Introduction

The energy and economic aspects of 20 cropping systems in developing and developed countries were analyzed. In developing countries, labor input was a major cost in terms of energy and economics while, as in developed countries, the major costs were mechanization and fertilizers. The energy inputs per hectare in developing countries ranged from 7732 MJ (wheat) to 54,647 MJ (cassava); in the United States (developed), the energy inputs ranged from 10,085 MJ (soybean) to 210,817 MJ (apple). Food calories produced per hectare in developing countries ranged from only 12,403 MJ (tomato) to 196,510 MJ (cassava); in the United States, production ranged from 37,947 MJ (wheat) to 128,755 MJ (apple). Grain yields per hectare increased as much as fourfold during the Green Revolution but most of this increase was due to fossil energy inputs including fertilizers, irrigation, and pesticides. Despite the Green Revolution and genetic engineering technologies, per capita grain yields during nearly two decades have been declining-a distressing trend with more than 3 billion people malnourished worldwide.