Along with Bill's tip, might also check link below - you'll need the tractor's full model number & serial number (I D plate prolly in the cavity under the tilting seat).... MTD may have the parts list for that machine with exploded disgrams in free downloadable pdf files even tho the machine is pushing 20 yrs old... Here is a link that might be useful: MDT manuals

I have to wonder if you understand what the first two letters in the model # of your tractor mean? YT stands for "yard tractor". YT's are somewhere between the simple, light duty LT or lawn tractor and the more robust GT's or Garden Tractors. I get the impression that you are about to ask your YT to perform the sort of work that a GT is designed to do. For sure, you could install Ag type bar-tread tires on the rear and load those tires with liquid ballast. In addition, you could also install rear-wheel weights to increase traction even further. Tractors are just like the proverbial chain that might have one weak link in it. With your YT, it's hard to say what might turn out to be the weak link but suppose for a second that you manage to make those back wheels really stick so that every horsepower that engine can generate gets transferred to the wheels that won't spin. Maybe the engine to hydro drive belt slips or breaks. No big deal. It's only a belt. But if the hydro itself breaks or a gear in the trans-axle lets go, then you might not like the price of repair. Even if there is warranty still on this tractor, the mods you make might give the dealer the necessary "out" to deny your claim. Just something for you to ponder.

Minnie's link reminded me...I've looked into mulch layers in the past and the farm equipment sites seem to indicate that you need a BIG tractor. Our Kubota is 24hp and, according to what I read, would be too small? How big is your tractor Jay? Is it having any trouble power-wise? The only beds I'm forming with plastic like your by-hand picture are my sweet potatoes, and that is way too good of exercise, I'm glad I only have 100 feet! The other heat lovers get used "lumber wrap" laid on the ground and stapled as needed. Lumber wrap is what covers the units of lumber when they leave the sawmill. It's heavy duty woven plastic, white on one side and black on the other. It comes in 4-5 ft widths and 25-60 ft long. For those of you without husbands in construction, you could probably get it at the lumber store. It works great and is way way easier to pull up at the end of the season. Downsides are that the winds catches it easier than the other plastic mulch that is tucked in everywhere, and it takes more room in the garbage at the end of the season. But free is a good price!

I make raised beds with our Disc hiller too, here are some we just made to plant tomatoes today. I couldn't run along the outside, so I had to shovel and rake them up. This is what our disc hiller looks like. This isn't my tractor, I tried it out with my parents tractor at their farm. I have a little Kubota B7100, it works just fine with it too! We get flat topped beds if we widen out the disks and driver really fast. Here are some raised beds we did last year for our winter squash. We laid drip tape on the ground, covering it up every 20 to 30 feet with a shovel full of dirt and then we came back and made the raised bed over the drip tape. When we turned on the drip tape, it really wetted the whole raised bed. Here is half of the very flat field. Jay