For any field operation, you need a reason to cultivate. If a field is reasonably clean or weed-free, don't cultivate. However, if you have a lot of weeds or if the soil is sealed or puddled due to the recent rains we've had, then the soil could benefit from a little aeration. If you cultivate in wet soil the weeds simply re-root and keep growing. Grasses are also difficult to manage with cultivation because of their fibrous root systems.
Proper timing is also important.
Small weeds that lack extensive or deep roots are easier to manage with the cultivator than larger, established weeds. Cultivating is most effective when done early in the season, when other farm activities demand attention, so it is often difficult to find the time. But when properly done, cultivation offers many benefits, especially for corn. Cultivating also aerates the soil, closes any cracks that may have formed as the soil's surface dried, and reduces puddling and runoff from subsequent rainfall. There are also disadvantages of cultivation, including the potential for increasing soil erosion as a result of burying crop residue and loosening the soil.