I have farms that have gained 2' of elevation in the last 20 years or so. I'm not the only one and I'm not doin a good enough job farmin to make soil that fast. Those farms can raise corn with the best of em and need no dry fert, year after year. All comes rite down the good ole Mississip and Des Moines. Take off up through Iowa, Nebraska, S Dak, ect after the wet years we've had since '93 and look at the tremendous erosion in field after field. You just cant make more dirt.