You,re LOOKING at the situation so you know better than anyone what needs to be done. But planting is always the last step. If its anything other than pure sand, there is nothing that creates a hardpan like a loaded log truck. Break that hardpan. Apply lime if needed. THEN work on erosion. Water bars, terraces, whatever. Get the water slowed down and out of the field early and often. THEN plant. Something won't be right after all that and you have all summer to correct the problem.