SUMMARYLow soil pH and associated soil infertility problems are considered to be amongst the major challenges to barley production in the highlands of Ethiopia. In response to this, an experiment was conducted at low soil pH (< 5 H2O) site on the effects of different levels of lime and phosphorus (P) fertilizer on soil pH, exchangeable aluminium (Al3+), grain yield and yield components of barley during 2010 and 2011 cropping seasons. The experiment comprised factorial combinations of five lime rates (0, 0.55, 1.1, 1.65 and 2.2 t ha−1) and four P rates (0, 10, 20 and 30 kg ha−1) in a randomized complete block design in three replications. The amount of lime that was applied at each level was calculated on the basis of Al3+. Results of soil analysis after 2 years of liming showed that liming significantly (P < 0.05) increased soil pH, and markedly reduced exchangeable Al3+. Liming at the rate of 0.55, 1.1, 1.65 and 2.2 t ha−1 decreased Al3+ by 0.88, 1.11, 1.20 and 1.19 mill equivalents per 100 g of soil, and increased soil pH by 0.48, 0.71, 0.85 and 1.1 units, respectively. Amongst the liming treatments, liming at the rate of 1.65 and 2.2 t ha−1 gave significantly (P < 0.05) the highest grain yield and yield components of barley. However, grain yield obtained by applications of 1.65 and 2.2 t ha−1 lime was statistically comparable. By additions of 10, 20 and 30 kg P ha−1, grain yield of barley increased by about 29, 55 and 66% as compared to control (without P). During 2010, however, the combined applications 1.65 t ha−1 lime and 30 kg P ha−1 gave 133% more grain yields of barley relative to control (without P and lime). Therefore, sustainable barley production on acid soils in the central highlands of Ethiopia should entail combined applications of both lime and P fertilizer.

This paper presents a case study of land-use/land-cover (LULC) changes from 1975 to 2014 in the central highlands of Ethiopia and traces out its impact on socioeconomic conditions of the local community in the study area. We used four time series Landsat satellite images, that is, Landsat MSS (1975), Landsat Thematic Mapper (1986), Enhanced Thematic Mapper (2000, and Landsat 8 OLI scenes (2014), to investigate the changes in LULC. In addition, individual interviews with 51 randomly selected households, discussions with focus group and key informants, and field observations were also incorporated for the study. The image classification indicated four categories of LULC classes: Natural forest, eucalyptus plantations, cropland/settlements, and grasslands. Between 1975 and 2014, cropland/settlements and eucalyptus plantations considerably increased, whereas grassland cover drastically decreased. According to the results, the area under cropland/ settlements and eucalyptus plantations increased by 62 and 335%, respectively, with 74% concomitant decrease in the area of grasslands in the same period. Survey results showed that deterioration of soil fertility (41.2%) followed by shortage of land (35.3%) is the major constraint for crop production for poor farmers in the study area. However, better-off farmers ranked deterioration of soil fertility (64.7%) followed by lack of credit (17.6%) as priority constraints for crop production. Interviews mainly focused on selected women group revealed that the expansion of eucalyptus in the area greatly curbed the burdens of collecting fuel woods from long distances in the past. The availability of too many religious holidays (on average 16 days/month) directly or indirectly contributes to the current seasonal food shortages of the community. Generally, our results show that the community in the study area is beset with a host of social, economic, and institutional challenges. As a result, majority of the farming households are destitute, unable to make a livelihood from their small plot of land and live in absolute poverty. Therefore, in light of these finding, it is imperative that timely interventions by government and other development stakeholders are needed to come to grips with problems of soil fertility, land-use change, and food insecurity in the study area.

The aim of this research is to investigate the patterns of vascular plant species richness, diversity, and distribution along an elevation gradient in the Abune Yosef mountain range, Ethiopia. Preferential systematic sampling was employed to collect vegetation and environmental data along the elevation gradient. We found that plant species richness declines monotonically from low to high elevations. Specifically, vascular plant species richness and diversity were lower in the Afroalpine grassland (high elevation) than in the Dry evergreen Afromontane forest and Ericaceous forest (low elevations). In contrast, endemic vascular plant richness was significantly higher in the Afroalpine grassland than in the Dry evergreen Afromontane forest and Ericaceous forest. Elevation showed a significant impact on the richness, diversity, and endemism of vascular plants. According to Sørensen's coefficient, the similarity between Dry evergreen Afromontane forest and Ericaceous forest vegetation types is higher (32%) than the similarity between Ericaceous forest and Afroalpine grassland (18%). Only 5% similarity was recorded between the Dry evergreen Afromontane forest and Afroalpine grassland. Growth forms showed different elevational richness patterns. Trees and liana increased monotonically up to 3300 m. Shrub and herb richness patterns followed a hump-shaped and inverted hump-shaped pattern along the elevation gradient. The elevation patterns of vascular plant species richness, diversity, and growth form in the present study may be attributed to differences in management intensity, spatial heterogeneity, microclimatic variations, and anthropogenic disturbances.

Introduction: Soil is the major reservoir of organic carbon. There is a paucity of soil organic carbon (SOC) stock data of afroalpine and sub-afroalpine vegetation in Ethiopia. Hence, this study was conducted to estimate the SOC stock and correlate it with soil physicochemical properties in Abune Yosef afroalpine and sub-afroalpine vegetation. Systematic sampling was employed to collect soil samples from upper 30 cm. Dry bulk density soil pH (1:2.5 water); organic carbon (Walkley and Black), and total nitrogen (Kjeldahl) were the methods used for soil analysis. Pearson correlation and linear regression analysis were performed in SPSS 24 statistical software. Results: The SOC stock of the study area was found to be 79.57 t C ha −1. Soil organic carbon stock showed statistically significant positive correlation with vegetation type (r = 0.522, p < 0.01), bulk density (r = 0.62, p < 0.01), total nitrogen (r = 0.41, p < 0.01), and altitude (r = 0.468, p < 0.01) and negative correlation with slope (r = − 0.298, p < 0.05). The present study revealed similar soil organic carbon stock (SOCS) with the Intergovernmental Panel on Climate Change (IPCC) default estimate for similar regions. Positive correlation of SOCS and altitude could be resulted from the variations in anthropogenic disturbances, temperature, and precipitation vegetation types. The negative correlation between SOCS and slope is the result from the predictably higher soil erosion at steeper slopes. Temporal livestock trampling increased the bulk density but never affected the SOCS to decline. Aspect did not show any significant relationship with SOCS due to either the under surveying of all aspects or similar solar radiation found in the study area. Moreover, gazing, aspect, and soil pH did not show statistically significant impact on SOCS. Conclusion: The SOCS of Abune Yosef afroalpine and sub-afroalpine vegetation is similar to the IPCC default estimate for similar regions. This is a great contribution both to the global and local terrestrial carbon sink.

Soil acidity associated with soil fertility problems are the main constraints hindering barley production in most highlands of Ethiopia. Field experiment was conducted to evaluate effects of lime and phosphorus (P) fertilizer application to acid soils on grain yield of barley and soil chemical properties during 2009 to 2013 cropping seasons at Bedi in Western Ethiopia. The experiment was laid out in randomized complete block design with three replications. Five levels of lime (0, 0.55, 1.1, 1.65 and 2.2 t/ha) and four levels of P (0, 10, 20, and 30 kg/ha) were combined in a complete factorial arrangement. Lime requirement of the soil was calculated based on its exchangeable acidity. The combined analysis over years showed significant improvement of barley grain yield and soil chemical properties due to the main and interaction effects of lime and phosphorus. Grain yield was progressively increased with incremental levels of lime and Phosphorus application. The highest yield was obtained from 2.2 t/ha lime application coupled with 30 kg/ha phosphorus fertilizer, but on par with 1.65 t/ha lime and 20 kg/ha phosphorus application. Grain yield is increased by 274.0% with 1.65 t/ha lime and 20 kg/ha Phosphorus application in the initial year compared with control; however, this yield increment declined over years and reached 99.5% after five years. This yield reduction after five years of lime application may indicate re-acidification of the soil which warrants re-liming. In this study, lime application was the major source of variation for soil chemical properties. Soil pH was sharply increased by liming with the highest value (5.9) and thereafter slightly declined to 5.3 over five years. Exchangeable acidity decreased significantly with increase in lime application to as low as 0.1 cmol/kg, while available P and exchangeable Ca 2+ were noticeably improved. Hence, lime application at the rate of 1.65 t/ha coupled with 20 kg/ha Phosphorus fertilizer could sustainably enhance barley production on acid soils of Bedi and similar areas with likely re-liming of the soils, every five years.