Can a continuous growth of agriculture be achieved in the sub-Sahara region without inducing irreversible damage to the ecosystem? Until now, doubts have been expressed as to the actual capacity of the soils to sustain a desirable increase of production which can match the requirements of a fast-growing population. Thirty years of investigation and a renewed comprehensive interpretation of research data on soil fertility show that a sustainable agriculture growth could be a practical possibility in a savannah region.

General Introduction.- 1 Scope of the Study.- I Fertility and Agricultural Development.- 2 Definition of Fertility.- 3 The Farming Environment.- 4 Population and Migration.- 5 Agricultural Policy.- II Present Fertility Status.- IIA Crop Yields in Recent Times.- 6 National Yield Trends.- 7 Yields in Project Areas.- 8 Summary: Moderate Yields Giving Concern for the Future.- IIB The Development of Soils Under Cropping in Practical Farming.- 9 Soil Development Under Traditional Farming.- 10 The Effect of Population Growth on the Soil.- 11 Agricultural Intensification and Its Consequences for the Management of Soil Fertility.- 12 Summary of Part II.- III Experimental Bases of Sustainability.- 13 Sustainable Yields.- IIIA The Ecological Approach.- 14 Farming and Physical Degradation of the Soil.- 15 Root Development of Crops and Biological Imbalance in Soils.- IIIB Soil Development and Crop Yield in Permanent Rain-Fed Farming - Long-Term Experiments.- 16 Introduction - The Interpretation of Long-Term Experiments.- 17 Year-to-Year Variation in Yield: The Effect of Rainfall and Its Distribution.- 18 Low Intensity Systems - Hand Cultivation.- 19 Hand Cultivation with Intensification.- 20 Systems Using Animal Traction.- 21 Summary of Part III: Indications from Long-Term Experiments.- IV Major Processes in the Development of Soil Fertility.- IVA Items in the Organic Matter Balance in the Soil.- 22 Introduction - Soil as a System.- 23 Items in the Organic Matter Balance of Cultivated Soils and Their Evolution.- 24 Tillage and the Organic Matter Balance of Cultivated Soils.- 25 Additions of Plant Nutrients and the Organic Matter Balance in the Soil.- 26 Establishing the Organic Matter Balance in Cultivated Soils.- IVB Items in the Nutrient Balance of the Soil and TheirEvolution.- 27 Forms of Mineral Material in the Soil and Their Distribution.- 28 Measurement of the Items in the Nutrient Balance of the Soil.- 29 Calculated Nutrient Balance for Several Systems.- 30 Establishing Nutrient Balance Sheets for Cultivated Soil.- 31 Summary of Part IV.- General Conclusions.- 32 Evolution of Soil Fertility in the Savannah Area to the South of the Sahara.- 33 Requirements for the Establishment of Sustainable Agriculture in the Savannah Zone.- References.