The Joys of Legumes
One of the many joys of having an organic lawn is harnessing the power of legumes. Legumes are from the Fabaceae family, also known as Leguminosae, that are well known for their ability to fix nitrogen out of the atmosphere via a symbiotic relationship with a beneficial bacteria in their root nodules. This process builds healthy soil and eliminates the need for chemical fertilizers.
Not only do they fix free biological nitrogen out of the air, they are also much more drought tolerant than traditional lawn grasses. In a climate like ours on a normal rainfall year, legumes do not require extra watering. This is a blessing as Bozeman is continuing to face a water shortage and 50% of the City’s treated water goes to lawns and landscaping in the summer. A healthy mix of grass and legumes can eliminate the need for not only chemical fertilizers, but also additional water.
Legumes also help build up a thick and healthy soil sponge. Many lawns, especially in newer construction areas, are starting from a difficult spot with compaction. Even older lawns with low diversity and high traffic can get compacted. While a core aeration is a good temporary fix, the long term solution involves healthy soils and more legumes. Legumes have different and deeper root structures than grass. They can help naturally relieve compaction and build more resilient soil in the long run. This also increases the effectiveness of the natural moisture we do receive.
Another great benefit of legumes is they fill ecological niches that monoculture grass can’t fill on their own. This provides the ecosystem services described above and also helps to crowd out noxious weeds like thistle. Noxious weed resistance goes up exponentially when you add in beneficial species diversity.
Some common legumes in Montana include many varieties of clover and black medic. Neither of these beneficial plants were ever considered weeds until the invention of chemical fertilizers and harmful pesticides. They have since been subjected to a sustained negative marketing campaign by the chemical industry. Appreciating legumes when you find them, and adding them back into your lawn if you don’t, is key to helping build a more sustainable future in Southwest Montana.
