Australia
May 2, 2007
Source:
GRDC's The Crop Doctor
Using disc seeders, seed priming
with water injections and using low seed rates and wide rows for
early sowing can minimise an established crop’s drought stress.
Department of Agriculture and Food researchers, Glen Riethmuller
and Dr Darshan Sharma, have provided some guiding principles on
seeder design, seed priming and water injection to help growers
and advisers develop technical strategies to reduce risks of low
crop establishment with poor autumn rains.
Mr Riethmuller said that the
Grains Research and Development Corporation (GRDC) supported
project suggested reduced risk of crop failure in marginal soil
moisture conditions in a dry autumn could be achieved by:
- Using disc seeders, not
points, to reduce soil drying.
- Combining seed priming and
water injection at rates of 50 -100 L/ha.
- Using low seed rates and
wide rows for early sowing in more fertile soil.
When topsoil moisture is marginal
and there is very little rain in the 10 -14 days after seeding,
double and single disc openers establish more reliable and rapid
crop development, compared to knife points.
Seed priming, which is practiced in rainfed areas in India, can
reduce emergence time of wheat seedlings. Research suggests that
time to field emergence could reduce from six to two days,
resulting in 236 kg/ha more grain at the business end of the
season, at little or no cost in a dry year.
Recent experimental results from Dr Sharma and Dr HS Dhammu of
the Centre for Cropping Systems, Northam, WA, showed absorption
rate was highly influenced by crop species, seed size and
soaking temperature, implying that seed soaking duration
probably needed to be determined for each seed lot.
Dr Sharma has suggested using a simple ‘finger nail’ test to
estimate when a cereal seed is suitably primed.
Combining water injection with seed priming is beneficial in
lower rainfall areas where lower seed rates are more common.
Although the water quantity applied to seeds is less with this
combination, the seeding rate must increase by 75 per cent to
accommodate the water in the seed for the same plant population.
This requires appropriate testing of priming time and some
development of practical seed drying equipment.
Moisture supply to shallow soil crops suffering mid-season
drought stress after early sowing and good early growth can be
reduced by very wide rows and lower seed rates.
Late sowing (June/July) should maintain normal row spacings,
unless there is a suitable grass weed control strategy. |
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The Crop Doctor is
GRDC Managing Director,
Peter Reading |
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