Cranfield University

Experimental Methods
Reference Surface
Centre of the Rut
Fishhooks
Troxler Measurement Area
Figure 19: Placement of Troxler, fishhook and reference surface in test area
The soil dry bulk density was determined in the depths of 50, 100, 200, and 300 mm (the
maximum depth possible for the system). At one location before and after the pass of the
combine harvester three access holes were made and each depth was measured once within
a hole. Relative densities before and after the passage of the combine harvester were re-
corded.
2.2.4 Rut Depth
Rut displacement and rut area were measured using a profile meter. The profile meter with
its rods was placed over the rut and the rods were lowered into the rut and fixed in their
position. Then the device was taken out and the shape of the rut and thereby the area of
disturbance was reproduced on a sheet of paper. The area on the paper was measured using
a planimeter. This method gave the total area of displacement. The width of the rut and
depth were measured. All these measurement were done in three replications. For further
information on rut measurements see Davies et al. (1973).
2.2.5 Pressure Measurement
Using ceramic pressure transducers embedded at the top of a 100 mm diameter aluminum
tube the pressure exerted by the tracks when rolling over the soil was measured at 250 mm
Ph.D. Thesis Dirk Ansorge (2007)
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