Perspectives on soil fertility change: a case study from southern Ethiopia

This paper explores the complexities underlying the apparently simple question—Is soil fertility declining?—for Wolayta in southern Ethiopia, an area famed for its high population densities and extreme pressure on resources. Drawing on extensive field research in the area, the paper examines differing perceptions of soil fertility decline, and attempts to pick apart the range of evidence of changes in soil fertility over time from a variety of different sources, ranging from historical interviews with farmers to fertilizer trials carried out over many years. In contrast to the definitive statements so often made in development policy statements, the actual situation is much less clear. A detailed understanding of soil fertility dynamics is only reached by a farm and field level examination of soil nutrient balances. Differences according to agroecological zone and socio-economic group are evaluated. These results show that soil fertility is indeed declining in some places, for some people and over certain periods, but it is not universal. Indeed, soil fertility is apparently increasing at certain sites. The implications of such findings for development policy and practice are briefly explored. Copyright © 1999 John Wiley & Sons, Ltd.     

Evaluation of Drought Tolerance in Tef [Eragrostis Tef (Zucc.) Trotter] Genotypes Using Drought Tolerance Indices

Journal of Crop Science and Biotechnology - A field experiment was conducted to identify drought tolerant, high yielding and stable tef genotypes using drought tolerance indices. Sixty-four tef...     

Phosphorus Use Efficiency of Common Bean Cultivars in Ethiopia

Phosphorus (P) deficiency in the soil is one of the major factors limiting common bean production in Ethiopia. A pot experiment was conducted in a glasshouse at Hawassa University in southern Ethiopia to evaluate twelve common bean cultivars for P use efficiency at three phosphorus rates (0, 120, and 240 kg P₂O₅ ha^?1). The results of the study revealed that the interaction effect of cultivar and P rates significantly (P < 0.01) influenced grain yield efficiency index (GYEI), grain yield and yield attributing traits, leaf P concentration, root length, diameter and surface area. Grain yield efficiency index at low and medium phosphorus rates indicated that Red-Wolaita, Dinkinesh, Tabour, Nasir and Haramaya are P-efficient, whereas Chore was found to be P-inefficient. These genotypic variations could be exploited for sustainable production of the crop by fitting suitable varieties to soils with variable P availability. Thus, the P-efficient cultivars indicated above could be recommended for cultivation by smallholder farmers in soil with low P availability that is dominant in the study area.     

Genetic diversity of Ethiopian <Emphasis Type="Italic">Xanthosoma sagittifolium</Emphasis> (L.) Schott accessions assessed with AFLPs

Xanthosoma sagittifolium (L.) Schott originated from the American tropics. Domestication may have occurred in various places as this Araceae species is an important food source. It has been cultivated for many decades. In this study, Amplified Fragments Length Polymorphism (AFLP) markers were used to analyze the genetic relationships among 78 Ethiopian X. sagittifolium accessions, for conservation purpose. Cormels were collected from Bench-Maji, Kefa, Dawuro and Wolaita zones, representing four populations. The accessions belonged to either green (G) or purple (P) colored leaf and petiole accessions. Three different AFLP primer combinations resulted in 478 scorable bands, of which 99.2% were polymorphic. The mean Nei’s gene diversity (He) within populations was 0.35 while the G accessions featured higher He (0.38) than the P ones (0.35). The Nei’s gene diversity (He) at entire collection level was 0.38. The detected high genetic diversity may indicate the X. sagittifolium plants growing in the country may derive from diverse parental genotype stock elsewhere and/or there may be multiple introductions to the country. Low levels of genetic differentiation were detected among populations (Gst?=?0.07) and between the G and P accessions (Gst?=?0.02). Insignificant genetic and geographic correlation was revealed by Mantel test. Clustering analysis grouped 91% of the accessions together. Conservation and management of X. sagittifolium in the country should concentrate on maintaining high level genetic diversity within each population as well as at entire collection level through both ex situ and in situ conservation actions.     

Evaluation of surge flow furrow irrigation for onion production in a semiarid region of Ethiopia

The study was conducted to evaluate surge irrigation against continuous irrigation in terms of irrigation and water use efficiencies to produce onion. It was carried out at Mekelle Agricultural Research Center, Ethiopia on 70 m long and 0.6 m center–center spacing furrows of 0.26% average slope on a clay soil. The treatments consisted of factorial combination of two discharges (Q ₁ = 1 l/s and Q ₂ = 2 l/s) and three-cycle ratios (CR₁ = 1/3, CR₂ = 1/2, and C = 1 for continuous irrigation). Surge flow treatments advanced faster than the respective continuous flow treatments with surge flow treatment SF₂₁ being the fastest. The best value of application efficiency (60%) was achieved for SF₁₁ and the least (46%) for CF₂. The maximum (87%) and minimum (68%) values of distribution uniformity were obtained for cycle ratios CR₁ and C, respectively. Storage efficiency was highest (89%) for CF₂ and lowest (78%) for SF₁₂. Onion yield was significantly affected (p < 0.05) by the interaction effect, the highest (14,400 kg/ha) and the lowest (13,363 kg/ha) yields were obtained for SF₁₁ and SF₂₁, respectively. The maximum irrigation water use efficiency (2.27 kg/m³) was observed for SF₁₁ and the minimum (1.68 kg/m³) for CF₂. Surge irrigation was found to be a promising irrigation practice for onion production in the study area as it saves water, reduces irrigation period, and increases the crop yield.