That’s a low calcium, high manganese weed. I might guess you have a clay soil and lower pH.
I don’t know if anything is gonna take that out without taking your clover and alfalfa with it. Check your soil test for pH and calcium levels. Calcitic Lime and gypsum probably won’t knock it out 100%, but could weaken it enough to where it’s not dominant any longer. Change the conditions and you change the output.
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