Certified Storm Water Operator Practice Exam

What nutrient do legumes provide to the soil?

1. Phosphorus

2. Nitrogen

3. Potassium

4. Calcium

The correct answer is: Nitrogen

Legumes play a vital role in enhancing soil fertility primarily through their ability to fix nitrogen from the atmosphere. They have a symbiotic relationship with certain bacteria, such as Rhizobium, which live in nodules on their roots. These bacteria convert atmospheric nitrogen into a form that plants can use, known as ammonium. This process enriches the soil with nitrogen, a crucial nutrient that supports plant growth and is often a limiting factor in agriculture. By incorporating legumes into crop rotations or cover cropping systems, farmers can naturally improve soil nitrogen levels without the need for synthetic fertilizers. This not only benefits subsequent crops planted in the same soil but also contributes to the overall health of the ecosystem by reducing the potential for nitrogen runoff and promoting biodiversity. Thus, the inclusion of legumes in agricultural practices is an effective strategy for sustainable land management.