As most have noticed, corn fields have a high amount of volunteer corn.
The question is how much it affects yields.
Volunteer corn becomes competitive with the planted corn and acts like a weed. Research found in South Dakota says volunteer corn can vary from 800 to 14,000 plants per acre. This causes a yield loss of anywhere of 0 to 13 percent.
Research done by Iowa State found that 1,700 plants per acre will reduce yields by 1.3 percent. Yield loss increases as dry conditions continue.