Soil compaction - Soil Essentials: Managing Your Farm's Primary Asset - page 127

Increased moisture stress on plants and soil organisms in dry or drought
conditions.
Increased waterlogging of topsoil during wet seasons, leading to poor plant
growth.
Waterlogged soils inhibit beneficial soil microbes and favour disease organisms,
increasing the risk of crop diseases.
Less crop or pasture growth leads to lower net farm income.
Poorer stock health, also leading to poorer net farm income.
Waterlogging
Water ponding on the soil surface after relatively light rain, or remaining ponded
for several hours after rain, can indicate soil structural decline (Figure 38 on
p. 117).
How to ameliorate compacted soils
Deep rip under favourable soil moisture conditions with an implement such as a
paraplough or a winged ripper. The soil should be evenly moist, neither too wet,
nor too dry for this treatment. (Deep ripping may not be effective on dispersive
soils.)
Follow up deep ripping by planting deep-rooted plants, then minimise traffic
by stock and machinery. The use of controlled traffic methods of sowing crops
(tramlining) using GPS guidance systems will limit compaction by machinery.
Use deep-rooted perennials in pasture mixes.
Applications of gypsum may help if the soil has high clay content only if the
clay is sodic or contains high levels of magnesium.
What does it cost to repair compacted soils (2006)?
Deep ripping
Cost per hectare will vary depending on soil conditions, depth of ripping and
equipment used. Contract rates are more or less locally determined, but will be of
the order of $150/ha. Farm owned machinery may be available, and therefore
making it cheaper per hectare, but contractors often have heavier machinery that
may more easily be capable of doing a high quality job.
Planting pastures
Cost per hectare to sow perennial pasture will depend on the seed mix and
fertiliser used but will be in the range of $250 to $350/ha done by the farmer.