Corn has to be planted every year. The seed grows the stalk, the corn stalk makes the ear, the corn kernels in the ear are allowed to mature to hard/dry kernels and that is what grows a new corn stalk. If they make silage the whole plant is cut off above the ground and chopped up and stored in a silo or a silage bag when it is partially dry so it will ferment into silage...... If the corn is grown for seed, or say for adding to feed like in chicken feed, the ears are harvested, or they are run through the combine and the seed is removed from the cob.... and then the stalks are often baled off the ground and used for bedding or even some are chopped for feeding so the cows get good roughage...
Some ears will fall when it is being harvested for dry corn for feeding and seed... and will grow the next year... most corn that is grown is hybrid and specifically grown to produce ears that they have "engineered" to be certain types.... there is not alot of open pollinated corn grown anymore... but the kernels will grow when they fall to the ground and get worked into the ground even if only from the machinery running over top of it some.
Most corn ground is planted in specifically measured rows, for optimal growth and pollination, and so that when it comes time the chopper or combine can go down the rows and the stalks will feed into the V-shaped cutters on the machine... and not run over and crush the plants and waste the plant and ear. It costs over $250-350 PER 50 lb bag of seed corn to plant so the farmer does not want any extra planted and does not want any missed spots in the rows either...