A topic which is often discussed in public is the danger that heavy tractors and other agricultural machinery pose to agricultural land. John Deere has worked intensively on how agricultural machinery can reduce soil compaction. Mathias Stettler and Roger Stirnimann from the University of Agriculture, Forestry and Food Economics explain how soil compaction occurs and what farmers can do about it.
What is soil compaction and how does it evolve?
In order to understand soil compaction, you have to know that around half of the soil consists of pores, explains Mr Stettler. If soil is compressed too much or if heavy weights exert too much pressure, then it will be compacted. This damage means the soil aeration, water and nutrient flows no longer function as they should. In addition, there is not enough room for the roots to grow. It is known that soil compaction can lead to a yield reduction of 10-20%. To avoid this, either the tyre contact area must be increased or the vehicle weight.
Mr Stettler explains the principles of soil compaction in the video:
Does a small and light tractor cause less soil compaction than a large, heavy tractor?
In principle, it is true that larger and heavier machines exert higher pressure on the ground, explains Mr Stirnimann. However, larger machines also allow larger working widths. As a result, the proportion of the ground area that is tracked decreases and the area on which no pressure is exerted increases. There are also several ways to reduce ground pressure. Large-volume, modern tyres, for example, increase the contact area due to their width and thus reduce the pressure on the ground.
The same applies to twin tyres. With the help of suitable tyres and a tyre pressure control system, the contact area when driving on the ground can be increased, thus reducing the pressure. Finally, crawler tractors should be mentioned, which can reduce the pressure on the ground even further thanks to their very large contact area.
In the video, Mr Stirnimann explains what influence the machine working width has on soil compaction: