How does the air seeder work?
An air seeder is an agricultural implement also called a planter
or seeder and it is used to plant usually a seed crop in a large
field. It was first patented in Australia in the 1950's.
For many years seeders had a seed box running the width of the
implement which allowed the seed to fall by gravity into the seed
row. It was difficult to fill, clean out and transport. The air
seeder has centrally located hoppers for seed and fertilizer which
distributes them through an air stream to individual seed rows. It
is convenient to fill, easy to clean out and move. Any crop that
can be grown from seeds - which might vary is size from oilseeds to
corn, can be sewn by an air seeder.
The grain and fertilizer hoppers are usually carried on a large
cart located behind or in front of the seeder. The air stream is
created by a high capacity fan mounted on the cart which blows air
through pipes located under the grain and fertilizer tank. Grain
and Fertilizer are metered out from the hoppers by a meter wheel
that is turning in a ratio set by the operator for the proper seed
rate or seed density. The seeds enter the pipe in the airstream and
follow the pipes which terminate in the seedbed. Openers pulled
through the soil make the opening where the seeds are place. They
are made of steel in the shape of points, discs or cultivator
shovels. Once placed in the seed bed, the air is blown out the
opening in the soil and the seed and fertilizer remain. The seeder
can then pack the seeds tight to retain moisture near the seed and
harrow the furrows so the field is not rough.
Air seeders can seed at speeds up to possibly 10 MPH - planting
many thousands of seeds a minute distributing them evenly and
accurately. How does the air seeder do this? Using a principle in
physics - a gas (air) will distribute itself evenly amongst the
divisions available to it. Just like they know where to go, the
seed and fertilizer granuals follow the air through divisions of
the piping evenly and accurately.
The width of the air seeder can expand for working width and to
fold together for transport and have been built to widths of 85 ft
- maybe more. Air seeders are expensive to purchase and operate.
They require expensive tractors to pull them and they need a steady
supply of seed, fertilizer and have wearing parts such as soil
openers. The operator must be competent and careful because a
mistake in setting the seed placement, seeding rate or in operating
the machinery can also be expensive. A mistake or delay in seeding
can cost lower grades or a growing season for the crop.
