If the soil is too alkaline, what can be added to lower its pH?

To lower the pH of alkaline soil, the addition of aluminum sulfate is effective. Aluminum sulfate acts as an acidifying agent, which can help in displacing the alkaline components present in the soil and effectively reducing its pH level. It achieves this by releasing sulfuric acid when dissolved in water, contributing to increased acidity in the soil.

Lime, on the other hand, is used to raise the pH in acidic soils, which is why it’s not the appropriate choice for alkaline soils. Cement can also elevate the soil's pH due to its high alkalinity, and sand does not have any significant effect on pH adjustment. Therefore, aluminum sulfate is the most suitable additive for lowering pH in alkaline conditions.