The researchers studied water and energy exchange in a maize-soybean farm in Nebraska from 2001 to 2005. They found that the amount of water used by the plants depended on their leaf area, with a threshold level above which water use stayed constant. Maize used more water than soybean during the growing season, but both crops still used water during the non-growing season. The researchers also discovered that the maximum canopy surface conductance of the plants was influenced by their nitrogen levels.