Reconciling indigenous knowledge with scientific assessment of soil fertility changes in southwestern Burkina Faso

Soil fertility decline has become a major concern of policy makers worldwide. While many researchers assume that the problem is universal, others question the assumptions, evidence, methodologies and scale upon which beliefs of soil decline are based. Reconciling competing visions of African soils requires a close examination of both farmer perceptions and scientific estimations of change at the local level. This paper discusses local soil knowledge in one small village in southwestern Burkina Faso and relates scientific measures of soil fertility to farmers' perceptions of soil types and changing soil fertility. Farmers' perceptions of soil types and characteristics match up very well with scientific investigations. It is with perceptions of soil degradation that differences occur. While farmers perceive that their soil is degraded, soil analyses show very little change. The goal here is not to argue that one type of knowledge is inherently wrong but to reconcile the two and see how and why differences emerge. Particularly important is a discussion of how contradictions emerge out of the social contexts in which perceptions at the local scale and beyond are embedded. © 2002 Elsevier Science B.V. All rights reserved