The evolution of agriculture within the last 11,000 yr marked the first major inflection point in food yield and changed forever the character of the human condition. The application of technology to agriculture early in the 20th Century induced the next major crop yield inflexion point. Identifying the technological wellspring from which increased rates of productivity will be obtained in the decades ahead is far less obvious than during the last century. The agronomic challenge for the decades to come is to increase productivity per unit of land enough to preclude appropriation of other ecosystems for cropland expansions while simultaneously increasing the efficiency of production inputs, reducing their leakage to the environment, and sustaining the integrity of those ecological processes that undergird these intense biological production systems. Such a goal will require different metrics to measure agricultural sustainability and garner public support, new funding sources, and more holistic institutional arrangements. Agronomists, while playing a major role in meeting this challenge, will not necessarily dominate the agenda.