Have you noticed those pretty yellow flowers, the ones that bring vibrance to dull gray roadways and life to otherwise monotone lawns? I am, of course, referring to those patches of lush green grass sporting sparse stems with butter-colored petals. Seeing that color is something I miss during winter, eagerly await in the spring, and gush over all summer. It is perennial peanut! This groundcover plant is not only used in ornamental landscapes but also in agriculture. A recent Ask IFAS publication discusses how nitrogen-fixing nodules enable legume plants, including perennial peanut, to serve as valuable resources.
How Legumes Fix Nitrogen
Legume roots produce substances that soil microbes consume for energy. These microbes produce nitrogen, which the plant uses for growth. Certain microbes will even form nodules directly on the legume roots. These are all parts of a process called biological nitrogen fixation. The presence of nodules is a good sign that the legumes are storing fixed nitrogen.
Benefits in Turfgrass
Perennial peanut is a nitrogen-fixing legume. Therefore, it requires little to no fertilizer supplements. For this reason, along with its drought tolerance and aesthetic appeal, perennial peanut works well as a turf alternative, per another IFAS blog. The plant can be used as turfgrass alone or incorporated with other grass types, according to a UF/IFAS gardening solutions webpage. Moreover, perennial peanut forms a thatch that helps preserve soil moisture and protects against soil erosion.
Benefits in Agriculture
Legumes’ nitrogen-fixing abilities provide various benefits in agriculture. Their belowground parts, meaning roots and nodules, will eventually decompose and continue the cycle of feeding soil microbes. At such time, they will also add plant-available organic matter to the soil. The aboveground parts, meaning the stems and leaves, similarly contribute organic matter when clipped or chopped and incorporated into the soil. These contributions of organic matter, though mostly from aboveground material, make perennial peanut a good cover crop and living mulch. Thus, perennial peanut improves soil fertility. Additionally, the aboveground plant parts are a nutritious source of animal feed, either when chopped or while still living. Finally, the plant’s pretty flowers attract pollinators!
Read Further
For more detailed information and identification tips, read the recent and relevant Ask IFAS publication: SL546, “Nitrogen-Fixing Legume Nodules.”
See Ask IFAS for various Ask IFAS publications on biological nitrogen fixation (SL501), perennial peanut as a living mulch (HS1474), its planting information (SS-AGR-349), and many more topics.
1
