What is the effect of ammonium fertilizers on soil acidity?

Ammonium fertilizers contribute to increased soil acidity primarily due to the process of nitrification. When ammonium (NH4+) is taken up by plants or converted to nitrate (NO3-) by soil bacteria, protons (H+) are released into the soil. This proton release results in a drop in soil pH, leading to an increase in acidity.

Additionally, as ammonium is transformed into nitrate, it can displace alkaline cations such as calcium and magnesium from the soil exchange sites, further contributing to the acidic effect. Therefore, using ammonium fertilizers directly influences soil chemistry by promoting acidity, which is a crucial consideration for soil management practices, particularly in agricultural settings where nutrient balance is vital for optimal plant growth.