If you really want to do it right, you need to setup a crop rotation. To have corn every year, you need to start with 3 plots. One plot will start as a cover plot, one as corn and the other as beans or other legume. The clover plot will stay the same for 3 seasons then rotate to a different field. The corn and beans alternate each year. Here is an example of an effecient rotation:

Clov-Bean-Corn
Clov-Corn-Bean
Clov-Bean-Corn>>Plant clover overseeded w/ wheat in fall in beans.
Corn-Clov-Bean
Bean-Clov-Corn
Corn-Clov-Bean>>Plant clover overseeded w/ wheat in fall in beans.
Bean-Corn-Clov
Corn-Bean-Clov
Bean-Corn-Clov>>Plant clover overseeded w/ wheat in fall in beans.
Etc.
Etc.

The benefit of doing this is the efficient use of soil nutrients. Corn and wheat are nitrogen users while beans and clover are nitrogen producers. Following the beans and clover with corn or wheat uses the nitrogen they produced and reduces the amount of N fertilizer you need to apply. This is why you will notice that farmers alternate corn and beans every year. Beans do well in the soil low in nitrogen, and corn uses up the nitrogen produced by the previous years beans. You will notice that when it's time to rotate the clover, you plant winter wheat into the bean ground. The wheat uses up the nitrogen from the beans to clear the way for the clover to take over the next spring.

If you feel you can get more than 3 good years out of a clover stand then you can extend the rotation to 5 years. Just add 2 more years of the corn-bean rotation per cycle.