To raise water to raise crabs, it is necessary to grow grass. Cultivating high-quality grass aquaculture water is an important prerequisite for breeding quality and large-scale river crabs. There are four kinds of aquatic plants commonly used in adult crab breeding: Goldfish, Hydrilla verticillata, Vallisneria, Elodea. These four kinds of aquatic plants are all water-suspended plants, and they are also proven water-grass varieties that can be used for breeding crabs after years of practice. Green Acrylic Tape,Strong Acrylic Tape,Acrylic Mounting Tape,Vhb Acrylic Foam Tape Kunshan Jieyudeng Intelligent Technology Co., Ltd. , https://www.jerrytape.com
First, biological characteristics
1. Leaves black algae. The characteristics of the algae on the leaves are high temperature, long growth period, good adaptability, and strong regeneration ability. The crabs like to eat, suitable for sowing or planting in well-lit ponds and large water surfaces. The black algae of the leaf can be rooted and cut off by the river crab, and has strong vitality, so it will not spoil the water quality.
2. Goldfish algae. Goldfish algae has the advantages of high temperature resistance, crablike food, and strong regeneration ability. The disadvantage is that it is prone to smelly water. According to this feature, goldfish is more suitable for cultivation in large water surfaces. In addition, when aquatic plants are prosperous, they must be thinned to avoid photosynthesis and dead grass stinking when they are too dense.
3. Elodea. Elodea germinates early and grows fast. When other aquatic plants have not grown in the early stages, only it can be considered an ideal place for growing crabs, habitats, shells, and avoiding the enemy. This grass is not heat-resistant and grows densely. When the water temperature reaches 30°C, the growth is basically finished, and it is also easy to smell water. Therefore, the coverage rate of this type of aquatic herb should be controlled within 20%, and farmers can use it as a transitional grass for planting.
4. Hardship grass. Vallisneria possesses the advantages of crab eating, high temperature resistance, and non-stinking water. The disadvantage is that it is easily damaged. Especially during the high-temperature period, the crabs are fed to change their seasons. If you do not pay attention to protection, the damage is very severe. Some cultivated waters, which are dominated by Vallisneria, are trapped by crabs in less than a week in the high-temperature period. It is too late for fish farmers to harvest grass. According to the author's calculations, the cost of aquaculture, which is dominated by bitter grass, is 70-120 yuan per 667 square meters (1 acre). Some of the water bodies that were not able to harvest grass in time have even experienced deterioration of water quality. Some water bodies have become odorous and “sweet green sharks†have appeared, causing a large number of deaths.
Second, planting and management
1. Cultivation and Management of Rotary Black Algae:
(1) The shoots are planted to breed. The Hydrilla verticillata belongs to the "pseudo-apical" plant with only adventitious roots. From April to August of each year, it is in the vegetative stage. The roots can be rooted after 3 days of planting to form a new plant.
(2) Nutrient transplants breed. Generally before and after the rain, drain the pond water, leaving 10-15 centimeters of sediment, cut up to 15 centimeters and grow 8 centimeters into the section, and pour 30-50 kilograms per 667 square meters. The section was immersed in mud and the pond water was added to 15 cm deep. After about 20 days, the whole pond shrouded in a new round of black-leafed black algae, which can add water to 30 cm. Afterwards, it gradually deepens the pool water so that the aquatic plants will not expose the water surface. In the initial stage of transplanting, the water quality should be kept clean, dry water should not be used, and chemical fertilizers should not be used. If moss grows, kill with moss-killing drugs.
(3) whole planting. In May-August each year, the natural algae in the natural waters has grown into 40-60 cm long, and once every 667 m2 of crab ponds has been fed with 100-200 kilograms of grass, part of them are directly eaten by crabs and some of them have to be rooted. Survive. Water quality management: The water depth during the day and the water in the evening will reduce the amount of herbivorous crabs and promote fibrous root formation.
2. Goldfish cultivation and management:
(1) Cultivation techniques of goldfish algae. There are several methods for cultivation of goldfish algae: First, after the end of October each year, after basic fishing is completed, the whole grass can be removed from the lake or river ditch for transplanting. Transplanting is carried out at this time, because there is no destruction of crabs and no special protection is required. The amount of grass used is generally 50-100 kg per 667 square meters. The second is that every year after May, new golden cryptophytes can be harvested for transplanting. At this time, the transplanting must be separated by a fence to prevent the plants from drifting away from the wind or being destroyed by the crabs. Seine area is generally 10-20 square meters, 2-4 square meters per 667 square meters, each grass volume of 667 square meters without using 100-200 kilograms. The seine net can be removed after the aquatic plants have settled down. The third is to set up a water culture zone in the corner of the river ditch to cultivate goldfish and algae. No herbivorous fish and crabs are stocked in the culture area. Transplanting will be carried out in October and a large number of plants will be available in April-May of the following year. For every 667 square meters, 50-100 kilograms of grass seed can be used, and about 5,000 kilograms of fresh grass can be harvested each year, which can provide 1.67-3. 3 hectares (25-50 acres) of water surface grass.
(2) Post-plant management. First, water level conditioning. Chrysoeoidea is generally planted at the confluence of deep water and shallow water. The water depth does not exceed 2 meters, and it is best to control it at about 1.5 meters. The second is water conditioning. Clear water is an important condition for the growth of aquatic plants. The water body is turbid and it is not suitable for aquatic plants to grow. It is proposed to use lime to adjust the water and then to plant the grass. It was found that soil and other debris were attached to aquatic weeds. The ship was used to navigate through the water grass area, and the dirt of the aquatic plants was gently rinsed with a paddle. The third is to remove weeds. When a large number of aquatic peanuts and valerian (also known as foxtail grass) are planted in the water body, especially in the furrows, they should be removed in time to avoid affecting the growth of aquatic plants such as goldfish and algae.
3. The cultivation and management of Vallisneria:
(1) Valerian planting techniques. Vallisneria is usually planted before and after Ching Ming. When the water temperature rises above 15°C, it is planted. For every 667 m2 (actual planting area), 100-150 g of Vallisneria seeds are planted. Intensive ponds are planted directly on the fields. Before the planting, fresh water is added to the pool 3–5 cm, and the deepest is not more than 20 cm. Large water surface should be planted in the shallows, the water depth should not exceed 1 meter to ensure that the grass can carry out sufficient photosynthesis. Choose sunny days for 1-2 days, then soak for 12 hours, then remove the seeds in the fruit. And wash away the mucus from the seeds, then use semi-wet fine soil or fine sand dressing to spread the whole pond. After rubbing the fruit there are still many seeds that have not been picked up and are also thrown into the pool.
(2) Post-plant management. First, water level conditioning. The bitter grass spreads quickly on the bottom of the water. In order to promote bitter weeding and to overcome the vegetative growth of the leaves, the pond water level should be controlled below 20 cm before mid-June. In late June, the water level increased to about 30 centimeters. At this time, Vallisneria has been basically full of ponds. The depth of water is increased to 60-80 centimeters in mid-July, and it can be increased to 100-120 centimeters in early August. The second is to strengthen feed feeding. When the normal water temperature reaches 10°C or more, some compound feed or animal feed should be fed to avoid the destruction of the bitter grass buds. When the high temperature period arrives, it is not possible to directly change the feed in terms of feeding, but gradually reduce the amount of animal feed, increase the amount of plant feed, so that the crab has an adaptation process. However, during the high temperature period, it is not possible to continuously feed animal feed but gradually reduce the proportion of animal feed to around 30% of daily feed. In this way, the normal nutritional needs of crabs can be guaranteed and premature weeding of aquatic plants can be avoided. The third is to set up a seine fence. This method is suitable for use in large water surfaces. The planting area of ​​the bitter grass was blocked with a fence, and the fence was removed when the trapping rate of the grass at the bottom of the tank reached more than 60%. At the same time, feed feeds will be strengthened. The fourth is to eliminate weeds. When inspecting the pond on a daily basis, you only need to find that there are floating grass floating on the surface of the water, and you need to take it away to prevent it from spoiling the water quality.
Third, the reasonable mix of aquatic plants Under normal conditions, regardless of the type of farming, the waterlogging coverage rate should be maintained at 50% -70%, planting aquatic plants in more than two species.
1. Pond or paddy field farming type. This species is generally selected Elodea, Vallisneria, Hydrilla verticillata. Use the characteristics of early and rapid growth of Elodea as a transitional plant. Provides an ideal place for the early growth of crabs to live in habitats, shells and avoiding enemies. When the high temperature period comes, Elliot's head should be cut off, leaving only about 10 centimeters above the roots to avoid death after smashing. The early hatching rate of this kind of aquatic herb should be controlled at about 20% and gradually eliminated in the high temperature period. Using the characteristics of crabs and eating seaweed, it is used as a "snacks" for crabs to ensure that crabs have ample botanical feed origin. This kind of aquatic herbage should be kept at a rate of 20% to 30%. In order to supply fresh and delicious “snacks†for crabs for a long period of time, weeds should be sowed in batches in stages to stagger the growth period to avoid a one-time destruction of crabs. It is cultivated using the characteristics of the high temperature of the leafy algae, the likes of the crabs, and the non-breakable characteristics, and it is used as the main straw of the pond or paddy field cultivation type. The entrapment rate of Hydrilla verticillata should be controlled between 40% and 50%, providing an ideal place for the summer and late growth of river crabs to shelter from heat, habitat, clam shells and avoid enemies.
2. River ditch or lake farming type. These two types of species are mainly Chrysospora or Hydrilla verticillata on the selection of aquatic plants, supplemented by Vallisneria and Elodea. Chrysoeoidea or Hydrilla verticillata is generally planted at the junction of shallow and deep water, and the rate of grass cover can be controlled at 40%-50%. Vallisneria is generally planted in shallow water, and the trapping rate is controlled at about 10%. If you want to cultivate a grass-cultivated water body in the “Light Pool,†you can plant some Elodea in the early days, limiting the trapping rate to 20%. about. During the high temperature period, Elodea's head was cut off, leaving only about 10 centimeters above the roots to avoid death after the death. Regardless of the type of plants, it is better not to use the surface of the water and not affect the waves.