Waterlogging, soil compaction and low fertility
can be so bad on some sites that tree survival and growth
wont be possible without intensive soil preparation.
If a potential site has such problems, growers might need
to invest in deep ripping, mounding, cultivation, and fertilisation.
In addition to improving growth, intensive soil preparation
is also often used to identify planting lines and reduce the
cost of contract planting. Planting crews can work faster
when planting into well-worked soil. Well-tilled soil can
also save farmers money because it allows open-rooted or very
small seedlings to be planted instead of seedlings in large
pots, which are more expensive to handle. Another advantage
of intensive site preparation is that it appears to improve
uniformity of growth across plantations. This might be a critical
consideration in large plantations managed at high stockings,
but may be of little concern to a grower considering wide
spacing and pruning regimes.
In many cases, farmers find that soil preparation is not essential.
On difficult sites or in small areas, it is often better to
save money and accept slower growth or less uniformity.
Many years of research in Victoria has demonstrated that there
is little or no response to ripping if the soil is shallow
and does little to impede root development. Large mounds can
reduce the risk of waterlogging around the root system and
can effectively increase soil depth. But mounds less than
about 30 centimetres high are unlikely to have a significant
effect on early growth. There is also a risk that intensive
soil preparation will increase the risk of wind throw and
butt sweep, exacerbate soil erosion, destroy pasture and encourage
the establishment of problem weeds. In heavy clay soils riplines
can form which may result in the loss of trees down the cracks
or cause drying out of exposed roots.
and nutrient decline
Planting trees to reduce
Waterlogging and Salinity.
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