– History:
– Early seed dressings used organo-mercurials against oat smut and bunt of wheat.
– Thiram was introduced in the 1940s to control Pythium and Fusarium.
– ICI commercialized Mergamma A in 1949, containing mercury and lindane.
– Seed dressings evolved to protect seeds from both fungal and insect attacks.
– Seed treatments databases provide information on seed treatments.
– Biocide:
– Imidacloprid, a neonicotinoid insecticide, was banned in France for maize.
– Dust from treated seeds caused health issues, prompting improvements.
– Pneumatic drills were enhanced to reduce dust release.
– Seed treatment compounds were improved to prevent dust-off.
– Organic certification in the US requires the use of untreated seed.
– Water-retainer:
– Water-absorbing polymers around seeds aid in water absorption in dry conditions.
– Polymers can delay germination until drought passes.
– Water-retaining technology has been utilized in the industry.
– The addition of polymers helps seeds survive in water-scarce environments.
– Water-retaining polymers are beneficial for seed germination.
– Fertilizer:
– Seed coatings may contain plant micronutrient fertilizers.
– Occasionally, slow-release macronutrients are included in seed coatings.
– Fertilizer doses in seed coatings enhance plant growth.
– Micronutrients in seed coatings support healthy crop development.
– Slow-release macronutrients ensure prolonged nutrient availability.
– Inoculum:
– Thick seed coatings can distribute seeds pre-inoculated with symbiotic microbes.
– The formulation of the coating slurry affects microbial viability.
– Academic formulations can maintain microbial populations for up to 9 months.
– Commercially coated seeds have utilized inocula.
– The viability of microbes in coated seeds remains a topic of study.
A seed treatment is a treatment of the seed with either biological or chemical agents or by physical methods. Usually done to provide protection to the seed and improve the establishment of healthy crops. Not to be confused with a seed coating.
In agriculture and horticulture, coating of the seed is the process of applying exogenous materials to the seed. Also referred to as seed dressing.
A seed coating is the layer of material added to the seed, which may or may not contain a "protectant" (biological or chemical pesticide) or biostimulant applied to the seed and possibly some color... By the amount of material added, it can be divided into:
- A Film coating, a layer of thin film applied to the seed typically less than 10% of the mass of the original seed.
- Encrustment, where the applied material is typically 100%–500% of the original seed mass, but the shape is still discernible.
- Pellet, where the applied material is so thick that the seed's original shape is not discernible.
Seed coating provides the following functions:
- For formulations with pesticides, direct application to seeds can be environmentally more friendly, as the amounts used can be very small.
- Color makes treated seed less attractive to birds, and easier to see and clean up in the case of an accidental spillage.
- A thick coating can improve handling, by hand or by machine. Thinner coatings may also help with characteristics like flowability.
- Thick coatings may accommodate additional features such as fertilizers, plant hormones, plant-beneficial microbes, and water-retaining polymers.
Specialist machinery is required to safely and efficiently apply the chemical to the seed. A cement mixer is enough for non-hazardous coating materials. The term "seed dressing" is also used to refer to the process of removing chaff, weed seeds and straw from a seed stock.