Limited Nitrate Leaching Beneath Intermediate Wheatgrass.

Nitrogen leaching from fertilized annual grain crops to groundwater is a health threat for citizens of rural communities relying on well water for drinking. Perennial crops have the potential to reduce nitrate leaching to groundwater because they have deeper roots, longer growing seasons, and require less fertilizers than annuals. Intermediate wheatgrass is a new perennial crop that has been bred to produce high grain yields for human consumption. Data from a three-year field study in Minnesota show that soil moisture and soil water nitrate was lower beneath the rooting zone of the perennial intermediate wheatgrass compared to a corn-soybean rotation. Field data from this study and others is being used to parameterize crop simulation models to predict intermediate wheatgrass grain yield, water use, and nutrient dynamics at the landscape scale. Models suggest that replacing annual row crops with a perennial like intermediate wheatgrass can reduce nitrate leaching to groundwater, and the timing of water and nutrient use in this perennial system is important for achieving water quality goals in Minnesota.