The Mayans practiced the slash and burn method . The slash and burn method is a fertilizer , the slash and burn method is dangerous for humans and crops . The ash from the flames and fire were used to help crops grow . The slash and burn method wasn ’ t a great one , the fertilizer only lasted 3-5 years . That may not seem bad but when you use the method , you have to wait 10 years just to use it again ! So you either have to wait 7 or 5 years to get more fertilizer . And the Mayan population was huge ! So waiting that long for crops to grow and be used it outrageous . I would have never used that fertilizer . The last main theory is DOEC . The region the Mayans lived suffered their longest drought ever ! It was between 1020 to 1100 , it lasted 2,000 years ! Can you believe it ? Do you believe that anything can last with little to no water ? Well no that ’ s not logically possible . To add animals and living things will be dying and or rotting . Going back to disease for a moment , when an animal is rotting humans can get sick with a disease of some sort . While that could be the case , there are other parts to environmental change . Drought is the main theory of DOEC . And those are the main four theory ’ s .