First time posting so please forgive me if this is in the wrong spot.

I'm searching for a good winter ground cover for my 50' x 100' summer garden. I only use this garden to grow tenders and sow/transplant 2 weeks or so after the last frost in early spring. There are several problems I would like to work on addressing.

1) Nitrogen - had the soil tested all is ok besides low on nitrogen - The garden sits in the middle of wild grass and flower meadow that gets mowed and bailed for hay twice a year for livestock.

2) Erosion - it also sits in between two hills West and East sides. And the south side is higher than the north side which is where a small creek is, no more that 100 ft away. I have a good trench running south to north so the water drains well but in the spring the north side is very wet and is the last part I can work. Although corn and cukes seem to love it down there...

3) Weed control - it's sitting the the middle of a meadow, weeding is a big chore mainly crabgrass... I can pull the black eyed susans and wild marigolds up before they get to big. But I would like some ground cover that would choke out the weeds if possible.

What I would like to do is... in the spring run my tiller where I would plant a row, wait a few days and plant that row. I would like to leave the ground cover growing in between the rows until it got tall enough to mow. then I could mow it to make a nice mulch in between the rows. If it grew some more I would just whack it back down and leave it lay as mulch

I was thinking I may be able to do all this with early fall planting of alfalfa but then again I'm not so sure.

I know this is a lot to ask from a ground cover... and most likely will be a on going struggle for many years to come... However, your thoughts/recommendations would be most appreciated.

Thanks