Net Energy Sequestered in Agricultural Labor

ABSTRACT NUMEROUS methods and much confusion exist in relation to evaluating the energy content of labor. These methods are examined and a new method, based on net energy analysis, is developed and demonstrated. The net energy analysis model of the energy sequestered in agricultural labor is based on a disassociation of the components of the Gross National Product and an esti-mation of the energy requirements and portion of each associated with labor. The energy sequestered in a US agricultural laborer in 1974 is determined to be 594 MJ/d, approximately 45 times the caloric value of the food which the laborer eats. An important consideration in agricultural energy analyses is the quantity of energy sequestered in agricultural labor. The energy consumed by agricultural labor may vary by more than three orders of magnitude, depending on the method chosen to determine the energy content of labor. The method used for assigning an energy quantity to labor is therefore influential on results and conclusions from energy analyses and on subsequent recommendations or actions. Whatever quantity is assigned may greatly affect, for example, recommendations concerning substitutions be-tween labor and other inputs, such as in decisions relating to mechanization or automation. This paper reviews various methods used to assign energy quantities to labor as well as results and rationale. It presents a net energy analysis of the energy se-questered in agricultural labor and several applications to agricultural systems. The net energy analysis method presented here, though emphasizing agricultural labor, should be applicable to any industry.