How to grow cotton seedlings from seed? Latest technical method tutorial
Cotton is an annual herbaceous plant of the Gossypium genus in the Malvaceae family, native to Mexico in the Americas. It is usually propagated by seed. The seed has a hard, thick seed coat and a well-developed embryo. A longitudinal groove on the ventral side of the seed is the hilum, and the pointed tip of the seed is the protrusion of the hilum. To increase cotton yield, in the early stage of seed sowing it is usually necessary to sun the seed, soak the seed and dress the seed. Let us take a look at cotton seed seedling technology below!
Sunning the seed
Generally, sunning the seed is carried out 15 days before sowing. It can break the dormant state of cotton seed, effectively kill the epidermal pathogens on cotton seed, reduce seedling-stage diseases, promote after-ripening of the seed, enhance the seed's water absorption and the seed coat's air permeability, improve the seed germination rate and germination vigor, and promote seed germination and seedling emergence. For fuzzy seeds, expose them to strong light for 3 to 5 days, sunning 5 to 6 hours each day. Generally, the spreading thickness should not exceed 10 cm, and turn them 3 to 4 times each day to ensure even and thorough sunning. For delinted coated seed, air-dry it for about 1 day under weak-light weather conditions. When sunning the seed, take special care not to sun the seed on stone slabs, cement ground or plastic film, so as to avoid high temperature burning the cotton seed and affecting the seed germination rate.
Soaking the seed
Warm-water seed soaking is a traditional fuzzy-seed treatment that China has continued to use to this day. Its main effect is to promote seed germination and seedling emergence, especially under conditions of poor soil moisture, and it helps achieve full seedling emergence in one sowing. Delinted coated seed cannot be soaked. Warm-water seed soaking generally does not have the effect of reducing seedling-stage diseases. On the contrary, if the soaking time is too long, causing too much nutrient loss from the seed, it may aggravate the occurrence of seedling-stage diseases. Therefore, the key to soaking the seed is to control it so that the seed does not absorb too much water. Generally, it is appropriate for the seed to reach 60 to 70% of its own air-dried weight, with the seed coat becoming soft and the cotyledons separating. The soaking time depends on the water temperature; at 18 to 20°C, soak the seed for 12 to 16 hours, then remove and drain it for chemical seed dressing. There is no need to emphasize warm-water seed soaking, and germination acceleration is not recommended.
Seed dressing
Chemical seed dressing can kill pathogens carried by the seed and pathogens in the surrounding soil after sowing, so as to improve the seedling emergence rate and prevent and control seedling-stage diseases. Combined use with insecticide seed dressing can also reduce the harm of seedling-stage insect pests. Seed dressing chemicals contain a certain amount of fungicides, insecticides and an appropriate amount of plant growth regulators, etc. A commonly used chemical and treatment method is to dress 20 jin of dry cotton seed with 50 g of 50% carbendazim wettable powder plus 30 g of 50% thiram wettable powder plus New High Lipid Film, or dress with 125 g of 40% seed dressing dual wettable powder plus New High Lipid Film.
Raising seedlings
1. Plastic-film frame seedling raising: Most ecological cotton regions across the country use the plastic-film frame seedling raising method. It mainly consists of sowing, covering with soil, then putting up arched frames and covering with film, sealing all around tightly, and ventilating to lower the temperature after full seedling emergence.
2. Nutrient-block seedling raising: Nutrient-block seedling raising is also called square seedling raising or cube seedling raising. Different places have different names because of the different measures adopted. For example, using river mud, pond mud, etc. as bed soil for square seedling raising is called river-mud square seedling raising.
3. Flat-laid plastic-film seedling raising: Flat-laid plastic-film seedling raising saves labor and cost, simplifies management procedures and has simple operating techniques, and is easy for people to master. The film is laid directly on the seedling bed, and when the cotton sprouts push through the soil, the film is broken to release the seedlings. The thickness of the plastic film used is only 18% of the thickness of commonly used agricultural film. In areas with much rainy weather during the seedling stage, disease seedlings and dead seedlings are relatively serious when this method is used for seedling raising. In production, the seedling raising period should be appropriately delayed, and it can be applied in cotton fields transplanted from late crops.
4. Double-film seedling raising: Double-film seedling raising is a seedling raising method in which, after sowing and covering with soil, a layer of plastic film is first laid flat, and then an arched shed is added. It solves the problem of stiff seedlings and diseased seedlings easily caused by rainy and low-temperature weather after early spring sowing. The cotton seedlings raised are of good quality and the squaring stage is advanced.
5. Ventilated mesh-film seedling raising: Ventilated mesh-film seedling raising is to cut conventional plastic film along the center line, sew a 10 to 15 cm wide nylon window screen in the middle, and cover it on the frame. Temperature and humidity are naturally regulated through the open part of the ventilated mesh, with no need to uncover by day and cover by night.