A display on one of the lots at the 2013 Farm Progress Show featured a land cutaway that showed compaction from combine tires. The dirt had lime layers in it. What you were supposed to see was how the combine tires pushed soil layers together. That resembles creating soil compaction in the field.
Companies say there are two ways to reduce that load without reverting back to smaller machines that carry reduced weight both in the machine itself and in the grain it carries. One is to mount tracks that tend to create less soil compaction. Some companies are selling considerably more tracked machines ordered that way straight from the factory today.
The other is to run lower air pressure in tires. You can't do that effectively unless you have new tire technology that consists of IF or VF construction. IF stands for increased flex in the tire construction. VF stands for very high flex. The bottom line is that these tires have the ability to carry lower air pressure and still wear and serve a long productive life.
Reducing the pressure by using these modern-designed tires brings the soil compaction potential about halfway down from running regular ties at full air pressure to tracks. Tracks are tough to beat in terms of spreading the load and dropping the risk of soil compaction.
The Farm Progress Show wasn't the first time someone created a pit, put in layers of soil and lime and then drove a combine over it to show how various tires made different patterns.
Michelin put on a demonstration at the Purdue University Animal Science farms a few years ago where they used the combine ploy to get their point across. Everything they tried in other aspects of the demonstration didn't always work – soil compaction is not an easy thing to demonstrate. However, it was easy to see how large combine tires with lots of air pressure could track and sink faster than tires built to run at lower air pressure.