Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Comparative transcriptome analysis of Ethiopian indigenous chickens from low and high altitudes under heat stress condition reveals differential immune response
    Park, W. ; Srikanth, K. ; Lim, D. ; Park, M. ; Hur, T. ; Kemp, S. ; Dessie, T. ; Kim, M.S. ; Lee, S.R. ; Pas, M.F.W. te; Kim, J.M. ; Park, J.E. - \ 2019
    Animal Genetics 50 (2019)1. - ISSN 0268-9146 - p. 42 - 53.
    highlands - lowlands - RNA-seq - thermal tolerance

    Ethiopia is an ecologically diverse country; the low altitude regions are hot and humid whereas the high altitude regions are cooler. In this study we analyzed the transcriptome response of high altitude (Addis Ababa) and low altitude (Awash) chickens to heat stress conditions that are prevalent in the low altitude regions. The chickens were free ranged for 20 h in an enclosure in Awash, and then the heart, breast muscle and spleen tissues were collected at 6:00 am, 12:00 noon and 6:00 pm to follow a daily circadian cycle. Through RNA-sequencing analysis, we identified differentially expressed genes (DEGs) that were significant (q < 0.05). These DEGs were subjected to protein–protein interaction (PPI) network and gene co-expression network (GCN) analyses to understand their role. KEGG pathway analysis and Gene Ontology analysis of all the identified DEGs and the genes identified from the PPI network and GCN analyses revealed that several immune-related pathways, such as proteasome, focal adhesion, influenza A, the ErbB signaling pathway and glycerophospholipid metabolism, were enriched in response to heat stress. These results suggest that the high altitude chickens were under heat stress and might be immunologically susceptible. Our findings will help in developing a genetic approach to mitigate production loss due to heat stress.

    Intensive groundwater use and (in)equity: Processes and governance challenges
    Hoogesteger van Dijk, J.D. ; Wester, P. - \ 2015
    Environmental Science & Policy 51 (2015). - ISSN 1462-9011 - p. 117 - 124.
    water - policies - india - sustainability - organizations - irrigation - strategies - management - highlands - depletion
    Groundwater forms the basis for millions of rural and urban livelihoods around the world. Building on insights from the theory of access, in this article we present how groundwater development has brought much well-fare in many parts of the world; and how resulting intensive groundwater use is leading to ill-fare through aquifer overexploitation and processes of water accumulation and dispossession. We show the difficulty of state regulation and the modest achievements of other governance approaches that aim to solve existing groundwater problems. To study these processes we propose a framework of analysis that is based on the study of hydrosocial-networks, the political economy of groundwater and the domains and discourses that define groundwater access. Such analysis highlights the challenges of devising policies and modes of governance that contribute to social and environmental sustainability in intensively used aquifers. These we argue should build on an analysis of equity that scrutinizes the discourses, actors, powers and procedures that define groundwater access. By inciting debates on equity a first and fundamental step can be made toward advancing more inclusive groundwater governance that crucially engages the marginalized and addresses their groundwater problems, concerns and needs.
    Feeding, crop residue and manure management for integrated soil fertility management - A case study from Kenya
    Castellanos Navarrete, A. ; Tittonell, P.A. ; Rufino, M.C. ; Giller, K.E. - \ 2015
    Agricultural Systems 134 (2015). - ISSN 0308-521X - p. 24 - 35.
    smallholder farming systems - western kenya - conservation agriculture - livestock systems - cycling efficiencies - exploring diversity - carbon dynamics - dairy-cows - highlands - resource
    Western Kenya is one of Africa’s most densely populated rural areas, characterised by intensive smallholder crop–livestock systems on degraded lands managed with small inputs of mineral fertiliser and animal manure. Competing uses for crop residues and other organic resources often results in poor nutrient cycling efficiencies at farm scale. Modifying livestock feeding, retaining more crop residues in the field, and improving manure management can help conserving considerable amount of nutrients on-farm. To examine to what extent such strategies would be feasible, we analysed whole-farm nutrient cycling efficiencies (NCE) of a range of farms differing in resource-endowment and production orientation, identifying the most efficient farmer strategies considering labour and financial constraints. Nutrient concentration in excreted cattle manure was relatively small (i.e., N <1.7%; P <0.6%). Current manure management practices led to low NCE’s (average 27%) due to nutrient losses from excretion through storage and application. Farmers have few incentives to improve manure management given the small amounts of excreta and nutrients to be recycled. Yet, manure, both composted and fresh, represented the greatest N (16 kg ha-1 season-1) and C returns to the soil (312 kg C ha-1 season-1). Retention of crop residues was the cheapest source of nutrient inputs for the next crop, especially when compared with manure, but farmers prioritised its use for cattle feeding. Our findings highlight the critical lack of nutrients and organic residues on smallholder farms in the densely-populated highlands of East Africa, as well as low NCE when it comes to manure. In these conditions, efficient nutrient cycling for manure and improved cattle feeding are essential to increase use efficiencies of any possible external nutrient added in these farms.
    Soil organic matter in Northern Ethiopia, current level and predicted trend: a study case of two villages in Tigray
    Corral-Nunez, G. ; Opazo-Salazar, D. ; GebreSamuel, G. ; Tittonell, P.A. ; Gebretsadik, A. ; Gebremeskel, Y. ; Tesfay, G. ; Beek, C.L. van - \ 2014
    Soil Use and Management 30 (2014)4. - ISSN 0266-0032 - p. 487 - 495.
    highlands - restoration - degradation - exclosures - dynamics
    Soil degradation resulting from permanent and high pressure on natural resources is a threat for the present and future of agricultural production in Ethiopia. Mono-cropping, cultivation on steep slopes, use of cattle manure and crop residues as an energy source for cooking are common practices that have led to declining soil organic matter (SOM) contents. The objective of this research was to evaluate the current status of SOM in farmlands and exclosures (areas protected from grazing to allow their natural restoration) in Northern Ethiopia and to explore the long-term effects of current agricultural practices and an improved scenario on SOM. At present, the SOM content of farmland soils is small, ranging from 2.1% to 2.9%, while exclosures showed a significant recovery after 20 yr of protection, with SOM contents ranging from 2.6% to 5.6%. However, the level of SOM in farmland soils is envisaged to decline given current agricultural practices, that is removal of crop residues and use of manure as an energy source for cooking. We found that applying manure alone appeared to be insufficient to revert this trend, due to limited availability and its alternative uses. Therefore, a multidisciplinary approach including improved manure and compost management needs to be supplemented with energy saving techniques, as fuel use is currently the largest competing claim for organic matter in the area.
    Land management in the north-western highlands of Ethiopia: adoption and impact
    Akalu Teshome Firew, ; Firew, A.T. - \ 2014
    Wageningen University. Promotor(en): Leo Stroosnijder, co-promotor(en): Jan de Graaff. - Wageningen : Wageningen University - ISBN 9789462571563 - 148
    grondbeheer - landdegradatie - hooglanden - waterbescherming - bodembescherming - ethiopië - land management - land degradation - highlands - water conservation - soil conservation - ethiopia


    Over the last four decades, the government of Ethiopia and various a consortium of donors have been promoting different land management (LM) practices in the highlands of Ethiopia to halt land degradation. However, the adoption rate of these practices has been low. This is because investments in LM practices are influenced by various institutional, socio-economic and bio-physical factors. The main objective of this research is to investigate the impact of these different factors on investments in LM in the north-western Ethiopian highlands. It focuses on the drivers of the different stages of adoption, on profitability of LM practices, and on land quality, land fragmentation, tenure arrangements and social capital.

    We examined the drivers of the different stages of adoption of soil and water conservation (SWC) practices using an ordered probit model. The results indicate that adoption of soil and water conservation (SWC) passes through four major phases: non-adoption/dis-adoption, initial adoption, actual adoption and final adoption. Some socio-economic and institutional factors have a different effect on the respective SWC adoption phases. Final adoption depends mostly on profitability, land-related factors, social capital and perception of erosion problems.

    We also investigated the effectiveness and profitability of three SWC practices (stone bunds, soil bunds and Fanya juu bunds) using the Universal Soil Loss Equation (USLE) and Cost Benefit Analysis (CBA). The results show that SWC practices are effective in controlling soil erosion, though the profitability of these SWC methods is dependent on the site where they are used. Fanya juu and stone bunds are generally profitable under standard conditions (e.g. medium slope and average soil quality and labour costs). However, the study also shows that different underlying assumptions change the CBA results considerably and consequently also change the conclusions regarding circumstances under which SWC measures are or are not profitable.

    Besides, we assessed farmers’ perceptions about land quality, land fragmentation and tenure systems and their influence on interrelated LM (Bunds, Compost/Manure and Fertilizer) investments using a multivariate probit (MPV) model. The study shows that investments in LM practices are interdependent. For example, compost/manure and fertiliser substitute each other to a certain extent (often not used together, or used interchangeably by farmers) in the farming system of the study areas. Land quality (e.g. slope and soil fertility status), land fragmentation (parcel size and distance of parcel from homestead) and tenure arrangements influence farmers’ investments in LM practices.

    In addition, the relationship between the different dimensions of social capital and investments in LM practices was explored. The results show that the different dimensions of social capital affect LM practices differently. In particular, the cooperation and trust dimensions of social capital are associated with the intensity of investment in SWC bunds and fertiliser use. The extent of participation in formal institutions has a positive effect on the use of fertiliser and compost.

    Furthermore, we evaluated different SWC practices using Multi-Criteria Analysis (MCA) to assess their ecological, economic and social impacts. The study reveals that MCA is an effective evaluation tool that can take into account non- monetary and less quantifiable effects of SWC measures, which is not possible with Cost Benefit Analysis. The results of the analysis indicate that farmers have a range of criteria to evaluate the performance of SWC measures. The relative importance of each criterion in the selection of SWC alternatives depends to a large extent on slope categories.

    For enhancing the adoption and impacts of land management, there is a need to increase knowledge about location specific viable LM practices, to promote collective action at watershed level, to pay more attention to farmers’ preferences and to improve the capacity and capability of farmers.

    Handling multi-functionality of livestock in a life cycle assessment: the case of smallholder dairying in Kenya
    Weiler, V. ; Udo, H.M.J. ; Viets, T.C. ; Crane, T.A. ; Boer, I.J.M. de - \ 2014
    Current Opinion in Environmental Sustainability 8 (2014). - ISSN 1877-3435 - p. 29 - 38.
    milk-production - food-production - systems - highlands - benefits
    Life cycle assessment (LCA) is an acknowledged method to assess the contribution of livestock production to greenhouse gas (GHG) emissions. Most LCA studies so far allocate GHG emissions of livestock to marketable outputs. Smallholder systems, however, provide several products and services besides the production of marketable products. We explored how to account for multi-functionality within the LCA method in a case of smallholder milk production in the Kaptumo area in Kenya. Expressed per kg of milk, GHG emissions were 2.0 (0.9–4.3) kg CO2-e, respectively in case of food allocation, 1.6 (0.8–2.9) kg CO2-e in case of economic function allocation and 1.1 (0.5–1.7) kg CO2-e in case of livelihood allocation. The two Carbon Footprint (CF) estimates of milk production considering multi-functionality were comparable to CF estimates of milk in intensive milk production systems. Future LCA's of smallholder systems should account for multi-functionality, because CF results and consequently mitigation options change depending on the functions included.
    Farmers' Perceptions of Land Degradation and their Investments in Land Management: a Case Study in the Cental Rift Valley of Ethiopia
    Adimassu, Zenebe ; Kessler, A. ; Yirga, C. - \ 2013
    Environmental Management 51 (2013)5. - ISSN 0364-152X - p. 989 - 998.
    soil fertility management - conservation practices - nutrient balances - tenure security - south wello - highlands - adoption - smallholders - erosion - area
    To combat land degradation in the Central Rift Valley (CRV) of Ethiopia, farmers are of crucial importance. If farmers perceive land degradation as a problem, the chance that they invest in land management measures will be enhanced. This study presents farmers’ perceptions of land degradation and their investments in land management, and to what extent the latter are influenced by these perceptions. Water erosion and fertility depletion are taken as main indicators of land degradation, and the results show that farmers perceive an increase in both indicators over the last decade. They are aware of it and consider it as a problem. Nevertheless, farmers’ investments to control water erosion and soil fertility depletion are very limited in the CRV. Results also show that farmers’ awareness of both water erosion and soil fertility decline as a problem is not significantly associated with their investments in land management. Hence, even farmers who perceive land degradation on their fields and are concerned about its increase over the last decade do not significantly invest more in water erosion and soil fertility control measures than farmers who do not perceive these phenomena. Further research is needed to assess which other factors might influence farmers’ investments in land management, especially factors related to socioeconomic characteristics of farm households and plot characteristics which were not addressed by this study.
    Co-investments in land management: lessons from the Galessa watershed in Ethiopia
    Adimassu, Zenebe ; Kessler, A. ; Stroosnijder, L. - \ 2013
    International Journal of Sustainable Development and World Ecology 20 (2013)6. - ISSN 1350-4509 - p. 532 - 541.
    grass-roots - soil conservation - degradation - highlands - adoption - systems - benefits - africa
    The use of co-investment activities to motivate farmers to carry out sustainable land management is increasingly recognized. Several co-investment efforts have been implemented to combat land degradation and increase agricultural production in the Ethiopian highlands. Nevertheless, these co-investment activities have not been documented. Moreover, the impacts of these activities have not been evaluated. This study presents a co-investment initiative for sustainable land management in the Galessa watershed in Ethiopia. It documents successful co-investment activities that trigger farmers to carry out land management practices, and assesses the impact of these activities on farmers’ land management investments. The most important co-investment activities that trigger farmers to invest in land management are co-investments in awareness creation, water provision, technology, and governance. Of these activities, co-investing in water provision is most successful, because it directly solves one of the basic needs of farmers in the watershed. Results reveal that the experimental group of farmers (participants in the co-investment initiative) – compared to the control group (nonparticipants) – invested significantly more in land management practices such as soil bunds, composting, and tree planting. This article concludes that use of multiple co-investment activities are crucial to trigger farmers to invest in land management in Ethiopia.
    Community Irrigation Supplies and Regional Water Transfers in the Colca Valley, Peru
    Vera Delgado, J.R. ; Vincent, L.F. - \ 2013
    Mountain Research and Development 33 (2013)3. - ISSN 0276-4741 - p. 195 - 206.
    highlands - commons - rights
    Water governance of Andean river valleys that are the site of large-scale water transfers and the home to highland communities with their own irrigation practices has been the subject of research and debate since the large water transfers began. In Peru, local and regional water governance has been shaped by changing national water laws that remain controversial regarding their effects on highland water users. This article presents findings from the Colca Valley, where water has been transferred to the Majes Irrigation Project since 1983, while many highland communities still struggle to access sufficient irrigation water. It summarizes the attempts by Colca Valley communities to protect their water rights and water management institutions under a system oriented to regional and national rather than local water resources management, with a detailed discussion of the community of Coporaque. It also presents data on the area's highly variable water allowances and water use patterns, which demonstrate the need for more transparency and agro-ecological understanding of local irrigation needs and efforts to support them. Processes of representation, participation, and water redistribution are discussed as critical issues in improved regional water governance in the Colca Valley
    Sustainable land management in dynamic agro-ecosystems: an Integrated, multi-scale socio-ecological analysis in Western Kenya highlands
    Mutoko, M.C. - \ 2013
    Wageningen University. Promotor(en): Rik Leemans, co-promotor(en): Lars Hein; C.A. Shisanya. - S.l. : s.n. - ISBN 9789461737854 - 157
    grondbeheer - duurzaamheid (sustainability) - duurzaam bodemgebruik - agro-ecosystemen - hulpbronnenbeheer - hooglanden - natuurbeheer - kenya - land management - sustainability - sustainable land use - agroecosystems - resource management - highlands - nature management - kenya

    This study was motivated by the puzzlingly localised implementation of available Sustainable Land Management (SLM) practices despite the urgent need to reduce both land degradation and general poverty levels in the western highlands of Kenya. This research aimed to not only unravel reasons for the restricted geographical diffusion of SLM practices but also make concrete contributions to foster the promotion of SLM practices. Four specific research objectives and questions were formulated, and an integrated, multi-scale socio-ecological systems framework designed to address these issues at various levels. At the farming system level, high livelihood diversity was found as households increasingly depend on off-farm income opportunities. Besides, results show low production efficiency (average 40%) across five distinct farm types with important implications on intensification in land use. The off-farm oriented and resource-poor farm types were the least likely to invest in SLM practices on their farms. For the forest ecosystem, the estimated local economic benefits of around US$ 450 ha-1 yr-1 were considerably less than half the forgone returns from agricultural activities if the forest were to be converted. Arguably, continued protection of the Kakamega rainforest is justified because of the unknown value of its rich biodiversity and stored carbon in its system, which does not currently generate local economic benefits. At the landscape level, this study found that Vihiga District has undergone rapid land-use changes in the past 25 years. In particular, there has been a major conversion of forest and bare land to agricultural land use. Results show that productivity of tea and to a lesser extent, vegetables increased but the yields of maize and beans—the most common crops—oscillated around 1 ton ha-1. As a result, per capita food crop production dropped by 28% during the past two decades. Empirical findings demonstrate that high and increasing population pressure on land does not necessarily lead to agricultural intensification. Finally, with stakeholder participation, I evaluate local potentials for initiating collaborative action towards wider promotion of SLM practices in the western highlands of Kenya. A positive correlation (rho = 0.83) was found between stakeholder co-operation and the success level of past SLM projects. Reasonable prospects such as some technology adoption activities and organisation of local actors were established, which are necessary for triggering the transformation process to sustainable state of productivity. Based on synthesis of the key findings presented in this thesis, I conclude that the difficulty of achieving wider geographical diffusion of SLM practices in the study area can be attributed to four main reasons. First, there is a practical challenge to properly target the technologies to the right farming households in order to achieve the greatest impacts. Second, the rampant decrease in productive resources (land, capital and labour) for farm production coupled with low efficiencies in common farm enterprises has created an additional aspect of poverty traps—a ‘maize-centred’ poverty trap—making it difficult for a majority of farmers to invest meaningfully in SLM practices. Third, increasing pressure on land from population growth has failed to stimulate better land management practices and efficient resource use in agriculture possibly because the community attempts to make for the shortfall from off-farm activities or by accessing the almost free forest resources where available in the district. Lastly, the low collaboration level among key stakeholders involved in promotion of various components of SLM practices indicates a thin spread of efforts on the ground and unexpectedly delays an accelerated technological transition process. Therefore, I recommend a paradigm shift to embrace a broader, integrated and multi-stakeholder approach to solving the problem of land degradation in the study area and other similar agro-ecosystems in SSA; an approach that equally promotes improved farm productivity and creates off-farm income opportunities.

    Movements against the current : scale and social capital in peasants’ struggles for water in the Ecuadorian Highlands
    Hoogesteger van Dijk, J.D. - \ 2013
    Wageningen University. Promotor(en): Linden Vincent; M. Baud, co-promotor(en): Rutgerd Boelens. - S.l. : s.n. - ISBN 9789461735904 - 193
    watervoorraden - waterrechten - water - boerenstand - inheemse volkeren - sociaal kapitaal - gemeenschappen - politieke bewegingen - watergebruik - instellingen - irrigatiesystemen - hooglanden - ecuador - water resources - water rights - water - peasantry - indigenous people - social capital - communities - political movements - water use - institutions - irrigation systems - highlands - ecuador
    This thesis is about peasant and indigenous struggles for water rights in the Ecuadorian Highlands. It is based on the following main research question: How have peasant and indigenous communities developed multi-scalar political agency in water governance to gain and maintain their water access and related rights in the Ecuadorian Highlands since the 1980s? To answer this question, this thesis analyses the histories and relationships between organized water users, water reforms and non-governmental development organisations (NGOs) active in the Ecuadorian irrigation sector. Through state reforms, and processes of coproduction between NGOs and local peasant and indigenous communities, water user associations were created in many supra-community irrigation systems. Once created, these organisations formed the basis for the development of provincial and national federations and policy advocacy networks and platforms that now form the building blocks of the Ecuadorian water users movement.
    Participatory integrated watershed management in the north-western highlands of Rwanda
    Kagabo, M.D. - \ 2013
    Wageningen University. Promotor(en): Leo Stroosnijder, co-promotor(en): Saskia Visser. - [S.l.] : s.n. - ISBN 9789461735492 - 104
    integraal waterbeheer - waterbeheer - beheer van waterbekkens - stroomgebieden - hooglanden - duurzaam bodemgebruik - duurzaamheid (sustainability) - rwanda - integrated water management - water management - watershed management - watersheds - highlands - sustainable land use - sustainability - rwanda

    This thesis is the result of assessments on the extent of existing resource use and management practices using a Participatory Integrated Watershed Management (PIWM) as a viable approach to promote best soil water conservation (SWC) measures towards more sustainable land use. The study was conducted in two contrasting agro-ecological zones of the north-western highlands of Rwanda, namely; Gataraga and Rwerere in the framework of “Agasozi ndatwa” referred to as PIWM. "Agasozi ndatwa" program is implemented at watershed scale and involves investments from the government in establishing soil and water conservation structures as well as other development related activities. A stratification sampling approach was used in selecting the study area. The first strata consisted of a watershed and the second-level of strata consisted of villages. Two villages with boundaries that nearly coincided with that of the micro-watershed were selected.The studywas started by assessing the ecological and economic sustainability of smallholder farms using the level of nitrogen recycling between farm activities and farm income as indicators. Soil fertility management components including farm inputs and improved farming systems combined with the knowledge on how to adapt these practices to local conditions at field, farm and watershed levels were evaluated. Following a proper participatory assessment of soil and water conservation, a field experiment was conducted to explore the efficiency of 20+ year old slow forming terraces in farmer’s fields. Finally, the impact of PIWM activities on Natural Resource Management (NRM), crops and livestock productivity on farmers’ livelihoodwas assessed and the integration of several policies that are operating simultaneously in the watershed was evaluated.Nutrient balances and flows differed for the two agro-ecological zones due to differences in crop management and the importance of livestock. Positive nutrient balances were found for relatively fertile volcanic soils, but on steep slopes and acidic soils, N, P and K stocks were declining at rates of 8.6, 1.4 and 17.5 kg ha-1 year-1, respectively. Nitrogen recycling between farm activities was low, varying between 1.8 and 6 %, which may decrease the adaptability and reliability of the current farming systems. Integrated Soil Fertility Management (ISFM) component treatments comprising thecombination of fertilizer, FYM and improved seeds significantly increased yields but resulted (i) in a lower Nitrogen Agronomic Efficiency (N-AE) across sites and on relatively fertile foot slopes and (ii) in a lower marginal rates of return (MRR) due to the high cost of seeds and N fertilizer. Slow forming terraces of 20+ year old showed a marked “within” spatial difference in both soil quality and crop yield. The soil in the lower part of the terraces showed as much as 57% more organic carbon content and 31% more available phosphorous than the soil in the upper part. The marked soil fertility gradients indicate that the sustainability of slow-forming terraces is threatened, unless a site-specific fertilizer strategy is developed. Results suggest that an PIWM approach has the potential of improving farmers’ livelihoods and increasing the resilience of a degraded environment. Furthermore, due to PIWM approach, synergy of policies was effective leading to (i) positive impact on the size and composition of livestock, (2) the availability and use of manure, (3) the increase of production of fodder and (4) the reduction of soil loss.

    Participatory policy development for integrated watershed management in Uganda's highlands
    Mutekanga, F.P. - \ 2012
    Wageningen University. Promotor(en): Leo Stroosnijder; Arthur Mol, co-promotor(en): Kris van Koppen; Saskia Visser. - S.l. : s.n. - ISBN 9789461733450 - 112
    beheer van waterbekkens - integraal waterbeheer - hooglanden - beleid - participatie - uganda - leren - watershed management - integrated water management - highlands - policy - participation - uganda - learning

    Soil erosion is a serious problem in the densely populated Uganda highlands and previous interventions were ineffective. This study, on the Ngenge watershed, Mount Elgon, was aimed at developing policy for the implementation of a new strategy for solving the problem, Integrated Watershed Management (IWM). For policy development, a user-friendly method for assessing erosion risk - using rainfall, slope and NDVI - enabled identifying priority areas for interventions, and a stakeholder analysis enabled identifying key stakeholders who participated in multilevel workshops for deliberating on appropriate interventions. In these workshops social learning was stimulated through constructing scenarios and developing action and work plans which are to inform policy. There was general satisfaction with the workshop processes and the participation of the stakeholders. However, considering IWM as a policy strategy, it was realized that it cannot be ‘rolled out’ but needs to be geared to specific biophysical and social context factors.

    Exploring determinants of farmers' investments in land management in the Central Rift Valley of Ethiopia
    Adimassu Teferi, Z. ; Kessler, A. ; Hengsdijk, H. - \ 2012
    Applied Geography 35 (2012)1-2. - ISSN 0143-6228 - p. 191 - 198.
    water conservation measures - developing-countries - soil conservation - highlands - adoption - degradation - technologies - decision - erosion
    Land degradation, especially water erosion and nutrient depletion, seriously affects agricultural production in the Central Rift Valley of Ethiopia. Farmers' investments to conserve their land are until now however quite limited. The objective of this study is to identify the major factors that determine farmers' decisions how much and where to invest in land management. Exploratory factor analysis and Pearson correlation were used to analyse the data from 240 households operating 738 plots in three different production domains. The study identified five major factors that influence farmers' decisions how much to invest in land management: (1) households' resource endowments, (2) farming experience and knowledge, (3) access to information, (4) social capital and (5) availability of family labour. This result implies that extension strategies aiming at sustainable land management should try to enhance households' resources endowments and improve their access to information. Moreover, the influence of social capital and availability of family labour indicates the crucial importance of collective action in land management. Similarly, the study revealed that farmers are more willing to invest in plots that (1) are vulnerable to water erosion, (2) have better soil fertility and (3) are larger. However, the influence of these factors on farmers' investments in land management was highly variable across the considered production domains. Hence, the diversity in social, economic, cultural and biophysical conditions must be taken into account by rural extension programmes. This calls for site-specific land management strategies that can be planned and implemented at micro-level with active participation of farmers
    Evaluating quantitative and qualitative models: an application for nationwide water erosion assessment in Ethiopia
    Sonneveld, B.G.J.S. ; Keyzer, M.A. ; Stroosnijder, L. - \ 2011
    Environmental Modelling & Software 26 (2011)10. - ISSN 1364-8152 - p. 1161 - 1170.
    soil loss equation - northern ethiopia - information - highlands - degradation - environment - prediction - scale
    This paper tests the candidacy of one qualitative response model and two quantitative models for a nationwide water erosion hazard assessment in Ethiopia. After a descriptive comparison of model characteristics the study conducts a statistical comparison to evaluate the explanatory power of the models, using an Ethiopian soil erosion data set as reference. The study, therefore, introduces a generic transformation procedure, whereby qualitative models reproduce quantitative results, while the outcomes of quantitative models are mapped on an ordered (qualitative) classification. The evaluation yields the following results. Application of the USLE model in Ethiopia is restricted by data paucity, while it ranks lowest in the statistical evaluation. However, it provides reliable results in areas where water erosion incidence is low. The Expert model, based on easily available data and expert judgements, covers a wide variability of the explanatory variables, which makes it suitable for a nationwide assessment. It is the second-best model in the statistical evaluation. Yet, its qualitative output complicates the assessment of the dynamic changes in soil productivity characteristics, while the postulated additive form of the logit model is not appropriate to assess erosion hazard. The quantitative AccDat model has the highest predictive power and is based on easily available data, but has a frail empirical basis and its application at a nationwide scale requires a careful interpretation. The varying performances in the different areas of the data domain justify the selection of a combination of models for a nationwide erosion assessment, rather than a single ‘best’ model.
    A longitudinal study on Anopheles mosquito larval abundance in distinct geographical and environmental settings in western Kenya
    Imbahale, S.S. ; Paaijmans, K.P. ; Mukabana, W.R. ; Lammeren, R.J.A. van; Githeko, A.K. ; Takken, W. - \ 2011
    Malaria Journal 10 (2011). - ISSN 1475-2875 - 13 p.
    malaria vector control - gambiae complex - spatial-distribution - land-cover - habitat characterization - transmission - highlands - arabiensis - identification - interventions
    Background - As the ecology of mosquito larvae can be complex there is need to develop a rational framework for undertaking larval ecological studies. Local environmental characteristics, such as altitude, climate and land use, can significantly impact on phenology and population dynamics of mosquito larvae, and indirectly affect the dynamics of mosquito-borne diseases. The aim of this study was to assess the feasibility of implementing an integrated approach to larval source management under the distinct ecological settings. Methods - The study was conducted in two highland villages and one village, at a lower altitude, in the Lake Victoria basin, where malaria is endemic and transmitted by the same Anopheles mosquito species. In each village the stability of mosquito larval habitats was classified as either temporary or permanent. The productivity of these habitat types was quantified by carrying out weekly larval sampling using a standard dipping method for a period of two years. During sampling the physical characteristic of the larval habitat, including the vegetation cover were noted. Ambient temperature, rainfall and relative humidity were recorded on a 21 × Micro-datalogger in each study site. Results - Anopheles gambiae sensu lato larvae were found in all study sites. Anopheles arabiensis was more abundant (93%) in Nyalenda (Lake Victoria basin) and Fort Ternan (highland area; 71%). In Lunyerere (highland area), An. gambiae sensu stricto comprised 93% of the total An. gambiae s.l. larvae. Larvae of An. gambiae s.l. mosquitoes were present in both temporary and permanent habitats with monthly variations dependent on rainfall intensity and location. Anopheles larvae were more likely to be found in man-made as opposed to natural habitats. Grassy habitats were preferred and were, therefore, more productive of Anopheles larvae compared to other habitat types. Weekly rainfall intensity led to an increase or decrease in mosquito larval abundance depending on the location. Conclusion - The majority of mosquito breeding habitats were man made in all sites. Both temporary and permanent habitats were suitable for An. gambiae breeding. In Fort Ternan temporary sites were favoured for mosquito breeding above permanent sites. Significant differences in larval abundance were found depending on weekly rainfall intensity. Larval source management programmes should target permanent and temporary habitats equally and work closely with land and home owners as a majority of the breeding habitats are man made
    Modern variety adoption and risk management in drought prone areas: insights from the sorghum farmers of eastern Ethiopia
    Cavatassi, R. ; Lipper, L. ; Narloch, U. - \ 2011
    Agricultural Economics 42 (2011)3. - ISSN 0169-5150 - p. 279 - 292.
    technology adoption - diversity - conservation - agriculture - highlands - africa - shocks - maize - size
    Adoption rates of improved or modern varieties (MV) of sorghum in eastern Ethiopia are generally low. Although these MV may represent an effective means of coping with droughts, given their early maturing traits, landraces could prove to be more drought-tolerant and better adapted to marginal production conditions. Whether MV adoption is a risk reducing technology is very much an empirical question which this article investigates using a unique dataset from eastern Ethiopia in a year of extreme weather conditions. Results show that risk-factors coupled with access to markets and social capital drive farmers’ decisions to adopt MVs. On the one hand, it appears that farmers use MVs to mitigate moderate risks. On the other hand, farmers who have been most vulnerable to extreme weather events are less likely to use MVs suggesting that MV adoption does not necessarily represent an effective means of coping with drought. Finally, findings show that MV growers are more likely to be affected by sorghum failure once controlling for exogenous production factors
    Performance assessment of smallholder irrigation in the Central Rift Valley of Ethiopia
    Halsema, G.E. van; Lencha, B.K. ; Assefa, M. ; Hengsdijk, H. ; Wesseler, J.H.H. - \ 2011
    Irrigation and Drainage 60 (2011)5. - ISSN 1531-0353 - p. 622 - 634.
    highlands - income - water
    The recent increase in smallholder irrigation schemes in the Central Rift Valley of Ethiopia has been associated with the overexploitation of water resources, while the economic viability of these schemes has been questioned. This paper assesses water use efficiencies of the Haleku Irrigation Scheme and quantifies improvement scenarios. The viability of these scenarios is discussed, taking into account the socio-economic performance of the Haleku Irrigation Scheme and the nearby Dodicha Irrigation Scheme – that feature similar settings but contrasting socio-economic performance. The irrigation efficiency of Haleku is 35%, but conveyance losses and application efficiencies vary widely across the scheme. Scenario results indicate scope for improvement and reduced water abstraction. Yields and economic returns of irrigated crops were higher in Haleku than in Dodicha, but yields are still lower than attainable yields. Any strategy to increase irrigation efficiency will have to include a programme to improve crop productivity and economic returns. Considering the over-abstraction of water resources, the poor irrigation performance of Haleku and the disappointing socio-economic performance of both Haleku and Dodicha suggest that policy should focus on improving existing schemes in the Central Rift Valley instead of further developing new ones. Copyright © 2011 John Wiley & Sons, Ltd. L'augmentation récente des périmètres irrigués à petite échelle dans la vallée centrale du Rift, en Éthiopie a été associée à la surexploitation des ressources en eau, tandis que la viabilité économique de ces emménagements a été mise en doute. Cette étude évalue l'efficacité de l'utilisation d'eau du système irrigué de Haleku et quantifie les scénarios d'amélioration. La viabilité de ces scénarios est discutée en tenant compte des performances socio-économiques de l'aménagement de Haleku et de celles du système irrigué de Dodicha. Les deux sont géographiquement proches, présentent des caractéristiques physiques similaires, mais diffèrent par les performances socio-économiques. L'efficacité de l'irrigation de Haleku est de 35%, mais les pertes de transport et efficacité de l'application varient considérablement au sein du périmètre. Les scénarios appliqués indiquent des possibilités d'amélioration et de réduction des prélèvements d'eau. Les rendements et la rentabilité économique des cultures irriguées sont plus élevés à Haleku qu'à Dodicha, mais les rendements sont toujours inférieurs aux rendements réalisables. Toute stratégie visant à accroître l'efficacité d'irrigation devra inclure un programme de l'amélioration de la productivité des cultures et la rentabilité économique. Compte tenu de la surexploitation des ressources en eau, la performance médiocre de l'irrigation à Haleku et la performance décevante socio-économique des deux emménagements Haleku et Dodicha, il est suggéré que la politique devrait se concentrer sur l'amélioration des systèmes existant dans la vallée centrale du Rift au lieu de continuer à développer de nouveaux.
    Assessing drought risk and irrigation need in northern Ethiopia
    Araya, A. ; Stroosnijder, L. - \ 2011
    Agricultural and Forest Meteorology 151 (2011)4. - ISSN 0168-1923 - p. 425 - 436.
    barley hordeum-vulgare - rainwater use - dry spells - rainfall - highlands - variability - model - index - conservation - efficiency
    Long-term climate data of four stations in the northern Ethiopia were analyzed in combination with information from local farmers and documented materials. From this analysis, a suitable drought-assessing technique was developed and site-specific needs for supplementary irrigation were explored. Results showed that our technique for assessing drought and crop failure corresponded well with farmer observations. The three major causes of crop failure (dry spells, short growing period and “total lack of rain”) which were explicitly listed and ranked by the local farmers were found to match the analyzed data well. The agro-meteorological variables with the most severe consequences were “short growing period” and “total lack of rain”. To prolong the growing period, supplementary irrigation is recommended in the month of September for three of the stations (Maychew, Mekelle and Adigudom) because: (1) rain frequently stops in early September or late August and crops have no other source of water for the rest of the growing period; (2) sufficient surface runoff can be harvested in July and August to be stored in farm ponds and used in September; (3) more cultivable land can be irrigated if supplementary irrigation is scheduled only for the month of September; and (4) giving supplementary irrigation in September can cut yield reduction by over 80% and crop failure by over 50%, except at Alamata. At Alamata, supplementary irrigation must be scheduled for July. The conditions experienced during the famine years of the early 1980s were primarily caused by the continued total rain failure over multiple years. Giving supplementary irrigation in July or September would probably not have mitigated the effects of these droughts, especially at Alamata and Maychew stations
    A tool for rapid assessment of erosion risk to support decision-making and policy development at the Ngenge watershed in Uganda
    Mutekanga, F.P. ; Visser, S.M. ; Stroosnijder, L. - \ 2010
    Geoderma 160 (2010)2. - ISSN 0016-7061 - p. 165 - 174.
    soil-erosion - land-cover - evapotranspiration - catchment - australia - highlands - ethiopia - forest - stream - basin
    This study tests a rapid, user-friendly method for assessing changes in erosion risk, which yields information to aid policy development and decision-making for sustainable natural resources management. There is currently a lack of timely, up-to-date and current information to support policy development on sustainable natural resources management in Uganda. The study was carried out in the Ngenge watershed, a typical catchment in the Ugandan Highlands, characterised by deforestation in favour of subsistence agriculture without adequate soil and water conservation measures. The watershed is experiencing soil erosion, sedimentation and flooding problems which are threatening agricultural productivity and food security. Sustainable management of environmental resources is needed to ensure a livelihood for the rural population which is dependent on the land. Historical erosion risk was evaluated in three steps using multi-temporal satellite data. First, current erosion risk was assessed by combining slope and vegetation cover during periods of high intensity rainfall. The data used for the assessment was obtained from public (free) satellite images. Erosion risk was then linked to land use and finally to the change in vegetation cover over the years 1980-2000. The analysis of erosion risk using rainfall, slope and NDVI (Normalised Difference Vegetative Index) as a proxy for vegetation cover gives an indication of the current erosion risk in the area. The results of historical vegetation cover change analysis indicate an overall increase in areas under erosion risk in the study area from 1980 to 2000. This method of erosion risk mapping provides a quick and straightforward means for identifying priority areas for interventions for soil and water resource management. Considering that resources are limited, the interventions to be appropriate have to be focused mainly on areas affected by degradation.
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