<prompt> Translate the following text to EnglishWalitumia mbinu ya kuchimba na kuchoma yams na millet, mbinu ambayo ilichosha udongo na kuwalazimisha kuishi kama wahamiaji kutoka eneo moja la msitu hadi jingine.  <response>: They practiced a slash-and-burn agriculture of yams and millet, a technique that exhausted the soil and imposed a semi-nomadic existence from one jungle clearing to another. 