Once the residents of Bloodpool learn how to plant wheat instead of corn, you can gain an infinite amount of wheat product from them as an offering. Use it on corn fields in other towns to teach them how to plant wheat as well. Wheat will allow populations to grow higher and quicker, since it feeds more people, and can't be destroyed by earthquakes. Therefore, after planting wheat somewhere, cause an earthquake to destroy the corn fields. Thereafter, the residents of the town will replant their crops, but this time, they'll plant wheat. Then, all you have to do is watch your population grow!