SOIL PREPARATION

FIGURE 9.2: Disc-harrow compaction at 15-20 cm depth in a vineyard (Photo: ARC Infruitec-Nietvoorbij).

Soil Strength (kPa) 0 200 400 600 800 1000 1200 1400 1600

0

New surface

-10

New surface

-20

-30

-40

Soil depth (cm) -50

-60

Immediately after Double delve After first pass After second pass

-70

FIGURE 9.3: Re-compaction due to a varying number of passes by tractor wheels on loose soil (redrawn after Van Huyssteen, 1983).

144 | RE-COMPACTION