Which of the following is considered a non-chemical weed control method?

Controlled burning is considered a non-chemical weed control method because it relies on the application of fire to eliminate unwanted plants. This method can effectively clear out weeds and invasive species by exposing them to high temperatures, which kill the plants without the use of chemical herbicides. Controlled burning can also benefit the soil and surrounding ecosystem by promoting the growth of desirable plants that are more resilient to fire.

In contrast, chemical sprays involve the use of herbicides to control weeds, thereby categorizing them as chemical methods. Manual weeding involves physically removing weeds by hand or with tools, which is a physical method but may not be as broadly recognized as a traditional non-chemical method like controlled burning in certain contexts. Soil fumigation, on the other hand, uses chemical agents to sterilize the soil and eliminate weed seeds, making it another chemical weed control method. Thus, controlled burning stands out as a distinct practice focused on non-chemical approaches in weed management.