What is a primary benefit of nitrogen-fixing bacteria in soils?

Nitrogen-fixing bacteria play a crucial role in maintaining soil health and fertility by converting atmospheric nitrogen, which is abundant but not directly usable by plants, into forms that plants can assimilate, such as ammonia or related compounds. This process, known as nitrogen fixation, is essential for plant growth since nitrogen is a key component of proteins, nucleic acids, and other vital molecules.

The ability of these bacteria to take nitrogen from the air and make it available in a form that plants can utilize significantly enhances soil fertility, thereby supporting agricultural productivity. This process not only improves the nutrient content of the soil but also promotes a healthier ecosystem by improving microbial activity and overall biodiversity within the soil.

While some of the other options mention important soil functions, they do not directly relate to the unique capability of nitrogen-fixing bacteria. For instance, while organic matter creation is beneficial for soil health, it is not a primary function of nitrogen-fixing bacteria. Preventing soil erosion is typically more influenced by plant root structures and soil conservation practices. The inhibition of other bacteria is not a primary function of nitrogen-fixing bacteria, as their main role focuses on nutrient conversion rather than affecting the populations of other microorganisms.