why did Olmec farmers move their farms from time to time?

Olmec farmers moved their farms from time to time in order to practice shifting cultivation, also known as slash-and-burn agriculture. This farming method involves clearing and burning a plot of land to use it for agriculture for a few years before moving on to a new plot of land. By moving their farms periodically, Olmec farmers were able to allow the soil to recover and replenish nutrients, ensuring the long-term productivity of their agricultural practices. Additionally, this practice also helped prevent soil exhaustion and allowed for a more sustainable way of farming in the region.