What are the main reasons soil becomes acidic over time?

The main reasons soil becomes acidic over time include factors such as rain, fertilizers, and the release of carbon dioxide (CO2) from plants. When rainwater, which is naturally slightly acidic due to dissolved carbon dioxide, percolates through the soil, it can leach essential base cations like calcium and magnesium, leading to higher acidity levels. Furthermore, the application of certain fertilizers, particularly those containing ammonium or sulfur, can contribute to soil acidity. These fertilizers can promote processes that increase hydrogen ion concentrations in the soil, making it more acidic.

Additionally, plants contribute to soil acidity through the release of CO2 during respiration. This CO2 combines with soil water to form carbonic acid, which subsequently contributes to lowering pH. Over time, these processes can significantly alter the soil's acidity levels, creating an environment that may impact nutrient availability and microbial activity.

Understanding these contributors to soil acidity is essential for managing nutrient levels, optimizing soil health, and maintaining appropriate pH for crop production.