Help identify this annoying weed!

[likeatourist86]

I don't know what this plant is, but it's taking over our backyard.
I'm in Canada.
The soil in my region is more alkaline, and the plants are overtaking the grass in the yard.
We tried pulling them all out last year, but now their back with a vengeance.
So if you know what this plant is, tell me what it's name is and any information that you know of.

It's very thin, string like roots that are all bunched together, usually, and it sort of smells like clover.

[rainbowgardener]

I think it is black medic, aka yellow trefoil. It smells like clover, because it is closely related to true clover. Like clover, it is nitrogen-fixing, so it has sometimes been grown to improve agricultural soils. It has been used for livestock fodder, as it is high in protein. You could just relax - my own lawn is in large part white clover. It looks just as green when mowed.

It is difficult to get rid of, but work on keeping conditions that keep your turf grasses happy - plenty of food, water, aeration- so they can compete better. Mow at a higher setting to shade the black medic out.