Agronomy Degree Practice Exam

Which process involves applying bacteria that fix nitrogen?

1. Applying bacteria that raise soil pH

2. Removing nitrogen fertilizer

3. Applying nitrogen fertilizer

4. Applying bacteria that fix nitrogen

The correct answer is: Applying bacteria that fix nitrogen

The process of applying bacteria that fix nitrogen involves introducing specific types of bacteria, such as Rhizobium or Azospirillum, into the soil or directly to plants. These bacteria have the unique ability to convert atmospheric nitrogen (N2), which plants cannot use directly, into forms of nitrogen (like ammonia) that can be assimilated by plants. This is particularly important for enhancing soil fertility and reducing the need for chemical nitrogen fertilizers. When beneficial nitrogen-fixing bacteria are applied to the soil, they form symbiotic relationships with the roots of certain plants, such as legumes, facilitating natural nitrogen fixation. This process not only improves soil health but also contributes to sustainable agricultural practices by minimizing the reliance on synthetic nitrogen fertilizers. The other options do not relate to the act of applying nitrogen-fixing bacteria. Raising soil pH, removing nitrogen fertilizers, or adding synthetic nitrogen fertilizers do not enhance nitrogen fixation or improve nutrient cycling in the same beneficial way that applying nitrogen-fixing bacteria does.