If you can grow rice in an impoundment and then flood it you should do well with ducks. Its more of a pain to grow than RR corn and corn works better. I know guys who have done rice because the deer always hammered their corn. They killed a few ducks, but they eventually put up a fence and switched back to corn and killed many more. If its a spot where you cant plant corn, ie a place that is too wet, rice is your best bet over jap millet or other grasses.
"If you have to be crazy to be a duck hunter, i dont wish to be sane" Robert Ruark
Its always duck season, there is just a long break from february to september.