Fertilizer research

, Volume 35, Issue 3, pp 227–235

Calculating soil nutrient balances in Africa at different scales

I Supra-national scale
  • J. J. Stoorvogel
  • E. M. A. Smaling
  • B. H. Janssen
Article

DOI: 10.1007/BF00750641

Cite this article as:
Stoorvogel, J.J., Smaling, E.M.A. & Janssen, B.H. Fertilizer Research (1993) 35: 227. doi:10.1007/BF00750641

Abstract

Nutrient balances were calculated for the arable soils of 38 sub-Saharan African countries. FAO production figures and forecasts for 35 crops for the period 1982–1984 and for 2000 were used to define land use systems, further characterized by fertility input through fertilizers, manure, rain and dust, biological N-fixation, and sedimentation, and fertility output through harvest of crops and removal of residues, leaching, denitrification, and erosion. The summarized output of the study is the sum of inputs minus the sum of outputs of nitrogen, phosphorus and potassium in the root zone. The alarming annual average nutrient loss for sub-Saharan Africa was 22 kg N, 2.5 kg P, and 15 kg K in 1982–84, and will be 26 kg N, 3 kg P, and 19 kg K in 2000. As the soil nutrient pool has to offset the negative balances each year, there is gross nutrient mining in sub-Saharan Africa. The need for integrated systems of nutrient management is emphasized, manipulating all inputs and outputs in a judicious way. Future scenarios of ‘continued mining’ and ‘conservation of soil fertility’ are discussed.

Key words

integrated nutrient management systems land use systems mineral fertilizers manure nutrient balance sub-Saharan Africa 

Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • J. J. Stoorvogel
    • 1
  • E. M. A. Smaling
    • 1
  • B. H. Janssen
    • 2
  1. 1.DLO The Winand Staring Centre for Integrated LandSoil and Water Research (SC-DLO)WageningenThe Netherlands
  2. 2.Department of Soil Science and Plant NutritionAgricultural UniversityWageningenThe Netherlands

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