seed testing method for coated seed
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Seed Testing Method for Coated Seed (Or) Pelleted SeedCoated 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.
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 Begonia Lettuce Onion Tobacco Seeds / lb (raw) 70,000,000 430,000 120,000 5,000,000 Pills / lb (coated) 250,000 12,500 - 40,000 15,000 - 30,000 165,000 Weight increase (%) 28,000 3,400 - 1,100 800 - 400 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
Everyone agrees that the real value of a seed is the genetic material that it hides inside. But theres a reason these days to look at whats 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 todays crop production systems. Early bird. Marty Hutcheson wont be waiting for oak leaves to reach the size of a squirrels ear before he plants corn in 2004. In fact, those squirrels will still be awaiting the official arrival of spring. Were 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 states Bootheel region, where the first corn seed wouldnt 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 Fielders 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 seeds 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 pestprotection package for corn. Brad Biddick, president and general manager of Trelay Seed Co.
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 todays 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
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 t