The earth's land surface could in theory feed many more people than now live on our planet. Yet global statistics must not blind us to local realities. Even today, over 20 developing countries are cultivating more land than is properly suited for agricultural production. Many more are over-exploiting their land. These countries are living on borrowed time, mining their agricultural resources, and degrading, in some cases irreversibly, the very basis of their future survival and prosperity.
It is more than a decade since FAO began its work on agro-ecological zones (AEZ). This investigation has now begun to assume extraordinary importance for the light that it sheds on the relationship between food and population in the developing countries. The AEZ project was one of the first to quantify systematically the extents of potentially cultivable land in the developing countries. It was the first study to provide estimates of the yields that can be expected for different crops in different parts of the developing world under varying levels of inputs. It also provided essential data for subsequent studies that assessed the population-supporting capacity of land in developing countries.
Today, it is possible to put this knowledge to practical and realistic use - a use which will enable us to reduce the numbers of people who are still hungry or starving. The AEZ technique makes it possible for developing countries to plan the future of their agriculture rationally.
AEZ studies inform planners about the land potential, which crops are best grown where, what they will yield, what levels of sustainable production may be expected under different levels of input use. Combined with FAO's Agriculture: Toward 2000 methodology the assessments quantify how much it will cost to conserve the soil, how much fertilizer, pesticide and power will be needed, and how to optimize the crop mix to maximize food production without damaging the environment. Above all, they will enable countries to undertake the balance sheet approach recommended in the Programme of Action for African Agriculture, and so ensure that agricultural plans are compatible with land resource potentials.
AEZ studies have thus been transformed from theoretical exercises into a vital weapon in the planner's armoury. The purpose of this publication is to explain how this weapon works and what questions it can answer. While the details may be complicated, the implications are clear. Some 450 to 500 million people are inadequately fed in the developing countries, where populations are still growing fast. In this situation, planners have no choice but to find out all they can about their countries' agricultural potential. The best possible use of every country's natural resources will go a long way toward solving the complex world food problems.
I hope that this publication will serve as yet another useful step in eliminating the anachronism of hunger and starvation from our planet.
Edouard Saouma
Director-General
Food and Agriculture Organization
of the United Nations