@rundocuri- First of all, I think that you need to give the soil a break from your annual corn crop. If you skip planting corn there for a few years, this will help. During the growing seasons that you don't plant corn there, planting a different crop will help to put back the nutrients that are depleted from the soil. Alfalfa, beans, peas, and potatoes are all good options that will benefit the soil.
You can also add a fertilizer to the soil along with your rotated crops. This will give it a boost, and benefit the plants that you put there in place of corn. After two or three years, you can give planting corn in the usual spot a try again. Don't forget that you can also plant your corn in another section of your garden while you rotate your crops.