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Page 1: Seed Testing Method for Coated Seed

Seed Testing Method for Coated Seed (Or) Pelleted Seed

Coated Seed:- Seed coating is a process designed to create a nutritious environment in the immediate

vicinity of the germinating seed. This provides a "boost" for the seedling in its critical early

stages of development.

Coated (or) pelleted seed history:-

First were developed for cereal seeds in the 1930's by Germains, a British seed

company.

Large scale commercial use of coating began in the 1960's with precision sowing for

the European greenhouse transplant industry.

When California outlawed the short handled hoe in the mid 1970's, the use of

coated seed for precision field seeders increased.

University and commercial research programs responded to this demand, producing

coatings now widely used for seeds of vegetables, flowers and some field crops.

Why is Seed Coated?

The six most important reasons why we coat seed are:

l. Pre-inoculation of legumes

2. Nutrient benefits

3. Protection from stress conditions

4. To improve ballistic properties and simplify seeding

5. Safe application of agricultural chemicals

6. Protection from rodents, birds and the harmful effects of some fertilizers.

Seed Coating Aim:-

Seed coating aims to influence the external physical properties of the seed, affecting

the sowing characteristics only.

By itself an ideal coating would be neutral in its influence on the speed.

Uniformity and percentage of germination when compared to the original raw seed

lot.

The ideal seed coating would perform in the same manner as the raw seed under a

wide range of environmental conditions.

Light, moisture, temperature, pH, soil type etc.

Also the stress of the coating process should not influence the germination pattern or

longevity (shelf life) of the seed lot adversely, nor induce secondary dormancy - i.e.

affect seed quality.

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Types of coating:- Two basic types of pill produced with inert coating powders are dissolving or "melt"

coats and "split" coats.

Melt coating:-

The melt coats dissolve when wet and gradually wash away from around the

seed.

The melt coats often require more water to wash the coating material away

from the seed

More time for the oxygen to reach the seed through the saturated coating

material.

Melt coats may offer advantages when soils are saturated , but oxygen

availability always influences the speed, uniformity and total percentage of

germination.

Split coating:-

Split coats initially retain their shape when wet and , by capillary action, pass

moisture through the pill to be imbibed by the seed.

The seed swells and cracks the pill by internal turgor pressure.

The split coat often permits germination with less water, as they split, allow

uniform, rapid oxygen access to the surface of the seed.

Multi-coated seeds:-

Multi-coated seeds having two or more coating layers, with the innermost coating

layer containing a water repellent such as a fatty acid or a metal salt thereof in higher

concentration than the other layer(s).

Powder coatings:-

Both split and melt, multiply raw seed rate and depending on the coating, the number

of seeds per pound may decrease dramatically.

Species Seeds / lb

(raw) Pills / lb (coated) Weight increase (%)

Begonia 70,000,000 250,000 28,000

Lettuce 430,000 12,500 - 40,000 3,400 - 1,100

Onion 120,000 15,000 - 30,000 800 - 400

Tobacco 5,000,000 165,000 3,000

In addition too the types of coating products described above, there is recent and

increasing use of "film-coating". A thin polymer film smoothes the surface of the seed for

better flow ability. The polymer also influences water uptake and the adherence of chemical

fungicide treatments. Film coating only increases the raw weight of the seed 1% to 5%, far

less than the powder coatings.

EV ERY

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Everyone agrees that the real value of a seed is the genetic material that it hides

inside. But there’s a reason these days to look at what’s on the outside of a seed as well.

Scientists have developed a number of new coating compounds that protect seeds from a

variety of hazards, from pests to cold soil temperatures. A new generation of seed-coating

machines allows these compounds to be layered on a seed gently and accurately. As a result,

more and more growers are opening seed bags containing a rainbow of colored coatings that

fit smartly into today’s crop production systems.

Early bird. Marty Hutcheson won’t be waiting for oak leaves to reach the size of a squirrel’s

ear before he plants corn in 2004. In fact, those squirrels will still be awaiting the official

arrival of spring. “We’re planning on getting the first corn in the ground around March 1,”

says this East Prairie, Mo., corn grower. His farm fields are near the Mississippi River in the

state’s Bootheel region, where the first corn seed wouldn’t typically be planted until March

25. Hutcheson can get away with extra early planting because he uses a specially coated seed

on those acres. He has been testing a product called Intellicoat, an intelligentpolymer coating,

applied to hybrids from Fielder’s Choice Direct. Intellicoat was launched on a commercial

scale to U.S. farmers for the 2003 growing season.

Quick change:-

The coating is derived from natural fatty acids from corn and soybean oils, and is

environmentally friendly. The coating stays hard and crystalline, like a shell, when seeds are

placed in cold soil. No water is allowed to penetrate this hard shell, so the seed cannot

germinate. When the soil reaches a temperature of about 55 degrees, however, a temperature

“switch” is flipped on and the coating suddenly changes to an amorphous state, which allows

water to penetrate so the seed can begin to germinate. The process is reversible and

repeatable as soils fluctuate above and below the point at which the temperature switch is set.

The coating can regulate the seed’s water uptake until the seed has absorbed enough water to

germinate. The result: corn that is planted early waits until conditions are right before it

emerges, allowing a full and uniform stand. “We planted a population of

33,000 in 2003, and got a 32,000 stand at harvest,” Hutcheson says. “The coated seed

expands the planting window because we can get some of our acres in early. It also comes out

of the field with less moisture at harvest.” A similar intelligent polymer called Pollinator Plus

is used to coat male inbred seeds used in the production of hybrid seed corn. Delayed

germination of these seeds widens the pollination window. The coating was used on 80,000

acres of seedcorn production in the U.S. during the 2003 growing season.

Multi-protection:-

New for canol growers is a seed coating called Prosper. This seed coating provides

multiple layers of protection including a new generation insecticide (clothianidin) along with

three fungicides: Vitavax, Thiram, and metalaxyl. The coating allows protection against both

disease and insects. Prosper 200 provides control of flea beetles from crop emergence

through the secondleaf stage. Prosper 400, with a higher level of the systemic insecticide,

provides protection from flea beetles through the fourthleaf stage. Diseases controlled by

these products include seed-borne blackleg, seed-borne Alternaria, seed rots, and seedling

blight. The fungicides also provide protection against early season root rot caused by

pathogens such as Rhizoctonia and Pythium.

Tech team:-

Improved insecticidal seed coatings have helped free farmers from the labor (and

exposure) associated with applying a separate insecticide at planting time. Now, seed

coatings may play an important role teamed up with technology traits to provide a full pest-

protection package for corn. Brad Biddick, president and general manager of Trelay Seed Co.

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in Livingston, Wis., says hiscompany purchased a computerized, continuousbatch seed

oating machine a couple of years ago specifically with this marriage in mind. “We saw that

the biotech rootworm hybrids were going to require an insecticide application to control

secondary pests,” Biddick explains. “Seed treatment seems to be an ideal fit.” The biotech

hybrids also require an adjacent refuge of susceptible corn, so those acres need additional

protection.

For example, Biddick points out that a new seed-applied insecticide called Poncho

250 could be used with biotech rootworm hybrids to protect against secondary pests such as

wireworms and white grub. On refuge acres, Poncho 1250 provides a higher rate of

insecticide that protects against those pests as well as rootworm control comparable to

conventional soilapplied insecticides. Using today’s technology to layer seed coatings into

cost effective combinations is exciting, Biddick says. “The long term possibilities are

endless.”

What kind of seed can be coated?

Virtually any kind of seed can be coated. However Precision Seed Coaters and its

sister company Canadian Seed Coaters specialize in the following species:

Canola

Alfalfa

Clovers

Trefoil

Other legumes

Bermudagrass

Centipede

Dichondra

Bluegrass

Fescues

Ryegrasses

Bentgrass

Bromegrass

Foxtail

Orchardgrass

Timothy

Native grasses

Seed coating equipment:-

1)Rotary pelleting equipment:-

Diameter 300 mm. This pelleting machine is suitable for the semi automatic pelleting of

small seed lots of flower-, vegetable- and agricultural seeds. The machine pellets a seed lot in

batches. The seed batches should be weighed manually and manually be discharged in the

pelleting room. Also the speed of the rotor and spinning disc should be adjusted manually.

2)Seed Film Coating Equipment:-

This semi automatic film coating machine is used for treating small quantities of

seeds manually. Using film coating liquids mixed with water and/or fungicides (or other), the

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seeds are treated uniformly in this batch system. The treating time per batch is very short in

this rotary film coating system, which makes it a fast system.

Advantages of a Coated Seed:-

The most apparent is the visibility of the seeds.

The coated seed allows the seed to be seen on the ground, this means a more even

seeding which will lead to a more even bed of colorful blossoms the whole season

long.

The coating also helps keep the smaller seeds from seperating from large seeds

during seeding, which again means that the beds will be more uniform throughout the

season.

The seed can be spread with a "cyclone" type spreader to make spreading seeds easier

and more uniform.

There is no need to mix with sand, sawdust or other material, which will save time

and money.

Another advantage is that to the best of our knowledge, the birds will not eat coated

seed.

We believe it is the color more so than the taste, birds do not associate the colored

seeds with edible seeds.

Seed Coated Future :-

Coated seed is the future. It allows and increases the ability to use on a variety of

surfaces and in extreme situations, it minimises soil cultivation requirements and provides for

a reduction of irrigation, as well as the coating giving a controlled application of fertilizer and

plant protection agents.

Coated Lawnseed

Protection of seedlings

Easy to sow

Protection from wind

Protection from birds