s:1326:"TI An ecological and economic analysis of phosphorus replenishment for Vihiga Division, western Kenya 
AU Soule, M. 
AU Shepherd, K. 
AB Soil scientists have identified phosphorus deficiency as a major constraint to improved maize and bean yields in the highland areas of western Kenya. This study evaluated the economic costs and benefits as well as ecological impacts of different phosphorus replenishment strategies from both a farm-level and a regional perspective using an economic-ecological simulation model. The study associated soil properties with representative farm types and showed how the impact of soil fertility replenishment depends on initial soil conditions as well as the resource endowment level of the farmer. Two hundred and ten different strategies for phosphorus replenishment with different sources of phosphorus applied at various levels were analyzed for seven farm types. The farm-level analysis showed that phosphorus replenishment was generally profitable for farms with low and medium pH (4.9–6.2) soils, but not for farms with high pH (6.2–7.0) soils. A regional analysis showed that benefits were higher when phosphorus replenishment was targeted to farmers with low and medium resource endowments on low and medium pH soils rather than spread evenly across all soil and farm types. 
";