Jeff9366: Do you use just the disc harrows to break the soil up or do you plow first? I have been doing a little research and is seems some people are just using the disc harrows and others are plowing too. The tiller we have used in the past does a good job just seems like a big area to rototil and it seems rough on them when you get into rocks.
In a few small areas where there was Bahia pasture grass sod, I broke the sod with a Moldboard Plow, then used the Disc Harrow to smooth. Plowed food plot area represents 10% of my food plot area. The other 90% I used only the Disc Harrow with two or three passes the first time I disc. As I live in Florida, I normally plant distinct Spring/Summer and Fall/Winter food plots so the plots get disced twice per year, one pass only per season, and stay soft. I sow a little thick; the local Ace Hardware sells Spring/Summer and Fall/Winter food plot seed for $22/fifty pounds.
Learning to adjust a Moldboard Plow is rather tricky. Plowing on sloping ground is REALLY tricky and I do not recommend it. Heck, finding a used Moldboard plow, complete and in good condition is difficult. It is difficult today to find replacement parts for the "wear" parts on Moldboard Plows.
A Disc Plow (which is NOT a Disc Harrow) would be my choice of plow for food plots if I were beginning now. Disc Plows are less prone to "hang up" on rocks and tree roots and are safer on slopes. Monroe Tufline still manufactures Disc Plows. Used Disc Plows show up on eBay all the time. Ken Sweet at Sweet Tractor in Canmer, KY., usually has refurbished Disc Plows which he sells on eBay.
Neither a Disc Plow nor a Disc Harrow is very good at cutting genuine sod. For that specialized task a Moldboard Plow excels.
Often people plow because their Disc Harrow is too light. There is kind of a magic number for Three Point Hitch mounted Disc Harrow general use effectiveness: 40 pounds total Disc Harrow weight bearing on each disc/pan. A Disc Harrow with 18" diameter pans barely makes 40 pounds, yet people buy 12" - 14" - 16" pan diameter Disc Harrows.
For food plots where the land has NOT been plowed 20" pan diameter is the minimum effective and 22" and 24" pan diameter better. However, most people will not pay for the weight, instead they plow. Go with Disc Harrow 9" spacing between pans rather than 7" spacing between pans. You want scalloped pans.
I usually, not always, Bush Hog new food plot land before scratching it with the Disc Harrow.
A Cultipacker will give you a better return on investment, when planting food plots, than will a plow.
Tractor work is influenced by what equipment people have on hand. Mine too.