Participatory Rural Appraisal for Diagnostic Analysis of spate irrigation systems in Raya Valley, Ethiopia

Spate irrigation is a complex and unique form of water management, which represent the main source of irrigation water in semi-arid river catchments. Water is diverted from seasonal rivers by using diversion structures made by stones, earth and brushwood, located within the river bed. The modernisation of spate irrigation realised in Raya Valley (northern Ethiopia) resulted in disappointing performances. One of the main reasons for this failure was the poor consideration of the characteristics of seasonal catchments and local communities’ needs and preferences. Local farmers, who showed a deep knowledge of the river system, were involved only at the level of consultation. The aim of this research was to develop a participatory Diagnostic Analysis (DA) for a traditional non-modernised spate irrigation system in Raya Valley, in order to involve local farmers within the development process, and to build a solid knowledge basis for effective improvements. A Participatory Rural Appraisal (PRA) of the Harosha spate irrigation system was undertaken. PRA techniques focusing on spatial, temporal, socio-economical and spatiotemporal aspects of the system were performed with local farmers in order to identify and rank main problems and constraints to development. Farmers recognised the need of more resistant diversion structures and gabion walls for the stabilisation of the river bank. The involvement of farmers also helped to highlight that not only irrigation-related problems, but also flood-related problems threaten agricultural production and rural livelihoods. Rather than an irrigation system approach, an approach integrating irrigation development and flood risk mitigation is suggested for framing future development strategies

Terraced Landscapes and Hydrological-Geological Hazards: Innovative Approaches and Future Perspectives

In the last few years, terraced landscapes have been receiving renovated interest all over the world (e [...

Spatial Variability of Soil Moisture in Newly Implemented Agricultural Bench Terraces in the Ethiopian Plateau

In arid areas prone to desertification and soil erosion, the effectiveness of radical bench terracing in reducing drought risk is dependent on its correct implementation. However, the relationship between proper terracing implementation and the landscape capacity of holding soil moisture is still not understood. Moreover, spatial patterns of Soil Water Content (SWC) within the same terraced hillslope are weakly studied. The present paper analyses SWC variations in four newly implemented terraced sites in Tigray Region, Ethiopia. In all sites, terraced areas show SWC significantly higher than non-terraced ones, with the lower part of the terraced hillslope more humid than the others. A Multiple Linear Regression (MLR) analysis highlighted significant dependency of SWC from the date of analysis, the position in the terraced slope, and its significant positive correlation with the percent of Water Stable Aggregates (WSA) analyzed at the study sites. Since high soil disturbance induces low soil aggregates stability, this result shows how low soil disturbance can significantly increase SWC of radical terraces. Overall, the results of the present paper testify the good performances of bench terraces in Northern Ethiopia in terms of soil water conservation, and can represent a benchmark study informing future terracing implementation in some arid and semi-arid agricultural areas of the world

The Genome Sequence of "Candidatus Fokinia solitaria": Insights on Reductive Evolution in Rickettsiales

"Candidatus Fokinia solitaria" is an obligate intracellular endosymbiont of a unicellular eukaryote, a ciliate of the genus Paramecium. Here, we present the genome sequence of this bacterium and subsequent analysis. Phylogenomic analysis confirmed the previously reported positioning of the symbiont within the "Candidatus Midichloriaceae" family (order Rickettsiales), as well as its high sequence divergence from other members of the family, indicative of fast sequence evolution. Consistently with this high evolutionary rate, a comparative genomic analysis revealed that the genome of this symbiont is the smallest of the Rickettsiales to date. The reduced genome does not present flagellar genes, nor the pathway for the biosynthesis of lipopolysaccharides (present in all the other so far sequenced members of the family "Candidatus Midichloriaceae") or genes for the Krebs cycle (present, although not always complete, in Rickettsiales). These results indicate an evolutionary trend toward a stronger dependence on the host, in comparison with other members of the family. Two alternative scenarios are compatible with our results; "Candidatus Fokinia solitaria" could be either a recently evolved, vertically transmitted mutualist, or a parasite with a high host-specificity