Planting techniques of aquatic plants in crab culture ponds

"crab size, look at water plants", which shows the importance of water plants in pond crab culture. According to the breeding practice for many years, the planting and maintenance techniques of aquatic plants in crab ponds are introduced as follows, which can be used as a reference for crab farmers.

Aquatic plant species

The aquatic plants in the crab pond should be mainly submerged plants and water-standing plants, supplemented by floating leaves and floating plants, in order to achieve the complementary role of regulation. The main submerged plants are: verticillium verticillata, bitter grass, Elodea, etc.; the main water-bearing plants are: Puccinia, Reed, Zizania caduciflora, etc.; floating plants are mainly: water peanut, hollow cabbage, duckweed, duckweed and so on.

Overall layout

It is suitable to plant submerged plants, floating leaves and floating plants in the deep water area of crab pond, and it is better to plant water-bearing plants in shallow water area. Attention should be paid to maintaining the stability and diversity of palatable aquatic plants in river crab culture ponds.

Planting method

1. Elodea: Elodea germinates early and grows fast. in the early days, when other aquatic plants did not grow, only it could provide an ideal place for river crabs to grow, inhabit, molt and avoid enemies. Elodea has a long growing period, can regenerate, and will not wither in winter. However, Elorella is not resistant to high temperature, and when the water temperature reaches 30 ℃, it basically stops growing and is easy to stink, so the coverage rate of Elorella should be controlled within 20%, and crab farmers can plant it as a transitional aquatic plant. Elodea is planted in winter and spring. The method is to insert 5 cuttings of grass 3cm into the mud, 15cm to 20cm on the mud, 50cm × 50cm between rows, and the dosage (667 square meters, the same below) is 1015kg. The water level in the planting area is about 30 cm. Elorella can also be cut into 10 cm long stems, like transplanting seedlings, a bunch of a bunch into a pool with mud (each bundle of 10 × 15 plants), plant spacing of 20 cm × 20 cm, dosage of 40 kg.

2. Verticillium verticillata: verticillum verticillata is characterized by high temperature tolerance, long growth period, good adaptability and strong regeneration ability. it is one of the aquatic plants that river crabs like to eat. it is suitable for sowing or planting in ponds and large water surfaces with sufficient light. Verticillium verticillata can take root after being cut off by river crabs, and its vitality is extremely strong, so it will not corrupt the water quality, so the coverage rate of this kind of aquatic plants can reach 40% to 50%. Planting adopts the method of transplanting plants, collecting aquatic plants before and after Grain Rain, kneading roots or phimosis nodes with wet clay, and putting them into the water, the dosage is 30 kg. The seeds can also be collected and sown in the spring of the next year, allowing them to grow naturally.

3. Sophora flavescens: Sophora flavescens is easy to grow, high yield, high temperature resistance, crisp and tender. It is a favorite plant bait for river crabs. It is known as "underwater forest" in crab waters, and its coverage rate is about 20%. Before and after the Qingming Festival, when the temperature reached 18 ℃, the grass seeds were soaked in snake skin bags for 7 days, then picked up and dried in the bags for 1 day, then soaked in water for 1 day, then mixed with soil and sprinkled evenly. The dosage is about 50 grams. Sufficient density can be produced in the middle and last ten days of June, and the shallow water level can be maintained at the initial stage of sowing (April to May), which is beneficial to the growth of grass buds.

4. Water peanut (lotus seed grass): water peanut has strong adaptability, can grow on land and water surface, and has strong cold resistance. It can sprout and grow when the temperature is 10 ℃. River crabs like to inhabit and feed on it, and the coverage rate is 10% to 20%. Water peanuts are transplanted in crab waters, before and after crab stocking, and fixed with bamboo stakes, wooden stakes or tripods.

5. Duckweed: duckweed has strong survival adaptability, winter buds sink to the bottom of the water to survive the winter, float to the surface in early spring and germinate into new individuals. Duckweed is a favorite plant bait for river crabs. Duckweed can be cultivated. Generally, a tripod of 1 square meter and 2 square meters is fixed according to 20 square meters. The duckweed is fixed on the surface of the crab pond to grow and reproduce, so as to supplement the deficiency of other aquatic plants.

Maintenance and management

1. Prophase nursing: in the early stage of breeding, it is necessary to stabilize and promote the root growth of aquatic plants, so that the plants are short and strong, and the leaves are broad. The roots are good, the aquatic plants grow well, it is not easy to float, absorb a lot of nutrients from the bottom of the pool, and the aquatic plants grow healthily. In the early stage, the water level basically reached the horizontal level, and then as the temperature rose, the water level should also rise slowly. From March to April, try to control the water level, keep the water depth 40-60 cm, and have a certain degree of transparency, which is conducive to the rise of water temperature and ensure that water plants grow under sufficient light. Apply high efficiency compound fertilizer, fermented organic fertilizer or biological fertilizer according to the fat and thin degree of Tangkou. The water body is too thin, and the growth of water plants is poor, so it is necessary to increase the fertility of water bodies and provide essential nutrients for the growth of water plants.

2. Mid-term nursing: in the middle of culture, the rapid growth of Elorella should be inhibited to prevent the drastic change of water quality caused by excessive consumption of nutrients in the pond. From the end of April to the beginning of May, the upper part of the aquatic plant can be cut off by 20cm to 30cm to promote the growth of roots and stems and leaves. Before the advent of the high temperature season, the algae can be removed again, leaving only about 10 to 15 centimeters of the root, which can not only purify the water quality, reduce the water temperature, but also maintain the flow of the water body, and prevent the high temperature rotting grass. After June, biological fertilizers and biological bacteria were applied to maintain the fertility of pond water, and aquatic plant maintenance products were used every 15 days. There are few aquatic plants, so water peanuts and duckweed must be replenished.

3. Late-stage nursing: in the later stage of culture (after September), mainly verticillium verticillata, keeping the coverage rate of aquatic plants up to more than 50%. To increase nutrients, promote the growth of aquatic plants, at the same time salvage dead grass, floating grass, to avoid the deterioration of water quality.