What Attachment?

[NCL4701]

I’m with @BAP. I wouldn’t plow unless I absolutely had to. Plowing will cost you an implement you’ll probably have no future use for (although you could sell it after you’re done with it) and, worse, is likely to leave you picking rocks way longer than it took to flatten your field.

Your original post said it isn’t flat because the prior owner ran a disc harrow over it in one direction and quit. So it’s only as lumpy and rowed up as would be caused by running a disc harrow over it, thus it would logically follow that it doesn’t need anything more aggressive than a disc harrow to flatten it:

My take:

1. Get a mower sufficient to mow it (rotary slasher or flail). Mow it; preferably when it’s hot out and you’re not getting rain for a couple days so it will dry, or when the stuff you’re mowing is already dormant and dry. You’ll have use for a mower long term as well, so buy a good one that’s a good fit for your place long term.
2. Buy, rent, or borrow a double gang disc harrow. Set it to full cut and start by cutting across the direction it was cut previously. You may have to cut multiple times in different directions or may not. The first goal is to get all the dirt well disturbed and vegetation finely diced so you don’t have big grass/weed clods.
3. Once you get it consistently busted up and reasonably fluffy, reduce the aggressiveness of cut and go over it another time or two in different directions (90 degrees or 45 degrees or circle or combo).
4. It needs to be dry for the last step. Shallow cut on disc. Chain a drag behind the disc and go over it until you’re happy with it.

Worst case, you go over it with the disc 3 or 4 times and it just isn’t getting it done. If that happens, buy the plow and get your mind right to pick a mess of rocks. You’ll need to disc it after plowing so you’ll need the disc anyway. Only thing you would have lost is about a half day of driving around in a small field and maybe 6 to 8 gallons of diesel.