Factors affecting soil erosion hazards and conservation needs for tropical steeplands

Abstract

Understanding the basic processes and factors that are responsible for inducing land degradation, particularly soil erosion and associated phenomena is critical to the conceptualization, design, and implementation of productive, stable, and sustainable agricultural systems. This is particularly so on steeplands where the potential for soil erosion and runoff water losses is high. The productivity and degradation hazards on these lands are determined by the site's climate, soil and topography. However, their uniqueness lies more with their topographic constraints than with other factors. Use of steeplands is an increasingly common situation in the tropics because of high population pressures and continuing encroachment on hilly lands. Erosion potential and actual erosion in these settings may exceed tens or even hundreds of tons of soil loss per hectare per year; thus the selection and design of cropping systems, land management systems, and water management systems must be tailored to attain effective runoff and erosion control in order to avoid their detrimental impacts both on-site and off-site. Contrary to the customary arguments for the ‘long-term’ nature of erosion impacts; enhancing the conservation-effectiveness of rainfed farming on tropical steeplands can be shown to provide both short- and long-term benefits to the farming system, the overall economy, and the environment. Productivity-enhancing crop and soil and water conservation management approaches (biological measures) may be more important than structural measures in imparting long-term sustainability. Incorporating indigenous knowledge into project design should be emphasized to assure the farmer's involvement and cooperation in planning, implementing, and maintaining conservation measures.