That video is awesome, thanks for sharing. I've tried using loading docks with little success. The compacted debris is just hard to overcome. I even hired a dozer to come in and try to clear the debris.
Old loading docks can be a real problem for use as food plots, because of soil compaction and the fact loggers often scrape away any soil beforehand to make the ground more solid for heavy equipment. This doesn't mean they're impossible to use as food plots, but they will take some work. Most of my food plots started as log-loading decks. And I'll be honest, it took about 3 years to turn them into productive plots. But the important part is, it can be done.
After trying multiple techniques to get these old log-loading deck plots in shape, my recommendations would be:
1) Deal with soil compaction first. If rock is not a problem in these soils, go with Boll Weevil's suggest - a ripper to break the soil as deep as possible. Unfortunately, in my situation big rock just below the surface limited this type of equipment. A ripper would have just brought a bunch of grapefruit to basketball-sized chunks of chert to the surface. Because of our rock problems, we went with an industrial-grade tiller. It doesn't take a monster tractor to run one of these - we used only a 32 HP 4x4 tractor - but it is going to be a slow process. Early on, I would spend half a day tilling a 1-acre plot. I would be travelling slower than walking speed. All we were trying to accomplish was water penetration into the soil, so only tilling down 6-8" was adequate (this also prevented too much large rock from being pulled to the surface). We also poured the lime and fertilizer to the plots
before tilling. We wanted the tilling to distribute that lime and fertilizer throughout the 6-8" of soil. It also helps to wait until a day or two after a good rain - anything to help soften what is normally concrete hard ground.
I would recommend tilling - spring and fall - for one to two seasons. After that comes soil building.
2) Soil building is the next critical step. As Megalomaniac and Popcorn often preach, proper soil building takes time. A true soil profile cannot develop if the ground is constantly being turned. "Green manure" - biological material - must sit and break down for years before a true soil profile develops. Once a new poor-soil plot has been broken a few times - either with a ripper, bog disk, or tiller - I would HIGHLY recommend planting with the throw-and-mow technique. This process allows for a soil profile to develop. An even more productive method is drilling in seed through mowed thatch. Seed drills are expensive, but they unquestionably do the best job of getting seed into the ground while maintaining the protective thatch. Mowed thatch
greatly reduces soil moisture loss during dry conditions. And again, left alone, that thatch eventually breaks down to become rich topsoil.
For my poor-quality thin-soiled, rocky ridge-top plots, we tilled them spring and fall for two years. Looking back, for those specific conditions, I might not even recommend tilling in spring. The soil is softest then and most easily tilled, but exposed soil going into a hot, dry summer is guaranteed to evaporate any soil moisture the soil has collected over the winter. I would probably just recommend throw-and-mow seeding of a summer crop that produces the maximum amount of green manure possible for mowing down and tilling in at fall planting.
Once you have your soil building regime in place, plantings such as perennial clovers are going to be the most cost effective over time. However, if deer food production is critical, and food plot acreage limited, I would go with annuals because annuals generally produce more "deer food" per season. But I would also plant annuals that are notorious for being able to be grown in poorer soil conditions. And if possible, look towards annuals that will reseed themselves. Then letting surviving plants go to seed before mowing.
Below are three pictures of one of our plots. The first picture is while it was being bulldozed out after it was used as a log-loading deck. The second picture is after I tilled it the first time. The first growing season, the soil was so poor it would barely grow Elbon Rye, which is notorious for growing anywhere. However, four growing seasons later it looked like the third picture, taken in spring, with a full crop of crimson clover and wheat.