Probably not a practical way to do this for a whole field. You can spray the plants with water which tends to wash the pollen down onto the ground, like the rain does. It would serve to water the area, too which stimulates growth, and not as much flowering (pollen). I do this with my power washer when my oak trees are producing clouds of pollen here.
The only other way would be to get a whole team of people to go around and snip off the flowering heads of the grasses and wildflowers. But then they won't seed and keep the whole place growing.
