What term describes the soil's ability to hold exchangeable cations due to negative charge sites?

• A. Cation exchange capacity
• B. Soil texture
• C. Nutrient availability
• D. Soil pH

Answer: (A)

The main idea here is the soil’s ability to hold exchangeable cations because of negative charge sites on soil particles. This capacity comes from the negative charges on clay minerals and organic matter, which attract positively charged nutrient ions such as calcium, magnesium, potassium, and ammonium. The total amount of these exchangeable cations that the soil can hold is called the cation exchange capacity. It represents how many nutrient ions can be exchanged with the soil solution, influencing nutrient retention and buffering against pH changes. So the term that fits this description is cation exchange capacity. The other terms describe different soil properties: texture is about particle sizes, nutrient availability is about whether nutrients can be accessed, and pH is about acidity/alkalinity, not the soil’s capacity to hold exchangeable cations.