INTRODUCTION

It has been forecast that the global human population will increase from the present six billion to eight billion by the year 2020. In order for there to be sufficient food, both for these additional people and to raise the standard of provision for those at present with an inadequate diet, a large increase in food production must take place. This increase in food production must come from approximately the same land area as is at present under agriculture, as the remainder is too dry, too wet, too cold, or too steep and mountainous to make a significant contribution. This inevitably means greater pressure will be put on prime lands, and especially those with the most fertile soils, to provide the extra food required. As demand increases, there will be increasing pressure also on the less productive soils, where the impact of soil degradation is most dramatically seen, and this could possibly result in the displacement of people from their homelands.

The effects of the increase in the human population on the world, especially in terms of the decline in food security, indicates that soil has ecological limits that change according to the variations within different ecosystems and the cultural relationships with the land and soil resources. There is an increasing imbalance in the production of food because of the difference in the rate of deterioration of soils and their functions and the rate of their regeneration.