Vertical and horizontal soil stresses beneath a modern combine harvester:Measurements and modelling

Vehicle traffic-induced subsoil compaction has negative influences on soil functions and ecosystems, which may cause the degradation of farmland. Rubber tracks are recommended for use on modern large agricultural vehicles due to its low ground pressure as compared to tyres. However, few studies have discussed the potential of the rubber tracks to reduce subsoil stress. In this study, we investigated the magnitude and distribution of soil stress below a rubber track and a tyre for a range of traffic velocities. The vertical and horizontal soil stresses were measured under the centrelines of the rubber track and tyre paths at a depth of 0.35 m by transducers buried in the soil. The SoilFlex model was adopted to simulate soil stress in the soil profile. Vertical stress was distributed with one peak under the tyre and multiple peaks under the rubber track. Horizontal stress exhibited one peak before and one peak after the passing of the axle. The maximum vertical and horizontal stresses were approximately 3.4- and 2.0-times higher, respectively, under the tyre than under the rubber track, indicating greater effectiveness of the rubber track in reducing the vertical stress than reducing horizontal stress. Both vertical and horizontal stresses presented a downward trend as the vehicle velocity increased.