Slash and burn was a technique that the Mayans used. The Mayans were expert farmers and pretty much masters of agriculture.
Depending on where a civilization is located, the civilizations will have different ways of providing food for people. The Mayan civilization had challenges so the farmers had to be creative.
They came up with the technique of slash and burn.
They took a sloth of trees and cut down the trees and vegetation. They then burned it to help with the fertilization process.
Now they had some extremely fertile soil and they could plant crops in this but it would only last 2-3 years because the land would be exhausted after.