What does soil acidification refer to?

Soil acidification refers to the process in which the pH of the soil decreases, leading to increased acidity. This phenomenon often occurs due to natural processes such as the nitrification of ammonium-based fertilizers, where the conversion of ammonium (NH4+) to nitrate (NO3-) produces hydrogen ions (H+), which contribute to lowering the pH of the soil.

The presence of these hydrogen ions makes the soil more acidic, impacting nutrient availability and microbial activity within the soil. Understanding this process is important for managing soil health, as excessive soil acidification can lead to issues such as nutrient deficiencies, particularly of calcium and magnesium, and can adversely affect plant growth and soil organisms.

In this context, the other options don't accurately describe soil acidification: increasing soil pH refers to alkalization, enhancing soil pH through liming is a corrective measure rather than describing the acidification process, and organic matter has varying effects based on its composition and interaction with soil chemistry, but it doesn't specifically indicate a direct impact of acidification.