The Great Mother, or Mother Nature, in her nurturing aspect is always shown with corn representing fertility and fecundity.
Psychological / Emotional Perspective:
To be harvesting corn is to be reaping the rewards of hard work. We may be linking with some very primeval needs and requirements.
Everyday Material Aspects:
Most dreams containing images of corn or wheat symbolize fertility or fruitfulness. They may also represent new life – either pregnancy or new developments in other ways.
Gender / Specific Meanings:
Women are much more in touch with the natural forces so tend to dream of goddesses and their attributes.
You might also like to consult the entries for Harvest and Mill / Millstone.