The maize development cycle is entirely altered by this mod, making it suitable for farming in Europe. Due to bad weather in October and November, you may now enjoy late harvests in December, which are common in Europe.
Qualities:
A whole new maize growth cycle
Better textures for a more authentic appearance
Wheel tracks that erode the stubble naturally
Variations in height to give maize a more organic look
Existing saves where you are growing maize may be impacted by the new growth cycle. The game will automatically adjust to the new system after the mod is loaded and maize is planted, so there's no need to start a new save.

Source: Don Juan 1994