What is the purpose of spreading lime on land affected by acid rain?

Spreading lime on land affected by acid rain serves the significant purpose of neutralizing soil acidity. Acid rain is a result of elevated levels of sulfuric and nitric acids in precipitation, which can lower the pH levels of the soil, making it more acidic. This increase in acidity can negatively impact plant health and soil organisms, leading to decreased biodiversity and agricultural productivity.

When lime, which is primarily composed of calcium carbonate, is applied to the soil, it reacts with the acids present to form neutral substances, thereby raising the pH level back toward a more neutral state. This process not only reduces soil acidity but also improves nutrient availability, as many essential nutrients become more accessible to plants in neutral to slightly alkaline conditions. Additionally, the application of lime enhances the overall health of the soil ecosystem, promoting the growth of beneficial microorganisms that contribute to soil fertility.

Promoting plant growth might be a secondary benefit of neutralizing soil acidity, but the primary action of lime is to counteract and adjust the pH levels. Increasing acidity levels and enhancing soil erosion are contrary outcomes to what is sought after when treating land impacted by acid rain; these would not be beneficial objectives in managing soil health and agriculture.