Participatory variety selection and scaling: Small grain cereals

United States Agency for International Developmen

Petrographic and Geochemical Study of Low Grade Metamorphic Rocks around Negash with Reference to Base Metal Mineralization and Groundwater Quality, Tigray, Northern Ethiopia

Petrographic and geochemical data of Upper Proterozoic, low grade metamorphic rocks (Tsaliet Group) in and around Negash is interpreted in this paper with their mineralization potential and influence on groundwater quality. Among the three types of metamorphic rocks, metavolcanics (MV), metavolcaniclastics (MVC) and metasediments (metapelites) (MP) are present in the study area. Metavolcanics are massive, non-foliated and show presence of relicts of plagioclase feldspar and pyroxenes set in a fine grained matrix. Metavolcaniclastics show presence of clasts set in a fine grained tuffaceous groundmass and indicate a significant compositional contrast between these, probably volcanic derived, groundmass and the clasts. The clasts vary in size and shape from angular, subrounded to rounded and even elliptical (due to shearing). Phyllite, the predominant lithounit of metasediments is composed of fine grained muscovite, quartz and chlorite with incipient foliation and at places well developed crenulations. Presence of chlorite together with poorly developed muscovite and biotite (rare) suggests low grade metamorphic conditions that prevailed in the area. Geochemical data of metavolcanics indicate variation in their composition from basalt to andesite. Metavolcaniclastics are relatively enriched in alkalis and silica and deficient in MgO compared to metavolcanics. Phyllite on the other hand is enriched in K2O and silica compared to metavolcanics. Development of chlorite, sericite and other minerals due to low grade metamorphism and hydrothermal alteration have modified the chemistry of the rocks particularly MgO by chlorite in phyllite. Shear zones are common in the rocks of the study area, trending N-S and showing presence of clasts with non-ideal tails, relatively higher amount of quartz veins, malachite stains, Cu anomalies and sericitisation. These stains and anomalies strongly suggest a shear zone-controlled copper mineralization. Island arc-setting, bimodal volcanism, intrusive granitic plutons and similar type of shear zone –controlled Zn-mineralization in the nearby Abrha Atsbha area indicate possible presence of a similar kind of mineralization elsewhere in the basement rocks around these plutons. Hydrogeochemical data indicate that groundwater is relatively fresh and among major elements Na, Ca and Mg show relatively higher values compared to K. Water from metasediments is relatively harder among others. Na though shows higher values compared to Ca and Mg does not indicate any particular trend. Ca and Mg concentrations are related to the mafic and plagioclase feldspar minerals. Among trace elements, iron, nickel and lead show relatively higher values compared to other analyzed elements. Fe and Ni are related to metavolcanics and metavolcaniclast, and Pb to metapelite. Key words: Low grade metamorphic rocks, Base metal mineralization, Petrography, Hydrogeochemistry, Negash, Ethiopi

Quantification of the Impact of Integrated Soil and Water Conservation Measures on Groundwater Availability in Mendae Catchment, Abraha We-Atsebaha, eastern Tigray, Ethiopia

The paper tries to evaluate the impact of integrated soil and water conservation measures on water availability in Mendae catchment (10.37 km2), which is located in the northeastern Tigray. Historical background of the catchment with respect to its land use was obtained from the local Bureau of Agriculture and Rural Development office. The hydrology of the area was characterized based on its land use, soil, slope, rainfall,  temperature, evapotranspiration, and runoff. Thornthwaite method and Thornthwaite soil-water balance model were used to determine potential and actual evapotranspiration, respectively. The mean annual runoff from the catchment was computed using runoff coefficient method. Before the intervention, the area was severely degraded and known with scarcity of water. Integrated soil and water conservation (physical and biological measures) was introduced to the area since 1993. The catchment is characterized by two rainy season and three dry seasons during the year. The rainy seasons in total have four months whereas the dry seasons comprises of eight months. The mean annual rainfall of the catchment is 565.8 mm, out of which rainy season accounts for 86.13% and the dry season for 13.87%. The rain that occurs with a very high concentration accounts 73.20 % of the mean annual rainfall of the catchment and this occur only in two months (July and August).The mean annual potential and actual evapotranspiration was found to be 832.67 mm and 405.61mm, respectively. The volume of runoff before and after the intervention was found to be 26.88 % and 17.19 % of the mean annual rainfall of the catchment, respectively. The groundwater recharge before and after the intervention was found to be 1.43 % and 19.04% of the mean annual rainfall of the catchment, respectively. The availability of groundwater has increased more than 10 times since 1993. Though the groundwater is being used for both complimentary and supplementary irrigation during the dry and rainy season, respectively, construction of additional physical conservation structures is suggested to further improve the groundwater availability in the area.Keywords: Groundwater, Mendae catchment, Surface runoff, Water balance, Tigray, Ethiopia

Investigation into the Nutritional Content and Microbiological Property of Abyssinian Donkey’s Milk

A study was carried out on donkey milk in Ada’a District of central Ethiopia to investigate the nutritional and microbiological properties of Abyssinian donkey’s milk. The study utilized primary data that were collected from 24 jennies in the study area. The physicochemical composition such as fat, total protein, lactose, minerals, vitamin C, pH, density, total solid and freezing points; and microbiological characteristics were analyzed. Results indicated that the Abyssinian donkey milk has close similarity with milk of other donkeys previously investigated elsewhere for most of the compositions. More importantly, the present findings confirmed that Abyssinian donkey milk has a very close similarity with human breast milk in its protein, lactose, vitamin C, pH, density, and zinc contents whereas, the concentrations of calcium, iron and magnesium were higher than those of human breast milk. Other unique properties of Abyssinian donkey milk were lack of fermentation and lower microbial load in contrast to cow’s milk. In conclusion, the findings of this preliminary study showed the existence of similarity between Abyssinian donkey’s milk and human breast milk in their physicochemical composition and thus could suggest that the Abyssinian donkey’s milk can serve as an alternative supplement for human breast milk despite differences in some aspects of the microbiological and sensory properties. However, Abyssinian donkey’s milk should be tested for its safety to human being before it is recommended for human consumption.Key words: donkey milk, Ethiopia, human breast milk, physicochemical propert

Preliminary Study on the Impact of Water Quality and Irrigation Practices on Soil Salinity and Crop Production, Gergera Watershed, Atsbi-Wonberta, Tigray, Northern Ethiopia

Possible long term effects on soil salinity and crop production due to the quality of water and irrigation practices is assessed in an area in Gergera Watershed in Atsbi-Wonberta, Tigray, northern Ethiopia. Ten water  samples collected from hand-dug wells and small household ponds, and thirty soil samples from different depths up to ~100cm were tested for  various parameters such as TDS, pH, anions and cations. Data indicate that both water and soil in terms of quality are acceptable for irrigation  purposes. However, at present the soil salinity is not a serious issue but the data suggests its possible increase with time as indicated by two samples. Some of the issues such as use of sprinklers, organic manure, blending, seasonal crops are discussed in the light of maintaining the  required quality, proper utilization of soil and water resources, and for sustainable development.Keywords: Watershed, Water quality, Soil quality, Hand-dug wells, House-hold Ponds

Participatory variety selection and scaling: Cool-season food legumes

United States Agency for International Developmen

Groundwater Suitability for Irrigation: a Case Study from Debre Kidane Watershed, Eastern Tigray, Ethiopia

The present paper tries to assess groundwater suitability for irrigation purpose in Debre Kidane Watershed (45.09 km2), northern Ethiopia. The goal was to evaluate the suitability of the groundwater for irrigation, examine the water types and to investigate possible long and short term impact on groundwater quality. Thirty six water samples each were collected in rainy and dry (irrigation) seasons from the active shallow hand dug wells. The well selection for detailed study and water sampling was done using stratified followed by random sampling technique. The number of wells selected for study is accounting 10% of the total available hand dug wells in the area. Parameters such as electrical conductivity (EC), pH, Total Dissolved Solids (TDS), temperature and other physical properties were recorded in the field. Major anions and cations (Ca2+, Mg2+, K+, Na+, CO32-, HCO3-, Cl-, SO42- and NO3-) were analyzed in the laboratory. Chemical data suggests that the water type in the area though varies from Mg-HCO3, Ca-HCO3, Mg-Cl, Na-HCO3 to K- HCO3, predominantly it is mixed cation-HCO3 type in the rainy season; and Ca-HCO3 (Piper diagram) and Na-HCO3 (Stiff diagram) in irrigation season. Dominance of Na in irrigation season and increase in Sodium Absorption Ratio (SAR) are primarily due to possible increase of Na absorption in the soil replacing Ca. According to the guidelines for irrigation water quality, the groundwater is suitable for irrigation with some minor exceptions. In rainy season, 89% of the samples fall under the water class “good” and 11% “permissible” whereas in irrigation season only 30% are classified as “good” and 70% under “permissible” class. Toxicity in terms of SAR and salinity though presently under control and there is no specific toxicity effect on vegetables and field crops, however, there are indications of their increase in due course of time if proper measures are not taken. Keywords: Groundwater, Irrigation, Salinity, SAR, Toxicity, Water quality, Hand dug well, Ethiopia

Hydrogeological Investigation and Groundwater Potential Assessment in Haromaya Watershed, Eastern Ethiopia

The paper assesses groundwater quality and productivity in Haromaya watershed, eastern Ethiopia. Continuous pumping test data, collected from seven boreholes was used to determine productivity of the aquifers. 14 water samples were tested for water quality. The aquifers on the basis of permeability, potential and extent of aquifers, are categorized into i) extended and shallow aquifers with intergranular porosity and permeability, and with moderate to high potential (alluvial and lacustrine sediments); ii) limited and shallow aquifers with fracture and/or karstic porosity and permeability, and with moderate potential (sandstone and limestone); and iii) limited and shallow aquifers with intergranular and fracture porosity and permeability, and with low potential (granite). On the basis of chemical data, the water is fresh except in lacustrine and swampy areas. HCO3-, Ca2+, Na+ and Mg2+ are the dominating ions in water from granite, sandstone and alluvium; and Cl and SO4 dominate in water from lacustrine sediments apart from HCO3-, Ca2+, Na+ and Mg2+. Areas suitable for groundwater development in the area are discussed. Keywords: Aquifer, Ethiopia, Groundwater potential, Haromaya, Hydrogeochemistry

Use of geographic information system and water quality index to assess suitability of groundwater quality for drinking purposes in Hewane areas, Tigray, Northern Ethiopia

The study area Hewane is situated in the southern zone of Tigray Regional State, Hintalo Wajirat wereda. It is geographically located between 1444000 to 1454000m N and 550000 to 558000m E with an aerial extent of 47.66 sq. km. The study was conducted having an objective of assessing suitability of groundwater quality for drinking purposes through geographic information system (GIS) and water quality index (WQI). Ten groundwater samples were collected from the study area and 13 physicochemical parameters such as TDS, TH, Alkalinity, pH, EC, Temperature, Na+, K+, Mg2+,Ca2+, Cl-, HCO3- and SO42- were analyzed. Inverse distance weighted (IDW) interpolation method has been used to generate the spatial distribution of the groundwater physico-chemical parameters and water quality index map. To estimate the water quality index, 9 parameters have been considered: pH, Na+, K+, Mg2+,Ca2+, Cl-, HCO3-, SO42-, and TDS. The WQI estimated for the groundwater samples of the study area ranges from 86.1 to 180.5 at groundwater samples GWS_2 and GWS_5, respectively. Based on the analysis, most of the area under study falls 70% in poor water class and 30% in good water class. Hence, the result revealed that 70% of the groundwater samples of the study area are hardly suitable for drinkingpurposes without water quality management activities.Key words: spatial distribution, GIS, WQI, groundwater quality, Hewane, Tigray, Ethiopi

Effect of Chemical and Mineralogical Composition of Rocks on the Groundwater Chemistry of Hewanie and its Surrounding Areas, Southern Tigray, Ethiopia

The study was conducted in Hewanie and its surrounding areas of 169.82 km2 with a major objective of identifying the effect of chemical and mineralogical composition of rocks on the chemistry of the groundwater quality. This was conducted by taking 11 groundwater and 5 rock samples from the main geological units of the study area. Water samples were analyzed for major cations and anions, trace elements, TDS, total hardness, pH, electrical conductivity, and alkalinity the rock samples for major cations and anions and trace elements using AAS. The data was used to qualify and assess the quality of groundwater in the study area. Concentration of Ca2+, Mg2+, Na+, K+, HCO3-, Cl- and SO42- of groundwater samples in mg/l varied from 84 to 412, 96 to 211.2, 19.09 to 43.93, 2.34 to 51.09, 244 to 585.6, 71 to 340.8 and 49.49 to 122.5, respectively. Concentrations of Ca2+, Mg2+, Na+, K+, HCO3-, Cl- and SO42- of rock samples in ppm varied from 2586.4 to 28540, 2575.8 to 5289.6, 28.83 to 6134.9, 190.3 to 2379, 293.74 to 3717.6, 433.1 to 1143.1, 2787.8 to 27849.6, respectively. The predominant cations trend in both the groundwater and rock samples the study area was Ca2+ > Mg2+ > Na+> K+. Therefore, it is concluded that the local rock chemistry is seriously affecting the groundwater chemistry.Key words: Rock-water interaction, groundwater, rock, mineralogical composition, quality, Hewanie, Ethiopia