Fertility of Soils: A Future for Farming in the West African Savannah

Front Matter....Pages I-XVIII
Front Matter....Pages 1-1
Scope of the Study....Pages 3-9
Front Matter....Pages 11-11
Definition of Fertility....Pages 13-17
The Farming Environment....Pages 18-31
Population and Migration....Pages 32-41
Agricultural Policy....Pages 42-46
Front Matter....Pages 47-47
National Yield Trends....Pages 49-60
Yields in Project Areas....Pages 61-70
Summary: Moderate Yields Giving Concern for the Future....Pages 71-71
Soil Development Under Traditional Farming....Pages 75-83
The Effect of Population Growth on the Soil....Pages 84-99
Agricultural Intensification and Its Consequences for the Management of Soil Fertility....Pages 100-111
Summary of Part II....Pages 112-115
Front Matter....Pages 117-117
Sustainable Yields....Pages 119-123
Farming and Physical Degradation of the Soils....Pages 127-131
Root Development of Crops and Biological Imbalance in Soils....Pages 132-145
Introduction — The Interpretation of Long-Term Expriment....Pages 149-153
Year-to-Year Variation in Yield: The Effect of Rainfall and Its Distribution....Pages 154-157
Low Intensity Systems — Hand Cultivation....Pages 158-163
Hand Cultivation with Intensification....Pages 164-167
Systems Using Animal Traction....Pages 168-177
Front Matter....Pages 117-117
Summary of Part III: Indications from Long-Term Experiments....Pages 178-209
Front Matter....Pages 211-211
Introduction — Soil as a System....Pages 213-215
Items in the Organic Matter Balance of Cultivated Soil and Their Evolution....Pages 216-221
Tillage and the Organic Matter Balance of Cultivated Soils....Pages 222-230
Additions of Plant Nutrients and the Organic Matter Balance in the Soil....Pages 231-243
Establishing the Organic Matter Balance in Cultivated Soils....Pages 244-261
Forms of Mineral Material in the Soil and Their Distribution....Pages 265-272
Measurement of the Items in the Nutrient Balance of the Soil....Pages 273-285
Calculated Nutrient Balance for Several Systems....Pages 286-295
Establishing Nutrient Balance Sheets for Cultivated Soils....Pages 296-302
Summary of Part IV....Pages 303-311
Front Matter....Pages 313-313
Evolution of Soil Fertility in the Savannah Area to the South of the Sahara....Pages 315-321
Requirements for the Establishment of Sustainable Agriculture in the Savannah Zone....Pages 322-334
Back Matter....Pages 335-348