What is the primary cause of pesticide breakdown in the soil?

The primary cause of pesticide breakdown in the soil is attributed to microorganisms such as fungi and bacteria. These organisms play a crucial role in the biodegradation process. They work by metabolizing the pesticide compounds, breaking them down into simpler, less harmful substances. This microbial activity is essential in detoxifying the pesticide and facilitating its natural decomposition within the soil ecosystem.

Exposure to sunlight, while it can contribute to the breakdown of certain pesticides through photodegradation, is not the primary mechanism in the soil. Chemical reactions with soil elements may play a role in altering pesticide properties, but they are not the predominant factor for breakdown. High levels of moisture can enhance microbial activity but are not the direct cause of pesticide degradation. Instead, moisture creates an environment conducive to the proliferation of microorganisms, thereby indirectly supporting the breakdown process.