ENERGY AND RESOURCE CONSTRAINTS ON INTENSIVE AGRICULTURAL PRODUCTION

This review explores the potential energy, soil, and water constraints on highly productive agricultural systems. It focuses on the process of agricultural intensification during the past 50 years, and it shows that multiple constraints-as opposed to a single constraint, such as energy-are needed to assess the future sustainability of intensive agr icultural production. Recent studies documenting changes in total fact or productivity based on long-term experimental trials and held survey s are discussed in detail. The results of these studies are worrisome; they indicate that degradation in soil quality and in the overall nat ural resource base may threaten the long-run viability of several of t he world's most intensive agricultural systems. Other studies are revi ewed that support a more optimistic view of resource availability and the ability of improved technology and management to overcome these ph ysical constraints. However, the combined evidence suggests that the i ncrease in agricultural prices required to induce the necessary change s in technology could be devastating to low-income households. Most of the world's poor consume more agricultural output than they produce, and they spend up to 80% of their incomes on food.