What is the first step in determining a soil's textural class using the soil textural triangle?

• A. Identify the percent of clay separate
• B. Identify the percentage of silt separate
• C. Identify the percentage of sand separate
• D. Measure the soil's pH level

Answer: (C)

To determine a soil's textural class using the soil textural triangle, the approach begins with identifying the percentage of sand separate. This is because the soil textural triangle is designed to classify soil types primarily based on the proportions of sand, silt, and clay. The first step involves determining the percentage of each component, and since sand typically constitutes the largest percentage in many soil types, it makes sense to start with sand for accurate classification. Once the percentage of sand is known, the next steps involve identifying the percentages of silt and clay.

While evaluating the pH level can provide valuable insight into soil health and nutrient availability, it does not play a role in determining soil texture. Knowing the percentages of clay or silt is also critical, but without first establishing the sand content, you cannot effectively locate the soil’s class on the triangle. Thus, starting with the sand percentage is essential for correctly identifying the soil's textural class.