What occurs during the nitrification process?

During the nitrification process, ammonia (NH₃) or ammonium (NH₄⁺) is oxidized to nitrate (NO₃⁻). This two-step biological process is crucial in the nitrogen cycle and involves specific bacteria. First, ammonia is converted to nitrite (NO₂⁻) by bacteria such as Nitrosomonas. Then, nitrite is further oxidized to nitrate by bacteria like Nitrobacter. Nitrate is a more accessible form of nitrogen for plants, making this process essential for plant nutrition and overall soil fertility.

The other options reflect different nitrogen transformations but do not accurately describe nitrification. For instance, the conversion of nitrogen to ammonium refers to the process of ammonification or mineralization, and the conversion of nitrate to nitrogen gas is associated with denitrification. Lastly, the transformation of organic matter to nitrogen involves processes such as decomposition but does not specifically focus on the nitrification process.