Resource degradation, technical change, and the productivity of energy use in U.S. agriculture

Abstract Two important issues surrounding future food production are the reliance of industrial agriculture on large quantities of fossil fuels and the degree to which technical change and farm management can offset degradation in the form of soil erosion, groundwater depletion, reduced genetic diversity, pest resistance, and so on. This analysis uses new and more consistent data on energy use in U.S. agriculture to assess the forces that shape the productivity of energy use from 1950 to 1990. The results of an econometric model indicate that changes in the quantity of energy used per hectare, the average size of farms, the quantity of land harvested, the ratio of livestock to crop production, and weather influence the productivity of energy use (in order of decreasing importance). Energy productivity shows strong diminishing returns to increases in energy use per hectare of land. The model indirectly tests for the effects of of resource degradation and technical change on energy productivity. The results do not support the hypothesis that the effects of soil erosion and other forms of resource degradation have diminished the productivity of energy use in the U.S. farm sector, presumably due to advances in technology and behavioral responses on the part of farmers. The significant increase in energy productivity since 1980 is due to a sharp reduction in energy use per hectare, a reduction in the quantity of land utilized, and continuing increases in average farm size. These results are consistent with other empirical analyses of aggregate energy productivity in industrial agriculture that indicate an improvement in energy productivity in response to the energy price increases.