiopia: Promising forage species to reduce CH4 emissions Berhanu, Yonas; Olav, Lars; Nurfeta, Ajebu; Angassa, Ayana; Aune, Jens B. This paper assesses the ability of fodder plants to reduce methane (CH4) emissions while simultaneously improving animal productivity in Ethiopia. Enteric CH4 emissions from ruminants in Ethiopia increased by 12% or 6197 Gg CO2-eq. in 2017 compared to the year 2011. In this study, six tropical multipurpose forages (Leucaena leucocephala (Lam.) de Wit, Moringa stenopetala (Bak.f.) Cuf., Sesbania sesban (L.) Merr., Cajanus cajan (L.) Millsp., Crotalaria juncea L., and Lablab purpureus L.(Sweet)) and maize stover were characterized in terms of chemical composition, in vitro CH4 production, and CH4 concentration (%). The objective was to identify forages with low CH4 production potential but with adequate forage quality. The forages differed significantly in chemical composition and in enteric CH4 emission. The dry matter (DM), ash, crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), and acid detergent lignin (ADL) ranged between 89.4-95.4%, 6.08-12.5%, 3.3-30.7%, 20.4-76.0%, 10.8-44.8, and 2.9-14.1%, respectively. All forage plants, except maize stover, contained high CP content above a threshold value (i.e., 7%). Cajanus c. generates the lowest amount of CH4 (32.83 mL/0.2 g DM incubated). CH4 concentration (%) was used as a potential indicator to determine the capacity of a plant to lower CH4 production. Among the studied species, L. purpureus showed the highest CH4 reduction potential (16%) followed by C. juncea (23.45%), M. stenopetala (24.2%), and L. leucocephala (25.5%). Moringa s. was the most frequently preferred by the farmers followed by C. juncea and L. leucocephala. We concluded that M. stenopetala, C. juncea, and L. leucocephala can be promoted as valuable feed resources for ruminants while simultaneously reducing CH4 emissions. © 2019 by the authors. Journal article

Effects of grazing intensity to water source on grassland condition, yield and nutritional content of selected grass species in Northwest Ethiopia

Tue, 01 Jan 2019 00:00:00 GMT

Effects of grazing intensity to water source on grassland condition, yield and nutritional content of selected grass species in Northwest Ethiopia Melak, Yaregal; Angassa, Ayana; Abebe, Aster Background: Savanna grasslands are globally important ecosystems consisting of one of the most extensive grazing lands with unique biodiversity. The objectives of the study were to assess the effect of grazing intensity on grassland ecosystem condition, herbaceous plant biomass production, and nutritional content of selected grass species. Methods: The study was conducted at Chagni Ranch, Northwest Ethiopia. Four transects to water source point at regular intervals of 20 m between sampling plots along transects were used for data collection. The distance between the four transects was 200 m in radius. Data were collected on grass composition, basal cover, litter cover, number of seedlings, and age distribution of dominant grasses (i.e., young, medium, or old in terms of stage of maturity), soil condition in terms of soil compaction, and soil erosion linked to the effects of trampling by grazing animals along transects (hereafter referred to as transect) to water source point. The total sample size for grass species was 160 plots. The grassland ecosystem condition, herbaceous biomass, and grass nutritional content were used as response variables linked to transect from water source point. The effects of transect on grassland ecosystem condition scores and grass nutritional content were analyzed using the analysis of variance (ANOVA). Results: Grassland condition factors like grass composition, basal cover, litter cover, age distribution of dominant grasses, and soil condition were significantly (P < 0.05) higher for the furthest transect to water source point than nearest transect. Out of the 28 identified herbaceous species, grasses accounted for 64.3% of the herbaceous community. Within grass species, about 55.6% were highly desirable in terms of palatability and grazing value (as most palatable species are susceptible to heavy grazing intensity). The results showed a significantly (P < 0.05) higher proportion of perennial grasses at the furthest transect to water source point than nearest transect. The dry matter yield at the furthest transect (TD4) and third transect (TD3) were significantly (P < 0.05) higher than the nearest transect to water source point (i.e., the first transect (TD1) and second transect (TD2)). Ash, neutral detergent fiber, acid detergent fiber, and acid detergent lignin contents of Cynodon dactylon, Sporobolus pyramidalis, and Digitaria ternata were significantly (P < 0.05) higher at the furthest transect to water source point than nearest transect. Grazing intensity had no significant effect on the crude protein content of Cynodon dactylon and Sporobolus pyramidalis at different transects. Conclusions: The results showed that the furthest transect to water source point were in good condition. Grass biomass production and the nutritional contents of grasses were higher for the furthest transect to water source point. The results suggested that increased grazing intensity towards water source point greatly reduced the abundance of desirable perennial grasses and the sustainability of grassland for livestock production. Journal article

Do herbaceous species functional groups have a uniform pattern along an elevation gradient? The case of a semi-arid savanna grasslands in Southern Ethiopia

Wed, 01 Jan 2020 00:00:00 GMT

Do herbaceous species functional groups have a uniform pattern along an elevation gradient? The case of a semi-arid savanna grasslands in Southern Ethiopia Bora, Zinabu; Xu, Xinwen; Angassa, Ayana; Wang, Yongdong; Zhao, Yongcheng Knowledge of the total (overall) and individual herbaceous vegetation species relating to a distinctive site might help in the development of management strategies for a large number of threatened herbaceous species. This paper assesses the total and functional group herbaceous biomass, species richness, evenness, and diversity at four elevation classes in Borana rangelands of arid thorn bush savanna grasslands in Southern Ethiopia. At each elevation class, a grid of 20 20 m main plot was placed, and individual herbaceous species samples were collected randomly from five 1 m2 quadrants within the main plot. Using a single-factor analysis of variance (ANOVA), the effects of four elevation classes were considered on whole-vegetation, grasses, graminoid, and forb species diversity, evenness, richness, and biomass. A total of 49 herbaceous species were recorded. Of the total identified herbaceous species, three grass species and two graminoid species were found across all studied elevation classes, but the forb species did not overlap along the studied elevation classes. The total richness, diversity, and evenness of herbaceous species were considerable and significant along elevation classes. The grass, graminoid, and forb species richness, diversity, and evenness responded differently, and the functional group of species may be a good indicator of the community processes of grassland across elevation classes. The contribution of forb richness to the total richness was more pronounced than grass and graminoid, which indicates the shift of savanna grassland to grazing tolerant herbaceous species. The results suggest that the pooled data analysis of herbaceous vegetation community structure and biomass could obscure complicate trends of the functional group at elevation classes and for managing herbaceous species in savanna grasslands, the management models should focus on the functional group species composition, community structure, and biomass. Journal Artcile

The contribution of frankincense to the agro-pastoral household economy and its potential for commercialization - A case from Borana, southern Ethiopia

Fri, 01 Jan 2021 00:00:00 GMT

The contribution of frankincense to the agro-pastoral household economy and its potential for commercialization - A case from Borana, southern Ethiopia Berhanu, Yonas; Vedeld, Pål; Angassa, Ayana; Aune, Jens B. Frankincense, gum arabic and myrrh are among the most valuable commercial non-timber forest products in the drylands of eastern Africa. This study examines the frankincense value chain and its contribution to the household economy in southern Ethiopia. The study applied a combination of sustainable livelihood and value chain framework to assess the values and the contribution of frankincense to household economies. Data were collected through a household survey, focus group discussions, key informant interviews and field observations. On average, the annual cash income generated from the harvest and sale of frankincense was estimated at 60 USD per adult equivalent unit (AEU) which was 35% of the total household annual cash income. Our analyses reveal that income from frankincense constitutes the second largest share of the total average household cash income after livestock, which accounted for 60%. The poorer households (44% of the sample) have a relatively higher reliance on frankincense income (49.8%), which is almost as much as the contribution from livestock and non-farm income combined (50.2%). Frankincense income functions as a supplementary source of income for the herders. The value chain analysis shows that the price increases from nearly 1 USD per kg at harvest sites to 5.5 USD per kg at the retail level. Nevertheless, despite the abundance of the resource and a growing domestic market demand, the marketed quantities are low, extraction practices are primitive and both local and national markets are poorly developed. Recommendations for researchers and development practitioners include improving harvesting and processing skills through training, introducing harvesting and post-harvest technologies, improving market access, providing credit services, and training to gatherers and local traders on value-adding activities and marketing skills. These measures could improve the economic returns from frankincense extraction and sale and contribute to increased incomes and more sustainable livelihoods. Journal article