Effect of Cover Crop, Slurry Application with Different Loads and Tire Inflation Pressures on Tire Track Depth, Soil Penetration Resistance and Maize Yield

Agricultural soils can be affected in their ecological functions by in-field traffic of agricultural machinery. A three-factorial research design was carried out in a field experiment to test the effect of slurry tanker filling level (filled, half-filled, empty), tire inflation pressure of the slurry tanker (high: 300 kPa, low: 100 kPa), and ground covering (+cover crop, −cover crop) on tire track and soil penetration resistance (averaged, 0–20 cm, 21–40 cm) after application on the fields in spring. Additionally, the effect on grain yield of the subsequent culture was considered. The total weight of the tractor slurry tanker combination was 16,470 kg (empty), 25,940 kg (half-filled), and 34,620 kg (filled). The low tire inflation pressure of the slurry tanker increased the mean tire–soil contact area by 75% (filled), 38% (half-filled), and 16% (empty tanker). The results obtained show a significant effect of tire inflation pressure and ground covering on the measured parameters. The tire inflation pressure reduction effect on track depth was highest in the filled slurry tanker (−17.8%). With increasing wheel load, the effect of reduced tire inflation pressure on soil penetration resistance (0–20 cm) increased. In the subsoil (21–40 cm), the effect of tire inflation pressure was much lower, indicating that a reduction of tire inflation pressure preserves the upper layers rather than the lower ones. Furthermore, cover crops are linked to a higher degree of soil deformation after traffic with the tractor–slurry combination due to their loosening effect on the topsoil. Tire tracks were 15.0% deeper in the cover crop field than in the field without a cover crop. It is assumed that cover crop mixtures with different types of root mass can influence the mitigation of soil compaction in an ameliorative way.