The property of clayey soil that prevents it from supporting thick vegetation is its?

Step 1: Analyze the question We're asked which property of clayey soil stops it from supporting thick vegetation.

Step 2: Recall the concept Clay soil has very fine particles, so:

• It has small pore spaces, meaning it is poorly drained and poorly aerated (not porous in the sense of large air spaces).
• It retains a lot of water, which makes it sticky and heavy.
• Because of poor drainage, it easily becomes waterlogged. Waterlogging drives out air, so roots cannot get enough oxygen for respiration, and many plants cannot grow well.

Step 3: Evaluate each option

• A. Chemically weathered granite rocks: Clay does form from weathered rocks, but this describes its origin, not a property that limits vegetation. Clay is also rich in nutrients. ❌
• B. Inability to retain much water: This is wrong. Clay retains a lot of water. This describes sandy soil. ❌
• C. Tendency of becoming waterlogged: This is correct. Poor drainage and poor aeration deprive roots of oxygen. ✅
• D. Porosity and low water retention: This is also wrong. It describes sandy soil, since clay has low porosity (in terms of drainage) and high water retention. ❌

Step 4: Answer

Tip 💡: Remember the contrast:

• Sandy soil: well drained, well aerated, low water retention, so plants suffer from drought.
• Clayey soil: poorly drained, poorly aerated, high water retention, so it becomes waterlogged.
• Loamy soil: the ideal balance.

If an option says clay "cannot retain water", it is almost certainly a trap.