18.11.2012 Views

Cranfield University

Cranfield University

Cranfield University

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Field Study With Full Size Combine Harvesters<br />

Depth (mm)<br />

0<br />

50<br />

100<br />

150<br />

200<br />

250<br />

300<br />

350<br />

400<br />

450<br />

500<br />

Pen etrom e ter Res is tance (M Pa)<br />

0 0,5 1 1,5 2 2,5 3 3,5 4 4,5<br />

Average Control<br />

Figure 54: Penetrometer resistance for clay control and the pass of a wheeled, tracked<br />

and a wheeled machine with high inflation pressure<br />

Clay penetrometer resistance was influenced by the clay sticking to the cone and shaft due<br />

to the high moisture content. It was not significantly affected by the single treatment. Inter-<br />

esting to note was the increased variation below 250 to 300 mm depth. During the excava-<br />

tion of the fishing hooks the reason became clear. It was the maximum working depth<br />

ranging to about 250 mm depth on this field. Below 250 mm the AP horizon changed to a<br />

B/C horizon of virgin clay mixed with stones.<br />

4.1.2.2 Penetrometer Resistance on Shallow Tilled Sandy Loam<br />

Controls for different treatments in the shallow tilled sandy loam soil are shown in Figure<br />

55. There were no significant differences so one control was used.<br />

Similar to the clay data, there were no significant differences between either the runs them-<br />

selves or even the control and the run as obvious from Figure 56. Because of the amount of<br />

interference amongst the different treatments close to the surface it did not allow any con-<br />

clusion. Maximum working depth on the clay was found to be between 250 – 300 mm; in<br />

the shallow tilled sandy loam it seemed to be at about 300 mm depth from the graph. This<br />

was confirmed when excavating the fishing hooks.<br />

Ph.D. Thesis Dirk Ansorge (2007)<br />

Tyre<br />

Track<br />

High<br />

LSD<br />

69

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!