Really could use a clearer picture for better ID, but you might compare to prostrate knotweed, Polygonum aviculare. Just guessin'.
If it is, aeration and pre-emergent herbicide are two more things to try. Pre-emergents for knotweed need to be down before late winter when it germinates, don't know exactly when that might be in MS. Check with your local extension service.
hortster

Hm I think I have this one too, it gets stuck on my gloves once I pull it and it can get quite matted and hard to mow. Once it choked my trimmer just like that. :P Good luck in getting rid of it.