CN114568363A

CN114568363A - Bionic molting nest and method for assisting river crab culture by utilizing rice processing byproducts

Info

Publication number: CN114568363A
Application number: CN202210398787.6A
Authority: CN
Inventors: 邵乃麟; 聂志娟; 高建操; 徐钢春; 孙毅; 曹丽萍; 杜金梁; 李全杰; 朱昊俊; 高俊
Original assignee: Freshwater Fisheries Research Center of Chinese Academy of Fishery Sciences
Current assignee: Freshwater Fisheries Research Center of Chinese Academy of Fishery Sciences
Priority date: 2022-03-28
Filing date: 2022-03-28
Publication date: 2022-06-03
Anticipated expiration: 2042-03-28
Also published as: CN114568363B

Abstract

The invention provides a bionic molting nest and a method for assisting ecological culture of river crabs by utilizing rice processing byproducts, and belongs to the technical field of river crab culture. The method comprises the following steps: 1) mixing and stirring the rice hull, the rice hull ash and the waste rice slurry to plug the holes on the inner wall of the crab pool; 2) mixing rice hull ash, waste rice pulp and water plant seeds to prepare a grass cake, and putting the grass cake into a crab pool; 3) planting water grass seeds; 4) putting juvenile crabs; 5) sprinkling fermented rice hulls in the moss breeding area, and sprinkling rice hull ash in a whole water tank; 6) and putting the bionic molting nest into the crab pool one week before the molting period of the river crabs. The method provided by the invention fully utilizes the rice processing by-products, changes the appearance of the black-shell crabs and improves the economic benefit of river crab culture.

Description

Bionic molting nest and method for assisting river crab culture by utilizing rice processing byproducts

Technical Field

The invention belongs to the technical field of river crab culture, and particularly relates to a bionic molting nest and a method for assisting river crab culture by utilizing rice processing byproducts.

Background

The rice is the first large grain crop in Jiangsu province, the perennial planting area is 3300 ten thousand mu, the rice is the sixth year, the total yield is about 390 hundred million jin, the rice is the fourth year, the rice is the largest main yield area of japonica rice in south China, and a plurality of rice processing factories exist, and the processed high-quality rice is sold at home and abroad. A large amount of rice husks are generated in the rice processing process, part of the rice husks are combusted to provide heat energy for processing rice to produce rice husk ash, and the rice is washed twice in the rice processing process, and part of broken rice impurities and starch precipitate to form waste rice pulp. Rice husk, rice husk ash, useless rice thick liquid all are the by-product of rice processing, but because the usable value is low, and the treatment cost is high, are by idle piling up more, pollute the surrounding environment, are unfavorable for the construction in sanitary country, sanitary town, and effective and abundant recycle has become the problem that needs to solve urgently.

Jiangsu is not only a rice main producing area but also a national river crab main producing area, and the river crab culture area in Jiangsu province is about 385 ten thousand mu, which accounts for 47 percent of the total area of the country; the total yield is 290 billion yuan, which accounts for about 60% of the total yield in China. Jiangsu is the origin of river crab export certification, and export is spread over 10 countries and regions. However, during the development of river crab culture for many years, the problem that crab seedlings cannot be transported for a long distance is still unavoidable; and because the pond is difficult to desilt or has high cost, most farmers and enterprises do not desilt, so that substances such as residual bait, excrement and the like are continuously accumulated on the bottom of the pond and are converted into sludge through microbial fermentation. The river crab has no swimming function due to the special appendage structure, and can only crawl at the bottom of the pool to obtain food and avoid enemies, so that the surface of the shell adsorbs pollutants to present dirty surface layers, namely the black shell crab is low in price and affects appetite. Although the crab washing powder (the main component of malic acid) can be used for decontamination, the side effect is obvious, the survival time of river crabs is only a few days, and the death rate is high.

Disclosure of Invention

In view of the above, the present invention provides a bionic molting nest and a method for assisting river crab cultivation by using rice processing byproducts.

The invention provides a bionic molting nest for ecological culture of river crabs, which comprises a cuboid frame and a top cover, wherein the top cover is fixed right above the cuboid frame through a support rod; four sides and the bottom surface parcel net piece of cuboid frame, four summits department downwardly extending foot strips of cuboid frame bottom surface, the foot strip is perpendicular with cuboid frame bottom surface.

Preferably, the top cover is a rectangular frame, and 2-3 layers of net sheets are wrapped on the top cover.

Preferably, the mesh size of the mesh is 15-25 meshes.

Preferably, the foot strip is connected with a positioning mark.

Preferably, the wet rice hulls are laid in the rectangular frame.

The invention also provides a method for assisting river crab culture by utilizing the rice processing byproducts, which comprises the following steps:

1) mixing and stirring rice husks, rice husk ash and waste rice slurry, mixing the mixture with a rat damage prevention and control drug to obtain a leaking stoppage mixture, and filling the holes in the inner wall of a crab pool with the leaking stoppage mixture;

2) mixing and stirring the rice hull ash and the waste rice milk, mixing the rice hull ash and the waste rice milk with the aquatic weed seeds to prepare a grass cake, drying the grass cake, and putting the grass cake into a crab pool;

3) planting water grass seeds, and covering rice husks on the planting surface layers of the water grass seeds; spraying rice hull fermentation liquor every 6-8 days after the aquatic weeds are planted;

4) putting juvenile crabs into the crab pool in months of 2-3;

5) sprinkling fermented rice hulls in a moss breeding area, and sprinkling rice hull ash in a whole water tank;

6) and putting the bionic molting nest into the crab pool one week before the molting period of the river crabs.

Preferably, in the preparation process of the plugging mixture in the step 1), the mass ratio of the rice husks to the rice husk ash to the waste rice pulp is 1:1 (1-2).

Preferably, the diameter of the grass cake in the step 2) is 15-30 cm, and the number of the grass seeds in each grass cake is 20-30.

Preferably, after mixing the microbial preparation, water and rice hulls, sealing and fermenting, separating the rice hulls as the fermented rice hulls in the step 5), and collecting liquid as the rice hull fermentation liquid in the step 3).

Preferably, the proportion of the rice hull ash mixed with water is 1 (1-3), and the sprinkling amount of the rice hull ash mixed with water is 100-200 kg/mu.

Compared with the prior art, the invention has the following beneficial effects: the bionic molting nest provided by the invention comprises a cuboid frame and a top cover, wherein the top cover is fixed right above the cuboid frame through a support rod; four sides and the bottom surface of cuboid frame parcel net piece, four summits department of cuboid frame bottom surface extend the foot strip, the foot strip is perpendicular with cuboid frame bottom surface.

The bionic molting nest is not easy to corrode by pond water, and a mesh can be easily replaced; the extending foot bars of the bionic molting nest are inserted into the sediment, the whole device is more stably fixed, and the positioning marks can well mark the position of the bionic molting nest and facilitate observation; the frame and the mesh of the cuboid frame can block the river crabs possibly existing in the pond during the period of the wild crayfish attacking and exuviating; the top cap can block the water bird that dives, can the shading cooling in summer.

Furthermore, the wet rice hulls are laid in the bionic molting nest, the material of the wet rice hulls can be changed regularly and can be used as fertilizer to promote growth of waterweeds, river crabs can be easily hidden in the bionic molting nest, the rice hulls can be molted in a relatively quiet and interference-free environment, the soft hulls are statically cured, sludge substances are prevented from being contacted in the period, and the pollutant adsorption of humus in sludge is reduced; the bionic molting nest provided by the invention can better observe the molting and the catching of soft-shell crabs.

According to the method for ecologically breeding the river crabs, provided by the invention, the rice processing by-products are fully utilized, the ecological breeding of the river crabs is realized, the appearance of the black-shell crabs is changed, the breeding cost of the river crabs is reduced, and the economic benefit of the river crab breeding is improved.

Drawings

Fig. 1 is a schematic structural view of the bionic molting nest provided by the invention, wherein 1 is a cuboid frame, 2 is a mesh, 3 is a top cover, 4 is a stay bar, 5 is a foot bar, 6 is a nylon rope, and 7 is a positioning mark.

Detailed Description

The invention provides a bionic molting nest for ecological culture of river crabs, which comprises a cuboid frame and a top cover, wherein the top cover is fixed right above the cuboid frame through a support rod; four sides and the bottom surface parcel net piece of cuboid frame, four summits department of cuboid frame bottom surface extend the foot strip, the foot strip is perpendicular with cuboid frame bottom surface.

In the invention, the bionic molting nest comprises a cuboid frame, and the cuboid frame is made of stainless steel bars; the stainless steel bars are not easy to corrode in the pool water; the diameter of the steel bar is preferably 0.8-1.2 cm, and more preferably 1.0 cm. In the invention, the length and the width of the rectangular frame are respectively 0.8-1.2 m, more preferably 0.9-1.1 m, and the height of the rectangular frame is preferably 8-12 cm, more preferably 9-11 cm; the height of the cuboid frame is set within the limit range, so that the river crabs in the shelling period of the wild crayfish invasion possibly existing in the pond can be blocked.

In the invention, meshes are wrapped on four side surfaces and the bottom surface of the rectangular frame, and the mesh size of the meshes is preferably 15-25 meshes, and is further preferably 20 meshes; the net piece is preferably made of nylon materials, and the net piece has the function of preventing other species such as wild crayfish from entering the bionic molting nest.

In the invention, the bionic molting nest further comprises a top cover, wherein the top cover is a rectangular frame, and 2-3 layers of meshes, preferably 2 layers, are wrapped by the top cover. In the invention, the top cover is made of steel bars made of stainless steel; the diameter of the steel bar is preferably 0.8-1.2 cm, and more preferably 1.0 cm. In the invention, the length and the width of the top cover are respectively 0.8-1.2 m, and more preferably 0.9-1.1 m. In the invention, the top cover is fixed above the rectangular frame through the support rods, the top cover is parallel to the rectangular frame, and the height of the support rods is preferably 10-20 cm, more preferably 12-18 cm, and even more preferably 15 cm. In the invention, the number of the support rods is preferably 2-4. The fixing mode of the stay bar is not particularly limited, and the conventional fixing method in the field can be adopted. In the invention, the top cover can block downwards-rushing water birds and can also shield light and cool.

In the invention, foot strips extend downwards from four vertexes of the bottom surface of the rectangular frame, the foot strips are perpendicular to the bottom surface of the rectangular frame, and the length of the foot strips is preferably 8-12 cm, more preferably 9-11 cm, and even more preferably 10 cm; the foot strips are preferably connected with positioning marks, the positioning marks preferably comprise ropes and markers, and the markers are preferably sealed empty plastic bottles; the length of the rope is preferably 1-2 m, more preferably 1.2-1.8 m, and even more preferably 1.5 m. According to the bionic molting nest, the foot bars are inserted into the bottom mud, so that the whole bionic molting nest is fixed more stably, the ropes and the sealed hollow plastic bottles connected to the foot bars float on the water surface, the positions of the bionic molting nest can be well identified, and observation is facilitated.

In the invention, wet rice hulls are laid in the rectangular frame. The dry rice husk has buoyancy, and the rice husk soaked in water absorbs water and sinks. In the invention, the wet rice hull is convenient to replace, can be replaced regularly, can be used as a fertilizer to promote the growth of waterweeds, can be easily hidden in river crabs, can exuviate in a relatively quiet environment, and can be kept still for the hardening of soft hulls, thereby avoiding the contact with sludge substances and reducing the pollutant adsorption of humus in sludge; the bionic molting nest provided by the invention can not generate black shell crabs, and promotes the improvement of the overall benefit of the ecological culture of river crabs.

In the invention, preferably, the bionic molting nest is put into a crab pool one week before the molting of the river crabs, and then bait is splashed around the bionic molting nest to attract the coming river crabs so as to enable the river crabs to adapt to the existence of the bionic molting nest.

4) putting juvenile crabs into the crab pool in months of 2-3;

5) sprinkling fermented rice hulls in the moss breeding area, and sprinkling rice hull ash in a whole water tank;

In the invention, rice husks, rice husk ash and waste rice slurry are mixed and stirred, and then mixed with a rat damage prevention and control drug to obtain a leaking stoppage mixture, and the leaking stoppage mixture is used for plugging holes in the inner wall of a crab pool. In the present invention, it is preferable that the river crab cultivation work is started when the water level in the crab pool is lower than 10 cm. In the present invention, the mass ratio of the rice husk, the rice husk ash and the waste rice pulp is preferably 1: (1-2), more preferably 1: (1.2 to 1.8), and more preferably 1:1: 1.5. The time and the rotating speed of the stirring are not particularly limited, and the stirring is preferably carried out until the mixture is viscous. In the present invention, the rodent control drug is preferably a state-approved rodent control drug. In the invention, the plugging mixture is preferably filled into the hole before being cured, and becomes hard after being naturally dried, so that the plugging effect is good. If rats are in the holes, the mixture of the rice processing byproducts containing the raticide can also obtain good control effect when the rats have ingestion or tooth grinding habits, and the loss of crab seedlings can be effectively reduced.

In the invention, the river crab ecological breeding method further comprises the steps of mixing and stirring the rice hull ash and the waste rice milk, mixing the mixture with the float grass seeds to prepare a grass cake, drying the grass cake, and putting the grass cake into a crab pool. In the invention, the mass ratio of the rice hull ash to the waste rice pulp is preferably (1.5-3): 1, more preferably (2 to 2.5): 1. the stirring time and the rotating speed are not specially limited, and the stirring is performed until the mixture is viscous and cannot be scattered when being taken up by hands. In the invention, the aquatic weed seeds are preferably soaked and foamed, and the soaking and foaming time of the aquatic weed seeds is preferably 6-8 days, and more preferably 7 days; the invention has no special limitation on the type of the aquatic weeds, and the aquatic weeds in the crab pool can be selected according to the conventional aquatic weeds, and the hydrilla verticillata can be specifically selected. In the invention, the diameter of the grass cake is preferably 15-30 cm, more preferably 18-25 cm, and still more preferably 20-22 cm; in the invention, the number of the aquatic weed seeds in each grass cake is preferably 20-30, and more preferably 22-28. In the invention, the drying is preferably natural air drying, the grass cakes are put in the pond, and the distance between the putting rows is preferably 0.9-1.1 m, and more preferably 1.0 m; the row spacing is preferably 1.4-1.6 m, more preferably 1.5m, and the planting is carried out by pulling the planting ropes in a straight line and uniformly spaced. In the invention, the grass cake quickly sinks under the influence of self gravity when entering water, and the rice milk mixture has viscosity, so that the rice milk mixture can absorb water to expand but cannot disperse after being put into the crab pool, thereby providing a high-quality attaching base for the growth of aquatic weeds.

In the invention, the river crab ecological breeding method further comprises the following steps: planting water grass seeds, and covering rice husks on the planting surface layers of the water grass seeds; and spraying the rice hull fermentation liquor every 6-8 days after the aquatic weeds are planted. In the invention, preferably, in 1-2 months, water grass seeds are planted in the morning on a sunny day, water in a crab pool is drained completely, the water grass is mainly made of elodea aegypti, after the water grass seeds are sown, water is added into the pool to a depth of 10-15 cm, rice husks are covered on the surface layer and the periphery of the water grass seeds, the rice husks are preferably soaked rice husks, and the thickness of the covered rice husks is preferably 10-15 cm. In the invention, after the waterweed is planted, the rice hull fermentation liquor is sprinkled once every 6-8 days, preferably the enzyme is sprinkled once every 7 days, and the sprinkling amount is 1-3 kg/mu, more preferably 2 kg/mu each time; in the invention, the rice hull fermentation liquor can supplement nutrition required by waterweeds and decompose harmful substances in sludge in the pond.

The covering and continuous fermentation of the rice husks provide a heat-preservation barrier for the aquatic weed seeds, so that the water surface is prevented from being frozen, the roots of the aquatic weed are frozen and killed due to sudden rain, snow and cold tides, and the fermented rice husks have a certain weight and can cover the aquatic weed, so that the condition that the early water level is shallow, and the aquatic weed floats due to wind disturbance and does not root and sprout is avoided. The juvenile crabs are put into the pool within 2-3 months and hide in the rice hull during the period, so that the juvenile crabs are prevented from pecking by water birds, the juvenile crabs are hidden in the pool, sludge at the bottom of the pool does not need to be drilled, holes are prevented from being punched at the edge of the pool, and the juvenile crabs become old crabs without eating baits. Therefore, the crab larvae eat relatively smoothly, sufficient nutrition is accumulated, the immunity is good, and the shelling weight gain rate is obviously increased.

Putting juvenile crabs into a crab pool in months of 2-3; in the invention, the putting amount of the juvenile crabs is preferably 1000-1400 per mu, more preferably 1100-1300 per mu, and even more preferably 1200 per mu, and the specifications of the juvenile crabs are preferably 25-35 knots/jin, and even more preferably 30 knots/jin. In the invention, the traditional mesh bag transportation is changed into covered turnover box transportation in the transportation process of the juvenile crabs, the covered turnover box is selected according to requirements, the turnover box is preferably made of foam, a layer of wet rice hulls with the thickness of 1.5-2.5 cm is preferably placed at the bottom of the turnover box, and the layer of wet rice hulls is preferably 2 cm; putting juvenile crabs of the crabs for 3cm, and then putting a layer of wet rice husks with the thickness of 1.5-2.5 cm, preferably 2 cm; and alternately placing the juvenile crabs and the wet rice husks until the juvenile crabs and the wet rice husks are filled, covering the surface layer with a cover, and then opening 25-35 air holes with the diameter of 1.5-2.5 cm on the cover, preferably opening 30 air holes with the diameter of 2 cm. In the invention, the rice hull provides intervals for protection and also plays a role in heat preservation and moisture preservation, so that the transportation time can be effectively prolonged, the survival rate after entering the pool is improved, the loss is reduced, and the crab larva supply range is enlarged.

In the present invention, the method for preparing the fermented rice husk and rice husk fermentation liquid preferably comprises the following steps: mixing microbial preparation, water and rice husk, sealing and fermenting, separating the rice husk into fermented rice husk, and collecting liquid as rice husk fermenting liquid. In the invention, the microbial preparation is preferably an EM microbial inoculum, the source of the EM microbial inoculum is not particularly limited, and the EM microbial inoculum can be obtained by adopting a conventional commercially available EM microbial inoculum. In the present invention, the mass ratio of the microbial preparation to water is preferably 50: (800 to 1200), more preferably 50: (900 to 1100), more preferably 50: 1000. in the invention, the sealed fermentation is preferably carried out in a cement pond, the water is preferably tap water, the water is preferably subjected to aeration treatment before the fermentation, and the aeration time is preferably 2-4 days, and more preferably 3 days. In the invention, the rice husk is preferably put into a mesh bag and then soaked in a mixed solution of water and a microbial preparation, and the mass ratio of the rice husk to the water is 1: (0.8 to 1.2), and more preferably 1:1. The sealed fermentation of the invention preferably adopts a film to cover the cement pool; the time for the sealed fermentation is preferably 50 to 70 days, more preferably 55 to 65 days, and even more preferably 60 days. After the sealed fermentation is finished, the collected liquid is rice hull fermentation liquid which is rich in EM microbial inoculum and contains a large amount of soluble elements such as phosphorus, potassium and the like which are dissolved in water, so that the nutrition required by waterweeds is supplemented, and harmful substances in pond sludge can be decomposed. The invention takes out the fermented rice husk for standby.

In the invention, the river crab ecological breeding method further comprises the following steps: and sprinkling fermented rice hulls in the moss breeding area, and sprinkling rice hull ash in a whole water tank. Before and after 3 months, the crab pool has more moss, a part of the moss is manually fished out, fermented rice hulls are sprinkled in a moss breeding area, and the sprinkling amount of the fermented rice hulls is preferably that the moss is fully covered by the rice hulls; because the two ends of the rice husk are sharp and have certain burrs, the rice husk is easy to adhere and cover the filamentous moss caused by the thinning of the water body in early spring, and the husk light-shielding layer is formed on the surface of the moss, so that the direct irradiation of sunlight is avoided. In the invention, the proportion of the rice husk ash mixed with water is 1: (1.5-2.5), more preferably 1: 2; the sprinkling amount of the rice husk ash is preferably 45-55 kg/mu, and more preferably 50 kg/mu. The invention simultaneously takes the rice husk ash as the water color regulator to be mixed with the water and sprinkled in the whole pool, leads the water in the pool to become turbid, reduces the light transmittance, and mainly inhibits the photosynthesis of the moss, thereby inhibiting the growth of the moss, and because the rice husk ash is smaller, the growing waterweeds can not be covered, the rice husk ash has no influence on the waterweeds. The fermented rice hulls and the rice hull ash splashed with water fully promote the water fertilization of the pond, the environment required by the growth of the moss is changed, the subsequent stock is gradually reduced, and the harm of death caused by the moss winding on river crabs is reduced by matching with manual fishing.

In the invention, the river crab ecological breeding method further comprises the following steps: and putting the bionic molting nest into the crab pool one week before the molting period of the river crabs. And (3) sprinkling baits around the bionic molting nest to attract the river crabs to come forward, so that the river crabs adapt to the existence of the bionic molting nest. The bionic molting nest is filled with wet rice husks, so that river crabs can be easily hidden in the bionic molting nest, can be relatively quietly molted, and is kept still until the soft shell is hardened, sludge substances are prevented from being contacted in the period, and the absorption of pollutants of humus in sludge is reduced; the bionic molting nest can better observe the molting and the catching of soft-shell crabs.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Bionic molting nest

The structure is as shown in figure 1, and comprises a cuboid frame 1, a net piece 2, a top cover 3, a stay bar 4, foot strips 5, nylon ropes 6 and positioning marks 7. The rectangular frame 1 is 1m long and wide and 10cm high, and is made of stainless steel bars with the diameter of 1cm, and single-layer meshes 2(20 meshes, nylon material) are wrapped around and at the bottom of the rectangular frame 1;

the length and the width of the frame of the top cover 3 are both 1m, the frame is made of stainless steel bars with the diameter of 1cm, and two layers of 20-mesh nylon meshes are wrapped on the frame;

and the support rods 4 are 15cm in height, are made of stainless steel bars with the diameter of 1cm, are 2 in number and are respectively positioned in the central positions of the two upper frames of the cuboid frame.

The foot bars 5 are long-grown of a frame (length of 10cm, made of stainless steel bars of 1cm diameter);

the nylon rope 6 is 1.5m long, and the positioning mark 7 is 250 ml.

Example 2

Bionic molting nest

The structure is as shown in figure 1, and comprises a cuboid frame 1, a net piece 2, a top cover 3, a stay bar 4, foot strips 5, nylon ropes 6 and positioning marks 7. The length and width of the rectangular frame 1 are 1.2m, the height is 12cm, the rectangular frame is made of stainless steel bars with the diameter of 1cm, and the periphery and the bottom of the rectangular frame 1 are wrapped by single-layer meshes 2(20 meshes, made of nylon);

the length and width of the frame of the top cover 3 are both 1.2m, and the frame is made of stainless steel bars with the diameter of 1cm and is wrapped by two layers of 20-mesh nylon meshes;

the support rods 4 are 15cm high, are made of stainless steel bars with the diameter of 1cm, are 4 in number and are respectively located in the center of four upper frames of the cuboid frame.

The foot bars 5 are long-grown of a frame (length of 12cm, made of stainless steel bars of 1cm diameter);

the nylon rope 6 is 2m long, and the positioning mark 7 is 250 ml.

Example 3

Bionic molting nest

The structure is as shown in figure 1, and comprises a cuboid frame 1, a net piece 2, a top cover 3, a stay bar 4, foot strips 5, nylon ropes 6 and positioning marks 7. The length and width of the cuboid frame 1 are both 0.8m, the height is 8cm, the cuboid frame is prepared by stainless steel bars with the diameter of 1cm, and single-layer meshes 2(20 meshes, nylon materials) are wrapped around and at the bottom of the cuboid frame 1;

the length and the width of the frame of the top cover 3 are both 0.8m, the frame is made of stainless steel bars with the diameter of 1cm, and two layers of 20-mesh nylon meshes are wrapped on the frame;

The foot bars 5 are long-grown of a frame (8 cm in length, made of stainless steel bars of 1cm in diameter);

the nylon rope 6 is 1.5m long, and the positioning mark 7 is 250 ml.

Example 4

When the water level of the crab pond is lower than 10cm, 1kg of rice hull and 1kg of rice hull ash left after rice processing are mixed with 1.5kg of waste rice pulp mixed liquid and fully stirred to be viscous, and are mixed with mouse damage prevention and control drugs approved by the state, the mixture is plugged into a mouse hole at the side of the crab pond before the plugging mixture is not solidified, and the plugging effect is good after the mixture is naturally dried. The mixture containing the rice processing by-products containing the raticide can also obtain good control effect when the rats are stored in the holes and the rats have ingestion or tooth grinding habits, and can effectively reduce the loss of crab seedlings.

1kg of rice hull ash is mixed with 0.5kg of waste rice milk and fully stirred to be viscous, the rice hull ash is taken up by hands and is not scattered, water plant seeds such as hydrilla verticillata and the like which are common in water plants planted in a crab pond are added to be soaked for one week to prepare round cake-shaped grass cakes with the diameter of 20cm, each grass cake contains 25 seeds, and after the grass cakes are naturally dried, the grass cakes are thrown according to the set position of river crab culture in a large water area. The grass cake is influenced by self gravity to quickly sink to the bottom, and the rice pulp mixture has viscosity, can expand but cannot scatter after being absorbed by the pool, so that a high-quality attaching base for growth of the aquatic grass is provided.

In the crab pond, pond water is drained in the morning of a sunny day in 1-2 months, waterweeds mainly comprising the elodea nutans are planted, water is added into the pond to reach the depth of 10cm, a circle of rice hulls soaked with water in a clean mode is covered on the surface layer and peripheral fixed points of an elodea nutans planting point, and the thickness of each rice hull is the same as the height of the water level at the moment. The wrapping and continuous fermentation of the rice husks provide a heat-preservation barrier, so that the phenomenon that the water surface is frozen and the roots of the aquatic weeds are frozen and killed due to sudden rain, snow and cold tides is avoided, and the fermented rice husks have certain weight and can cover the aquatic weeds, so that the early stage water level is avoided, and the aquatic weeds are disturbed by wind power and float without roots and sprout. The juvenile crabs are put into the pool in the period of 2-3 months and hide in the rice hull pile in the period, thereby avoiding pecking by water birds, having a house without drilling mud at the bottom of the pool, avoiding punching holes at the edge of the pool, and becoming old crabs without eating baits. Therefore, the crab larvae eat relatively smoothly, sufficient nutrition is accumulated, the immunity is good, and the shelling weight gain rate is obviously increased.

And (3) preparing the rice hull fermentation liquor, adding tap water into an indoor cement pond, aerating for three days, and then adding 50kg of microbial preparation EM strain per ton of water to prepare the rice hull fermentation liquor. And then 1000kg of rice husks transported back by a rice factory are put into a mesh bag, tied up and then put into a pool for soaking, the surface layer in the pool is covered with a film, sealed and fermented for 60 days, and then the fermented rice husks in the rice husk bag are taken out for standby. The mixed liquor left after the rice hull bag is soaked is rich in EM bacteria, and a large amount of soluble elements such as phosphorus, potassium and the like are dissolved in water, and the mixed liquor is splashed once every 7 days after the waterweeds are planted, wherein the splashing amount is 2 kg/mu each time, so that the nutrition required by the waterweeds is supplemented, and harmful substances in the sludge in the pond can be decomposed.

1-3 months, changing a traditional crab seedling mesh bag into a plastic foam turnover box with a cover, selecting the turnover box according to needs, placing a layer of wet rice hulls with the thickness of 2cm at the bottom of the foam box, placing juvenile crabs to fully cover the crab seedlings for 3cm, placing a layer of wet rice hulls with the thickness of 2cm again, alternately placing the wet rice hulls until the crab seedlings are fully filled, and opening 30 air holes with the thickness of 2cm after covering the surface layer; after the juvenile crabs are transported to the crab pond, putting the juvenile crabs into the crab pond according to the putting amount of 1200 crabs per mu.

Before and after 3 months, the crab pool has more moss, a part of moss is manually fished, and the part of moss breeding along the bank, which is not easy to fish, is fished for later use after the fermentation by using EM (effective microorganisms) bacteria, and the fermented rice hulls are splashed in the moss breeding area, so that the aim is to ensure that the whole moss is fully covered after the rice hulls fall on the surface of the moss; because the two ends of the rice hull are sharp and have certain burrs, the rice hull is easy to adhere and cover the filamentous moss caused by the thinning of the water body in early spring, and a husk shading layer is formed on the surface of the moss, so that direct sunlight is avoided. Meanwhile, the rice husk ash is used as a water color regulator to be mixed with water and is sprinkled in a whole pool (50kg of the rice husk ash is mixed with 100kg of water and is sprinkled for one mu), so that the pool water becomes turbid, the light transmittance is reduced, the photosynthesis of moss is mainly inhibited, the growth of moss is inhibited, and the rice husk ash cannot cover the growing waterweeds gradually because the rice husk ash is small, so that the waterweeds are not influenced. The fermented rice hulls and the rice hull ash splashed with water fully promote the water fertilization of the pond, the environment required by the growth of the moss is changed, the subsequent stock is gradually reduced, and the harm of death caused by the moss winding on river crabs is reduced by matching with manual fishing.

According to the molting rule of the river crabs, the bionic molting nest shown in the figure 1 in the embodiment 1 is put in the molting period of the river crabs for one week.

And then, splashing bait to the periphery of the bionic molting nest step by step to attract the river crabs to come forward, so that the river crabs adapt to the existence of the bionic molting nest.

The invention carries out a preliminary test in the Yanzhong base of the research center of freshwater fishery of the Chinese academy of aquatic science, the hydrilla verticillata seeds of the grass cake germinate normally during the test period, the germination effect is better than that of the original seeds buried into silt manually, the germination rate of 22-28 seeds reaches more than 80%, and the planting is simple and easy; the plugging and killing effect of the rat hole is good, and the occurrence frequency of the phenomenon that the juvenile crab is bitten by the rat and only stump is remained is obviously reduced by 60 percent compared with the traditional pond patrol; the waterweeds are wrapped by the rice husks for heat preservation and are not influenced by freezing of ice and snow, the water plants germinate and grow earlier than the water plants in the past year, so that the time for the river crabs to enter the pool is advanced, sufficient time is provided for the crabs to accumulate energy, and the shelling success rate of 50% is improved; because the rice hull is laid on the layer during crab larva transportation, the number of crab larva extrusion death is reduced, the crab larva transportation time is obviously prolonged by 1-2 h, the radius of a transportation area is increased by 60-100 km, and the fatality rate caused by limb injury after entering a pool is obviously reduced by 30% compared with the conventional net bag-packaging mode; due to the existence of the molting nest, in the cultivation process of the commercial river crab, the observation of the molting of the river crab is more convenient, the soft-shell crabs which are pretty in summer in the market are more convenient to capture, about half of the cultivation cost is recovered in advance, and the cultivation risk is reduced; in the pond with the bionic molting nest, the molting environment of river crabs is relatively secret and clean, the body surfaces of grown crabs are clean, the residual crab rate is 40 percent lower than that of other crabs in the pond which is not placed, the profit per mu can reach 4000-5000 yuan, and the benefit is obviously increased.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A bionic molting nest is characterized by comprising a cuboid frame and a top cover, wherein the top cover is fixed right above the cuboid frame through a stay bar; four sides and the bottom surface parcel net piece of cuboid frame, four summits department downwardly extending foot strips of cuboid frame bottom surface, the foot strip is perpendicular with cuboid frame bottom surface.

2. The bionic molting nest of claim 1, wherein the top cover is a rectangular frame, and 2-3 layers of meshes are wrapped on the top cover.

3. The bionic molting nest according to claim 1 or 2, wherein the mesh size of the mesh is 15-25 meshes.

4. The biomimetic molting nest of claim 1, wherein the foot bars are connected with positioning markers.

5. The biomimetic molting nest of claim 1, wherein wet rice husks are laid in the rectangular parallelepiped frame.

6. A method for assisting river crab culture by utilizing rice processing byproducts is characterized by comprising the following steps:

2) mixing and stirring the rice hull ash and the waste rice milk, mixing the rice hull ash and the waste rice milk with the float grass seeds to prepare a grass cake, drying the grass cake, and putting the grass cake into a crab pool;

4) putting juvenile crabs into the crab pool in months of 2-3;

6) one week before the molting period of river crabs, the bionic molting nest according to any one of claims 1 to 5 is put into a crab pool.

7. The method as claimed in claim 6, wherein in the preparation process of the plugging mixture in the step 1), the mass ratio of the rice husk to the rice husk ash to the waste rice pulp is 1:1 (1-2).

8. The method as claimed in claim 6, wherein the diameter of the grass cake in the step 2) is 15-30 cm, and the number of the grass seeds in each grass cake is 20-30.

9. The method as claimed in claim 6, wherein the step of separating the rice husk after mixing the microbial preparation, water and rice husk and sealing fermentation is the step 5) of fermenting the rice husk, and the liquid collected is the step 3) of fermenting the rice husk.

10. The method according to claim 6, wherein the proportion of the rice husk ash mixed with water is 1 (1-3), and the sprinkling amount of the rice husk ash mixed with water is 100-200 kg/mu.