Chemistry Reference
In-Depth Information
density, Soane & Van Ouwerkerk
38
demonstrated that applied N can be cut by
almost 30% and maintain output. Other research has shown up to 6% increases
in wheat yield in the absence of soil compaction.
39
Soil compaction increases
the
penetration
resistance
of
soil,
which
is
a
major
limitation
to
crop
d
n
1
r
2
n
g
|
8
productivity.
9,40
The impact of soil compaction on crop yield varies considerably between soil
types and regions. A recent study applied 'light' (1 pass) and 'heavy' (8 passes)
compaction stresses to soils with different textures and then sowed the fields
with wheat.
24
The yield reduction due to 'heavy' soil compaction in a sandy
loam soil was almost 50%, whereas for a clay soil the yield was not changed by
applying 'heavy' compaction stresses. The authors attributed the results found
for the clay soil on the buoyancy effect of pore water. In a review of many
studies examining soil compaction impacts on yields, Chamen
10
found a large
variability in yield decrease caused by compaction. In comparisons of
trafficked vs. non-trafficked soils, 15% yield decreases were quite common,
but unstable soils could have yield decreases greater that 40%, whilst some
crops and soils had increased yield following compaction.
Figure 2 shows a conceptual diagram of the implications of soil compaction
to agricultural productivity and the environment. Decreased water infiltration
caused by a reduction in pore space leads to greater surface run-off of water
Figure
2
A conceptual diagram that shows the various implications of soil
compaction to the environment. The potentially negative implications to
crop
productivity
are
not
shown.
(Source:
adapted
from
Soane
and
Vanouwerkerk).
37
