58 research outputs found

    Исследование информационных процессов в некоторых повторяющихся играх

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    Рассматривается неантагонистическая повторяющаяся игра с непрерывным временем. Один раз за всю игру может подействовать возмущающий фактор. Он изменяет существующую ситуацию равновесия на другую. При этом выигрыш второго игрока уменьшается. Найдены равновесные стратегии и оптимальный дискретный режим получения информации. Показано, что наблюдатель оценивает режим получения информации как оптимальный или избыточный в зависимости от модели реальности, которой он пользуется.The non-antagonistic repeated game are considered. The disturbance is able to act once the game. It changes the existing situation of equilibrium for another one. For this the second player gain decreases. The equilibrium strategies and the optimum discrete regime of the information receipt are found. It is shown that observer estimates the regime of the information receipt as the optimum or surplus regime depending on the model of reality which is used by him

    Nutrition profiles of farm households across different farming systems in Ethiopia: Unpacking the determinants and implications for nutrition-sensitive interventions

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    Tackling nutrition insecurity remains a critical challenge in developing countries. In the predominantly rain-fed and smallholder-based farming systems of Ethiopia, production diversity and livelihood strategies of the farm households vary across geographic areas. However, the effects of household socioeconomic characteristics, production diversity, and household incomes on nutrition profiles in distinct settings have been inadequately understood. Therefore, this study was undertaken to examine the association of farming system type, sources of income, and household wealth status with household nutrition profiles in three remote locations such as Mennisa, Welmel Tiqa, and Agam Wuha that represent root crops-based farming, maize-based semi-pastoral farming, and teff-based cereal farming systems, respectively. A combination of qualitative and quantitative data collection techniques was employed. A multistage sampling procedure was used to select a total of 265 smallholder households for the structured survey interviews. Standard statistical tests and Tobit regression analyses were performed after determining the wealth category of each household. Results revealed a diversity of income sources used by each of the farm households with average values of 9 in Mennisa, 10 in Agam Wuha, and 11 in Welmel Tiqa, with the contributions of each income source varying by household wealth category and location. As expected, expenditures on food significantly exceeded those on non-food categories for poor households and vice versa for rich wealth households. The average total food variety score (FVS) for Welmel Tiqa was twice that for Agam Wuha, confirming the need for site-specific nutrition profile assessments. Despite the observed differences in household nutrition profiles among wealth categories and locations, the apparent intakes of vitamin A, vitamin B12, vitamin D, and calcium were consistently below the population-level estimated average requirements across all locations. The number of adequately consumed nutrients by farm households was negatively associated with family size, age of household heads, livestock holdings, wealth categories, and irrigation use, and positively associated with crop production diversity, income diversity, and FVS. The negative association between irrigation use and nutrition security was likely due to the focus on producing crops with a high market value on land under irrigation, coupled with ineffective allocation of generated income for enhancing household nutritional outcomes. Therefore, programs that include irrigated agriculture investments should consider adopting a more integrated nutrition-sensitive interventions, including consideration of locally adapted nutritious crops, such as orange-flesh sweet potato, to address critical deficiency of Vitamin A, nutrition training coupled with development of recipes and cooking demonstrations, and marketing and promotion for nutritious crops

    Nutrient-Dense Orange-Fleshed Sweetpotato: Advances in Drought-Tolerance Breeding and Understanding of Management Practices for Sustainable Next-Generation Cropping Systems in Sub-Saharan Africa

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    Almost half of children < 5 years old living in sub-Saharan Africa (SSA) suffer from vitamin A deficiency and 60% suffer from iron deficiency. Thus, there has been a strong commitment to breeding for, promoting awareness of, and delivering adapted pro-vitamin A rich orange-fleshed sweetpotato (OFSP) in SSA during the past two decades and for enhanced iron content since 2014. This review article focuses on major breeding efforts in SSA to enhance the drought tolerance of OFSP and reviews integrated crop management practices for improved and sustained sweetpotato production in SSA farming systems. Under climate change, the frequency and severity of droughts is expected to increase. Technical issues are presented in the context of addressing challenges along the entire value chain to ensure adoption. First, the use of an accelerated breeding scheme reduced the breeding cycle from 8–10 to 4–5 years. Since 2010, 19 drought-tolerant OFSP cultivars have been released in Mozambique, 7 in Malawi, and 2 in South Africa. Moreover, research in four breeding populations using the heterosis exploiting breeding scheme (HEBS) demonstrated that within one breeding cycle of 5 years, clones with significantly higher root yield, abiotic tolerance, host plant resistance to pests and diseases, and early maturity can be produced. In the future, HEBS will be combined with greater use of modern genomic tools, new phenotyping tools, and CRISPR/Cas9-mediated gene editing. Second, beyond genetic enhancements, evidence is presented that using improved crop management systems, existing sweet potato yields can be increased 2–4 times. Current knowledge is reviewed concerning sweetpotato’s role in diverse farming systems, but integrated crop management is clearly under researched. Third, the outlook for drought tolerance breeding indicates that two distinct classes of nutrient-rich cultivars are emerging: (1) Early maturing cultivars (< 4 month growing period) that escape drought but also serve humid environments with small landholding size per capita; and (2) Medium maturing (4–6 month growing period) cultivars that avoid drought, are drought tolerant and exhibit continuous root formation. Increasing commercialization of the crop and climate change will drive demand, and the willingness of farmers to invest in improved sweetpotato crop management

    Spatial variation in soil properties and crop yield on stone bund terraces in southwest Ethiopia

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    Erosion and associated soil degradation are major threats to cropland productivity on the steep slopes of the Ethiopian highlands. To limit erosion from cultivated land on sloping terrain, stone bunds for soil conservation have been used for decades, resulting in the formation of terraces. Although qualitatively well known, the difference in soil properties and crop performance between the upper and lower sections of the terraces (intra-bund areas) has not been documented quantitatively. Here, we assess differences in soil properties of the plough layer and crop performance in the upper and lower sections of terraces in between stone bunds in southwest Ethiopia. A total of 27 terraces, with a length of 28.5–57 m and a distance of 6.5–14.7 m in between adjacent stone bunds, were sampled on six different farms during the 2018 and 2019 cropping seasons. The difference in soil properties was analysed using analysis of variance (ANOVA). Results showed that, in the lower section of a terrace, the concentration of soil organic carbon (18.6 g kg−1), total soil nitrogen (2.1 g kg−1) and exchangeable potassium (328 mg kg−1) was significantly greater (p < .01) than in the upper section. Also, grain yield and biomass of maize, teff, broad bean and sorghum were significantly greater (p < .05) in the lower section. This was particularly true for maize for which the yield in 2018 increased from 0.7 t ha−1 in the upper sections to 2.6 t ha−1 in the lower sections. Optimizing crop yields on terraces requires adaptive fertilizer application and crop choice

    Using AquaCrop as a Decision-Support Tool for Small-Scale Irrigation Systems Was Dictated by the Institutional and Market Incentives in Ethiopia

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    The threat of water scarcity in sub-Saharan Africa is exacerbated by the expanding agricultural water needs, increasing climate variability and inappropriate land use. It calls for technological and institutional innovations to improve water productivity, while sustaining the resources base. This study was undertaken to examine the effect of deficit and supplementary irrigation for staggered production of potato driven by market opportunities at different periods in northeastern Ethiopia. We used potato (Solanum tuberosum) to demonstrate AQUACrop as a tool for improving water productivity during Belg (short) and Meher (long) rainfall seasons. A field experiment was undertaken using supplementary irrigation at different levels of potato crop water satisfaction (50% ETc, 75% ETc, 100% ETc and rainfed conditions) during the Belg (February–May 2020) and Meher (July–October 2020) seasons. Upon proper calibration of AquaCrop for the local potato variety (Belete), long-term simulations revealed that the mean net irrigation requirements were 249 mm during Belg season while the probability of applying supplementary irrigation during Meher was <10% when the effective precipitation was greater than the crop water requirement (ETc) in more than 75% of the years. Although there was significantly higher potato tuber yield from the 100% ETc than that from the 75% ETc, the latter had higher water supply efficiency than the former. Long-term simulations further revealed that the number of rainfall days was more important than the amount of rainfall during the growing period. We engaged water users' associations to employ the recommendation and enforce supplementary irrigation as predicted by the model and we present farmers' response and reasons for resistance toward water saving approaches. Hence, we concluded that 50% ETc and 75% ETc irrigation levels can still be recommended upon proper scheduling to address long dry spells, especially during the middle growth stages in the face of irrigation conflict. However, the institutional settings and market incentives associated with it are the major drivers of adopting improved irrigation water management practices

    Drought vulnerability drives land-use and land cover changes in the Rift Valley dry lands of Ethiopia

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    The Ethiopian Rift Valley is a dry land zone where for a long time pastoral communities have made their living from acacia-based woodlands. But many pastoralists have changed from a pastoral way of life to mixed farming over time. The aim of this study was to evaluate land-use and land cover (LULC) changes in the Central Rift Valley dry lands of Ethiopia, and determine the role of drought vulnerability as a driver. A combination of GIS/remote sensing techniques, drought vulnerability analyses, field observation and surveying were employed. Because drought vulnerability is linked more closely to the types of land-uses and social contexts rather than only climatological events, it was examined based on locally perceived criteria of drought. Accordingly, the pastoral way of life was vulnerable to severe drought during 25% of the last 28 years while the mixed farming (livestock and maize farming combined) system was vulnerable to severe drought only during 4% of the years. Over the last 5 decades, cultivated lands increased to threefold while the dense acacia coverage declined from 42% in 1965 to 9% in 2010. The observed LULC changes were driven by the interplay of recurrent drought, socioeconomic and institutional dynamics, access to markets and improved technologies such as early-maturing maize cultivars and better land management. Proper policy and technological interventions are required to develop appropriate drought adaptation strategies and avert the increasing degradation of woodlands in the Rift Valley dry lands where a pastoral way of life is still present

    Drought vulnerability drives land-use and land cover changes in the Rift Valley dry lands of Ethiopia

    No full text
    The Ethiopian Rift Valley is a dry land zone where for a long time pastoral communities have made their living from acacia-based woodlands. But many pastoralists have changed from a pastoral way of life to mixed farming over time. The aim of this study was to evaluate land-use and land cover (LULC) changes in the Central Rift Valley dry lands of Ethiopia, and determine the role of drought vulnerability as a driver. A combination of GIS/remote sensing techniques, drought vulnerability analyses, field observation and surveying were employed. Because drought vulnerability is linked more closely to the types of land-uses and social contexts rather than only climatological events, it was examined based on locally perceived criteria of drought. Accordingly, the pastoral way of life was vulnerable to severe drought during 25% of the last 28 years while the mixed farming (livestock and maize farming combined) system was vulnerable to severe drought only during 4% of the years. Over the last 5 decades, cultivated lands increased to threefold while the dense acacia coverage declined from 42% in 1965 to 9% in 2010. The observed LULC changes were driven by the interplay of recurrent drought, socioeconomic and institutional dynamics, access to markets and improved technologies such as early-maturing maize cultivars and better land management. Proper policy and technological interventions are required to develop appropriate drought adaptation strategies and avert the increasing degradation of woodlands in the Rift Valley dry lands where a pastoral way of life is still present
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