Smallholder farmers' use of integrated nutrient-management strategies: patterns and possibilities in machakos district of Eastern Kenya

摘要

Depletion of soil nutrients is a major constraint to crop productivity in serai-arid cropping systems characterized by low and highly variable rainfall and soils that are deficient in inherent soil nutrients, waterholding capacity and organic-mattercontent. In these areas crop yields vary considerably between on-station experiments or researcher-managed on-farm trials and those that farmers achieve on their plots (KARI, 1995). Crop improvement and better natural resource management (NRM) practices- particularly soil, water and nutrient management - are therefore essential for increasing productivity and sustaining the resource base. Yet, although farmers frequently use new seed varieties, they consistently ignore extension recommendations on improved NRM practices (Rukadema et al., 1981; Muhammad and Parton, 1992; Tiffen et al., 1994). Consequently, the quality of soil resources and its productive capacity remains low and many farmers realize a small proportion of the potential productivity gains possible from adoption of new crop varieties. This chapter examines the factors that condition farmers' choice of soil-fertility maintenance practices in a semiarid cropping system. It describes recent data on farmers' soil-fertility maintenance practices in a semiarid area of Kenya and draws implications for testing and developing practical soil-fertility management options with farmers.