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

Crop rotation is recognized as a non-chemical method of pest control because it involves altering the types of crops grown in a specific area over time. By rotating crops, farmers can disrupt the life cycles of pests and diseases that tend to accumulate when the same crop is grown repeatedly in the same location. This practice not only helps in managing pest populations but also improves soil health and fertility, as different types of plants contribute varying nutrients to the soil.

In contrast, chemical pesticide application explicitly involves the use of chemical substances to control pests, and synthetic fertilizers are chemicals used to enhance plant growth rather than manage pest populations. Increased irrigation typically serves to improve plant health but does not directly address pest issues and can sometimes create conditions that are favorable for pest outbreaks if not managed correctly. Thus, crop rotation stands out as an effective, environmentally friendly strategy to mitigate pest issues without the reliance on chemicals.