What is the process of nitrification in soil?

Nitrification in soil is the biological process of converting ammonium into nitrites and then into nitrates by bacteria.

Nitrification is a crucial part of the nitrogen cycle in the soil, which is essential for plant growth. It involves two steps and is carried out by two groups of bacteria. The first group, Nitrosomonas, oxidises ammonium (NH4+) to nitrite (NO2-). This is then further oxidised to nitrate (NO3-) by the second group of bacteria, Nitrobacter. This process is aerobic, meaning it requires oxygen.

Ammonium is produced in the soil through the decomposition of organic matter by bacteria and fungi. This is a form of nitrogen that can be used by some plants, but most prefer nitrate. This is where nitrification comes in. The Nitrosomonas bacteria convert the ammonium into nitrite. However, nitrite is toxic to most plants, so it is quickly converted into nitrate by Nitrobacter bacteria. Nitrate is the form of nitrogen most readily absorbed and used by plants.

The process of nitrification is sensitive to soil conditions. It is most efficient in warm, well-aerated and moist soils. If the soil is too dry, too wet, or lacks oxygen, the nitrification process can be inhibited. This is because the bacteria involved in nitrification are aerobic and require oxygen to survive and function.

In addition to providing plants with a usable form of nitrogen, nitrification also plays a role in soil acidification. This is because the process of converting ammonium to nitrate releases hydrogen ions, which can increase the acidity of the soil. This is an important consideration in soil management, as high levels of acidity can be harmful to certain plants.

In summary, nitrification is a vital process in the soil nitrogen cycle, converting ammonium into a form of nitrogen that is more readily usable by most plants, while also influencing soil acidity.