A couple things occur to me. The source of the flooding is important. The drainage characteristics of your soil profile is important. The type of soil and it's ability to hold nutrients and pH is important. It's hard to make a general statement here. I have two five acre fields just feet above the natural water table and adjacent to swamp. The top six inches to two feet is a nice, sandy loam. Beneath is a sticky clay, the kind used to make pottery. Most of the flooding in these two fields is from water piling up from upstream. The swamp water rises and floods the fields. I'm not sure of the pH of that water, but I've read it can be something like 4 to 5 with too many factors to consider to make a more specific call. If would be a perfect solution to apply to those two fields if the pH was too high and I need to drive it down.
Other times, the rain water just has no where to go. The soil is full. The swamp is full. So, it sits. Some areas will drain well when all the other water finds its way downstream. But there are spots that literally turn into small duck ponds.
It's a gamble but somehow we manage to grow some brassicacs, clovers, corn, and soybeans....but it can be spotty. I often doubt the wisdom of liming and fertilizing. It can only be diluted and washed away by all that water. Small grains like rye and wheat seem to do OK in these situations, but my brassicas drowned last year. The clovers I use would never be ready for a fall attraction. Plant what you want to plant and hope for the best is all I have. Good luck!
