Why is a high CEC beneficial for fertility management?

Why is a high CEC beneficial for fertility management?

• A. It increases water capacity exclusively
• B. It indicates higher pH
• C. It allows soil to hold more positively charged nutrients, reducing leaching
• D. It means the soil drains faster

Answer: (C)

High CEC means the soil can hold more positively charged nutrients on its exchange sites, thanks to clay minerals and organic matter. Those nutrients—potassium, calcium, magnesium, ammonium—are cations that bind to negatively charged surfaces. With a greater capacity to hold them, nutrients stay in the root zone longer and are less likely to be washed away by rain or irrigation, making fertility management more efficient. You can feed plants more effectively over time and reduce leaching losses.

Remember that water-holding capacity depends mainly on soil texture and structure, not CEC, so higher CEC doesn’t automatically mean more water stored. And CEC isn’t a direct measure of pH; soil pH affects nutrient availability, but not the soil’s capacity to hold cations. Also, high-Cec soils can drain more slowly if they’re also clay-rich, though the key benefit remains nutrient retention and reduced leaching.