Soil acidification is a process in which the pH levels of the soil decrease, leading to an increase in the concentration of hydrogen ions. This can be caused by factors such as acid rain, agricultural practices, and the use of certain fertilizers. Soil acidification can have negative effects on plant growth and soil health, as it can reduce the availability of essential nutrients and impact the activity of soil microorganisms. Researchers study soil acidification to understand its causes, impacts, and potential management strategies to maintain healthy soil ecosystems.