Vallisneria is a typical submerged plant, which is also indispensable in crab culture. It is often used as the underwater material in garden waterscape or courtyard pool, which is very suitable for water greening, or used to decorate aquarium. So how to breed bitter grass? Let's go and have a look!
Breeding methods of Vallisneria (basic knowledge): the best propagation time: sowing propagation is generally carried out at the end of April and the middle of May; Ramet propagation usually takes place from May to August;
The best growing soil: Vallisneria has no strict requirements on soil, and mostly grows in ditches, rivers, ponds and lakes. Most of the wild plants grow on hillsides, streams and ditches under the forest, and it is suitable to plant Vallisneria in southern provinces;
The best growth temperature: Vallisneria is warm and resistant to shade. The optimum growth temperature in water is 18 ~ 22 ° C;
The best growth light: the bitter grass likes the sun, and the light in the water should be enhanced when it is cultured in the water.
Cultivation methods of bitter grass: fertilizer application: 2500 kg of base fertilizer per mu of planting land, the best mixture is turf mud, human and animal manure, calcium, magnesium and phosphorus. According to the condition of the water area, topdressing should be adopted, generally 10kg superphosphate or 2kg three element compound fertilizer should be applied per 667 square meters; If the silt is thick and the water quality is fertile, fertilization is not necessary to prevent excessive growth.
It takes more than 3 months from transplanting to harvesting to apply fertilizer 4-5 times in stages. In the early stage of growth, 500-800 kg of water can be applied per mu; Nitrogen, phosphorus, potassium compound fertilizer or urea can be applied in the later stage.
Key points of watering: if there is no rain in continuous sunny days after planting, strengthen watering and keep moist. Generally, after 1-2 weeks of transplanting, when the seedlings resume growth, check the plants and timely replant the missing seedlings to ensure the whole seedlings. Vallisneria in the whole growth process need more water, later to often drench water, promote growth.
The propagation of Vallisneria is divided into seed propagation and asexual propagation. Sexual reproduction: in March to April, the seeds collected in the first year were washed and seeded. After different water temperatures of 20 ℃ - 28 ℃ - 10 ℃, with or without substrate, the germination rate was higher when the water temperature was 28 ℃.
Sowing and seedling raising: select the soil and container for cultivation, after disinfection treatment, soak 1 / 2 of the pot with water, after the water is clarified, spread the seeds that have been sprouted or gently rubbed on the surface of the soil, cover with fine soil, add 3-5cm water, cover with glass or plastic film, keep the temperature at about 28 ℃, shade, and complete the germination in about 40 days. Then the ventilation is turned on for light transmission, and the budding seedlings can also be separated for breeding. If the amount of reproduction is large, the pond with good ventilation, fertile soil and good water source should be selected. Weeds and foreign matters should be removed, the soil should be leveled and rammed. After the water is clarified, the seedlings can be transplanted, and the spacing of seedlings is generally 10-20cm. In the seedling period, weeds should be removed in time, pest control should be strengthened, and topdressing should be applied 1-2 times to promote the growth and development of plants. In this case, the water level should be deepened at any time to prevent the leaves of the plant from dying due to sunlight and affect the time of transplanting and planting. The spacing of transplanting and planting should be determined according to the seedling size, plant height and ornamental angle. It is 20-30cm in aquarium and 50-80cm in waterscape.
Ramet propagation: it is usually carried out in May to August, and the branches on the underground stems are cut for propagation. This method is simple and can be transplanted directly for viewing.
Tissue culture: the stem segments of 2-3cm long at the tip of rhizome were cut and sterilized on the surface, and then induced into seedlings in 1 / 2ms 6BA (2) iba0.2 medium. After that, the plantlets were transferred into aquarium and pond for culture.
Pest control: the main pest of Vallisneria at seedling stage is water earthworm, especially in the pond with thick silt, which often leads to low emergence rate. The use of carbofuran mixed with soil or seed dressing has a certain effect; Adjusting the sowing water level to 40-60cm can effectively control the number of water earthworms and inhibit their harm; At the seedling stage, we should also pay attention to the prevention of herbivorous fish, livestock and poultry.
In the flowering period of Vallisneria, aphids are the main pests. The control effect is good by spraying 800 times dichlorvos or 1000 times Omethoate.
The value of Vallisneria: 1. Ornamental value
The plant of Vallisneria angustifolia has long leaves, green and clump, which is a good underwater greening material for botanical garden waterscape, scenic spot waterscape and courtyard pool. It is also suitable for indoor water greening. It is a good material for decorating aquarium and is often used as background grass.
2. Medicinal value
The whole herb of Vallisneria can be used as medicine. It is bitter in taste and cold in nature. It has the effect of clearing away heat and toxin, detumescence and pain, and has a good curative effect on the treatment of sore throat. 3. Economic value
Feed for fish, duck, pig, etc. The expanded bulb at the end of its stolon is the main food for birds.
A small amount of crabs, prawns, carp, crucian carp and Siniperca chuatsi in the water area of seed production of Vallisneria can effectively control the ineffective tillers, improve the yield and quality of seed production, and significantly improve the economic effect. The size of 80-120 crabs / kg, density of 200-300 crabs / 667 square meters, or the size of 2000-3000 crabs / kg, 1000 crabs / 667 square meters, overwintering young shrimps 5-10kg / 667 square meters; Or 500-1000 Jian carp, Allogynogenetic crucian carp, mandarin fish summer flower, etc. / 667 square meters. It can produce 15-40kg / 667m2 adult crabs, 20-30kg / m2 adult shrimps, or 40-50kg / 667m2 large size fingerlings.