The basic reason tracked tractors are so popular on the Palouse is that the tracks have a much larger footprint on the ground compared to even the 8 wheeled tractors. This gives them superior traction and pulling power, particularly on soft, hilly and/or wet ground. And they don't compact the soil as much which helps crop yields. They can also turn a tighter corner. From what I hear, tracks ride better on soft ground but ride rougher on hard ground (i.e. a dried plowed clay field). Tracks have their downside too. The mains one being you can't cruise down the road between fields as fast and they cost more.