Cultivation techniques of aquatic plants in river crab ponds that provide bait for shade and summer

In the process of breeding river crabs in the pond, the quality of aquatic plants plays a very important role. It mainly has the functions of purifying water quality, increasing dissolved oxygen, shading and avoiding summer heat, avoiding enemy damage during molting (reducing cannibalism), providing bait, habitat, improving sediment, reducing water temperature, avoiding or reducing precocious puberty of river crab, etc. Therefore, the growth state of aquatic plants determines the specifications, quality, yield and economic benefits of river crabs. It can be seen that aquatic plants are very important for ecological and healthy breeding of river crabs. Here are some views on the cultivation of aquatic plants.

Planting of aquatic grass in river crab pond

1. The selection of aquatic plant varieties.

The varieties of aquatic plants in ① Crab Pond are Eloe algae, goldfish algae, bitter grass, hollow cabbage, verticillata, duckweed and so on. The seaweed suitable for early stocking in crab ponds is Elorella (Elorella vulgaris is resistant to low temperature, germinates early, grows fast and crabs like to eat), but when the water temperature is above 30 ℃, it is easy to stink and destroy the water quality, so it is a transitional aquatic plant and the planting area should not be too large. Other aquatic plants are resistant to high temperature, long growth period, good adaptability, strong regeneration ability, river crabs like to eat, are the main aquatic plants in the middle and later stage of the pond.

The aquatic plant in ② pond is not suitable for a single variety, but the combination of sinking and floating aquatic plants makes the river crab have palatable aquatic plants at different growth stages. Planting verticillium verticillata in deep water, bitter grass in shallow water, and Ellosia in the transition area are conducive to the balanced growth of aquatic plants in the pond, maintain the appropriate density of aquatic plants, and the area of aquatic plants accounts for 40% of the water surface of the pond, ensuring the smooth flow of water. River crabs can move freely, facilitate the flow of pond water, and help to increase the oxygen dissolved in the air.

two。 The cultivation of aquatic plants.

① is suitable for planting when the water temperature is above 5 ℃ in February, when the water depth of the pond is about 10cm and the medicine of quicklime pond disappears. The specific method is as follows: cut the grass stem into 10-15cm long, 5-10 plants into a bunch of mud into 3-5cm, the dosage is 20 kg / mu. After the grass survives, add water to drown the 10cm of Elodea.

② verticillium verticillata is suitable for planting in May. The specific method is: throw the whole grass into the water, 200 kilograms per mu. Some aquatic plants are eaten by crabs, and some aquatic plants are stained with muddy fibrous roots to grow.

③ bitter grass was sown with seeds (100g / mu) in shallow water before and after Qingming Festival, and the whole plant was transplanted in May (200kg / mu).

3. The management and protection of aquatic plants. Low temperature, fertilizer and water, create a good water environment, promote the rooting and growth of aquatic plants, improve the survival rate of young crabs and reduce the growth of moss. According to the growth trend of aquatic plants, fertilizers should be sprinkled in time to promote strong roots and long grasses. To further do a good job in the management and protection of aquatic plants, specific measures:

In the early stage of ① aquatic plant planting, the young crab should be temporarily raised in the fence, and when the aquatic grass grows normally, it should be put into the river crab, which is conducive to the growth of aquatic grass.

② water level regulation: the water level should follow the principle of "shallow in spring, full in summer and moderate in autumn". The water level in summer should not be too deep, generally no more than 2 meters, preferably about 1.5 meters. Too deep water grass is not suitable for photosynthesis, easy to rot roots, damage the water quality.

③ water quality regulation: the water should not be turbid, and the mud and suspended matter in the water are easy to stick to the aquatic plants, which is not conducive to photosynthesis, resulting in the yellowing and death of the aquatic plants. The application of raw lime paste and microecological agents to purify the water quality, make the water body refreshing, high transparency, and maintain the strong photosynthesis of aquatic plants.

④ topdressing: if the growth of aquatic plants is not prosperous, the application of amino acid fertilizers to promote root growth, thus promoting the growth of the whole grass. When the ⑤ aquatic plant grows vigorously, it should be cut off in time to keep the aquatic plant under the water surface for 10-15cm. Too dense, should remove too many water plants, remove rotten grass in time, so as not to damage the water quality.

⑤ appears the phenomenon of grass entrapment of river crabs, so feed containing trace elements and vitamins, fresh snails, wheat, corn and fresh aquatic plants should be fed in time, so that the problem of grass entrapment of river crabs can be alleviated.