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
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