Soil metal pollution as a function of traffic density and distance from road in emerging cities: a case study of Abeokuta,southwestern Nigeria

The distribution of Zn, Cu, Cd, Cr, Pb, Ni, and Mn in the soil, and related soil properties was studied in Abeokuta, southwestern Nigeria. Their soil pollution source was hypothesized to be automobile traffic. Consequently, their variations were assessed as a function of traffic density, distance from road and traffic, and soil depth. Soil samples were collected from the areas of high, medium, and low traffic densities at 0, 50, 100, 150, and 200 m from roadside; at depths 0–20, 20–40, 40–60, 60–80, and 80–100 cm. The potential effects of these metals on environment and agricultural activities were also assessed. Results indicated that the major sources for the metals’ contamination are emissions from vehicles. High and medium traffic volume impacted more metals of the soils. Zinc, Cu, Cd, and Cr were concentrated at depths 0–40 cm, Pb, Ni, and Mn were concentrated at 0–20 cm and appeared bound to soil organic matter (SOM). Significantly lower concentrations of metals are found at distances of 100 m and beyond. Concentrations of these metals are generally low compared with standards and their uptake by crops is not probable. However, their continuous accumulation might be a threat in the future.     

Biodiversity in Ethiopian linseed (<Emphasis Type="Italic">Linum usitatissimum</Emphasis> L.): molecular characterization of landraces and some wild species

Molecular characterization of germplasm is important for sustainable exploitation of crops. DNA diversity was measured using inter-retrotransposon-amplified-polymorphism and inter-simple-sequence-repeat markers in 203 Ethiopian landraces and reference varieties of linseed (flax, Linum usitatissimum) and wild Linum species. Molecular diversity was high (PIC, 0.16; GD, 0.19) compared to other reports from the species. Genotyping separated reference from landrace accessions, and clustered landrace accessions from different altitudes and geographical regions. Collections showed evidence for recent introduction of varieties in some regions. The phylogeny supported L. bienne Mill. as the progenitor of domesticated L. usitatissimum. Markers developed here will be useful for genetic mapping and selection of breeding lines. The results show the range of characters that can be exploited in breeding lines appropriate for smallholder and commercial farmers in Ethiopia, producing a sustainable, secure, high-value crop meeting agricultural, economic and cultural needs.     

Potential of indigenous multistrata agroforests for maintaining native floristic diversity in the south-eastern Rift Valley escarpment, Ethiopia

Most studies undertaken in the field of agroforestry have focussed on system design, soil fertility management, and system interactions. Less emphasis has been placed on biodiversity aspects. The aim of this study is to investigate the potential of indigenous, multistrata agroforests for maintaining native woody species diversity in the south-eastern Rift Valley escarpment, Ethiopia. A total of 60 farms, representing three agroforest types (enset-AF, enset-coffee-AF and fruit-coffee-AF), were randomly selected along altitudinal gradients. Enset (Ensete ventricosum) is a perennial, herbaceous monocarpic banana-like plant which serves as a food plant in Ethiopia. The three agroforests are results of the domestication of natural forests and intensification of the landuse systems centuries ago. Sample-based assessment protocols were employed to place sample quadrats and to measure all individuals in the quadrats. A total of 58 woody species, belonging to 49 genera and 30 families, was recorded. Of all woody species identified, 86% were native. The highest proportion of native woody species was recorded in enset-AF (92%), followed by enset-coffee-AF (89%) and fruit-coffee-AF (82%). Among native tree species, Millettia ferruginea and Cordia africana were the most widespread. In all, 22 native woody species were recorded as of interest for conservation, acccording to IUCN Red lists and local criteria. Among them, Pygeum africanum and Rhus glutinosa were categorised as vulnerable in the wild, and in need of conservation priority. The introduction of non-native fruit trees in agroforests can be a threat to maintenance of native woody species. Management strategies favoring enset and coffee will also put other native tree species at risk. A smaller number of native woody species was recorded in fruit-coffee-AF, but a higher mean basal area and stem number. The mean basal area and stem number ranged from 5.4?±?0.5 to 11.7?±?1.0?m^2?ha^?1 and 625?±?84 to 1,505?±?142 stems?ha^?1, respectively. Altitude explained 68 and 71% of the variation in species richness and abundance, respectively. Finally, it is concluded that recognition of the indigenous agroforestry system as an option for maintaining native woody species should be given more attention, to counteract the local threat of these species from the wild.     

Major causes of mastitis and associated risk factors in smallholder dairy farms in and around Hawassa, Southern Ethiopia

A cross-sectional study was carried out from October 2008 to May 2009 in smallholder dairy farms in and around Hawassa to estimate the prevalence of mastitis, to isolate and characterize major bacterial pathogens, and to identify possible associated factors. The study involved a total of 201 milking cows randomly drawn from smallholder farms. The prevalence of clinical and subclinical mastitis was determined through clinical examination of the udder and using mastitis indicator paper (Bovivet indicator paper, Kruuse, Denmark). The prevalence of mastitis at cow and quarter level was 30.3 (61/201) and 10.3 (79/766), respectively. Subclinical mastitis was 25.4% and 5.0% was clinical. Stage of lactation significantly affected (P < 0.05) the prevalence of mastitis, with the highest prevalence observed in the late stage of lactation (41.3%) as compared to early (25.0%) and mid (22.1%) stages of lactation. Floor type and bedding had association (P < 0.05) with mastitis prevalence. Cows housed in concrete-floored houses had lower prevalence (19.0%) of mastitis compared to cows kept in soil-floored houses (47.6%). Mastitis prevalence was low in farms which do not use bedding (23.5%) as compared to farms using hay/straw bedding (37.4%). However, age, parity, and history of mastitis had no association (P > 0.05) on the prevalence of mastitis. The pathogens isolated from mastitic cows were Staphylococcus aureus (48.6%), other staphylococci species (15.7%), Streptococcus agalactiae (11.4%), other streptococci (17.1%), Bacillus species (2.9%), and coliforms (Escherichia coli and Klebsiella species) (4.3%). Strict hygienic measure of housing and bedding should be considered, in reducing the prevalence of mastitis.     

Rapid seed-based propagation method for the threatened African cherry (Prunus africana)

Studies on the germination characteristics of various seed groups, extent of seedling and wildling establishment, as well as measurements on early seedling growth, were conducted on Prunus africana (Hook. f.) Kalkm. (syn. Pygeum africanum Hook. f.) (Rosaceae). Germination of seeds gathered en masse (together with soil and litter) from beneath Prunus trees was significantly greater (P < 0.01) compared to those collected in pure form from the ground (with or without fruit flesh) or those picked from the trees. Treating seeds with 10 or 100 µmol gibberellic acid (GA₃) showed better germination than the control, but the difference was not statistically significant. Gibberellic acid at 1000 µmol (10^–3 M) inhibited germination significantly (P = 0.02). Seedlings survived better in the glasshouse (90%) than in the nursery (87%). Whereas 60% of the 280 wildlings between 2.5 and 4.0 cm successfully established, only 10% of the 220 wildlings between 8.0 and 13.0 cm survived 3 mo after these had been maintained in the glasshouse. Seedlings derived from the GA₃-treated seeds showed higher initial growth than the control owing to rapid hypocotyl elongation. Transferring seedlings to larger pots enhanced growth significantly after a lag period of about two weeks. Seedlings maintained in the glasshouse grew better than those in the nursery (P < 0.01). The study found that germination of seeds/fruits (gathered en masse from beneath trees) on a seedbed is convenient, technically less demanding, and is cost-effective.     

Contribution of participatory forest management towards conservation and rehabilitation of dry Afromontane forests and its implications for carbon management in the tropical Southeastern Highlands of Ethiopia

Participatory forest management (PFM) has been applied as an approach to create a framework for collaborative forest management between local communities and government forestry agencies. This study was designed to assess the contribution of PFM approach in improving forest status in the Southeastern Highlands of Ethiopia. Landsat satellite imageries of four years were used to evaluate the trends and rate of deforestation before and after PFM interventions. Socio-economic data were collected from sample household surveys, key participants, focus group discussions, and field observations. The results showed that there was high rate of deforestation before PFM intervention as forestland has decreased by 19% (2531 ha) between 1990 and 2000. However, after the PFM intervention (2000–2016), the forest cover has increased by 247 ha (2.2%). During this period, net 1016 ha of shrub-lands were converted into forestland owing to significant forest regeneration. In addition, most sampled households (94% and 96% from lower and upper altitudes, respectively) perceived that PFM had significantly contributed to improve forest regeneration in their locality. This study revealed that PFM can serve as a stepping stone for carbon financing mechanisms to reduce greenhouses emission and enhance carbon sinks via forest resources.     

Cultivated emmer wheat (Triticum dicoccon Schrank), an old crop with promising future: a review

Cultivated emmer wheat, Triticum dicoccon Schrank, a tetraploid species with hulled grain, has been largely cultivated during seven millennia in the Middle-East, Central and West Asia, and Europe. It has been largely replaced by hulless species and is now a minor crop, with the exception of some countries like India, Ethiopia and Yemen, where its grain is used for preparing traditional foods. Nutritional qualities and specific taste and flavor of emmer wheat products have led to a recent development of the cultivation in some European countries. Emmer wheat also possesses valuable traits of resistance to pests and diseases and tolerance to abiotic stresses and is increasingly used as a reservoir of useful genes in wheat breeding. In the present article, a review concerning taxonomy, diversity and history of cultivation of emmer wheat is reported. Grain characteristics and valuable agronomic traits are described. Some successful examples of emmer wheat utilization for the development of durum or bread wheat cultivars are examined, and the perspectives in using emmer wheat as health food and for the development of new breeding germplasm are discussed.     

Rural innovation systems and networks: findings from a study of Ethiopian smallholders

Ethiopian agriculture is changing as new actors, relationships, and policies influence the ways in which small-scale, resource-poor farmers access and use information and knowledge in their agricultural production decisions. Although these changes suggest new opportunities for smallholders, too little is known about how changes will ultimately improve the wellbeing of smallholders in Ethiopia. Thus, we examine whether these changes are improving the ability of smallholders to innovate and thus improve their own welfare. In doing so, we analyze interactions between smallholders and other actors to provide new perspectives on the role played by smallholder innovation networks in the agricultural sector by drawing on data from community case studies conducted in 10 localities. Findings suggest that public extension and administration exert a strong influence over smallholder networks, potentially crowding out market-based and civil society actors, and thus limiting beneficial innovation processes. From a policy perspective, the findings suggest the need to further explore policies and programs that create more space for market and civil society to participate in smallholder innovation networks and improve welfare. From a conceptual and methodological perspective, our findings suggest the need to incorporate rigorous applications of social network analysis into the application of innovation systems theory.     

Survey of ixodid ticks in domestic ruminants in Bedelle district,Southwestern Ethiopia

A survey aimed at determining the status of ticks in cattle, sheep and goats in Bedelle district (Southwestern Ethiopia) was carried out from November 2007 to April 2008. Out of the total 330 animals examined, 314 (95.2%) were found to be infested (harbouring of at least a single tick). High rates of infestations were recorded across all three host species. Factors like month of collection, age and sex of host species did not show significant association with infestation rates. A total of 5,507 ticks belonging to three genera (i.e. Amblyomma, Boophilus and Rhipicephalus) were collected during the study period of which six species were identified. The species of ticks encountered comprise of Amblyomma cohaerens (44.1%), Amblyomma variegatum (13.8%), Amblyomma lepidum (1.2%), Boophilus decoloratus (24.9%), Rhipicephalus evertsi evertsi (14.3%) and Rhipicephalus lunulatus (1.7%). As about 86.7% (4,772) of the ticks were collected from cattle, it was recognised that this could be an evidence of host preference where cattle are serving as principal host while sheep and goats serve as alternative hosts. The role of ecological factors and little attention paid by livestock owners for treatment of animals against ticks are suggested to result in the abundance of ticks. Acaricide spraying should be strategically applied to control ticks. Better result could be achieved if an emphasis is being put on spraying cattle. Studies on tick-borne diseases, involvement of wildlife species as well as related factors are recommended as they may provide a valuable basis for designing and launching an all-round control programme in the country.