Certified Crop Advisor Practice Exam

Which of the following is not needed for rapid nitrification to occur?

1. Ammonium

2. Nitrite

3. Nitrate

4. Oxygen

The correct answer is: Nitrate

For rapid nitrification to occur, the essential components include ammonium, nitrite, and oxygen. Nitrification is a microbial process that converts ammonium to nitrite and then nitrite to nitrate. This process is carried out by specific bacteria, including ammonia-oxidizing bacteria (AOB) that first convert ammonium to nitrite, and nitrite-oxidizing bacteria (NOB) that subsequently convert nitrite to nitrate. Oxygen is also crucial, as it serves as the electron acceptor for the bacteria involved in nitrification. They require aerobic conditions to effectively carry out these transformations. While nitrate is a product of nitrification, it is not a substrate required for the initial stages of the process to start. Therefore, it is not needed for rapid nitrification to occur, as the process begins with ammonium and proceeds through the formation of nitrite. Only the intermediates (ammonium and nitrite) and the necessary condition (oxygen) are required to drive the nitrification process forward.