SUSTAINABLE MANAGEMENT OF PRIVATE AND COMMUNAL LANDS IN NORTHERN ETHIOPIA

Land degradation in sub-Saharan Africa reduces the land's potential productivity through soil erosion, nutrient depletion, soil moisture stress, deforestation and overgrazing. Efforts to reverse land degradation require an understanding of why it takes place and what factors govern farmers' willingness to invest in land conservation. These factors differ importantly between private and public lands. This study synthesizes results from analyses of the technological and institutional factors determining the adoption of natural resource conservation at both the household and the community levels in the northern Ethiopian region of Tigray. Using 1995-96 data from 250 Tigray farm household interviews, it first examines private land management, focusing on 1) What factors determine farmer perceptions of the severity and yield impact of soil erosion? 2) Is soil conservation profitable, and if so, then under what conditions? 3) What determines farmers' illingness to invest in soil conservation? Using 1998-99 data from a survey of 100 Tigray villages, it proceeds to examine the management of communal lands (grazing lands and woodlots), focusing on 4) What makes communities engage in collective NRM activities? 5) What determines the ffectiveness of collective NRM? At the household level, results highlight the importance of (1) the physical characteristics of plots and villages in shaping farmer perceptions, (2) the land tenure horizon and access to capital in determining willingness to invest in soil conservation. At the community level, they highlight the importance of population density, agricultural potential, as well as access to markets and external rganizations in determining community collective action and its effectiveness in establishing and managing protected grazing areas and woodlots.Land Economics/Use,

RECONCILING FOOD-FOR-WORK OBJECTIVES: RESOURCE CONSERVATION VS. FOOD AID TARGETING IN TIGRAY, ETHIOPIA

Food-for-work (FFW) projects face the challenge of addressing three kinds of objectives: to feed hungry people, to build public works where needed, and to be feasible for prompt project implementation. In the debate over how to target FFW to the poorest of the poor, the last two program objectives are often overlooked. This research examines FFW afforestation and erosion-control programs in central Tigray, Ethiopia, during 1992-95 in order to examine how these sometimes conflicting objectives were reconciled. The study decomposes the factors determining a household's FFW participation into three decision stages. First, at the regional level, project planners choose where to locate a FFW resource conservation project. Second, at the village level, a committee decides which villagers will be eligible to participate. Finally, the eligible households may decide whether and how much to participate. Using probit and truncated regression methods, the study finds that project implementation feasibility most influenced the probability that FFW projects would be available in the 25 villages surveyed. Among the 129 households in villages with FFW available, FFW eligibility was inversely related to household land area per capita and household size, results which are consistent with anti-poverty targeting. However, the model performed poorly at predicting non-eligibility for FFW, which suggests that anti-poverty targeting was not efficient. Among households eligible for FFW, those with greater resources (larger families that did not lease out land) tended to participate and supply more days of FFW labor than poorer households. The only households eligible for FFW which did not participate were unable (rather than unwilling) to do so, being comprised mostly of elderly women. Overall, anti-poverty targeting was sub-optimal but reasonable, given the feasibility constraint that these resource conservation projects to be sited in where labor and materials could be made available.Food Consumption/Nutrition/Food Safety,

INVESTMENT IN SOIL CONSERVATION IN NORTHERN ETHIOPIA: THE ROLE OF LAND TENURE SECURITY AND PUBLIC PROGRAMS

Soil erosion seriously threatens the future agricultural productivity of Ethiopia's highlands. In analyzing the determinants of soil conservation investments there, this study goes beyond the conventional physical factors to examine institutional, social capital and public program effects. The double hurdle statistical analysis from 250 farms in the Tigray region reveals different causal factors for soil conservation adoption versus intensity of use. The determinants of adoption of soil conservation measures vary sharply between stone terraces and soil bunds. Physical propensity toward erosion (e.g., slope, slope shape and soil texture) and land suitability for conservation helped determine conservation investments in all cases. But institutional and social determinants of investment differed importantly between bunds and terraces. Long-term investments in stone terraces were associated with secure land tenure, labor availability, proximity to the farmstead, and learning opportunities via the availability of food-for-work projects. By contrast, short-term investments in soil bunds were strongly linked to insecure land tenure and the absence of food-for-work projects. Farm beneficiaries of public soil conservation programs were less likely to invest privately in either type of conservation practice. Social capital, as measured by farmer perception of community pressure to curb soil erosion, did not contribute significantly to either kind of conservation investment. The intensity of stone terrace adoption (measured as meters of terrace per hectare) was determined by expected returns but not by capacity to invest. Higher intensity of stone terrace construction was favored by fertile-but-erodible silty soils in (rainy) highland settings that offered valuable yield benefits from soil conservation. Intensity of terracing was also greater in remote villages where limited off-farm employment opportunities made construction costs relatively low. Previous research has highlighted the need for public policy interventions to supplement private incentives to make soil conservation investments in erosion-prone mountain areas. Our results highlight the importance of the right kind of public interventions. Direct public involvement in constructing soil conservation structures on private lands appears to undermine incentives for private conservation investments. When done on public lands, however, public conservation activities may encourage private soil conservation by example. Secure land tenure rights clearly reinforce private incentives to make long-term investments in soil conservation.Land Economics/Use,

Weathering of the Ethiopian volcanic province: a new weathering index to characterize and compare soils

© Walter de Gruyter Berlin/Boston 2015.Soil formation occurs through numerous physical and chemical weathering processes acting to alter the parent rock on the Earths surface. Samples of surface soils were collected over a range of elevations (2000-3600 m) from profiles directly overlying basaltic to more felsic parent rocks, over a region in NW Ethiopia. The soils were investigated to determine their chemical composition and X-ray diffraction was used to identify and quantify individual mineral phases. The data set was analyzed using non-parametric statistics (Spearmans Rank and Mann-Whitney U tests) to compare the soils forming over the two parent rocks. Principal component analysis (PCA) was used to identify the mineral alteration assemblage and formation during pedogenesis. The extent of alteration was quantified using several chemical weathering indices (Chemical Index of Alteration = CIA; Chemical Index of Weathering = CIW), including an index calculated by multivariate analyses of the soil chemical composition data (weathering W index). Further to this we devised and tested a new weathering index (Wmin) using multivariate analysis of the soil mineralogy, to estimate the extent of weathering and physico-chemical proprieties of the parent rock from which the soil formed. The soils present a fair to advanced stage of alteration, with abundant iron (Fe) oxides (up to 40 wt%) and phyllosilicates (up to 57 wt%), including kaolinite-smectite (K-S) mixed-layer phases. The K-S was composed of either 30-50% kaolinite or 94-98% kaolinite layers. Discrete kaolinite was also present. The bimodal K-S mineralogical composition is likely due to two precursor phases: feldspar for the kaolinite-rich K-S and volcanic glass for the smectite-rich K-S. K-S with intermediate composition (50-94% kaolinite) was rare, due to its instability. Statistical analysis showed significant differences between the chemical compositions of the soils developed on the two different parent volcanic compositions. The soils overlying the more felsic parent rocks were less altered than those overlying the flood basalt. When comparing the weathering indices calculated in this study, we conclude that while the CIA and CIW may be more readily determined, the W and Wmin indices can elucidate information on the composition of the original rock from which they formed. The W index is more sensitive to certain variables when compared with the newly derived mineralogical Wmin index; however the Wmin index takes into account mineral phases within the sample, which provides a more detailed interpretation of weathering rates than chemistry alone. In addition the Wmin index correlated with meteorological variables, such as elevation (and consequently temperature and precipitation), known to influence the degree of pedogenesis. The Wmin index can be used to enhance our understanding of the processes that occur during weathering processes to supplement information gained from traditional chemical weathering indices

Anatomical variations and distributions of obturator nerve on Ethiopian cadavers

Variations in anatomy of the obturator nerve are important to surgeons and anesthesiologists performing surgical procedures in the pelvic cavity, medial thigh and groin regions. They are also helpful for radiologists who interpret computerized imaging and anesthesiologists who perform local anesthesia. This study aimed to describe the anatomical variations and distribution of obturator nerve. The cadavers were examined bilaterally for origin to its final distribution and the variations and normal features of obturator nerve. Sixty-seven limbs sides (34 right and 33 left sides) were studied for variation in origin and distribution of obturator nerve. From which 88.1% arises from L2, L3 and L4 and; 11.9% from L3 and L4 spinal nerves. In 23.9%, 44.8% and 31.3% of specimens the bifurcation levels of obturator nerve were determined to be intrapelvic, within the obturator canal and extrapelvic, respectively. The anterior branch subdivided into two, three and four subdivisions in 9%, 65.7% and 25.4% of the specimens, respectively, while the posterior branch provided two subdivisions in 65.7% and three subdivisions in 34.3% of the specimens. Hip articular branch arose from common obturator nerve in 67.2% to provide sensory innervation to the hip joint. Accessory obturator nerve was not observed at all in this study. Key words: Variations, obturator nerv

Observation of resonant interactions among surface gravity waves

We experimentally study resonant interactions of oblique surface gravity waves in a large basin. Our results strongly extend previous experimental results performed mainly for perpendicular or collinear wave trains. We generate two oblique waves crossing at an acute angle, while we control their frequency ratio, steepnesses and directions. These mother waves mutually interact and give birth to a resonant wave whose properties (growth rate, resonant response curve and phase locking) are fully characterized. All our experimental results are found in good quantitative agreement with four-wave interaction theory with no fitting parameter. Off-resonance experiments are also reported and the relevant theoretical analysis is conducted and validated.Comment: 11 pages, 7 figure

ELECTROCHEMICAL BEHAVIOUR AND VOLTAMMETRIC DETERMINATION OF GESHOIDIN AND ITS SPECTROPHOTOMETRIC AND ANTIOXIDANT PROPERTIES IN AQUEOUS BUFFER SOLUTIONS

The electrochemical behaviour of Geshoidin was investigated at a glassy carbon electrode in mixtures of citric acid and di-sodium hydrogen orthophosphate aqueous buffer system over a wide pH range (pH 2-11) using cyclic voltammetry. Chemically irreversible single oxidation and reduction peaks were obtained in the potential and pH range investigated. Variations in the peak potential and peak current of the oxidation peak have been observed as function of pH. The wave characteristics, the reversibility of the reactions, the diffusion coefficient and the number of electrons transferred have been studied. Linear sweep voltammetry was applied for the voltammetric determination of Geshoidin and a linear calibration curve over the range 1.00 x 10-6 - 1.00 x 10-4 M Geshoidin was achieved. The detection limit was found to be 5.00 x 10-7 M Geshoidin. For eight successive determinations of 1 x 10-5 M Geshoidin, a relative standard deviation (RSD) of 3.2 % was obtained. The voltammetric method was applied to the direct determination of Geshoidin in Gesho. The absorption spectra of Geshoidin are interpreted in terms of structural changes caused by protonation and deprotonation of the molecule as a result of changes in pH. The pKa values of the compound have been determined from the voltammetry and spectrophotometry measurements. The superoxide anion scavenging ability of Geshoidin was examined by differential pulse voltammetry and its antioxidant activity has been compared with natural antioxidants. KEY WORDS: Gesho, Geshoidin, Rhamnus prionoides, Electrochemical behaviour, Voltammetric determination, Spectrophotometry, Antioxidant activity Bull. Chem. Soc. Ethiop. 2007, 21(2), 189-204