Long-term Agricultural Research: A Research, Education, and Extension Imperative

T o meet the growing world demand for food, fuel, and fiber, and at the same time sustain the environment's ability to provide economic, social, and environmental services to society, agricultural innovations are essential. Such innovations must derive from a comprehensive understanding of the long-term functioning of agricultural systems and their resiliency. Soil, water, and energy limitations pose longstanding and persistent problems for agricultural productivity, profitability, and social acceptability; for global agricultural competitiveness; and for environmental quality and security. Long-lasting solutions to these problems require a comprehensive, systems-level understanding of the linkages among basic biophysical processes and human activity, an understanding that can serve as a solid foundation for informed management and policy decisions. This understanding can be achieved best-or perhaps only-through long-term research that integrates multiple processes, both biophysical and socioeconomic, across multiple spatial and temporal scales. Practical solutions depend on long-term research because robust solutions to many of the problems facing agriculture require evaluation in the context of climatic, social, ecological, and other factors that change on decadal (or longer) time scales. Long-term research also allows the impacts of management to be distinguished from impacts caused by long-term environmental trends such as land use and regional climate change.