Waterfowl plots are grains grown on dry ground, then shallow-flooded (roughly 4–8 inches) in fall to make the seed available to ducks. The crop has to either tolerate wet feet or mature before flooding.
Japanese millet is the workhorse because it handles moisture and matures fast enough for late plantings; corn, grain sorghum, and other millets add high-energy seed. Water control is half the game — plan your flooding before you plant.