Certified Crop Advisor Practice Exam

What is the expected effect of adding lime to acidic soils?

1. Increase potassium levels

2. Decrease nitrogen levels

3. Neutralize acidity

4. Enhance phosphorus uptake

The correct answer is: Neutralize acidity

Adding lime to acidic soils primarily serves to neutralize soil acidity. Acidic soils typically have a pH less than 6.0, which can adversely affect plant growth and nutrient availability. Lime, which is primarily composed of calcium carbonate, reacts with soil acidity to raise the pH, making the soil more neutral. By increasing the pH, lime improves the overall soil environment, allowing for better nutrient availability and biological activity. Nutrients such as phosphorus, potassium, and magnesium become more accessible to plants, enhancing overall soil fertility. Furthermore, neutralizing acidity mitigates the detrimental effects of high aluminum and manganese levels, which can be toxic to plant roots in very acidic conditions. While lime can indirectly influence nutrient levels, its primary function is the amendment of soil acidity, making the choice to neutralize acidity the correct answer in this context.