What type of plants are known for adding nitrogen to the soil?

Legumes are known for their unique ability to fix atmospheric nitrogen through a symbiotic relationship with Rhizobia bacteria found in their root nodules. This process is crucial for enriching the soil with nitrogen, which is an essential nutrient for plant growth. By converting nitrogen gas from the atmosphere into a form that plants can use, legumes help to improve soil fertility. This characteristic makes them particularly valuable in crop rotation and sustainable agricultural practices, where enhancing soil health is necessary for successful farming.

Herbaceous plants, while they contribute to the ecosystem in various ways, typically do not have the ability to fix nitrogen. Succulents are adapted to arid environments and store water but do not play a role in nitrogen fixation. Trees may contribute to soil health through leaf litter and root systems, but they do not have the same nitrogen-fixing capabilities that legumes possess. Thus, legumes stand out as the primary plant type known for adding nitrogen to the soil.