Which action is not recommended for controlling fairy rings?

The action of leaving wood material in the root zone is not recommended for controlling fairy rings because it can actually contribute to the problem rather than mitigate it. Fairy rings are fungal growths that can thrive on organic matter, including wood. When wood is left in the root zone, it can serve as a food source for the fungi, allowing them to persist and potentially worsen the fairy ring condition by increasing the amount of fungal vegetation in the area.

Other control measures, such as deep tilling of the soil, may help to disrupt the fungal structures in the soil, and proper irrigation can help mask symptoms temporarily without promoting further fungal growth. Additionally, frequent testing of soil pH can improve overall soil health and lead to better management practices but is not directly related to the control of fairy rings. Hence, avoiding the practice of leaving wood material in the root zone is crucial for effective control of fairy rings.