Contents - Greenmount Press

Outside of the weather, which we know can be hard to
control, the number one impact on plant establishment is the
management that is applied at planting time.
Some work that was carried out by Dr Steve Allan from CSD
last season in southern NSW picked up a number of issues that
were occurring when planting. In Figure 3, look at the sowing
depths for Condobolin and Whitton.
In this example, four by one metre soil transects were evaluated
showing the depth of seed in a side profile. In these examples, we
are seeing a range of depths from two to five cm at the same sites
in the same transects, which can only be caused by one thing. The
planter is travelling at speed, and ‘popping’ is occurring with the
seed being bounced in the soil profile. This causes a number of
issues such as seed not planted into moisture, late germination,
and gappy stands due to seedling death.
FIGURe 3: Emergence and establishment
assessment southern NSW
FIGURe 4: Soil temperatures at Hillston, Whitton
and Jerilderie
FIGURe 5: Population trials at Hillston,
Darlington Point and Narrandera
Planting dates and time of emergence
Sites at Whitton, Dpt1, Jerilderie, Hilt1, HilH3 and HilM3 took
from 18 to 24 days to emerge with the Jerilderie site being a
replant and the others sites being late in maturity. In comparison
Condobolin, Dpt2 and HilJ1 that are highlighted were planted
into October only took seven days to emerge. This supports the
theory of picking the best forecast for rising temperatures and
planting on that. This is supported by the weather data for the
region. Late September and early October temperatures were
very cool as seen in Figure 4.
Soil Temperatures at these sites were cool up until October
11 when temperatures began to rise. The Jerilderie site that was
replanted was estimated to cost the grower two bales per hectare
in yield.
Another way of ensuring that a good even plant stand is
obtained is to plant slightly heavier than what would be normal
on your farm. There is no significant yield loss by having extra
plants in your plant stand up until a point (around 15–16 plants
per metre), but as mentioned before, a skippy stand will cause a
reduction in yield. This was supported by work that was carried
out last season with three population trials conducted in southern
NSW. Planting rates of 20, 16, 12 and eight kg per hectare were
evaluated. In Figure 5 we see the results of these trials.
There was no significant difference in yield between each of
the populations at all three sites. A slight increase in yield was
seen in the eight kg per hectare treatment at Darlington Point,
but was not significant. In the trial planted at 20 kg per hectare,
plant stands came out between 15–16 plants per metre and
similarly the eight kg per hectare treatment had plants stands
between five to seven plants per metre.
The results suggest that if there are rough planting conditions,
or for instance moisture is slightly variable, a heavier planting rate
could be used with no yield reduction so that a consistent plant
stand can be obtained.
This work is supported by results from population trials
conducted in the northern growing regions as seen in Figure 6.
There is no significant yield difference between populations
from six to 17 plants per metre.
Other things to consider at planting time:
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Soil bed preparation;
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Irrigation scheduling – pre-water or watering up;
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Planter inspection and calibration;
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Temperature monitoring of the soil at 10 cm;
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Protecting the seed from insects using a suitable seed
treatment; and,
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Making staff aware of planting issues through training.
For further information in relation to any of the topics mentioned in this
article, please contact your local CSD Extension and Development
Agronomist or visit the web site www.csd.net.au
FIGURe 6: CSD plant population trials
October–November 2012 The Australian Cottongrower — 57