In soil testing, which parameter is sometimes included alongside pH and nutrient levels?

• A. Earthworm count.
• B. Plant species list.
• C. Soil texture.
• D. CEC and buffering.

Answer: (D)

Understanding soil fertility requires looking beyond pH and nutrient levels to how the soil holds nutrients and resists pH changes. Cation Exchange Capacity (CEC) measures the soil’s ability to hold positively charged nutrient ions on clay and organic matter surfaces, which directly influences how much fertilizer the soil can store and then release to plants. Buffering capacity describes how resistant the soil is to shifts in pH when acids or lime are added, guiding how much lime might be needed to raise or lower soil pH to the desired range. Together with pH and nutrient concentrations, these measures give a fuller picture of nutrient availability and lime requirements, helping you interpret test results more accurately. Earthworm counts or a plant species list aren’t standard chemical indicators reported with soil test results, and while soil texture matters, it’s a different kind of property and isn’t the measure that directly informs nutrient availability like CEC and buffering do.