ADVANTAGES OF COATED SEED
Coating has several advantages to offer canola
seed growers:
l) The most important of these is that it is a
safe, effective method of chemical treatment.
Secondary benefits include:
2) Some coatings offer the seedling an initial
boost from the fertilizer contained within the coating.
3) Coated seed removes the need to
"bulk" seed prior to sowing, thus ensuring better
control of your seeding rate and allowing you to seed at the
same rate as bare seed.
1) Chemical Treatments:
To help ensure maximum yield, chemical treatment
of canola seed is essential. The most suitable chemicals available
are those "combination products" which contain both
insecticides (for flea beetle control) and fungicides for
control of fungal diseases such as Blackleg.
In the past, there have been several problems
associated with chemical treatment of canola seed. These include:
a) Methods of Application:
Conventional treaters can "miss" a
significant portion of the seed as it passes through the drum.
Also, once the chemical has been applied, it dries and is then
able to "dust off" the seed, thus becoming less
effective - coating overcomes both these problems.
1) During the coating process, flowable
formulations of chemicals are used by thoroughly mixing them with
a liquid adhesive. In order to be coated, every seed must be
completely covered by the adhesive, which contains the required
chemicals. Thus we can be 100% certain that if the seed is coated,
it must contain the adhesive and consequently any chemical that
has been combined with the adhesive.
2) The outside of the coat is sealed by a hard
layer of adhesive, which ensures that the chemical is contained
within the coat and that it is virtually impossible for the
chemical to "dust off".
b) Human Toxicity Factors:
The second problem alleviated by the use of seed
coating is the possibility of accidental poisoning during the
chemical application process. Coated seed ensures that the farmer
does not come into direct contact with the chemicals either during
the treating process or during seeding. The distinctive coating
around the seed prevents all contact with the chemical and also
acts as a "marker" ensuring the seed will not
inadvertently be used for food or feed.
c) Shelf Life:
Germination trials on canola seed indicate that
seed treatments applied in the Chemseal® coating
process have no significant detrimental effect on the seed.
Research continues in this area, however, it appears that coated
canola may be stored for considerably longer than the nine months
currently recommended for treated bare seed.
2) A second advantage of coated seed is
that it is possible to add fertilizer to the coating, which
provides a "starter package" for the seedling.
Our Chemseal® canola seed coating
does not contain fertilizer, however, we are continuing to
research the "fertilizer aspect" of coated canola seed
in an attempt to be able to offer a complete "nutrient
package" in the future.
3) Seeding Rates:
Many growers seed at higher rates than necessary
simply because canola seed is very small and many drills are not
suitable for this type of seeding work. Coating increases the size
of the seed, making control of the seeding rate simpler and
removing the necessity to "bulk" the seed.
As coated seed contains approximately 8% coating
materials and 92% seed, many growers may be tempted to increase
the seeding rate compared to their bare seed rate. This is not
necessary. Many trials have concentrated on seeding rate
comparisons. The recommended seeding rate in most locations is
from five to seven pounds per acre, however, lighter seeding rates
are recommended where drought is a hazard.
The following is an extract from the Canola
Council of Canada’s publication - "Canola, Canada’s
Rape Seed Crop".
"Canola is a rather unique crop in that
variations in seeding rate or plant population over relatively
wide ranges, have very little effect on yields under normal
conditions. In field trials, yields from rates varying from two to
eleven kilograms per hectare were not significantly different.
When plant population density is low, the individual plants tend
to branch and spread out more and seed pods generally extend lower
on the plant. With heavy stands, particularly under drought
conditions, competition between plants often results in fewer and
smaller pods, concentrated on the upper part of the plant. High
seeding rates sometimes produce lower yields. They are sometimes
used to reduce the amount of straw and improve maturity under high
levels of "nitrogen".
COST
Provided seeding rates used remain the same as
with bare seed, we expect the cost of using coated chemically
treated seed will be about the same as chemically treated bare
seed.
RESEARCH WORK
Canadian Seed Coaters commenced our canola
research program in the spring of 1980 with trials at the
Vegreville Environmental Centre and also at Agriculture Canada’s
Beaverlodge Research Station. In addition, several on-farm trials
were seeded.
These trials all had the same three basic aims.
These were:
1) To ensure chemicals can be safely applied
within a seed coating
a) without loss of efficacy, or
b) without having any detrimental effect on the seed.
2) To ensure coated seed established as well as
bare seed and resulted in at least an equal yield.
3) To investigate comparative seeding rates for
bare and coated seed.
Today, we continue our research programs to
develop new improved coatings to further benefit the Canadian
canola grower.
DISCUSSIONS AND CONCLUSIONS
Since coated canola seed was first released in
commercial quantities in 1982 its acceptance has been nothing
short of phenomenal with an estimated 75% of the certified,
treated canola seed used in Canada being coated in one form or
another. Canadian canola growers now accept the fact that in the
majority of cases a coated seed product containing 92% seed will
result in improved establishment, which can translate into
increased yields. However the most important factor in the
acceptance of Chemseal® is the protection the
coating offers growers in that the chemical is safely sealed
within the coating ensuring that grower’s exposure to the
chemical (especially from "dusting off") is
significantly reduced. This factor alone will keep coated canola
usage at its present levels or greater for many years to come.
Canola (rapeseed) makes up approximately 10% of
the world’s total oil seed production and ranks fourth behind
soybeans, sunflowers and palm oil in this respect. Canada is now
the world’s leading producer of canola seed and this crop ranks
second to wheat as the most important crop grown in Canada. In
view of the importance of the crop to the Canadian economy, it is
not surprising that the many advantages available to the grower
through the use of coated seed have been utilized in Canada since
the early eighties.
