What is the process called when nitrogen is lost from the soil to the atmosphere?

The process in which nitrogen is lost from the soil to the atmosphere is known as denitrification. This occurs when certain bacteria convert nitrate and nitrite in the soil back into nitrogen gas (N₂) or, to a lesser extent, nitrous oxide (N₂O), which then gets released into the atmosphere. Denitrification is an essential part of the nitrogen cycle, as it helps to regulate the amount of nitrogen in the environment and prevents the accumulation of excess nitrates in soil and water systems, which can be harmful.

In contrast, nitrification refers to the microbial process that converts ammonia into nitrates and nitrites, not the loss of nitrogen. Ammonification is the process where organic nitrogen compounds are converted into ammonia, which can then undergo nitrification. Nitrogen fixation is the process that converts atmospheric nitrogen into forms usable by plants, essential for incorporating nitrogen into the soil but not related to its loss back into the atmosphere. Understanding these processes is vital for managing soil health and fertility in agriculture.