Seed treatment is one of the pre-planting operations in crop production. This practice is obscure to most farmers, especially those procuring seeds from agro-allied companies; they feel treating the seed is irrelevant.
What most farmers are familiar with is crop protection, through the use of herbicides and pesticides.
Seed treatment is a pre-planting operation; hence, it must be carried out before planting the seeds. The question that comes to your lips is how can seed be treated before planting? It is very simple and easy but depends on your purpose and types of seed treatment you are willing to implement. You need to determine what you want to achieve with the seed treatment operation.
Seed treatment is carried out for several reasons. It could be to hasten germination, to protect seeds from destructive pests under the soil, to enhance uniform growth in crops etc.; you need to know what you want to achieve with this operation for you to know how to treat seed. In this article, the type of seed treatment we shall discuss is known as seed scarification.
Seed scarification is one of the seed treatment methods aimed at facilitating quick germination in sown seeds. This type of seed treatment softens the seed coat of the seeds such that it allows imbibition of growth enhancing parameters (water and gases) in seeds, thus, facilitating rapid growth in seeds. Seed germination takes series of processes before the shoot emerges; however, seed scarification has been proven to be very effective in increasing the chance of seed germination.
There are various methods of scarification and these are;
1. Chemical or acid scarification:
The purpose of this method is to soften hard or impermeable seed coats through the action of an acid. This is done by soaking the seeds in concentrated sulphuric acid for a period of 2-4 hours according species. After treatment, seeds are thoroughly washed with clean water to make them free of acid and then sown immediately.
2. Mechanical scarification:
In this method, seeds with impermeable or impervious seed coat are rendered permeable to water and gases through rubbing or abrading the seed coat on a hard surface. This can be achieved by:
- Placing the seeds between two sand papers, one stationed and the other revolving and rubbing aggressively on the seed coat of the seed.
- Rubbing seeds with sharp-sand.
- Passing seeds through a machine that scratches the surface.
- Filing and notching the seeds to make the seed coats permeable to water.
3. Boiled water scarification:
This is another method of seed treatment. It involves boiling of water to boiling point (100oc); the seeds are then poured in a cloth that is less porous. Then the cloth will be suspended or inserted into the water. The seeds will be there until the water cools. The seeds are then removed from the cloths are sun-dried. When the seeds are properly dried, they can be planted. The method is good for small-sized seeds like: jute (ewedu) seeds, celosia seeds, pepper seeds etc.
4. Soaking in water:
This is the simplest method of seed scarification. The purpose of soaking seeds in water is to soften hard seed coats, to remove growth inhibitors and to reduce time of germination. The time of soaking seeds in water depends on the hardness of the seed coats. Examples are peas, beans etc.
5. Stratification or moist chilling:
This is another effective method of seed scarification. It involves exposing seeds to low temperature; this brings about prompt and uniform germination. The seeds are arranged in layers of sand in shallow boxes for pits and trenches. This condition helps in rapid germination. It is commonly used for crops like: peach, cherry, oat, grapes.
Seed treatment is important to prevent seed borne, soil borne and air borne diseases. Scarification, being one of the types of seed treatment, softens the seed coats of a seed to aid imbibition of water into the protoplasm of the seed. Seed treatment is very important as it hastens germination of the seed and enhances the overall productivity of the cultivation. Identify the seed scarification method that can be used on the rice seeds above.