Soil nutrient balances: what use for policy? I. Scoones a,* , C. Toulmin b a Environment Group, Institute of Development Studies, University of Sussex, Brighton BN1 9RE, UK b Drylands Programme, International Institute for Environment and Development, 4 Hanover Street, Edinburgh EH2 2EN, UK Abstract This paper reviews the application of the nutrient budget and balance approach from a range of settings and scales in Africa. The paper asks: can such analyses help in the design of effective policy which supports improved soil fertility management by Africa's small-holder farmers? Through the examination of existing studies, the paper highlights some of the dif®culties with nutrient budget analyses, including potential problems with a snapshot approach when trying to understand longer term dynamic processes; the danger of extrapolation to wider scales from limited locale-speci®c data sets; the challenges of understanding diversity, complexity and uncertainty within small-holder farming systems; and the importance of insights into the many socio-economic and institutional factors which in¯uence decision-making at farm level and so mediate the processes of environmental change. The paper concludes by recognising the potential contribution of nutrient budget analyses to the policy process, but suggests caution over uncritical use; particularly the employment of aggregate studies to diagnose generalised problems and suggest blanket solutions. The paper also highlights how nutrient budget analyses can be used as simple devices to encourage debate and dialogue among farmers, technical scientists and policy actors in a participatory process of negotiating interventions or policies for tackling issues of agricultural sustainability in Africa. # 1998 Elsevier Science B.V. All rights reserved. Keywords: Soil fertility; Nutrient budgets; Scale; Sustainability; Policy; Africa 1. Introduction In recent years, nutrient budget and balance approaches have become widely applied in the African context. Studies have been undertaken at a variety of scales: from plot and catchment to regional analyses and, sometimes, even continent-wide assessments. The conclusions emerging from many such studies point to widespread processes of `nutrient mining' and soil fertility decline. Considering the urgent need to increase agricultural production in Africa, these are alarming conclusions. These, in turn, have prompted a variety of responses at a policy level, where conclu- sions from nutrient budget and balance assessments are increasingly used to justify policies and interven- tions, both at national and international levels (e.g. IFPRI, 1995; FAO, 1996; World Bank, 1996). This paper asks: do nutrient budgets give us the information needed to understand the status and dynamics of soil fertility across small-holder African farming systems? Can such analysis help design pol- icy to support improved soil fertility management by Africa's small-holder farmers? Agriculture, Ecosystems and Environment 71 (1998) 255±267 *Corresponding author. Fax: +44 01273 62 1202; e-mail: i.scoones@sussex.ac.uk 0167-8809/98/$ ± see front matter # 1998 Elsevier Science B.V. All rights reserved. PII: S0167-8809(98)00145-5