Are those numbers pounds per acre or parts per million? Nitrogen in slow-release form is the main need.
Since there was a water problem last year. Make your plans for this year to avoid a repeat; clearly you should have added seed to restore the field last fall. So...add seed in spots to restore the thin spots this spring. You may need to add perennial rye at the goalmouths before or after every game. Can you build a practice field or two to preserve the good field for games? Force the band to practice on the pavement.
What kind of grass? Most soccer fields suffer from excessive use. Goalmouths tend to thin out. Can you come up with a plan to shift field 100 feet left or right or east and west in odd numbered weeks, to reduce the concentration of traffic. Is drainage adequate? Does the coach keep off the field when it is wet? Does it have at least an 18" crown down the center of the field?