Certified Arborist Practice Exam

If the pH of soil is less than 7 on the scale, it is considered:

1. Acidic

2. Alkaline

The correct answer is: Acidic

A soil pH of less than 7 indicates acidity in the soil. Soil pH is a measure of the hydrogen ion concentration in the soil, with lower values representing higher acidity. When the pH falls below 7, it suggests an abundance of hydrogen ions, which creates a more acidic environment. Acidic soils can affect nutrient availability and the health of plants, making it essential for arborists to understand and manage soil pH for optimal tree growth and health. In contrast, a pH above 7 indicates alkaline conditions, which reflect lower hydrogen ion concentrations. The scale ranges from 0 to 14, where 7 is neutral, and understanding this scale is crucial for assessing soil health.