A considerable degree of polarization has arisen between conventional high-production farmers who depend on inorganic fertilizers for nutrient supply and those who avoid using them for what they perceive to be environmental and ethical reasons. The latter, commonly called organic or biodynamic farmers, base their crop production on organic sources of nutrients and rotations.

In many developing countries, where soils are poorly structured and low in base fertility, and where the availability of inorganic fertilizers is limited, crop production has depended on periodic clearing of the forest and cropping for only 1 to 3 years—a practice commonly known as slash-and-burn agriculture. Traditionally, this method involved cropping the area only once over the 12- to 15-year “rotation.” In recent years, population pressures have reduced the interval between cropping phases, and this method has begun to fail.

The experience with arthropod pest, disease, and weed control has been remarkably similar to that of nutrient provision. Prior to World War II, pests were controlled mainly by rotations and the use of cultural techniques. The development of extremely effective insecticides, fungicides, and herbicides in the 1940s transformed agriculture and led to virtually complete dependence on pesticides. Not until the 1960s was it realized that extensive use of broad-spectrum pesticides, often applied over large areas from the air, had led to major environmental problems.

Beginning with the introduction of the concept of integrated pest management (Stern et al., 1959), there was a systematic movement toward the use of improved pesticide formulations and localized applications of minimal amounts of pesticides, combined with appropriate cultural and biological control techniques. This trend still continues, in both developed and developing countries, and it has led to significant decreases in the amount of pesticides used on many crops.

Integrated pest management holds a clear lesson for nutrient provision and management. If sustainable agriculture and natural resource management is to be promoted on a global basis, similar principles must be developed for the provision of nutrients. The use of minimal amounts of inorganic fertilizers—applied as a “topping off” only when necessary, placed in