Future Cropping Systems To Ensure Global Food Security

Sunday, February 17, 2013
Room 210 (Hynes Convention Center)
Kenneth G. Cassman , University of Nebraska, Lincoln, NE
While a there is strong scientific consensus about need to achieve a substantial increase in food production and a large decrease in negative environmental impact, there is considerable disagreement about the appropriate form of agriculture to meet this challenge. Perspectives range from those who believe major changes are required in structure of existing cropping systems to those who feel improvement of existing systems is the way forward. “Changers” argue that current reliance on a handful of major crops and cropping systems is not sustainable due to lack of diversity and environmental damage resulting from large inputs of nutrients and energy from non-renewable fossil fuels. Changers often promote organic agriculture and local or regionally-focused production systems. “Improvement” backers believe continuous scientific innovations are up to the task by modification of existing systems. They do not believe alternative systems are productive enough without massive conversion of natural ecosystems to farmland and attendant negative environmental impact. Improvers emphasize major commodities, high yields with high efficiencies, and global trade. Although scientific controversy is healthy, the polar nature of this disagreement makes prevents effective prioritization of research and policy development for global food security. It was a strong global consensus about magnitude and urgency of impending food shortages that was the galvanizing force of the green revolution. How do we bring these polar perspectives closer together?

Reducing polarity depends on achieving greater consensus about biophysical dimensions of the food security challenge. What is the magnitude of food production increase required? How much food can be produced on existing farmland? How much land and water are available to support sustainable production? Although many studies have addressed these issues, there are large differences in results and little effort to understand reasons for them. For example, a new initiative seeks to estimate food production capacity, and the gap between current farm yields and potential yields, on every hectare of existing farmland (www.yieldgap.org).

Performance metrics are also needed to evaluate capacity of different cropping systems to meet demand with available resources. Net energy yield, nutrient-use efficiency, and water productivity are important metrics, among others, and there is need for robust, low cost methods to estimate them. It should be possible to track performance of every hectare of existing crop land. Such benchmarking would more efficiently identify production practices that contribute to increased yields and environmental goals concurrently, and to match the most effective practices to specific soil and climate regimes where they work best.

Identifying the most appropriate crops and cropping systems for future food security will be difficult without agreement on biophysical dimensions of the food security challenge and robust biophysical performance metrics.