Producing a healthy and sustainable food supply for 10 billion people by 2050 is perhaps the greatest environmental, scientific, and social challenge of the 21st century. Meeting this challenge will require a substantial increase in crop productivity, yet yields in developing countries are limited by drought and poor soil fertility, exacerbated by ongoing soil degradation. At the same time, moreover, there is increasing competition for land use not associated with agriculture. Alleviation of these challenges through intensive fertilization and irrigation is economically and ecologically untenable in the poorest regions with the greatest food insecurity. Our growing understanding of the biology of plant roots has opened the possibility of developing crops with increased yields on poor soils without intensive inputs -- a "second Green Revolution." Three core issues will be addressed in this symposium: first, improving the roots ability to acquire essential nutrients from poor soils by breeding for optimal root architecture; second, developing crops that are tolerant of soils with toxic levels of aluminum, a principal constraint to plant growth in acid soils; and, third, discovering modifications in root function that increase a plant's ability to acquire water under drought conditions. Each speaker will draw on cutting-edge research results as well as high impact studies under field conditions in their talks.