1 Prairial: Luzerne (alfalfa, lucerne, Medicago sativa)
First off, it’s a new month here in the French Republican Calendar. Happy Prairial! Prairial takes its name from prairie, a pasture or meadow.
Today’s plant is in the Fabaceae family, which is just about my favorite, and I was about to talk about that when I skimmed over this fascinating detail from Millin: “The root, composed of very fine fibers, can be used to clean teeth.” I never knew. I wonder whether people were separating out the fibers as a floss, or using the chewed/frayed root the way twigs have been used?
So, the Fabaceae. The legume family. Peas! Beans! The noble soy! It’s a wonderful family, immensely diverse, including trees like redbud and acacias, field wildflowers like clover, vines like wisteria and kudzu—and today’s plant, alfalfa. Alfalfa is grown primarily as a protein-rich animal fodder, usually as hay (appropriate for the first day of Prairial). Why alfalfa? Because—like other legumes—its roots have an astonishing symbiotic relationship with bacteria. The bacteria (in this case Sinorhyzobium meliloti) inhabit special root nodules, where they convert nitrogen from its relatively inert atmospheric form into forms that other organisms can use to create the basic building-block molecules like nucleotides (for RNA and DNA) and amino acids (for proteins).
Are you alive? You are using nitrogen that was probably converted by a bacterium living in a legume root!
Having this up-close spot in the nitrogen cycle gives the legume an advantage in a field of competing plants—and then, when the legume dies, it leaves all that lovely nitrogen in the soil. This makes crops like alfalfa especially important in agriculture: they can take a turn in a field rotation, where after using the field to grow alfalfa fodder the farmer can plow in its remains as fertilizer for another crop.