In general, ponds do not only require water quality management. The management of pond water and grass has a great impact on aquaculture. The ponds of different breeding projects, the types of water plants required for water conservation and the management methods of water plants are also different. Today, let's learn about the conservation management of river crab ponds.
1. Common factors affecting the growth of aquatic plants in river crab ponds
1. Crab pond bottom lack of fertilizer or water quality
The lack of fertilizer in the pond generally occurs in the early stage. The water temperature is low, the base fertilizer is insufficient or the snails are too much, causing the water to be thin, or the newly opened crab pond, the organic matter is less, and the water grass is difficult to grow roots. Therefore, for the newly opened pond, it is necessary to expose the mature mature soil layer after tillage, and then add the organic fertilizer to plant the grass. The excessive water quality causes a decrease in transparency, which affects the photosynthesis of aquatic plants, making it difficult for aquatic plants to grow. The pond mouth with excessive water quality can be solved by changing water or placing snails. During the breeding process, the bacteria and sodium humate can be used regularly to regulate water quality, increase transparency, enhance photosynthesis of aquatic plants, and use long-rooted potassium fertilizer to promote water grass growth.
2. Grass has attached matter
Due to poor water quality and turbidity, a large number of pollutants are attached to the stems and leaves of the aquatic plants. Microscopic examination revealed many algae, ciliates, organic matter or snail eggs. Attachment directly affects photosynthesis of aquatic plants, causing water plants to wither and even die. Therefore, water transfer products should be used in the breeding process to keep the water fresh and enhance the photosynthesis of aquatic plants.
3. Excessive drug residues in Qingtang or improper pond clearing
If the content of heavy metals in the soil is too high, etc., for clear ponds with excessive lime or heavy metals such as copper sulfate, the water should be changed in time after the failure of the drug to reduce the concentration of harmful substances in the water body and reduce the harm to the water plants.
4. Water level and water grass density have a greater impact on aquatic plants.
Taking Elodea as an example, when the stems and leaves of the leaves of Elodea are 40-50 cm away from the water surface, the stems and leaves are lush and green, and the roots have strong grip; when the heads are <30 cm away from the water surface, the stems and leaves begin to turn yellow slowly; When the head is 30 cm away from the water surface, the leaves are aging, but the stems begin to rot. When the grass head is out of the water, the stems and leaves are yellow and black, and they start to rot and rise from top to bottom. Therefore, if the density of aquatic plants is too large, the pond should be pulled out in time.
Second, the common problems and treatment of aquatic plants
Water grass aging
Reason: After about 3 months of growth, the water grass is too lush, the density is too large, blocking the circulation of water, especially the water is exposed to the water surface, after sun exposure, stop growing, after a period of time, the roots rot, the water grass rises, the water quality is destroyed, and the water color is caused. Reddened and blackened.
Treatment: The aging water plants should be processed in a timely manner (head cutting). The dense water grass pulls out the passage in time, and generally pulls out the passage of 2 meters around 5 meters to enhance the fluidity of the water body. If the water grass has yellow roots, black roots and rot, it should be treated with oxidative bottoming, detoxification and applying grass fertilizer.
2. Water grass pests
Reasons: Pests occur mostly during the rainy season. Elodea and Hydrilla verticilla are more common, especially Hydrilla verticillata is susceptible to red worms and white nematodes (Ranunculus larvae). Once a large number of outbreaks occur, the leaves can be eaten in 7 to 15 days.
Treatment: The pond should be thoroughly cleaned, and the grass head should be submerged 10 cm in the high season of insect pest control. Diligently change the bottom, apply a small amount of grass fertilizer several times, enhance the grass root grip, and enhance the insect resistance of water plants. Regularly apply compound strains and amino acid fertilizers to cultivate good water color and eliminate the application of farmyard manure and fertilizer. If pests have already appeared, they can be killed by avermectin and killed again after 7 days. Detoxification and water transfer should be done in time after insecticide.
3. Water plants floating up
Reason: One situation is that the grass roots rot, floating during the day + sinking at night; another situation is that the river crabs cause the grass to float. With the increase of water temperature, the feeding habits of river crabs will be slower towards plant-based bait. If the water and bottom management are not in place in the middle and late stages, it will easily lead to the floating of water plants (mostly bitter grass). In severe cases, the ponds can be made in about 7 days. All drifted to the surface, seriously affecting the water quality, and ultimately affecting the growth of the crab shell.
(1) Treatment of water and grass floating due to insufficient nutrients in the roots and rot: the pond is ploughed before planting grass, which is beneficial to the rooting of water plants. After the plants are planted, the long-rooted fertilizer is combined with the long grass fertilizer to make the water grass “stable and solidâ€. In the rainy season, it is necessary to pay attention to the bottom, improve the environment at the bottom of the pond and reduce the growth of bacteria. For the watery grass that has been yellowed and blackened, the oxidative bottoming can be used first, and then the grass fertilizer can be applied to make the aquatic grass grow new roots and grow.
(2) Causes and treatment of floating grass caused by river crabs: 1 Insufficient bait, resulting in river crabs. Treatment: can increase the amount of feed. 2 River crabs lack vitamins and minerals. Treatment: The amount of vitamins and minerals should be increased during the feeding process. 3 The weather mutation caused the crab stress. Treatment: Splash V C + glucose. 4 The bottom of the pond is corrupt. Processing: Usually do diligently change the bottom. 5 river crabs are infected with bacterial diseases or parasites. Treatment: symptomatic treatment. 6 The water is turbid and the dissolved oxygen at the bottom is insufficient. Treatment: Detoxification, diligently changing the bottom, reducing water toxins and increasing dissolved oxygen at the bottom.
4. Water grass blossom
Reason: The water grass enters the slow growth period and tends to age. At this time, the water grass is prone to yellow root, black root and rotten root. Treatment: The water grass can be turned 1/3, which reduces the top advantage of the head of the water grass. Reduce the water level to about 20 cm from the head of the head after the head, and replenish the long root fertilizer and the fat water paste in time. After that, the water is 2 to 3 cm every 2 days until the water level is suitable. The water grass is kept at 20 cm below the water surface. The head of the water grass should pay attention to: the water does not hit the water, the grass does not hit the dirty roots, and the water does not hit the green water. After the water grass starts, the bottom is fertilized in time, and the composite bacteria are used to stabilize the water body.
5. Water grass is long
Reason: 1 root is undernourished and the stems and leaves are slender. 2 The water quality is thin, the transparency is too large, and the photosynthesis is too strong. 3 water level is low. 4 In the early days, too many plants were planted, and too much feed was fed. 5 water grass varieties are single. Hazard: 1 The water grass is too dense to affect the scope of the crab activity, forming a "lazy crab." 2 water grass too dense to affect the feeding. 3 The water body has poor fluidity, which affects the dissolved oxygen in the water body. 4 high temperature water plants floating on the rot, ruin the water quality.
Treatment: Strengthen management, arrange planting position and density when planting grass early, and variety of water plants; use long-root fertilizer to promote root growth regularly after planting. When the water plants are too lush, the excess and decayed grass should be removed in time to leave the grass path and increase the fluidity of the water. When the grass grows too fast, the water level is deepened so that the grass head does not enter the water surface by 30 cm, inhibiting its growth.
The above is all the contents of today, breeding crabs, aquaculture farmers can learn more, more exciting content can continue to pay attention to this site!
Source: "Scientific Fish Farming"
Author: Lu Wei Liu Xu Wang Xu direction group
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