A B S T R A C TIn response to the intensive tillage in maize, operating under high seasonal rainfall variability, this study examined the agronomic and economic responses of tillage and water conservation management in the central rift valley (CRV) of Ethiopia. An experiment was laid out as a split plot design with conventional tillage (CT), minimum tillage (MT) and zero tillage (ZT) as main plots and mulch, no mulch and planting basin as subplots. The MT and ZT were considered as conservation agriculture (CA) plots. Results showed that CT had 13-20% higher grain yield than MT and 40-55% higher than ZT; and MT had 27-37% higher yields than ZT. Mulching had 23-33% and 14-19% higher grain yield than no mulch and planting basin respectively. The CT had 28 and 89% higher labor productivity and 6 and 60% higher gross margin than MT and ZT respectively. The MT had 37% higher gross margin than ZT. The highest yield response in CT resulted in its highest gross margin and labor productivity. This shows that regardless of water conservation management, CT yielded better agronomic and economic responses over CA. However, the practice of CT is highly constrained by the availability of draft power and the short window period for planting. Likewise, regardless of tillage management, mulching tended to be more attractive and promising in suppressing weed density and hence reducing labor demand for weeding, despite improving volumetric soil moisture content and maize yield. Yet the viability of practicing mulching is highly constrained by the widely practiced open grazing on stubble after harvest. Therefore, future studies are needed to further identify appropriate tillage and water conservation management which make maize more resilient to the high rainfall variability, and sustainably improve food security, and farmers' livelihoods in the CRV of Ethiopia.2014 Published by Elsevier B.V.

This study examines the agronomic response, efficiency and profitability of fertilizer microdosing in maize. An experiment with the following treatments was conducted: control without fertilizer, microdosing treatments, with the rate of 27 + 27, 53 + 53 and 80 + 80 kg ha fertilizer rate increased the grain yield by 19, 45 and 46% at Hawassa, Ziway and Melkassa, respectively, and it was equivalent to the higher rates. The value cost ratio (VCR) was highest with the lowest fertilizer rate, varying between seven and 11 in the treatment with 27 + 27 kg ha of DAP + urea rate makes it low cost, low risk, high yielding and profitable. Therefore, application of this particular rate in maize may be an option for the marginal farmers in the region with similar socioeconomic and agroecological conditions. OPEN ACCESSAgronomy 2014, 4 437

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Background: Renewable energies such as biogas are considered as clean sources of energy that minimize environmental impacts and are sustainable with regard to current and future economic and social needs. Biogas offers an attractive option for replacing the unsustainable usage of traditional energy sources such as firewood, cow dung, and charcoal in developing countries. In Ethiopia, these energy sources have been in decline. To address these challenges, mainly in rural areas, biogas technology has been domesticated since 2009, as seen in the National Program. The purpose of this study is thus to examine factors that influence households' decisions of adopting biogas technology in rural areas in southern Ethiopia. Methods: A sample of 268 households with 134 biogas adopters and 134 non-adopters were surveyed using simple random and purposive sampling techniques, respectively. The data were collected through individual interviews of households using a semistructured questionnaire. Descriptive statistics and a binary logistic regression model were used for the data analysis. The binary logistic regression model was applied to identify determinant factors affecting the adoption of biogas technology. Results: The results of the study indicated that biogas adopter and non-adopter households had significant mean differences in education level, cattle size, household income, farmland size, number of planted trees as well as the distance to water sources, market places, and firewood sources. Level of education, level of income, access to credit, distance to firewood sources, and access to electronic media had a significantly positive influence on the adoption of biogas technology. Conversely, distance to water sources and access to electricity had a significantly negative influence on the adoption of biogas technology. Conclusions: Biogas technology mostly appears in privileged households having a better socioeconomic status and other resource endowments. The beneficiaries are thus households that can afford the higher initial investment costs for bio-digester installation, maintenance services and purchasing bio-digester spare parts; as well as households that have access to credit facilities, water sources for adequate water supply, markets for purchasing spare parts and electronic media for information, and also households residing far away from firewood sources.

Technological change has been the major driving force for increasing agricultural productivity and promoting agriculture development in developing countries. To improve the agricultural productivity and farmers' livelihoods, several agricultural technologies (improved crop varieties and related agricultural practices) were introduced by various agencies to the farmers in the Rift Valley of Ethiopia. Thus, the objective of this study is to identify these technologies, and evaluate their characteristics and sustainability. The data were collected from farmers, agricultural extension workers, and agricultural experts, through a series of focus group discussions, key informant interviews, and farm observations, selected through purposive and random sampling techniques. Results showed that extension systems, social networks, or research projects were the agencies that introduced the technologies to the farmers. Haricot beans (Phaseolus vulgaris L.) and early and mid-maturing maize (Zea mays L.), as well as agricultural practices like row-sowing, banding fertilizer application, intercropping, and traditional rainwater-harvesting, were found to be in continuous use by the farmers. In contrast, the use of extra-early-maturing maize, sorghum (Sorghum bicolor L.) and finger millet (Eleusine coracana L.), as well as the use of related practices, including harvesting maize at physiological maturity, seed priming and fertilizer microdosing, were the technologies that were discontinued at the time of pursuing this study. Most of the continuing technologies had a high potential for reducing the vulnerability of the rain-fed agriculture to rainfall variability. Regardless of sources, the national extension system supported technologies that were integrated into the system only. Most of the discontinued technologies were found to be introduced by the research projects. These technologies were not brought into the attention of policy-makers for their integration into the extension system. The farmers also disliked a few of them for unfitting the existing socioeconomic setting. Whereas, the technologies that were introduced by the social networks were found to be widely used by the farmers, though they were not supported by the extension system. This is because most such technologies offer better yield and income. For instance, social networks have popularized haricot beans and hybrid maize because of their higher benefits to farmers. Farmers consider both socioeconomic and agroecological conditions for selecting and using technologies, whereas the extension system centers on existing agroecological conditions for recommending and supporting agricultural technologies. Consideration of both socioeconomic and agroecological settings would increase the prospect of a technology for sustainable adoption. Overall, rainfall variability, high price and poor access to improved seeds, farmers' poor economic conditions, and the inadequate linkage between extension systems, social networks and research projects, remain critical factors influen...

SUMMARYIntensification of maize production is imperative to improve food security for the rising population in the central rift valley (CRV) of Ethiopia, whose livelihood is principally based on rainfed maize that operates under shrinking landholding and high seasonal rainfall variability. This study examined different levels of intensification options in maize production by sequentially introducing minimum tillage and seed priming, phosphorus (P) fertilizer microdosing, surface mulching and nitrogen (N) fertilizer microdosing. Field experiments were conducted with five treatments, steps or levels consisting of conventional tillage (farmers practice as a control); minimum tillage + seed priming, unfertilized (step 1); step 1 + microdosing 53 kg ha−1 P (step 2); step 2 + 4 ton ha−1 maize stover as surface mulch (step 3) and step 3 + 53 kg ha−1 N (step 4). These steps represented increasing levels of intensification. Except at the lowest level (step 1), agronomic and economic responses improved with increasing levels of inputs. Relative to the very high and increasing gross margin, production costs were low but slowly increased with increasing levels of inputs. Except at the lowest level, the value cost ratio was above 4 even at the highest levels of inputs, demonstrating that such kind of intensification can be achieved with low risk. Likewise, the fertilizer use efficiency was quite high even at the highest of levels of inputs signifying the efficiency of the pocket application of fertilizer through the microdosing method. The improvement in maize establishment and yield and the reduction in the days to maturity could contribute to make maize production more adaptive to the existing seasonal rainfall variability. Depending on the affordability to the external inputs and their feasibilities, the different technology packages in the intensification ladder may give different choices for the farmers to improve maize production in the CRV of Ethiopia.

On‐farm seed priming has been reported to improve emergence, crop establishment, and yield besides improving economic benefits in dryland agriculture. These benefits can further be improved by fertilizer micro‐dosing. The purpose of this study was to investigate the effect of on‐farm seed priming and fertilizer micro‐dosing on the agronomic and economic returns of maize (Zea mays L. var. Melkassa‐2) in semi‐arid agro‐ecological conditions in Ethiopia. The experiments consisted of four treatments: no priming and no fertilizer; no priming and fertilizer; priming and no fertilizer; and priming and fertilizer. The experiments were conducted in three locations viz., Melkassa, Ziway, and Hawassa in the central Rift Valley. Analysis of variance for each location was performed separately at p ˂ .05. Results of each location were similar over the experimentation years, and hence, there was no need for carrying out combined analysis. Regardless of fertilization, primed plants showed faster emergence; better uniform crop stands; more vigorous plants; earlier flowering; earlier harvest; and higher grain and stover yield than no primed plants. Germination was 2–3 days earlier, and flowering and maturation of primed plants were 10 to 13 days earlier than no primed plants. Average grain yield increased by 11, 8, and 6% in Melkassa, Ziway, and Hawassa, respectively, by priming over no priming. Fertilizer micro‐dosing combined with priming further improved most of the agronomic characters. Fertilizer micro‐dosing combined with priming increased the average grain yield by 75, 69, and 33% in Melkassa, Ziway, and Hawassa, respectively. The economic returns also increased in the same pattern as the agronomic responses for priming, micro‐dosing or their combination. To realize the potential of seed priming of increasing agronomic performances, future research and development efforts should focus on understanding the possible underling physiological and biochemical basis of this poorly understood process with the different priming techniques.

Although biogas technology has been introduced as a national program to respond to the ever-increasing energy demand in Ethiopia, empirical studies on the technical, institutional and socioeconomic constraints to the domestication and functionality of the technology are scant. Thus, this study provides an overview of these constraints. The study is based on, key-informant interviews, legislation and strategy documents, extensive literature reviews and observation of bio-digesters. Limitations in technical, economic, sociocultural and institutional perspectives are the major factors constraining the domestication and functionality of the technology. The constraints pertain to the adequacy of institutional follow-up; management of bio-slurry; availability and cost of maintenance service; price, availability and accessibility of appliances at local markets; availability of credit associations; adequacy of masons skill; skill and level of awareness of users; and sociocultural acceptance to connecting toilets to bio-digesters. Primarily, these constraints emanate from the weak organizational and institutional alignment among key stakeholders. Thus, for the realization of sustainable domestication of the ABOUT THE AUTHOR Getachew Sime currently works at Hawassa University. Getachew does research in climate change, rural food and energy security, climatesmart agriculture and traditional agricultural practices. The current article is part of the undergoing project tilted Bioenergy -Ethiopia -Norway.