Cranfield University

Field Study With Full Size Combine Harvesters
Depth Depth (cm) (mm)
600 400 200 0
0
20
40
60
Tire
Track
High Inflation Pressure
Regression Line Tire
Regression Line Track
Regression Line High Inflation Pressure
0 0
2
20
4
40
6
60
8
80
10
100
Deformation Displacement (cm) (mm)
Figure 50: Soil displacement and regression lines for clay with pooled groups
Table 12: Regression line parameters for displacement on clay soil
Treatment Intercept d0 (mm) 95% - CI Int. Slope s 95%-CI Slope R 2
Individual Groups
Tyre 1 51.1 37.3 – 64.9 -0.148 -0.193 - -0.103 0.756
Tyre 2 47.4 31.5 – 63.3 -0.169 -0.224 - -0.115 0.746
Track 1 23.6 7.5 – 39.7 -0.087 -0.142 - -0.032 0.455
Track 2 21.7 3.5 – 40.0 -0.086 -0.144 - -0.029 0.450
High 70.0 51.8 – 88.2 -0.203 -0.260 - -0.140 0.802
Combined Groups
Tyre 49.0 38.7 – 59.2 -0.157 -0.191- -0.123 0.727
Track 22.7 11.6 – 33.9 -0.087 -0.123 - -0.051 0.454
High 70.0 51.8 – 88.2 -0.203 -0.260 – -0.140 0.787
4.1.1.2 Sandy Loam Subsoiled
In this section only the diagrams with the pooled data will be shown and discussed because
of the experience gained in the analysis in the previous section. For completeness data for
both the pooled and the individual groups was included in Table 13. As can be seen
graphically from Figure 51 and numerically from Table 13, the track and the tyre were
statistically significantly different. The track created the smallest soil displacement. This
was in agreement with Ansorge (2005, a), Section 3.2 and with the results found on clay.
Ph.D. Thesis Dirk Ansorge (2007)
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