Ideas
and innovations
Seeding
Modification separates seed and fertiliser
K
ondinin Group member Murray Dodd has
modified his new Alfarm A550 air seeder
to separate seed and fertiliser when sowing
crops on his property at Kalannie, Western
Australia.
Murray and his wife Therese crop about
2000 hectares of Eradu noodle wheat, 1000ha
of lupins and 300ha barley on their sandy loam
property.
In early 1995 Murray decided to buy an
Alfarm A550 air seeder (see Machinery
Evaluation, Farming Ahead No 52, page 23)
and matching 13.7 metre, 75 tine A 5 3 0
cultivator to meet his cropping commitments.
Although the seeder had a simple belt
conveyer, micrometer type metering system
and non pressurised seed and fertiliser bins,
the unit was not fitted with a double shoot
system. Murray immediately set about
modifying the unit to separate seed and
fertiliser.
Modification
He fixed a divider plate in the mixing
chamber and venturi to keep the seed and
fertiliser separated after they left the flat belt
conveyer. A second long divider plate was
fitted to the primary distribution duct to
separate seed and fertiliser as the material is
carried to the primary head.
Murray ordered his air seeder with a 17
outlet primary head but he has added an eight
outlet plate to the existing nine hole plate on
the cultivator drawbar.
He has also replaced the original Alfarm
secondary heads with 17 plastic John Shearer
secondary heads.
The modification of the venturi and primary
Murray Dodd has fitted a dividing plate to the primary distribution duct on his Alfarm A550 air seeder.
duct allowed grain to be delivered from the
seed compartment through the mixing
c h a m b e r, primary duct, primary head,
transition piece hoses and through eight metal
tubes to eight secondary heads.
Fertiliser was separately delivered from the
fertiliser compartment through nine steel tubes
to the nine secondary heads.
The Shearer secondary heads allowed
Murray to close off outlets where required and
distribute seed and fertiliser independently and
evenly across the width of the bar.
The modifications cost Murray about $2500
which included replacement hoses and 15
hours of work.
Gas burner
The original diesel motor driven fan was
also replaced with a higher speed Harmon fan,
driven by a hydra motor.
Murray said the new fan and drive has cost
about $2500 but he is expecting a significant
increase in air volume.
The original venturi inspection cover was
removed and replaced with two perspex
covers, retained by simple release spring clips.
These made it easier to visually check the
venture and mixing chamber for blockages.
Although the perspex can become covered
in dust and lose its transparency, Murray said
it is has allowed faster access to the mixing
chamber.
- Alan Montgomery
Murray mounted a gas burner beside the fan
air intake to eliminate moisture in the fertiliser
hoses but the hoses failed after only 1200ha of
work.
Murray believes the heat from the burner
may have contributed to the failure of the
original non-reinforced hoses. He has
replaced them with reinforced rubber hoses
which have been interwoven to reduce
bending when the rig is turned.
Tubes and hoses on the right carry grain and
those on the left carry fertiliser.
FARMING AHEAD No. 53 -May 1996
Easy to operate clips hold perspex inspection
covers over the mixing chamber and venturi.
The transition piece has two nine hole connecting
plates with interwoven reinforced rubber hoses.
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