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Reforestation and afforestation either through natural regeneration, tree planting or both methods have been globally promoted to motivate ecological restoration of degraded lands and to improve livelihoods. However, moisture stress and infertile soils limit the survival and growth of trees planted for restoration in drier areas. Hence, understanding the factors that determine the restoration success of drylands through tree planting is critical. We conducted a factorial experiment in Tigray, Ethiopia to evaluate the survival, growth performance and biomass of planted seedlings of the multipurpose agroforestry tree species Acacia saligna over 24 months. The treatments were application of watering (W), mulching (M) and compost (C) separately and in combinations (WM, WMC). We established experimental plots on farmland and on a nearby hillside-exclosure to examine the role of planting niches on seedling performance. Seedlings treated with watering, mulching, and compost (WMC) revealed significantly greater height, root collar diameter (RCD), and dry biomass compared to the other treatments. Seedlings planted in farmland showed significantly greater height, RCD, and total dry biomass compared to those planted at the hillside-exclosure. Although the survival rate was slightly higher in farmland, we also found sufficient survival rates in the hillside-exclosures. Therefore, post-planting care and activities including mulching, watering and fertilization are crucial to enhance the survival and growth performance of A. saligna or other tree species so that efforts in reversing land degradation and restoration of drylands will be successful., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The conversion of an agroforestry based agricultural system to a monocropping farming system influences the distribution and composition of arbuscular mycorrhizal fungi (AMF). The aim of this paper was to analyze AMF species diversity, spore density, and root colonization across different agroforestry practices (AFP) in southern Ethiopia. Soil and root samples were collected from homegarden, cropland, woodlot, and trees on soil and water conservation-based AFP. AMF spores were extracted from the soil and species diversity was evaluated using morphological analysis and root colonization from root samples. The AMF spore density, root colonization and composition were significantly different among the AFP (P < 0.05). In this study, 43 AMF morphotypes belonging to eleven genera were found, dominated by Acaulospora (32.56%), followed by Claroideoglomus (18.60%). Home gardens had the highest spore density (7641.5 spore100 g - 1 dry soil) and the lowest was recorded in croplands (683.6 spore100 g - 1 dry soil). Woodlot had the highest root colonization (54.75%), followed by homegarden (48.25%). The highest isolation frequency (63.63%) was recorded for Acaulospora scrobiculata. The distribution of AMF species and diversity were significantly related to soil total nitrogen and organic carbon. The homegarden and woodlot AFP were suitable for soil AMF reserve and conservation., (© 2023. The Author(s).)

The present work focuses on total concentrations of trace elements such as chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), and lead (Pb) and their operationally defined speciation in surface sediments from three Ethiopian Rift Valley Lakes (Hawassa, Koka, and Ziway). Total concentrations were determined using inductively coupled plasma-mass spectrometer (ICP-MS). A six-step sequential extraction was also applied to evaluate the mobilization potential of these elements. Compared with the consensus-based sediment quality guidelines (SQGs) developed for freshwater ecosystems, the total Zn concentration in sediments from Lakes Hawassa and Ziway, as well as Cr, Ni, and Zn in sediments from Lake Koka, was higher than the probable effect concentration (PEC), suggesting that these elements could have a negative effect on benthic organisms. The sequential extraction results showed that Cd, Mn, and Se were to a certain extent associated with the reversible fractions (F1-F3) in sediments, and thereby more mobile than the other investigated trace elements. Predictions of mobility of trace elements using the distribution coefficients (K d ) values were also in agreement with the sequential extraction results. Furthermore, multivariate statistical analyses showed that redox-sensitive fractions (F4 and F6) and the residual fraction (F7) were the dominant factors controlling most trace element mobility. Finally, applying the Risk Assessment Code (RAC) classification system, results showed that Mn in Lake Koka could pose a high risk, while Cd and Mn in Lake Hawassa as well as Cd, Mn, and Se in Lake Ziway sediments could pose medium risk to benthic organisms., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Among smallholder maize farmers in Ethiopia (and similar areas in Africa), yield and stress tolerance traits in maize varieties are important. While high yields remain a major objective, breeding and seed system development programs are increasingly based on the recognition that farmers also have an interest in other agronomic and consumption traits. In this paper we illustrate these issues by measuring the trade-offs farmers may be willing to make for specific traits in the mid-altitude maize markets in Ethiopia. Based on Choice Experiments among 1499 respondents, we estimate the preference for a set of agronomic and consumption traits relative to yield. by capturing farmers' "willingness to sacrifice yield". The results suggest a significant willingness to sacrifice yield for drought tolerance among both male and female household members, but not for early maturity per se. There was also a high willingness to sacrifice yields for plant architecture traits like closed tip and lodging resistance among male participants, but not among females. Heterogeneity in responses according to gender, education and land area under maize cultivation suggests that market segmentation is necessary for seed system development to become more demand-led and inclusive. Final and realistic segmentation will depend on the commercial viability or social impact potential of each segment., Competing Interests: The authors have declared that no competing interests exist.

The feasibility of using biowaste for the production of biochar and its use in agriculture depends on its environmental and economic performance. This paper quantifies environmental and economic life cycle impacts of biochar production and agricultural use in six developing and middle-income countries (Ethiopia, Indonesia, Kenya, Peru, Vietnam, and China). Two types of production technologies typical for rural and urban areas were investigated (flame curtain kiln and gasifier, respectively), and comparisons were made with composting (either home composting or windrow composting) as alternative biowaste management systems. The results showed that both pyrolysis systems performed better than composting and both were expected to bring environmental benefits. The largest environmental benefits were observed for the gasifier systems, mainly due to the substitution of electricity production from the grid. Damage to ecosystems and human health ranged from -1 × 10 -7 to -2 × 10 -8 species×yr and from -1 × 10 -5 to -5 × 10 -6 DALY per kg of biowaste treated, respectively (negative scores indicating environmental benefits). However, net economic benefits were only achieved when low-cost simple kilns were used in countries with low labor cost, like Ethiopia, Kenya and Vietnam (net profit from 0.01 to 0.08 USD per kg of biowaste treated). Further, high investment and operating costs and relatively small electricity revenue from substituting the grid electricity resulted in gasifier scenarios being economically unsustainable (net loss from 0.29 to 1.58 USD per kg of biowaste treated). Thus, there are trade-offs between positive environmental impacts for society and net market loss for the individual decision-maker (company or individual farmer) that should be considered when making decisions regarding the implementation of biochar technology in developing and middle-income countries. The use of simple kilns in countries with relatively low labor costs appears to be favorable., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)