Quick question: which species earned that nickname in Midwestern rotations about a century ago for nitrogen fixation and a deep taproot? I’m tracking down the origin in 1920s extension bulletins to calibrate realistic N credits and soil-structure gains versus alfalfa in a 4-year rotation aimed at stabilizing corn yields…
Sweet clover — especially yellow sweetclover (Melilotus officinalis) — was the “poor man’s alfalfa,” credited in 1920s Midwest bulletins with a deep taproot and roughly 60–90 lb N/acre, a notch below alfalfa. If you’re calibrating credits, check Illinois or Minnesota circulars on 2‑year sweetclover under small grains; it’s the budget model, not the Cadillac.
Sweetclover — yellow Melilotus officinalis — was the poor man’s alfalfa; @jgarcia57 is right, and if you want those old bulletin-level N credits, inoculate with S. meliloti and lime to pH 6.5+, then terminate at early bud — I see about 60–80 lb N on silt loam but notably less on heavy clay; what soil are you on?
Yellow sweetclover (Melilotus officinalis) fits that bill. I’ve gotten the best N and taproot punch by drilling scarified seed after oats in mid‑August, letting it overwinter, then mowing at early bloom before corn; on tight clay I had to lime and inoculate to see similar gains — @morris_k78, what soil are you working with?