Plant scientists are working to improve important food crops such as rice, maize, and beans to meet the food needs of a growing world population. However, boosting crop output will require improving more than what can be seen of these plants above the ground. Root systems are essential to gathering water and nutrients, but understanding what's happening in these unseen parts of the plants has until now depended mostly on lab studies and subjective field measurements. Imaging of root systems has, until now, largely been done in the laboratory, using seedlings grown in small pots and containers. Such studies provide information on the early stages of development, and do not directly quantify the effects of realistic growing conditions or field variations in water, soil, or nutrient levels. The imaging system permits tracking ion movement from soil to root as well as from root to distal parts of the plant.