Crop rotation is an essential part of a healthy garden system.  Every crop you grow will have different needs based on the type of plant grow.  A heavy feeder like corn is going to use up a lot of available nitrogen in the soil and so some method of replenishing the soil is necessary.  You can fertilize the soil but what if you followed with a cover crop that would return nitrogen in the soil like legumes do instead?  That is where you can plan your beans.  Grow pole beans or bush beans after the corn and the decaying plant materials from those beans will help to put nitrogen back into the soil.