Well, that's good news I guess, at least for now. If you've suffered drought conditions like here those stemmy weeds are really tough. Once you get it tamed down and mowing more tender weeds & grass, it should handle it much better. About all you can do now is take a smaller swath, except on an opening swath, then pick it up a bit making a first round, then drop down to the cutting level you're at.
Most rotary cutter blades looking from the top turn CCW, so if you take 2/3-3/4 swath, with the 1/3-1/4 swath side running on what has already been cut may help unload debris to the side instead of carrying it around to the rear to discharge. Taking a full swath, some of those long stemmy weeds may have to go around twice before getting chopped up enough to be discharged. But taking a partial swath as mentioned may not chop up the stemmy weeds as fine as you want, being your planning on planting in it next year.
Blade sharpness makes a big difference too, but in that stemmy Golden Rod and Marestail, and saplings you don't want them real sharp, or it will leave mini bungee sticks which can get rough on tires. If the blades are dubbed off some, it should be leaving battered ends on the ends of those stemmy weeds.
Not sure what tillage tools you plan to use to work the ground, but those long stems could give you fits with a moldboard plow (my preferred method). Hopefully over the winter they will get brittle, and coulters will cut through or break them up.
I can tell you you've got quite a seed bank built up there. Be prepared to do a LOT of cultivating and hoeing for more than several years. Do a Google search for the seed viability for what you're seeing out there, you'll be amazed.
Personally, when I cultivate, I only cultivate the top 2"-2-1/2". Any deeper and you're just bringing more weed seeds to the top to germinate. Anything deeper than that more than likely won't germinate but may when you roll it over the following year.
Might be an idea to get a soil sample this Fall and send it in and see what you need. You can get sample bags at your County Extension Office. You should also get a sheet along with it and you can select what results you want back. At least get the basics for N-P-K and PH levels. I did get an additional Organic Matter level for my hay field several years back just to see what it was but cost extra. Basic test was $8.50. With the price of fertilizer, it beats guessing at what you need. You get your samples, then you mail them off to the University of KY. Results usually take 10-14 days. Your Extension Agent will go over them with you when they/you get the results back. Looking at the growth you're mowing off, I'd guess you're close, or even high in phosphorous.
If the PH needs adjusted, lime could be applied now to start working.
Not sure what set plants you plan on growing, but I mulch around mine with leaves. I collect from neighbors and know a couple guys that have and work for lawn services that do leaf pickup in the Fall that are more than happy to drop their loads of leaves here, rather than paying to dump them at a compost facility. Just a little FYI if you know of any lawn services close that provide that service. The season is nearly upon us for that, if you have plenty of room for them to dump. Here are a couple pics of my tomatoes this year. I mulched them mid-June, second pic is 2 weeks ago. Nearly weed free, and this year was a life saver with the drought retaining what little moisture they did get. Held them over until we got the 3-1/2" of rain from Helene, now they are back going like gangbusters, while everyone else's in the area are long dried up. Going out and pick a couple bushel's this morning.
I'm getting way ahead of the game here, better quit...
