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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    Mobilizing farmers to stop land degradation: A different discourse from Burundi
    Kessler, Aad ; Reemst, Laurie Van; Beun, Micael ; Slingerland, Erik ; Pol, Laura ; Winne, Ruben De - \ 2020
    Land Degradation and Development (2020). - ISSN 1085-3278
    Stopping land degradation is one of the biggest challenges worldwide and particularly in Burundi, with its unprecedented rates of soil loss and growing food insecurity. This article proposes a different discourse on how to engage people in stopping land degradation, and presents results and lessons learned from a bottom‐up inclusive approach implemented since 2014 in Burundi: the integrated farm planning (PIP) approach. The PIP approach aims to build a solid foundation for sustainable change toward enhanced food production and good land stewardship, based on three foundation principles (motivation, stewardship, and resilience) and three guiding principles (empowerment, integration, and collaboration). This article is based on two studies undertaken in 2018: an impact study among 202 households and a qualitative study using the most significant change methodology with 30 households. Findings from both studies provide initial support that the PIP approach generates considerable changes at household, farm, and village level. Based on a vision and a plan for their farm, motivated PIP households are currently investing in the resilience of their farms and applying a diversity of conservation practices, while in all PIP villages concrete collective action is undertaken for sustainable land stewardship. Given its rapid upscaling in Burundi and the potential of the PIP approach to mobilize farmers for motivated action, the article concludes with a reflection on the core elements of a different discourse to stop land degradation.
    Effect of village savings and loan associations on adoption of index-based crop insurance under limited liabilities
    Ndagijimana, Marcien ; Asseldonk, Marcel van; Kessler, Aad ; Ndimubandi, Jean - \ 2020
    Journal of Agriculture and Rural Development in the Tropics and Subtropics 121 (2020)1. - ISSN 1612-9830 - p. 23 - 33.
    Burundi - Community savings and credit associations - Index-based crop insurance - Integrated farm planning - Risk management

    A household survey and focus group discussions were conducted to quantify the general determinants of an indexbased crop insurance adoption under limited liabilities in Burundi, and specifically the effect of existing Village Savings and Loan Associations (VSLAs). The survey sample comprised of 40 crop insurance adopters, 40 non-adopters and 40 drop-outs in Bukirasazi and Makebuko communes of Gitega province. The results indicated that saving money (by VSLAs) for upcoming premium payments and regularly VSLA meetings attendance increase insurance adoption with relative risk ratio (RRR) = 0.21, p ≤ 0.001) and (RRR = 0.01, p ≤ 0.01), respectively. In addition, VSLAs’ members with more knowledge in land management (RRR = 0.07, p ≤ 0.05), crop management (RRR = 0.05, p ≤ 0.001) and integrated farm planning (RRR = 0.03, p<0.05) were more likely to adopt the crop insurance. Furthermore, smallholders being aware and less appreciative limited liability were more likely inclined to adopt crop insurance with RRR = 0.12 (p ≤ 0.01) and RRR = 0.01 (p ≤ 0.001), respectively. Given the importance of VSLA in fostering crop insurance adoption, we recommend strengthening VSLAs in their operation, save for upcoming premium payments as jointly agreed and set in their constitution, and encourage smallholders to run their farms with integrated farm planning. Due to limited knowledge of smallholders about the mode of crop insurance operation, a more extensive capacity building coupled to a coaching by experts in this domain is more than a necessity.

    How farmers’ characteristics influence spontaneous spreading of stone bunds in the highlands of Ethiopia: a case study in the Girar Jarso woreda
    Abi, Meskerem ; Kessler, C.A. ; Oosterveer, P.J.M. ; Tolossa, Degefa - \ 2020
    Environment, Development and Sustainability 22 (2020)1. - ISSN 1387-585X - p. 317 - 335.
    sustainable land management - readiness to change - intrinsic motivation - social capital - extension strategies
    This study aims to identify key differences between farmers who spontaneously implement stone bunds (i.e. farmers implementing stone bunds by their own initiative) and farmers who do not. Data were collected in the Girar Jarso woreda in the central highlands of Ethiopia, through a household survey with 80 farmers: 40 with spontaneously implemented stone bunds and 40 without. Independent samples t test, principal component analysis and regression analysis were used to analyse the data. Results show that five key-factors explain differences between the two groups of farmers: (1) readiness to change, (2) available resources, (3) social capital, (4) type of family, and (5) commitment. These factors together explain 73% of the variance in the data set and show that particularly characteristics related to the farmer’s intrinsic motivation play a crucial role to spontaneously implement and integrate stone bunds into the farming system. Furthermore, results show that young farmers are most committed to soil conservation: they are often intrinsically motivated dynamic farmers who are ready to change their future and improve productivity and food security. The study suggests that government extension programmes should therefore focus more on these young and dynamic farmers and foster their readiness to change. This implies that extension workers and government officials should better understand the crucial role of farmers’ intrinsic motivation when dealing with sustainable land management, and also reformulate extension strategies and messages. This is particularly important when developing a scaling-up strategy that helps to sustainably increase agricultural production and achieve food security of small-holder farmers in Ethiopia.
    Community-based finance and Climate-Smart Agriculture
    Asseldonk, M.A.P.M. van; Ndagijimana, M. ; Kessler, C.A. ; Deering, Karl ; Girvetz, Evan ; Hella, Joseph ; Karanja, Stanley ; Masoud, Thabit ; Osiemo, Jamleck ; Wesenbeeck, Lia van; Oostendorp, Remco ; Recha, John ; Radeny, Maren ; Gathiaka, John ; Mulwa, Richard ; Wattel, C.J. ; Pamuk, H. ; Ruben, R. - \ 2019
    In: The 5th Global Science Conference on Climate-Smart Agriculture 2019, 8-10 October 2019, Bali, Indonesia. - Australian Centre for International Agricultural Research (ACIAR) - p. 64 - 65.
    Community-based finance and Climate-Smart Agriculture
    Recha, John ; Radeny, Maren ; Ndagijimana, M. ; Kessler, C.A. ; Deering, Karl ; Girvetz, Evan ; Hella, Joseph ; Karanja, Stanley ; Masoud, Thabit ; Osiemo, Jamleck ; Wesenbeeck, Lia van; Oostendorp, Remco ; Gathiaka, John ; Mulwa, Richard ; Wattel, C.J. ; Pamuk, H. ; Ruben, R. ; Asseldonk, M.A.P.M. van - \ 2019
    - 1 p.
    Exploring entrepreneurial-group formation by smallholder Burundian farmers
    Mupfasoni, Bélyse ; Kessler, Aad ; Lans, Thomas ; Ngenzebuke, Rama Lionel - \ 2019
    Journal of Agribusiness in Developing and Emerging Economies (2019). - ISSN 2044-0839
    Burundi - Entrepreneurial teams - Group formation - Internal states - Motivation - Rural development - Sustainable agriculture

    Purpose: The purpose of this paper is to analyze the role of specific internal states (i.e. the set of sustainable values and motivations) that underlie group formation and joint business idea identification of farmer groups in the context of Burundi. Design/methodology/approach: Quantitative and qualitative data were combined in this study. Quantitative data were analyzed using basic statistics. Qualitative data were collected in focus group discussions with farmer groups. Findings: Findings revealed that groups are not just formed on the basis of homophily (same level of internal states) but also on “compensation” and “committed leadership.” Moreover, prior sustainable behavior of members influences sustainability of new group business ideas and the nature (e.g. focus on farming) of that business idea. Research limitations/implications: As this study was done at an early stage of group formation and does not include group dynamics over a longer period of time, further monitoring of the groups is needed to examine if the observed motivation persists. Originality/value: Although there is a vast amount of literature on entrepreneurial and top management teams, literature on the (early) mechanisms of entrepreneurial group formation in an emerging economy and rural context is relatively scarce.

    Adapting the current mass mobilization approach in Ethiopia to enhance its impact on sustainable land management: Lessons from the Sago-kara watershed
    Teka, M.A. ; Kessler, C.A. ; Oosterveer, P.J.M. ; Tolossa, Degefa - \ 2019
    Journal of Environmental Management 248 (2019). - ISSN 0301-4797 - 9 p.
    participatory training - intrinsic motivation - integrated farm planning - drought mitigation - sustainable land management
    This paper analyses the effect of an adapted – more participatory and more integrated – mass mobilization training approach on Ethiopian farmers' motivation to practice integrated farming and invest in Sustainable Land Management (SLM). It is based on the results of an experiment carried-out in the Sago-kara watershed in the Central highlands of Ethiopia, in which a group of 26 farmers received an adapted training at the start of the mass mobilization campaign in 2016, which aimed to strengthen farmers' knowledge and awareness about natural resource management, drought mitigation and integrated farm planning. One year later, both qualitative and quantitative data were collected through group discussions, field observations and household surveys. For the before-after comparison we used descriptive statistics to analyze the data; the with-without comparison (with a control group) differences were statistically tested at 1% and 5% probability levels. The results show that the adapted training approach enhanced awareness of farmers, created motivation for integrated farm management and fostered implementation of SLM practices in the field. Most interesting is that farmers who followed the training better plan for drought mitigation and are more aware of the possible effects of drought on their farming activities. The study concludes that the current mass mobilization approach in Ethiopia can have more impact on SLM if it would pay serious attention to: 1) creating awareness on the causes and effects of erosion and drought focusing on sustainability issues, 2) fostering farmers' intrinsic motivation to be good stewards of their land; 3) training in integrated farm planning, and 4) developing farm plans based on farmers’ visions for resilient farming. In order to make agricultural extension in Ethiopia more effective, one has to start with capacity building of the rural extension staff in participatory training methods, followed by empowering and motivating farmers for SLM. This will not only lay a foundation for sustainable agriculture and more food security on the farm, but is also crucial for the scaling-up of resilient farming to watershed and landscape levels in Ethiopia.
    Understanding farmers' investments in sustainable land management in Burundi : A case-study in the provinces of Gitega and Muyinga
    Ndagijimana, Marcien ; Kessler, Aad ; Asseldonk, Marcel van - \ 2019
    Land Degradation and Development 30 (2019)4. - ISSN 1085-3278 - p. 417 - 425.
    Burundi - farmers' investments - land degradation - multinomial regression - sustainable land management

    Understanding farmers' decision-making to tackle land degradation by means of sustainable land management (SLM) practices is essential for policy makers. The main objective of this study was to identify factors that influence farmers' investments in SLM. A survey was conducted in two provinces of Burundi (Gitega and Muyinga) among 160 households. Methods for data analysis comprised descriptive statistics and multinomial logistic regression. It was derived that both provinces experience severe land degradation, with soil erosion experienced by 88% of the farmers and soil fertility depletion by 92%. Furthermore, findings show that occurrence of soil erosion on the farm (p = 0.025), access to credit (p = 0.022), education level (p = 0.040), engagement of the household head in farming (p < 0.001), and age of the household head (p = 0.050) are significantly and positively associated with higher investments in SLM. Moreover, the findings reveal that the yearly costs per farmer associated to the SLM practices' implementation ranged from US$10.08 for soil and water conservation practices up to US$36.24 for organic fertilizers. Therefore, in order to foster SLM, we recommend policy makers in Burundi to improve access to credit markets in rural areas and enhance efforts to strengthen smallholders' skills, bringing as such more integrated and effective solutions to cope with land degradation problems.

    100 jaar Wageningen
    Heusinkveld, B.G. ; Marcelis, L.F.M. ; Kessler, C.A. ; Wamelink, G.W.W. ; Mücher, C.A. ; Vliet, A.J.H. van; Oost, J. van der; Timmermans, A.J.M. ; Wijffels, R.H. - \ 2019
    Contribution of systems thinking and complex adaptive system attributes to sustainable food production : Example from a climate-smart village
    Jagustović, Renata ; Zougmoré, Robert B. ; Kessler, Aad ; Ritsema, Coen J. ; Keesstra, Saskia ; Reynolds, Martin - \ 2019
    Agricultural Systems 171 (2019). - ISSN 0308-521X - p. 65 - 75.
    Climate-smart agriculture - Complex adaptive systems - Food production system - Systems thinking - West Africa

    Climate-smart agriculture (CSA) conceptually has the potential to contribute to the sustainable development goals of achieving zero hunger, reducing land degradation, eliminating poverty, tackling climate change, and promoting gender equality. The scaling-up needed to achieve goals of CSA represents a challenge, as it entails understanding synergies between often opposing socioeconomic and environmental priorities and trade-offs over temporal and spatial scales. In this paper, we tested new approaches to support scaling-up of sustainable food production through investigating the contribution of systems thinking as a conceptual approach and complex adaptive system (CAS) attributes as a framework for analysis of CSA. This was done through examining (i) to what extent CSA represents a CAS and (ii) what contribution systems thinking and CAS attributes can make to understanding and scaling-up sustainable food production systems through CSA. The CSA situation was conceptualized through systems thinking sessions with women farmers in the climate-smart village (CSV) of Doggoh-Jirapa, northern Ghana, and was guided by the Distinctions, Systems, Relationships and Perspectives (DSRP) framework. Systems thinking, and CAS attributes provide system-wide understanding of elements, dynamics and trade-offs over temporal and spatial scale in selected agri-food systems. As such it could aid horizontal and vertical scaling-up by informing policy developoment and selection of a context-specific portfolio of technologies and practices at landscape and farm levels to achieve synergies between goals. In this study, systems thinking enabled women farmers in the CSV to identify income-generating and tree planting activities, with desirable simultaneous system-wide impact. The paper calls for further testing of tools, approaches, and methods that enable dynamic systems thinking to inform scaling-up efforts, while embracing the transdisciplinary nature and complexity of CSA as a constituent of the food production system.

    How rural out-migrations drive changes to farm and land management : A case study from the rural Andes
    Caulfield, Mark ; Bouniol, Judith ; Fonte, Steven J. ; Kessler, Aad - \ 2019
    Land Use Policy 81 (2019). - ISSN 0264-8377 - p. 594 - 603.
    Ecuador - Labour availability - Land degradation - Out-migrations - Remittances - Soil and water conservation

    Rural-urban migrations are one of the most conspicuous patterns in global population shifts in recent decades and can have considerable impacts on land-use and management in the rural migrant-sending communities. To better understand these impacts, we employed household surveys and semi-structured interviews to generate a small, but detailed and relatively complete set of data (43 out of a total of 57 households) from a rural indigenous Kichwa community in the Andean highlands of Ecuador. We conducted linear regression analyses (LR) between migration-related attributes of each household and farm management variables in order to provide greater insight into the complex relationships and impacts of rural out-migration on farm and land management. Our findings indicated that reduced household labour availability was associated with a decrease in the use of physical soil and water conservation (SWC) techniques (p = <0.01), while remittances received from rural out-migrations were associated with an increase in the use of pesticides and chemical fertilizers (p = <0.01). The results of the LRs were used to develop a Structural Equation Model (SEM) to elucidate the direct and indirect effects between increased access to financial resources (as a result of temporary out-migrations) and the use of agro-chemicals and mechanized tillage (industrialized farming techniques). Our analysis suggests that temporary out-migrations were indirectly related to the use of industrialized farming techniques through their effects on household financial resources and subsequent farm-level decisions to increase the proportion of potato cash crops. As a consequence, it is probable that the effects of out-migration, at least in this case-study, are negatively affecting the agroecosystems of the landscape. However, the results of the SEM suggest that this response may be specific to this particular socio-ecological context. Rural development policies, programmes and projects must therefore explicitly recognise and better understand these broader socio-ecological contexts and their effects on farm-level decisions in view of rural out-migration in order to develop more effective intervention strategies.

    Global efforts to foster sustainable soil management
    Kessler, C.A. - \ 2018
    WURcast
    soil management - soil fertility management
    Sustainable Agricultural Entrepreneurship in Burundi: drivers and outcomes
    Mufasoni, B. ; Kessler, A. ; Lans, T. - \ 2018
    Journal of Small Business and Enterprise Development 25 (2018)1. - ISSN 1462-6004 - p. 64 - 80.
    Purpose
    The purpose of this paper is to contribute to the emerging literature on sustainable entrepreneurship by studying knowledge, motivation and early stage outcomes of sustainable agricultural entrepreneurship in the context of farmer groups in Burundi.
    Design/methodology/approach
    Quantitative and qualitative data were combined in a multiple-source case study. Data were analyzed using content analysis and basic statistics.
    Findings
    Results revealed that farmer groups’ prior knowledge (PK) on environmental sustainability is better developed than their social and economic sustainability. This is reflected in the environmental sustainability part of the business plans (BPs), which is generally better than the economic and social sustainability parts. Moreover, the top groups on PK identified opportunities directly related to their PK. Pro-activeness of the group was a more determining factor than risk taking and innovativeness. Furthermore, there seemed to be a positive interplay between the groups’ PK, entrepreneurial orientation and knowledge motivation (KM) and the quality of the sustainable BP. In particular, KM seemed to be important, but other variables also explained the quality of the BP, such as level of education.
    Originality/value
    This research fills a gap in literature because there are few empirical studies on agricultural entrepreneurship that focus on the earliest phase of opportunity recognition, let alone studies that focus on sustainable opportunity recognition in the context of emerging economies such as Burundi. Furthermore, in this research, the authors studied well-known knowledge, motivations and outcomes of sustainable entrepreneurship
    Assessing farmers'willingness to participate in campaign-based watershed management : Experiences from Boset District, Ethiopia
    Assefa, Samuel ; Kessler, Aad ; Fleskens, Luuk - \ 2018
    Sustainability 10 (2018)12. - ISSN 2071-1050
    Ethiopia - Mass mobilization - Outcomes - Perceptions - Soil and water conservation - Willingness

    This study assessed farmers' perceptions of the outcomes of the Campaign-BasedWatershed Management (CBWM) program in Ethiopia, and how this influences their willingness to participate in the program. Key informant interviews, a household survey, and the Google Earth Engine were used to collect and analyze the relevant data. Results show that farmers' perceived outcomes of the CBWM program hardly motivated them to participate in the program. Particularly, farmers were not motivated by the physical effects of the program, because of the limited direct benefits to individual households, and destruction of previously developed micro-watersheds by frequent runoff and human and animal disturbances. Similarly, farmers were not motivated by the economic effects of the program, because of the limitations/absence of benefit-sharing mechanisms and resultant conflicts among farmers. The only motivating outcome of the program concerned its effect on personal capacities, which was particularly appreciated in localities that were vulnerable to erosion. The results of the study suggest the need to (1) better integrate actions at watershed level to come to effective water runoff control, (2) enhance the participation of all local actors to come to more effective area closure initiatives with transparent benefit-sharing mechanisms, and (3) give much more emphasis to capacity building as a cross-cutting component in the program. Hence, in order to enhance the willingness of farmers to genuinely participate in the CBWM, the program should adopt a more participatory and integrated approach.

    Modelling and mapping erosion in smallholder agro-ecosystems, Tanzania
    Wickama, Juma ; Kessler, Aad ; Sterk, Geert - \ 2018
    Land Degradation and Development 29 (2018)8. - ISSN 1085-3278 - p. 2299 - 2309.
    agro-ecosystems - biophysical factors - soil erosion - Tanzania - West Usambara Highlands

    The West Usambara Highlands in north-eastern Tanzania have many smallholder agro-ecosystems with unknown composition, management, and vulnerability to erosion. Their specific locations and spatial extent are difficult to trace by satellite images or remote sensing imagery alone. To address these limitations, we combined ground soil surveys, geographic information system, and erosion modelling to (a) locate and map smallholder agro-ecosystems, (b) determine their biophysical characteristics, and (c) model their soil losses. Land resource information was collected from 301 random 0.1-ha plots sampled from a total area of 200 km2. Annual soil losses were estimated using the universal soil loss equation. The study located six dominant agro-ecosystems with the following spatial extent: maize-bean (24.9%), maize-bean-agroforestry (31.2%), maize-bean-agroforestry-high value trees (18.9%), tree farms (7.0%), forests (15.6%), and grazing lands (2.3%). Agroforestry and other tree-based agro-ecosystems dominate the area due to historical land use change and later institutional interventions. This study finds combined use of soil surveys, geographic information system, and modelling to be reliable in locating, mapping, and assessing soil losses in smallholder agro-ecosystems. The agro-ecosystems differ significantly (p < 0.05) in slope, vegetation cover, soil conditions, and soil losses. Soil loss in the maize-bean agro-ecosystem (28.3 t ha−1 yr−1) was 18 times higher compared with natural forests (1.57 t ha−1 yr−1) due to lower soil cover and inefficient conservation and cultivation practices. Our results show that adoption of soil conservation measures and improved vegetation cover technologies across the agro-ecosystems reduces soil losses by 37% and increases organic carbon levels by 16%.

    Understanding the spontaneous spreading of stone bunds in Ethiopia : Implications for sustainable land management
    Abi, Meskerem ; Kessler, Aad ; Oosterveer, Peter ; Tolossa, Degefa - \ 2018
    Sustainability 10 (2018)8. - ISSN 2071-1050
    Ethiopia - Integrated farm management - Mass mobilization - Spontaneous spreading and adoption - Stone bunds - Sustainable land management

    This study deals with the spontaneous spreading of stone bunds in the central Ethiopian highlands, i.e., the adoption and implementation of stone bunds by farmers on their own initiative. The study tests the hypothesis that spontaneously implemented stone bunds, as compared to stone bunds implemented by mass mobilization campaigns, are more integrated with other land management practices and lead to higher yields. Data are collected in the Girar Jarso woreda through field observations and household surveys. Descriptive statistics are used to analyze and test the data at 1% and 5% probability levels. Results show that stone bunds are spontaneously implemented mainly on farmlands located nearby the homesteads where farmers perceive severe erosion, poor soil fertility and steep slope gradients. Compared to stone bunds implemented by mass mobilization, spontaneously implemented stone bunds are perceived as better maintained, more frequently modified to fit the farming system and better integrated with soil fertility management practices, such as applying fertilizer, compost and manure. Particularly, this better integration with other practices is very important, because it makes stone bunds more effective in reducing erosion, leading to beneficial effects on soil moisture and soil productivity, as perceived by farmers. The study, therefore, suggests that the mass mobilization campaign should use a more participatory and integrated approach, in which there is ample space for awareness raising and learning concerning the benefits of integrated farm management, and in which farmers themselves have a leading role in the decision on where to construct stone bunds. Such a strategy will lead to more sustainable impact on soil fertility and food security than the current top-down intervention approach.

    The quest for improving soil fertility : Why an integrated approach is needed
    Beek, Christy van; Herold, Nadine ; Kessler, Aad ; Vonk, Remko - \ 2017
    Outlook on Agriculture 46 (2017)4. - ISSN 0030-7270 - p. 289 - 294.
    Africa - Fertilizer - Interventions - Soil nutrients - Stakeholders
    Improving the productive capacity of lands has been on the international development agenda for many years. Yet, to date insufficient progress has been made. Although there have been successes, they tend to be of limited impact, and spontaneous spreading of good practices is low. In this article, different intervention paradigms are reviewed. It is concluded that interventions differ in their fundamental view of drivers for change. We found interventions that aim to increase the total amount of nutrients within the soil, either through increasing inputs or through increasing demands, but seldom both at the same time.We also found interventions that aim to increase the efficacy of existing soil nutrients through either increasing the nutrient holding capacity (e.g. through mulching) or the release of nutrients (e.g. through liming). The differentiation of these approaches has strong effects on the institutional organization of the intervention. This article makes the case for integrating these different approaches and for more collaboration at institutional levels to facilitate this process.
    Facing climate change in burundi with an integrated agricultural and health insurance approach
    Ndagijimana, M. ; Asseldonk, M.A.P.M. van; Kessler, C.A. ; Habonimana, Oswald ; Houtekamer-van Dam, Annette - \ 2017
    In: The state of microinsurance Microinsurance Network (Microinsurance Network's Annual Journal 3) - p. 32 - 37.
    Assessing the effect of water harvesting techniques on event-based hydrological responses and sediment yield at a catchment scale in northern Ethiopia using the Limburg Soil Erosion Model (LISEM)
    Grum, Berhane ; Woldearegay, Kifle ; Hessel, Rudi ; Baartman, Jantiene E.M. ; Abdulkadir, Mohammed ; Yazew, Eyasu ; Kessler, Aad ; Ritsema, Coen J. ; Geissen, Violette - \ 2017
    Catena 159 (2017). - ISSN 0341-8162 - p. 20 - 34.
    Calibration - Northern Ethiopia - Rain intensity - Runoff - Soil erosion
    Runoff and sediment yield in semi-arid catchments are highly influenced by infrequent but very heavy rains. These events occur over short temporal scales, so runoff and sediment transport can only be understood using an event-based analysis. We applied a hydrological and soil-erosion model, LISEM, to the Gule catchment (~ 12 km2) in northern Ethiopia. The objectives of the study were: (a) to evaluate the performance of LISEM in describing event-based hydrological processes and sediment yield in a catchment under the influence of different water harvesting techniques (WHTs), and (b) to study the effect of the WHTs on catchment-scale event-based runoff and sediment yield. The model performed satisfactorily (NSE > 0.5) for most of the events when discharge was calibrated at the main outlet (Gule) and at a sub-outlet (Misbar). Runoff coefficients for the Gule catchment and Misbar sub-catchment were expectedly low due to the implementation of WHTs, which can store runoff from the rains and increase infiltration into the soil. Simulated and measured sediment yields were of similar orders of magnitude. LISEM generally overestimated sediment yield compared to the measurements. The poor performance of LISEM in predicting sediment yield could be attributed to the uncertainty of several factors controlling soil erosion and the inadequacy of LISEM in describing soil erosion on steep slopes. Catchment-scale model simulations indicated that runoff and sediment yield could be effectively reduced by implementing WHTs. The model estimated 41 and 61% reductions in runoff and sediment yield at the Gule outlet, respectively. Similarly, runoff and sediment yield at the Misbar sub-outlet were reduced by 45 and 48%, respectively. LISEM can thus be used to simulate the effects of different existing or new WHTs on catchment hydrology and sediment yield. The results of scenario predictions could be useful for land-use planners who intend to implement different measures of catchment management.
    Effect of in situ water harvesting techniques on soil and nutriënt losses in semi-arid Northern Ethiopia
    Grum, Berhane ; Assefae, Dereje ; Hessel, R. ; Woldearegay, Kifle ; Kessler, C.A. ; Ritsema, C.J. ; Geissen, V. - \ 2017
    Land Degradation and Development 28 (2017)3. - ISSN 1085-3278 - p. 1016 - 1027.
    Land degradation, mainly due to soil erosion and nutrient losses, is a global problem for sustainable agriculture. Farmlands in the Ethiopian
    highlands are susceptible to water erosion because of steep slopes and extensive cultivation. A field experiment was conducted in the Gule
    sub-watershed in northern Ethiopia to assess the efficacy of in situ water harvesting techniques in reducing soil and nutrient losses. The
    research was carried out on a sandy clay loam soil under semi-arid conditions. Soil erosion and nutrient losses were monitored during the
    rainy season (June to September) in 2013 and 2014. Five treatments with tied ridges, wheat-straw mulch and effective microorganisms, alone
    or in combination, and an untreated control were tested. Combined tied ridges and straw mulch, with and without effective microorganisms,
    significantly reduced average soil loss over the two rainy seasons by 82 and 90% respectively compared with the control. Tied ridges alone
    reduced average soil loss by 60%. Straw mulch with and without effective microorganisms decreased average soil loss by 81 and 85%
    respectively. Combined tied ridges and straw mulch significantly decreased average total nitrogen and total phosphorus losses by 82 and
    83% respectively. Average nutrient losses were also significantly decreased by tied ridges (59% for nitrogen, 52% for phosphorus) and straw
    mulch (63% for nitrogen, 68% for phosphorus). Our results indicated that in situ water harvesting techniques can effectively reduce soil and
    nutrient losses from farmland and were more efficient when the techniques were combined
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