Quantifying energy issues associated with agricultural systems, even for a two-crop corn ( Zea mays L.) and soybean ( Glycine max [L.] Merr.) rotation, is not a simple task. It becomes even more complicated if the goal is to include all aspects of sustainability (i.e., economic, environmental, and social). This Issue Paper examines energy issues associated with and affecting corn/soybean rotations by first defining the size of the system from both a U.S. and global perspective and then establishing boundaries based on the Farm Bill definition of sustainability. This structured approach is essential to help quantify energy issues within corn/soybean systems that are themselves best described as "systems of systems" or even "systems within ecosystems" because of their complex linkages to global food, feed, and fuel production. Two key economic challenges at the field and farm scale for decreasing energy use are (1) overcoming adoption barriers that currently limit implementation of energy-conserving production practices and (2) demonstrating the viability of sustainable bioenergy feedstock, production as part of a landscape management plan focused not only on corn/soybean production but on all aspects of soil, water, and air resource management. It is also important to look beyond direct energy consumption to address the complex economics affecting energy issues associated with corn/soybean systems. To help address the complex energy issue, life cycle assessment is used as a tool to evaluate the impact of what many characterize as a simple production system. This approach demonstrates the importance of having accurate greenhouse gas and soil organic carbon information for these analyses to be meaningful. Traditional and emerging market and policy forces affecting energy issues within corn/soybean systems are examined to project the effects of increasing bioenergy demand associated with the Energy Independence and Security Act of 2007. Uncertainty with regard to biofuel policy is a major factor affecting energy issues in all aspects of agriculture. This uncertainty affects investments in biofuel production and energy demand, which together influence commodity prices, price volatility for food and feed, and agricultural energy decisions. The authors conclude by offering an approach, including decreased or more efficient energy use, that can enhance all aspects of sustainability. Their strategy, defined as a "landscape vision," is suggested as an agricultural system approach that could meet increasing global demand for food, feed, fiber, and fuel in a truly sustainable manner.
