Browsing by Author "Okoba, B. O."

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    Farmers’ preferences and physical effectiveness of soil and water conservation measures in the east african highlands
    (JSS, 2011) Tenge, A.J.; Sterk, G.; Okoba, B. O.
    Soil erosion by water is a serious threat to sustainable agricultural production in the East African Highlands. Despite the severity of the soil erosion problem, there is not much quantitative information on the effectiveness of the recommended soil and water conservation (SWC) measures, rendering their planning and adoption difficult. This study was conducted in Kwalei catchment Tanzania to assess the physical effectiveness of bench terraces, grass strips and fanya juu terraces, which are the most important SWC measures used in the East African Highlands. Additional information was collected from Gikuuri catchment in Kenya. Trench ditches (at Gikuuri) and runoff plots (at Kwalei) were used to assess the physical effectiveness, while interviews and group discussions were used to obtain farmers' reasons for preferences of certain SWC measures. The results obtained showed significant effects of the tested SWC measures. Surface runoff and soil loss generally decreased, while soil moisture retention and crop yields improved due to the SWC measures. Fanya juu terraces are the most effective measure in reducing soil and water losses followed by bench terraces and grass strips. However, bench terraces retained more soil moisture and increased maize and bean yields than fanya juu and grass strips. Apart from bio-physical criteria to evaluate SWC measures, farmers have other criteria, which depend on their social and economic situations. Important farmers’ criteria are provision of fodder, fertility improvement and low costs for implementation. To facilitate adoption of SWC measures there is a need for consideration and integration of farmers’ criteria into the planning and design of SWC measures, and implementation of SWC activities. Further research work is recommended for identifying economically feasible SWC measures under different biophysical and socio-economic conditions.
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    Participatory soil and water conservation planning using a financial analysis tool in the West Usambara highlands of Tanzania
    (Wiley, 2006) Tenge, A. J.; Okoba, B. O.; Sterk, G.
    Despite decades of soil and water conservation (SWC) efforts in Tanzania, the adoption of the recommended SWC measures by farmers is minimal. In the past, SWC plans did not incorporate farmers' knowledge, and the economics of SWC was not given much attention at the planning stage. This research evaluated the applicability of two tools for participatory soil erosion mapping using farmers' indicators of soil erosion and financial analysis of SWC measures at the planning stage. The two tools were evaluated in Kwalei catchment in the West Usambara highlands, Tanzania. The participatory soil erosion‐mapping tool uses farmers' indicators of soil erosion to identify, classify and map soil erosion at the catchment level. The financial analysis tool involves farmers in a stepwise analysis of the costs and benefits of SWC measures before the implementation. The erosion‐mapping tool increased farmers' awareness on the severity of soil erosion problems, and they realised the need for SWC plans at both field and catchment scales. With the financial analysis tool farmers participated in the cost and benefits analysis and were able to select SWC options that were feasible under their socio‐economic situation. The two tools were able to demonstrate that farmers' participation in SWC planning increases the acceptance of SWC measures because they solve problems that are perceived by themselves. The financial analysis tool demonstrated how farmers could make selection of SWC measures that are feasible under their biophysical and economic condition if they are informed about the costs and benefits.
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    Participatory soil and water conservation planning using an erosion mapping tool in the central highlands of Kenya
    (Wiley, 2007) Okoba, B. O.; Tenge, A. J.; Sterk, G; Stroosnijder, L.
    Despite several approaches that aimed at mobilising East African farmers to embrace soil and water conservation (SWC) activities, farmers hardly responded since they were seldom involved in the planning of SWC activities. Two tools that employ farmers' participation were developed and applied at Gikuuri catchment in Kenya. The first tool involved farmers to map soil erosion using their own indicators and determine the soil erosion status at catchment scale. This formed the basis upon which they undertook to plan for SWC measures at catchment scale. Farmers also predicted crop yield losses based on the soil erosion status. Farmers widely approved the soil erosion status map since their own indicators and perceptions were used. The second tool provided cash flow trends for a variety of SWC activities and farmer situations. Farmers can use land with a high, moderate or low erosion status and often have rather different socio‐economic settings. The net benefits over 5 yr for bench terraces, fanya juu terraces and grass strips were illustrated to assist farmers in making informed decisions on SWC adoption. The two tools increased awareness on the need for collective actions among farmers and showed fields that cause run‐on on downslope fields. The improved awareness of erosion problems and the related financial consequences increased farmers' willingness to share the investment costs for cut‐off drains.