CN114793972A

CN114793972A - Rice and crab symbiotic large-size crab culture method

Info

Publication number: CN114793972A
Application number: CN202210323513.0A
Authority: CN
Inventors: 石伟; 管卫兵; 张朝阳; 李斌; 马金林; 邱小琮; 马虎; 周学林; 王小奕; 堇学锋; 杨柳; 石常晋; 徐铖元; 黄晓晨
Original assignee: Yinchuan Kehai Biotechnology Co ltd
Current assignee: Yinchuan Kehai Biotechnology Co ltd
Priority date: 2022-03-30
Filing date: 2022-03-30
Publication date: 2022-07-29

Abstract

The invention discloses a rice-crab symbiotic large-size crab culture method, which comprises the following steps of modifying a culture field; the device comprises a rice field and a fish pond, tail water of the fish pond is connected into the rice field, ridges are arranged on the periphery of the top of the rice field, a culture pond is dug at the position 50cm away from the ridges, a pond dike is arranged outside the culture pond, the depth of the culture pond is 150cm, the width of the culture pond is 600cm, the slope is 45 degrees, a water inlet pipe penetrating into the rice field is arranged outside the culture pond, a drain pipe is arranged at the bottom of the culture pond, a bridge leading to the outer side of the culture pond is arranged in the rice field, a crab escape-preventing net is arranged, the net height is 0.5 m, and defense transformation is realized; breed the pond top and set up defense device, defense device divide into lead wire stake and alignment stake, and the lead wire stake is pre-buried in the outside of breeding the pond. The rice-crab symbiotic large-size crab culture method has the advantages of optimizing rice yield, crab yield and defense, and needs to optimize and improve water quality, crab species, environment, natural enemy defense and the like in the culture method during northern culture.

Description

Rice and crab symbiotic large-size crab culture method

Technical Field

The invention relates to the technical field of symbiotic cultivation of rice and crabs, in particular to a method for cultivating large-size symbiotic rice and crabs.

Background

The rice and crab planting is based on the theory of rice breeding crabs, crab breeding rice and crab symbiosis, in the environment of rice and crab planting, the crabs can clear weeds in the field, eat pests, and excrement can fertilize the field to promote the growth of rice; the rice provides rich natural bait and good inhabitation conditions for the growth of the river crabs, and is mutually beneficial to form a benign ecological cycle.

In the large-scale breeding process, due to the fact that the crabs are large in variety difference and poor in quality, the Liaoxie crabs are small in size in breeding, economic benefits are seriously affected, and the crabs are difficult to adapt to the northern environment, and during northern breeding, water quality, crab species, environment, natural enemy defense and the like need to be optimized and improved in the breeding method, so that a rice-crab symbiotic large-size crab breeding method is needed, and the industrial requirements of northern crab breeding are met.

Disclosure of Invention

The invention aims to provide a rice-crab symbiotic large-size crab culture method to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for culturing rice-crab symbiotic large-size crabs comprises the following steps;

1) modifying a culture field; the crab escape prevention device comprises a rice field and a fish pond, tail water of the fish pond is connected into the rice field, ridges are arranged on the periphery of the top of the rice field, a culture pond is dug at the position 50cm away from the ridges, a pond dike is arranged outside the culture pond, the depth of the culture pond is 150cm, the width of the culture pond is 600cm, the gradient of the culture pond is 45 degrees, a water inlet pipe penetrating into the rice field is arranged outside the culture pond, a drain pipe is arranged at the bottom of the culture pond, a bridge leading to the outer side of the culture pond is arranged in the rice field, a crab escape prevention net is arranged in the rice field, and the net height is 0.5 m;

2) defense transformation; the top of the culture pond is provided with a defense device, the defense device is divided into lead piles and line-setting piles, the lead piles are embedded in the outer side of the culture pond, the line-setting piles are embedded in the top of the ridges, the lead piles correspond to the line-setting piles one by one, the embedded distance is 100com, and white fish lines are used as barriers for the defense lines of crabs against natural enemies of birds;

3) water inlet and drainage transformation; the water outlet end of the water inlet pipe is sleeved with a hose, the hose is 100-300cm, the diameter of the hose is matched with that of the soft net pipe of the water inlet pipe, and a trapezoidal cement step is arranged below the outlet water of the hose; the top of the drain pipe is provided with a corrugated pipeline which can stretch one meter at the longest, the top of the corrugated pipeline is provided with a filter screen, and the height of the pipe orifice is adjusted and controlled by adopting a manual gate valve to lift and adjust, so that the height of the water level is controlled;

4) water circulation; water in the culture pond enters the inside of the rice field through a water inlet pipe, the rice field water enters a large ditch through a water outlet pipe, and the water in the large ditch is pumped by a water pump and enters the culture pond to circulate;

5) a cyclic mode; two water pumps are arranged outside the culture pond, one pump is responsible for conveying water in the culture pond into the rice field through a water inlet pipe, the other pump is responsible for circulating water in the large ditch into the culture pond, and water at other positions flows by utilizing a height difference;

6) monitoring the water quality; the method comprises the following steps of monitoring the water quality of inlet and outlet water and water bodies in the middle of water circulation for multiple times, collecting mixed water samples of an upper layer and a middle layer, wherein the detection indexes are water quality indexes such as dissolved oxygen, water temperature, soluble phosphate, salinity, nitrite nitrogen, ammonia nitrogen, pH, total particle suspended matters (TPM) and the like, the sampling time is 10:00-11:00 in the morning, and monitoring the change conditions of the water quality of pond engineering recirculating aquaculture, the water quality of a rice and crab co-operation system and the water quality of an ecological ditch (big ditch);

7) the water quality change condition of the pond engineering recirculating aquaculture system; the dissolved oxygen at the water inlet is obviously higher than that of the middle water body and the water outlet (P is less than 0.05), which shows that the coupling system can continuously provide high-dissolved-oxygen running water for the flume, is beneficial to maintaining the dissolved oxygen level of the flume and avoids the death of a large number of fishes caused by oxygen deficiency; the concentration of the soluble phosphate in the middle water body of the water flowing channel is obviously higher than that of the water inlet and the water outlet, which shows that the residual bait and the fish feces can release the soluble phosphate to the water body, and the concentration of the soluble phosphate in the water outlet is only slightly higher than that of the water inlet, which shows that the water flowing channel system has certain self-cleaning capability and can self-clean most of the soluble phosphate; the salinity of the water inlet of the water flowing groove is obviously higher than that of the middle water body and the water outlet, which shows that the salinity of the water body can be reduced by fish culture in the water flowing groove, and the improvement of saline-alkali soil is facilitated; the flowing water tank system can cause the concentration of nitrite nitrogen and ammonia nitrogen in the water body to be greatly increased due to feeding and fish metabolism; the total alkalinity of the water inlet is extremely higher than that of the water outlet (P <0.01), the total alkalinity of the water inlet is slightly higher than that of the middle water body, and the total alkalinity of the middle water body is slightly higher than that of the water outlet, so that the flowing water channel system can obviously reduce the total alkalinity of the water body, and the flowing water channel fish culture is completely feasible in the saline-alkali land area and is beneficial to improving the soil salinity and alkalinity; the pH value of the water inlet is obviously higher than that of the middle water body (P is less than 0.05), but the pH value of the water inlet is only slightly higher than that of the water outlet, which indicates that the water tank system can properly reduce the pH value of the water body; the TPM of the whole pond is not obviously changed, and the TPM of the water outlet and the TPM of the middle water body are slightly higher than the water inlet. The flow channel system can slightly increase the TPM of the water body;

8) the water quality change condition of the rice and crab cooperative system is as follows: the dissolved oxygen at the water outlet is remarkably higher than the dissolved oxygen of the middle water body (P <0.01), the dissolved oxygen at the water outlet is remarkably higher than the dissolved oxygen at the water inlet (P <0.05), and the dissolved oxygen at the water inlet is slightly higher than the dissolved oxygen of the middle water body, so that the dissolved oxygen of the water body can be increased by the rice field system, and the tail water of the pond can be improved at the dissolved oxygen level; the water temperature changes are not obvious, which shows that the water temperature of the water body of the whole system is not changed greatly in the circulation process, and the water temperature of the water body in the middle of the rice field is not lowered due to shading of rice, so that river crabs can be prevented from not climbing to the middle of the rice field for foraging due to low water temperature, the foraging range of the river crabs can be expanded, and the yield of the river crabs can be improved; the concentration and salinity of the soluble phosphate of the intermediate water body are slightly higher than those of the water inlet and the water outlet, and the concentration and salinity of the soluble phosphate of the water inlet are slightly higher than those of the water outlet, so that the rice field system has a certain absorption effect on the phosphate, can reduce the salinity of the water body, but has weak effect; the concentration of nitrite nitrogen in the middle water body of the rice field is extremely low, which shows that the rice can obviously reduce the content of nitrite nitrogen in the water body, but as hairy crabs are cultured in the circular ditches, the content of nitrite nitrogen in the water body purified by the rice and crab co-culture system is higher; the ammonia nitrogen concentration of the water inlet and the water outlet is remarkably higher than that of the intermediate water body (P <0.01), and the ammonia nitrogen concentration of the water inlet is remarkably higher than that of the water outlet (P <0.05), so that the rice and crab co-working system has good absorption and purification effects on the ammonia nitrogen of the water body and can remarkably reduce the ammonia nitrogen content of the water body; the total alkalinity of the middle water body of the rice field system is obviously increased, which indicates that the total alkalinity of the water body can be increased when rice is planted, the total alkalinity of the water outlet of the rice field system is lower than that of the middle water body and slightly higher than that of the water inlet, and indicates that the total alkalinity of the water body can be reduced to a certain extent when river crabs are cultured in the circular ditch of the rice field; the pH value of the middle water body is slightly lower than that of the water inlet and the water outlet, which shows that the influence of the rice field system on the pH value of the water body is not great; the TPM of the water inlet is obviously higher than that of the middle water body (P <0.01), the TPM of the water outlet is obviously higher than that of the middle water body (P <0.05), and the TPM of the water inlet is slightly higher than that of the water outlet, which indicates that the rice field system can slightly lower the TPM of the water body;

9) the change of dissolved oxygen of the ecological ditch system is not obvious, which indicates that a small amount of grass carps are cultivated and the dissolved oxygen of the water body in the ditch can not be reduced by only feeding green feed; the phosphate concentration of the water in the middle of the ecological ditch system is highest, and the phosphate concentration of the water outlet is slightly higher than that of the water inlet, so that the content of the water soluble phosphate is increased when the 'clear water' of the rice field system flows into the ecological ditch, and the water soluble phosphate is close to a water suction pump after flowing for seven hundred meters, so that the phosphate concentration of the water is greatly reduced; the salinity of the water body and the water outlet in the middle of the ecological ditch is higher, and the experiment area is probably located in saline-alkali soil, so that the terrain of the ecological ditch is low, and the salinity of the water body is increased because the saline-alkali of the accessory is dissolved in the ecological ditch; regardless of the high or low nitrite nitrogen concentration at the water inlet, the nitrite nitrogen content of the ecological ditch can always keep a lower level, so that the ecological ditch can purify the nitrite nitrogen in the water body and provide water with low nitrite nitrogen for the launder; the ecological ditch system has good absorption and purification effects on the ammonia nitrogen in the water body, and can obviously reduce the content of the ammonia nitrogen in the water body; the ditch system has no obvious effect on the total alkalinity and pH value of the water body; the aqueduct system can slightly reduce the TPM of the water body. The ecological ditch system has obvious absorption and purification effects on nitrite nitrogen and ammonia nitrogen, does not have obvious influence on other water quality indexes, but can be used as a 'buffer zone' to prevent rapid deterioration of water caused by fertilization and pesticide application in a rice field to cause mass death of fishes in a launder.

As a still further scheme of the invention: the height of the anti-escape net is 50cm, the anti-escape net is buried under soil by 10-15 cm, the inner and outer edges of the anti-escape net are paved and tamped by broken soil, the deep-water crabs can be hidden in holes in the culture pond and forage for the deep-water crabs in the culture pond along with water circulation, the culture environment of deep-water crab varieties is met, and the shallow-water crabs can be hidden in ridges or rice fields to perch and forage for the deep-water crabs.

As a still further scheme of the invention: the shallow water crabs mainly inhabit between a rice field and a ridge, the shallow water crabs are hidden by the rice, meanwhile, natural enemies of the flying birds can be prevented by arranging the defense devices, the deep water crabs are not in the rice field in the area, the natural enemies of the flying birds are prevented by mainly relying on the defense devices, the flying birds need a certain punching or buffering distance in the process of taking off and landing, the defense lines with the pre-buried distance of 100com can enable the breeding area not to meet the landing and taking off conditions of the natural enemies of the flying birds, and the breeding crabs can be effectively protected.

As a still further scheme of the invention: the soft net pipes can meet the sorting requirement, meanwhile, the cultured crabs can be prevented from entering the pipeline, in order to meet the condition that the water level difference can be drained controllably, the height of the pipe orifice is adjusted and controlled in a manual gate valve lifting adjusting mode, and when the water level is lower than the pipe orifice, the water drainage is stopped.

As a still further scheme of the invention: the excrement of the crabs cultured in the culture pond enters the inside of the rice field through the water inlet pipe, the excrement can be absorbed as fertilizer of the rice field, weeds in the rice field and pests can be used as cultured crabs in the rice field, part of the weeds can circulate to the large ditch along with water flow, and water in the large ditch flows back to the culture pond after being recycled.

As a still further scheme of the invention: when the water circulation is performed by using the water level difference, the water level gradually becomes lower, and the water level needs to be raised by using the water pump to return the water to the high water level.

A defense device for symbiotic large-size rice and crab cultivation comprises lead piles and alignment piles;

a lead pile; the wire leading pile comprises a first ground nail, a winch is fixedly installed at the top of the first ground nail, a wire pipe is fixedly installed at the top of the winch, a rotatable rotating shaft is installed inside the wire pipe, an iron head is movably installed at the top of the wire pipe, a rotatable fixing shaft is installed on the left side wall of the winch, a wire coil is fixedly installed on the outer side of the fixing shaft, a rotatable screw rod is installed on the right side wall of the winch, the left end of the screw rod is rotatably connected with the fixing shaft, a brake disc is connected to the outer side of the screw rod in a threaded mode, and the right side of the brake disc is fixedly connected with the right side wall of the winch through a telescopic rod;

pile alignment; the alignment pile comprises a second ground nail, a pile column is fixedly mounted at the top of the second ground nail, a clamping groove is formed in the top of the pile column, and a top cover is connected to the inner thread of the clamping groove.

As a still further scheme of the invention: the wire coil is connected with the iron head through a defense line, and the diameter of the iron head is larger than the width of the clamping groove.

As a still further scheme of the invention: the crab escape-proof net is tied up outside the first ground nail through an iron wire or a nylon rope, and the first ground nail is arranged at the top of the pool embankment.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the method for breeding the large-size crabs in the rice-crab symbiosis, the water quality change condition of a pond engineering circulating water breeding system, the water quality change condition of a rice-crab co-operation system and the oxygen dissolving change condition of an ecological ditch system are obtained through water quality monitoring, the breeding environment of the fishes and the crabs is improved, the crabs can be bred in the breeding pond and the rice field, the crabs can live in the rice field, ridges and the breeding pond through life habits, the crabs in the breeding pond can climb over the ridges at night to find food in the rice field, the breeding conditions of the crabs with different habits are met, and the circulating water quality is guaranteed to improve the breeding yield of the crabs by matching with the water quality monitoring.

2. According to the rice-crab symbiotic large-size crab culture method, the water circulation system can balance water quality indexes such as soluble phosphate, salinity, nitrite nitrogen, ammonia nitrogen, pH, total particle suspended matters (TPM) and the like, the quality of the circulating water is guaranteed by matching with water quality monitoring, and the rice yield is improved.

3. According to the method for breeding the large-size rice-crab symbiotic crabs, the defensive line is arranged on the defensive device through the matching of the lead pile and the alignment pile, the degree of freedom is high, the defensive line can shrink freely, and the loss of natural enemies of flying birds to crab breeding is reduced.

Drawings

FIG. 1 is a schematic structural diagram of a rice-crab symbiotic large-size crab culture method;

FIG. 2 is a schematic structural diagram of a lead pile in a rice-crab symbiotic large-size crab culture method;

FIG. 3 is a schematic structural diagram of a alignment peg in a rice-crab symbiotic large-size crab culture method;

FIG. 4 is a cross sectional view of a lead wire pile in a large-sized crab breeding method for symbiosis of rice and crabs;

FIG. 5 is a longitudinal sectional view of a lead pile structure in a rice-crab symbiotic large-size crab culture method;

FIG. 6 is a water circulation diagram of a rice-crab symbiotic large-size crab culture method;

FIG. 7 is a schematic diagram showing the change of dissolved oxygen in a rice-crab symbiotic large-sized crab cultivation method;

FIG. 8 is a schematic diagram showing the change of phosphate in a method for cultivating large-sized symbiotic crabs;

FIG. 9 is a schematic diagram showing the variation of ammonia nitrogen in a rice-crab symbiotic large-size crab culture method;

FIG. 10 is a schematic diagram showing the variation of nitrite in a rice-crab symbiotic large-sized crab cultivation method;

FIG. 11 is a schematic diagram showing the variation of salinity in a rice-crab symbiotic large-sized crab cultivation method;

FIG. 12 is a schematic diagram showing the change of suspended matters in a rice-crab symbiotic large-sized crab culture method;

FIG. 13 is a statistical chart of dissolved oxygen of a rice-crab symbiotic large-sized crab breeding method;

FIG. 14 is a water temperature statistical chart of a rice-crab symbiotic large-size crab culture method;

FIG. 15 is a nitrate statistical chart of a rice-crab symbiotic large-sized crab culture method;

FIG. 16 is a salinity statistical chart of a rice-crab symbiotic large-size crab culture method;

FIG. 17 is a nitrite state salt statistical chart of a rice-crab symbiotic large-size crab culture method;

FIG. 18 is a statistical diagram of ammonia nitrogen in a rice-crab symbiotic large-size crab culture method;

FIG. 19 is a total alkalinity statistical chart of a rice-crab symbiotic large-size crab breeding method;

FIG. 20 is a PH statistical chart of a rice-crab symbiotic large-sized crab culture method;

FIG. 21 is a TPM statistical chart of a rice-crab symbiotic large-size crab culture method.

In the figure: 1. a rice field; 2. ridging; 3. a culture pond; 4. a pool dike; 5. a water inlet pipe; 6. a first ground nail; 7. a winch; 8. a conduit; 9. a rotating shaft; 10. an iron head; 11. a handle is rotated; 12. a screw; 13. a bearing; 14. a second ground nail; 15. pile columns; 16. a card slot; 17. a top cover; 18. wire coils; 19. a fixed shaft; 20. a telescopic rod; 21. a brake disc.

Detailed Description

First embodiment

Referring to fig. 1 and 6, in an embodiment of the present invention, a method for breeding large crabs with symbiotic rice and crabs includes the following steps;

1) modifying a culture field; the method comprises the following steps that (1) a rice field and a fishpond are formed, tail water of the fishpond is connected into the rice field 1, ridges 2 are arranged on the periphery of the top of the rice field 1, a culture pond 3 is dug at a position 50cm away from the ridges, a pond dike 4 is arranged outside the culture pond 3, the depth of the culture pond 3 is 150cm, the width of the culture pond is 600cm, the slope is 45 degrees, a water inlet pipe 5 penetrating into the rice field 1 is arranged outside the culture pond 3, a water discharge pipe is arranged at the bottom of the culture pond 3, the rice field 1 is provided with a bridge leading to the outer side of the culture pond 3 and is provided with a crab escape-proof net, and the net height is 0.5 m;

2) defense transformation; the top of the culture pond 3 is provided with a defense device which is divided into lead piles and line-setting piles, the lead piles are embedded in the outer side of the culture pond 3, the line-setting piles are embedded in the top of the ridges 2 and correspond to the line-setting piles one by one, the embedded distance is 100com, and the defense line uses white fish lines as a barrier for the crabs to defend natural enemies of birds;

3) water inlet and drainage transformation; a hose is sleeved at the water outlet end of the water inlet pipe 5, the hose is 100-300cm, the diameter of the hose is matched with that of the soft net pipe of the water inlet pipe 5, and a trapezoidal cement step is arranged below the outlet water of the hose; the top of the water discharge pipe is provided with a corrugated pipeline which can stretch one meter at most, the top of the corrugated pipeline is provided with a filter screen, and the height of the pipe orifice is adjusted and controlled in a manual gate valve lifting adjustment mode, so that the height of the water level is controlled;

4) water circulation; water in the culture pond 3 enters the rice field 1 through a water inlet pipe 5, the rice field 1 water enters a large ditch through a water outlet pipe, and the water in the large ditch is pumped by a water pump and enters the culture pond 3 to circulate;

5) a cyclic mode; two water pumps are arranged outside the culture pond 3, one pump is responsible for conveying water in the culture pond 3 into the rice field 1 through a water inlet pipe 5, the other pump is responsible for circulating water in the large ditch into the culture pond 3, and water at other positions flows by utilizing a high potential difference;

7) the water quality change condition of the pond engineering recirculating aquaculture system; the dissolved oxygen at the water inlet is obviously higher than that of the middle water body and the water outlet (P is less than 0.05), which shows that the coupling system can continuously provide high-dissolved-oxygen running water for the flume, is beneficial to maintaining the dissolved oxygen level of the flume and avoids the death of a large number of fishes caused by oxygen deficiency; the concentration of the soluble phosphate in the middle water body of the water flowing channel is obviously higher than that of the water inlet and the water outlet, which shows that the residual bait and the fish feces can release the soluble phosphate to the water body, and the concentration of the soluble phosphate in the water outlet is only slightly higher than that of the water inlet, which shows that the water flowing channel system has certain self-cleaning capability and can self-clean most of the soluble phosphate; the salinity of the water inlet of the water flowing groove is obviously higher than that of the middle water body and the water outlet, which shows that the salinity of the water body can be reduced by fish culture in the water flowing groove, and the improvement of saline-alkali soil is facilitated; the flowing water tank system can cause the concentration of nitrite nitrogen and ammonia nitrogen in the water body to be greatly increased due to feeding and fish metabolism; the total alkalinity of the water inlet is extremely higher than that of the water outlet (P <0.01), the total alkalinity of the water inlet is slightly higher than that of the middle water body, and the total alkalinity of the middle water body is slightly higher than that of the water outlet, so that the flowing water channel system can obviously reduce the total alkalinity of the water body, and the flowing water channel fish culture is completely feasible in the saline-alkali land area and is beneficial to improving the soil salinity and alkalinity; the pH value of the water inlet is obviously higher than that of the middle water body (P is less than 0.05), but the pH value of the water inlet is only slightly higher than that of the water outlet, which indicates that the water tank system can properly reduce the pH value of the water body; the TPM of the whole pond does not change obviously, and the TPM of the water outlet and the middle water body is slightly higher than the water inlet. The flow channel system can slightly increase the TPM of the water body;

8) the water quality change condition of the rice and crab cooperative system is as follows: the dissolved oxygen at the water outlet is remarkably higher than the dissolved oxygen of the middle water body (P <0.01), the dissolved oxygen at the water outlet is remarkably higher than the dissolved oxygen at the water inlet (P <0.05), and the dissolved oxygen at the water inlet is slightly higher than the dissolved oxygen of the middle water body, so that the dissolved oxygen of the water body can be increased by the rice field system, and the tail water of the pond can be improved at the dissolved oxygen level; the water temperature changes are not obvious, which shows that the water temperature of the water body of the whole system is not changed greatly in the circulation process, and the water temperature of the water body in the middle of the rice field is not lowered due to shading of rice, so that river crabs can be prevented from not climbing to the middle of the rice field for foraging due to low water temperature, the foraging range of the river crabs can be expanded, and the yield of the river crabs can be improved; the concentration and salinity of the soluble phosphate of the intermediate water body are slightly higher than those of the water inlet and the water outlet, and the concentration and salinity of the soluble phosphate of the water inlet are slightly higher than those of the water outlet, so that the rice field system has a certain absorption effect on the phosphate, can reduce the salinity of the water body, but has weak effect; the concentration of nitrite nitrogen in the middle water body of the rice field is extremely low, which shows that the rice can obviously reduce the content of nitrite nitrogen in the water body, but as hairy crabs are cultured in the circular ditch, the content of nitrite nitrogen in the water body purified by the rice-crab co-working system is higher; the ammonia nitrogen concentration of the water inlet and the water outlet is remarkably higher than that of the intermediate water body (P <0.01), and the ammonia nitrogen concentration of the water inlet is remarkably higher than that of the water outlet (P <0.05), so that the rice and crab co-working system has good absorption and purification effects on the ammonia nitrogen of the water body and can remarkably reduce the ammonia nitrogen content of the water body; the total alkalinity of the middle water body of the rice field system is obviously increased, which indicates that the total alkalinity of the water body can be increased when rice is planted, the total alkalinity of the water outlet of the rice field system is lower than that of the middle water body and slightly higher than that of the water inlet, and indicates that the total alkalinity of the water body can be reduced to a certain extent when river crabs are cultured in the circular ditch of the rice field; the pH value of the middle water body is slightly lower than that of the water inlet and the water outlet, which shows that the influence of the rice field system on the pH value of the water body is not great; the TPM of the water inlet is obviously higher than that of the middle water body (P <0.01), the TPM of the water outlet is obviously higher than that of the middle water body (P <0.05), and the TPM of the water inlet is slightly higher than that of the water outlet, which indicates that the rice field system can slightly lower the TPM of the water body;

9) the change of dissolved oxygen of the ecological ditch system is not obvious, which indicates that a small amount of grass carps are cultivated and the dissolved oxygen of the water body in the ditch can not be reduced by only feeding the green feed; the phosphate concentration of the water in the middle of the ecological ditch system is highest, and the phosphate concentration of the water outlet is slightly higher than that of the water inlet, so that the content of the water soluble phosphate is increased when the 'clear water' of the rice field system flows into the ecological ditch, and the water soluble phosphate is close to a water suction pump after flowing for seven hundred meters, so that the phosphate concentration of the water is greatly reduced; the salinity of the water body and the water outlet in the middle of the ecological ditch is higher, and the experiment area is probably located in saline-alkali soil, so that the terrain of the ecological ditch is low, and the salinity of the water body is increased because the saline-alkali of the accessory is dissolved in the ecological ditch; whether the nitrite nitrogen concentration of the water inlet is high or low, the nitrite nitrogen content of the ecological ditch can always keep a lower level, so that the ecological ditch can purify the nitrite nitrogen in the water body and provide water with low nitrite nitrogen for the flume; the ecological ditch system has good absorption and purification effects on the ammonia nitrogen in the water body, and can obviously reduce the content of the ammonia nitrogen in the water body; the ditch system has no obvious effect on the total alkalinity and pH value of the water body; the aqueduct system can slightly reduce the TPM of the water body. The ecological ditch system has obvious absorption and purification effects on nitrite nitrogen and ammonia nitrogen, does not have obvious influence on other water quality indexes, but can be used as a 'buffer zone' to prevent rapid deterioration of water caused by fertilization and pesticide application in a rice field to cause mass death of fishes in a launder.

The working principle of the invention is as follows: in 8 months, water quality monitoring is carried out for 5 times on water inlet and outlet of three systems of rice and crab combined farmland, water state ditches and pond engineering circulating water aquaculture and water bodies in the middle of the systems, 6 sites are selected for sampling detection, mixed water samples of the upper layer and the middle layer are collected, and the production condition of the base is good in the period. The detection indexes are 9 water quality indexes such as dissolved oxygen, water temperature, soluble phosphate, salinity, nitrite nitrogen, ammonia nitrogen, total alkalinity, pH, total particle suspended matters (TPM) and the like, the sampling time is 10:00-11:00 in the morning, and the result shows that the coupling of the rice and crab combined field and the pond engineering circulating aquaculture system is beneficial to improving the specification and the fullness of river crabs, the rice yield and the fish survival rate; the pond engineering recirculating aquaculture system can cause water quality deterioration, cause dissolved oxygen to reduce, soluble phosphate content to rise, nitrous nitrogen and ammoniacal nitrogen content to obviously improve, total particle suspended matter content slightly rises, and the rice and crab combined system can purify the tail water of the pond well, can reduce water phosphate, salinity, TPM and total alkalinity to a certain extent, can obviously reduce water ammoniacal nitrogen content, but does not have obvious purification effect on the nitrous nitrogen content; the pond engineering circulating water aquaculture system can reduce the salinity, the total alkalinity and the pH of the water body, which shows that the pond engineering circulating water aquaculture system can improve the salinity and the alkalinity of the water body, 13 times of water quality monitoring is carried out on inlet and outlet water of 3 fishponds of the intensive fishpond system and water bodies in the middle in 8-10 months, mixed water samples of the upper layer and the middle layer are collected, and the production condition of a base is good in the period. The detection indexes comprise 8 water quality indexes such as dissolved oxygen, water temperature, soluble phosphate, salinity, nitrite nitrogen, ammonia nitrogen, pH, total particle suspended matters (TPM) and the like, and the sampling time is 10:00-11:00 in the morning;

the water temperature of the three ponds is at a normal level; the pH value of the water body of the three ponds is between 8 and 9; the salinity of the water in the three ponds is less than 0.8 per thousand; the dissolved oxygen content of the water bodies of the two ponds reaches 5mg/L in most of time, and the dissolved oxygen content of one pond is lower; the ammonia nitrogen content and the phosphate content of the water body of the three-mouth pond are respectively less than 1mg/L and 0.15mg/L in most of time; the nitrite content in two ponds is less than 0.15mg/L most of the time, while the nitrite content in one pond is higher; the content of total particle suspended matter in the water outlet is greatly increased. Experimental analysis proves that the circulating water can discharge a large amount of nutrient substances in the pond out of the pond and maintain the relative stability of the water quality of the pond, and the experimental data and analysis show that the temperature, the pH and the salinity of the water body in the three ponds are generally kept at normal levels in thirteen sampling days under the action of the circulating water in a fishpond-ecological ditch-rice crab combined field mode, and the pH and the salinity are not continuously increased in the pond along with the time; under the action of phytoplankton and circulating water, the phosphate content of the water body in the three-mouth pond is also kept below 0.15 mg/L; the dissolved oxygen content in the west 4 and east 6 ponds reaches the surface water class III standard (more than 5mg/L) on most sampling days, but the dissolved oxygen content in the west 1 pond is lower; in the aspect of ammonia nitrogen, the three ponds reach the III-class standard (less than 1mg/L) of surface water on most sampling days; the nitrite content of the West 1 pond and the east 6 pond is lower than 0.15mg/L on most sampling days, the pond meets the III-class standard of surface water (GHZB1-1999), and the nitrite content of the West 4 pond is higher; the content of the suspended matters in the pond is greatly influenced by the circulating water, and the circulating water can bring a large amount of suspended matters out of the pond, so that the stability of the ecological environment of the pond is maintained. In the case of low west 1 dissolved oxygen and high west 4 nitrite content, additional measures such as mechanical aeration, fresh water filling, physical adsorption and the like should be taken to restore the normal state, in short, in the fishpond-ecological ditch-rice and crab combined field culture mode, circulating water continuously enters the pond to update the water body, so that the water quality can be maintained at a normal level. Ponds in this mode have many advantages over normal intensive culture ponds that do not circulate. As the water quality is improved, the quantity of the sterilizing medicine is correspondingly reduced; the tail water of the pond is discharged into the rice and crab combined field and can be reused; the water body which is circulated continuously can save water resources. The results fully prove that the recirculating aquaculture is a novel ecological culture mode with high efficiency, saving and high economic benefit.

Second embodiment

Referring to fig. 1 and 6, in an embodiment of the present invention, referring to fig. 1, a method for breeding large-sized symbiotic rice and crabs for crabs in an embodiment of the present invention includes the following steps;

3) water inlet and drainage transformation; a hose is sleeved at the water outlet end of the water inlet pipe 5, the hose is 100-300cm, the diameter of the hose is matched with that of the soft net pipe of the water inlet pipe 5, and a trapezoidal cement step is arranged below the outlet water of the hose; the top of the drain pipe is provided with a corrugated pipeline which can stretch one meter at the longest, the top of the corrugated pipeline is provided with a filter screen, and the height of the pipe orifice is adjusted and controlled by adopting a manual gate valve to lift and adjust, so that the height of the water level is controlled;

6) monitoring the water quality; water quality monitoring is carried out on inlet water and outlet water in water circulation and water bodies in the middle for multiple times, mixed water samples of an upper layer and a middle layer are collected, detection indexes are water quality indexes such as dissolved oxygen, water temperature, soluble phosphate, salinity, nitrite nitrogen, ammonia nitrogen, pH, total suspended matter (TPM) and the like, the sampling time is 10:00-11:00 in the morning, and the change conditions of the water quality of pond engineering recirculating aquaculture, the water quality of a rice-crab co-operation system and the water quality of an ecological ditch (big ditch) are monitored;

7) the water quality change condition of the pond engineering recirculating aquaculture system; the dissolved oxygen at the water inlet is obviously higher than that of the middle water body and the water outlet (P is less than 0.05), which shows that the coupling system can continuously provide high-dissolved-oxygen running water for the flume, is beneficial to maintaining the dissolved oxygen level of the flume and avoids the death of a large number of fishes caused by oxygen deficiency; the concentration of the soluble phosphate in the middle water body of the flume is obviously higher than that of the water inlet and the water outlet, which indicates that the residual bait and the fish feces can release the soluble phosphate to the water body, and the concentration of the soluble phosphate in the water outlet is only slightly higher than that of the water inlet, which indicates that the flume system has certain self-cleaning capability and can self-clean most of the soluble phosphate; the salinity of the water inlet of the water flowing groove is obviously higher than that of the middle water body and the water outlet, which shows that the salinity of the water body can be reduced by fish culture in the water flowing groove, and the improvement of saline-alkali soil is facilitated; the flowing water tank system can cause the concentration of nitrite nitrogen and ammonia nitrogen in the water body to be greatly increased due to feeding and fish metabolism; the total alkalinity of the water inlet is extremely higher than that of the water outlet (P <0.01), the total alkalinity of the water inlet is slightly higher than that of the middle water body, and the total alkalinity of the middle water body is slightly higher than that of the water outlet, so that the flowing water channel system can obviously reduce the total alkalinity of the water body, and the flowing water channel fish culture is completely feasible in the saline-alkali land area and is beneficial to improving the soil salinity and alkalinity; the pH value of the water inlet is obviously higher than that of the middle water body (P is less than 0.05), but the pH value of the water inlet is only slightly higher than that of the water outlet, which indicates that the water tank system can properly reduce the pH value of the water body; the TPM of the whole pond is not obviously changed, and the TPM of the water outlet and the TPM of the middle water body are slightly higher than the water inlet. The flow channel system can slightly increase the TPM of the water body;

8) the water quality change condition of the rice and crab cooperative system is as follows: the dissolved oxygen at the water outlet is remarkably higher than the dissolved oxygen of the middle water body (P <0.01), the dissolved oxygen at the water outlet is remarkably higher than the dissolved oxygen at the water inlet (P <0.05), and the dissolved oxygen at the water inlet is slightly higher than the dissolved oxygen of the middle water body, so that the dissolved oxygen of the water body can be increased by the rice field system, and the tail water of the pond can be improved at the dissolved oxygen level; the water temperature changes are not obvious, which shows that the water temperature of the water body of the whole system is not changed greatly in the circulation process, and the water temperature of the water body in the middle of the rice field is not lowered due to shading of rice, so that river crabs can be prevented from not climbing to the middle of the rice field for foraging due to low water temperature, the foraging range of the river crabs can be expanded, and the yield of the river crabs can be improved; the concentration and salinity of the soluble phosphate of the intermediate water body are slightly higher than those of the water inlet and the water outlet, and the concentration and salinity of the soluble phosphate of the water inlet are slightly higher than those of the water outlet, so that the rice field system has a certain absorption effect on the phosphate, can reduce the salinity of the water body, but has weak effect; the concentration of nitrite nitrogen in the middle water body of the rice field is extremely low, which shows that the rice can obviously reduce the content of nitrite nitrogen in the water body, but as hairy crabs are cultured in the circular ditches, the content of nitrite nitrogen in the water body purified by the rice and crab co-culture system is higher; the ammonia nitrogen concentration of the water inlet and the water outlet is remarkably higher than that of the middle water body (P <0.01), and the ammonia nitrogen concentration of the water inlet is remarkably higher than that of the water outlet (P <0.05), so that the rice and crab co-working system has a good absorption and purification effect on the ammonia nitrogen of the water body and can remarkably reduce the ammonia nitrogen content of the water body; the total alkalinity of the middle water body of the rice field system is obviously increased, which indicates that the total alkalinity of the water body can be increased when rice is planted, the total alkalinity of the water outlet of the rice field system is lower than that of the middle water body and slightly higher than that of the water inlet, and indicates that the total alkalinity of the water body can be reduced to a certain extent when river crabs are cultured in the circular ditch of the rice field; the pH value of the middle water body is slightly lower than that of the water inlet and the water outlet, which shows that the influence of the rice field system on the pH value of the water body is not great; the TPM of the water inlet is obviously higher than that of the middle water body (P <0.01), the TPM of the water outlet is obviously higher than that of the middle water body (P <0.05), and the TPM of the water inlet is slightly higher than that of the water outlet, which indicates that the rice field system can slightly lower the TPM of the water body;

In a preferred embodiment, the shallow water crabs mainly inhabit between the rice field 1 and the ridge 2, the shallow water crabs are hidden by rice, meanwhile, natural enemies of the flying birds can be prevented by arranging a defense device, the deep water crabs are located in the area without the rice field, the natural enemies of the flying birds are prevented by mainly relying on the defense device, the flying birds need a certain piercing or buffering distance in the process of taking off and landing, and the cultured area can not meet the landing and taking off conditions of the natural enemies of the flying birds by pre-burying a defense line with the spacing of 100com, so that the cultured crabs can be effectively protected.

In a preferred embodiment, the flexible net pipes can meet the sorting requirement and prevent the cultured crabs from entering the pipeline, in order to meet the condition that the water level difference can be controlled for draining, the height of the pipe orifice is adjusted and controlled in a lifting adjusting mode of the manual gate valve, and the water draining is stopped when the water level is lower than the pipe orifice.

In a preferred embodiment, the excrement of the crabs cultured in the culture pond 3 enters the interior of the paddy field 1 through the water inlet pipe 5, the excrement can be absorbed as fertilizer of the paddy field, the weeds in the paddy field 1, the pests can be used as the cultured crabs in the paddy field 1, part of the weeds can be circulated to a large ditch along with water flow, and the water in the large ditch is circulated and then flows back to the culture pond 3.

The working principle of the invention is as follows: sampling five-mouth rice and crab co-cropping fields for irrigating pond water and one-mouth rice and crab co-cropping fields for irrigating yellow river water in four growth periods, namely a tillering period (6 months and 15 days), an elongation period (7 months and 20 days), an ear leveling period (8 months and 12 days) and a maturation period (9 months and 15 days). The rice and crab combined field for irrigating the water of the fishpond is a test field, sampling is carried out in the water inlet area, the middle area and the water outlet area of the rice field, three sampling points are arranged in each rice field, a five-point sampling method is adopted for each sampling point, namely, each square meter sample is randomly sampled in the four sides and the middle of a diagonal line of the test area, and 10 holes are sampled at each sampling point. Setting the rice and crab co-culture field for irrigating yellow river water as a control group, and adopting a five-point sampling method;

the rice variety is 'autumn excellent 88', the whole growth period is generally 122 days, and the rice variety belongs to middle and late maturing aromatic rice variety. The rice is sown about 5 months and 1 day, and harvested about 9 months and 22 days. Before the rice is sowed, organic fertilizer is applied to each field, phosphate fertilizer is applied twice during the growth period, and large weeds are manually removed. The test field irrigation mode is that the fishpond water is pumped for irrigation, and diagonal lines of each field are opened to serve as a water inlet and a water outlet. The control was used as an original sample field for irrigating no pond water, and for irrigating yellow river water introduced from Tang-come canal. The depth of the circumferential furrow around the rice field is 1 to 1.5 meters, and the width is 4 to 6 meters. The breeding variety is Eriocheir sinensis with anti-escape net at each field edge, and the net height is 0.5 m. One of the two water pumps has the power of 5000 watts with an eight-inch caliber, and the other water pump has the power of 3000 watts with a six-inch caliber, and is used for pumping the water in the fishpond to irrigate the rice field.

The grey correlation degree of the rice in the water inlet area of the rice field is distributed between 0.4779 and 0.8321, the correlation degree of the root-stem forming factors of the rice and the yield of the rice is sequentially from strong to weak: the outer diameter of the stalk base part (0.6599) > root length (0.6182) > stalk length (0.5647) > plant height (0.5629) > ear length (0.5053) > ear base part outer diameter (0.4968), the outer diameter of the stalk base part is a root stalk component factor with the largest correlation degree with rice yield, and the outer diameter of the ear base part is a root stalk component factor with the smallest correlation degree with rice yield; the correlation degree of the rice yield composition factors and the rice yield is sequentially from strong to weak: the effective ear number (0.8321) > above-ground biomass dry weight (0.6623) > root dry weight (0.6026) > hole number per hectare (0.5781) > thousand kernel weight (0.546) > fruit setting rate (0.511) > ear number (0.4846) > ear forming rate (0.4779), the effective ear number is a yield construction factor with the maximum correlation degree with rice yield, and the ear forming rate is a yield construction factor with the minimum correlation degree with rice yield.

The rice gray correlation degree in the middle area of the rice field is distributed between 0.4596 and 0.8030, and the correlation degrees of the root-stem constituent factors of the rice and the rice yield are sequentially from strong to weak: the outer diameter of the ear base part (0.5906) > the root length (0.5366) > the stalk length (0.5286) > the ear length (0.5198) > the plant height (0.5169) > the outer diameter of the stalk base part (0.4883), the outer diameter of the ear base part is a root stalk forming factor with the largest correlation degree with the rice yield, and the outer diameter of the stalk base part is a root stalk forming factor with the smallest correlation degree with the rice yield; the correlation degree of the rice yield composition factors and the rice yield is sequentially from strong to weak: the effective ear number (0.8030) > ear number (0.6597) > fructification rate (0.6450) > hole number per hectare (0.5752) > thousand kernel weight (0.5731) > ear forming rate (0.5653) > above-ground biomass dry weight (0.4808) > root dry weight (0.4596), the effective ear number is a yield construction factor with the maximum correlation degree with rice yield, and the root dry weight is a yield construction factor with the minimum correlation degree with rice yield.

The rice grey correlation degree in the rice outlet area is distributed between 0.5574 and 0.8180, and the correlation degrees of the root stalk forming factors of the rice and the rice yield are sequentially ordered from strong to weak: root length (0.7342) > stalk length (0.7013) > ear base outer diameter (0.6822) — stalk base outer diameter (0.6822) > plant height (0.6330) > ear length (0.5574), root length is a root and stalk constituting factor with the largest correlation degree with rice yield, and ear length is a root and stalk constituting factor with the smallest correlation degree with rice yield; the correlation degree of the rice yield composition factors and the rice yield is sequentially from strong to weak: the dry weight of the biomass on the ground (0.8180) > the dry weight of the root (0.7405) > the effective spike number (0.6694) > the thousand kernel weight (0.6495) > the spike number (0.6033) > the seed setting rate (0.6007) > the number of holes per hectare (0.5719) > the ear forming rate (0.5663), the dry weight of the biomass on the ground is a yield forming factor with the maximum correlation degree with the rice yield, and the ear forming rate is a yield forming factor with the minimum correlation degree with the rice yield.

The grey correlation degree of rice in the pond water irrigated rice and crab cooperative cropping field is distributed between 0.5669 and 0.8728, the correlation degree of each rice rhizome stalk forming factor and the rice yield is sequentially from strong to weak: ear length (0.8361) > ear base outer diameter (0.7891) > stem base outer diameter (0.7891) > plant height (0.7618) > stem length (0.7300) > root length (0.6897), ear length is a root and stem component factor with the largest correlation degree with rice yield, and root length is a root and stem component factor with the smallest correlation degree with rice yield; the correlation degree of the rice yield composition factors and the rice yield is sequentially from strong to weak: the number of grains per ear (0.8728) > maturing rate (0.8441) > effective number of ears (0.8358) > number of holes per hectare (0.8060) > ear forming rate (0.7976) > thousand seed weight (0.7768) > above-ground biomass dry weight (0.6715) > root dry weight (0.5669), the number of grains per ear is a yield construction factor with the largest correlation degree with rice yield, and the root dry weight is a yield construction factor with the smallest correlation degree with rice yield.

The grey correlation degree of rice in the rice-crab cooperative cropping field irrigated by the yellow river water is distributed between 0.4182 and 0.8043, and the correlation degree of each rice rhizome stalk forming factor and the rice yield is sequentially ordered from strong to weak: the stalk length (0.8043) > the ear base outer diameter (0.8004) > the ear length (0.7338) > the plant height (0.6658) > the stalk base outer diameter (0.4434) > the root length (0.4182), the stalk length is a root and stalk forming factor with the largest correlation degree with the rice yield, and the root length is a root and stalk forming factor with the smallest correlation degree with the rice yield; the correlation degree of the rice yield composition factors and the rice yield is sequentially from strong to weak: the number of grains per ear (0.7084) > the earring rate (0.6909) > the setting rate (0.6895) > the number of holes per hectare (0.6805) > the dry weight of roots (0.6307) > the weight of thousand grains (0.6289) > the dry weight of biomass on the ground (0.5191) > the number of effective ears (0.4698), the number of grains per ear is a yield construction factor with the maximum correlation degree with the rice yield, and the number of effective ears is a yield construction factor with the minimum correlation degree with the rice yield.

Third embodiment

Referring to fig. 2 to 5, in the embodiment of the invention, a defense device for large-size symbiotic rice and crab cultivation includes a lead pile and a routing pile;

a lead pile; the lead wire pile comprises a first ground nail 6, a winch 7 is fixedly mounted at the top of the first ground nail 6, a spool 8 is fixedly mounted at the top of the winch 7, a rotatable rotating shaft 9 is mounted inside the spool 8, an iron head 10 is movably mounted at the top of the spool 8, a rotatable fixing shaft 19 is mounted on the left side wall of the winch 7, a wire disc 18 is fixedly mounted on the outer side of the fixing shaft 19, a rotatable screw 12 is mounted on the right side wall of the winch 7, the left end of the screw 12 is rotatably connected with the fixing shaft 19, a brake disc 21 is in threaded connection with the outer side of the screw 12, the right side of the brake disc 21 is fixedly connected with the right side wall of the winch 7 through a telescopic rod 20, the screw 12 and the fixing shaft 19 are both rotatably connected with the winch 7 through a bearing 13, a rotating handle 11 is arranged at the right end of the screw 12, and the brake disc 21 is conveniently rotated and adjusted by a user, the left end of the fixed shaft 19 is matched with the rotating handle 11;

pile alignment; the alignment pile comprises a second ground nail 14, a pile 15 is fixedly mounted at the top of the second ground nail 14, a clamping groove 16 is formed in the top of the pile 15, and a top cover 17 is connected to the inner thread of the clamping groove 16.

In a preferred embodiment, the wire coil 18 is connected with the iron head 10 through a defense line, and the diameter of the iron head 10 is larger than the width of the clamping groove 16.

In a preferred embodiment, the crab escape prevention net is tied outside the first ground nail 6 by a wire or a nylon rope, and the first ground nail 6 is disposed on the top of the embankment 4.

The working principle of the invention is as follows: the pre-buried interval of the lead piles and the alignment piles is 100cm, the pre-buried positions of the lead piles and the alignment piles correspond one to one, a wire coil 18 of the lead piles is connected with a defense line, the defense line extends to the outer side through a rotating shaft 9, an iron head 10 is used for throwing and fixing, a user can throw the other end of the defense line to the other side of the culture pond 3 through the throwing iron head 10, the iron head 10 is placed into a clamping groove 16 of a second ground nail 14 of the alignment pile, a top cover 17 is in threaded connection with the clamping groove 16, the iron head 10 is fixed in the second ground nail 14, a screw 12 rotates to drive a brake disc 21 to move left and right, when the brake disc 21 moves to one side close to the wire coil 18, the brake disc 21 is in contact with the wire coil 18, under the action of friction force, the brake disc 21 limits the rotation of the wire coil 18, when the brake disc 21 moves to one side far away from the wire coil 18, the friction force disappears, and the wire coil 18 can rotate freely, in the line loosening process, manual line releasing is not needed, the line releasing efficiency can be effectively improved, the flying birds need one section of sprint or buffer distance in the taking-off and landing process, the defense line with the pre-embedded distance of 100cm can enable the breeding area not to meet the landing and taking-off conditions of natural enemies of the flying birds, the defense line is a white fish line, the flying birds are firm and firm, the eyesight of the birds is two to three times that of people, the white fish line can be clearly seen and whether the flying birds are suitable for landing can be judged, and the flying birds are difficult to find.

It should be noted that the above embodiments belong to the same inventive concept, and the description of each embodiment has a different emphasis, and reference may be made to the description in other embodiments where the description in individual embodiments is not detailed.

The above-mentioned embodiments only express the embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A rice-crab symbiotic large-size crab culture method is characterized by comprising the following steps;

1) modifying a culture field; the device comprises a rice field (1) and a fishpond, wherein fishpond tail water is connected into the rice field (1), ridges (2) are arranged on the periphery of the top of the rice field (1), a culture pond (3) is dug at the position 50cm away from the ridges, a pond dike (4) is arranged outside the culture pond (3), the depth of the culture pond (3) is 150cm, the width of the culture pond is 600cm, the slope of the culture pond is 45 degrees, a water inlet pipe (5) penetrating into the rice field (1) is arranged outside the culture pond (3), a water discharge pipe is arranged at the bottom of the culture pond (3), the rice field (1) is provided with a bridge leading to the outer side of the culture pond (3), and is provided with a crab escape-preventing net, and the net height is 0.5 m;

2) defense transformation; the top of the culture pond (3) is provided with a defense device, the defense device is divided into lead piles and routing piles, the lead piles are embedded in the outer side of the culture pond (3), the routing piles are embedded in the top of the ridge (2), the lead piles and the routing piles correspond to each other one by one, the embedded distance is 100com, and the defense line uses white fish lines as a barrier for the crabs to defend against natural enemies of birds;

3) water inlet and drainage transformation; a hose is sleeved at the water outlet end of the water inlet pipe (5), the hose is 100-300cm, the diameter of the hose is matched with that of the soft net pipe of the water inlet pipe (5), and a trapezoidal cement step is arranged below the outlet water of the hose; the top of the water discharge pipe is provided with a corrugated pipeline which can stretch one meter at most, the top of the corrugated pipeline is provided with a filter screen, and the height of the pipe orifice is adjusted and controlled in a manual gate valve lifting adjustment mode, so that the height of the water level is controlled;

4) water circulation; water in the culture pond (3) enters the rice field (1) through the water inlet pipe (5), the rice field (1) water enters the large ditch through the water outlet pipe, and the water in the large ditch is pumped by the water pump and enters the culture pond (3) to circulate;

5) a cyclic mode; two water pumps are arranged outside the culture pond (3), one pump is responsible for conveying water in the culture pond (3) into the rice field (1) through a water inlet pipe (5), the other pump is responsible for circulating water in the large ditch into the culture pond (3), and water at other positions flows by utilizing a height difference;

9) the change of dissolved oxygen of the ecological ditch system is not obvious, which indicates that a small amount of grass carps are cultivated and the dissolved oxygen of the water body in the ditch can not be reduced by only feeding the green feed; the phosphate concentration of the water in the middle of the ecological ditch system is highest, and the phosphate concentration of the water outlet is slightly higher than that of the water inlet, so that the content of the water soluble phosphate is increased when the 'clear water' of the rice field system flows into the ecological ditch, and the water soluble phosphate is close to a water suction pump after flowing for seven hundred meters, so that the phosphate concentration of the water is greatly reduced; the salinity of the water body and the water outlet in the middle of the ecological ditch is higher, and the experiment area is probably located in saline-alkali soil, so that the terrain of the ecological ditch is low, and the salinity of the water body is increased because the saline-alkali of the accessory is dissolved in the ecological ditch; whether the nitrite nitrogen concentration of the water inlet is high or low, the nitrite nitrogen content of the ecological ditch can always keep a lower level, so that the ecological ditch can purify the nitrite nitrogen in the water body and provide water with low nitrite nitrogen for the flume; the ecological ditch system has good absorption and purification effects on the ammonia nitrogen in the water body, and can obviously reduce the content of the ammonia nitrogen in the water body; the ditch system has no obvious effect on the total alkalinity and pH of the water body; the aqueduct system can slightly reduce the TPM of the water body. The ecological ditch system has obvious absorption and purification effects on nitrite nitrogen and ammonia nitrogen, does not have obvious influence on other water quality indexes, but can be used as a 'buffer zone' to prevent rapid deterioration of water caused by fertilization and pesticide application in a rice field to cause mass death of fishes in a launder.

2. The rice-crab symbiotic large-size crab cultivation method is characterized in that the height of the escape-proof net is 50cm, the escape-proof net is buried under the soil by 10-15 cm, the inner edge and the outer edge of the escape-proof net are paved and tamped by broken soil, deep-water crabs can be hidden in holes in a cultivation pond (3) and forage in the cultivation pond (3) along with water circulation, the cultivation environment of deep-water crab varieties is met, and shallow-water crabs can be hidden in ridges (2) or rice fields (1) to perch and forage.

3. The method is characterized in that the shallow water crabs mainly inhabit between a rice field (1) and a ridge (2), the shallow water crabs are hidden by rice, meanwhile, natural enemies of flying birds can be prevented by arranging a defense device, the deep water crabs are located in an area without the rice field, the natural enemies of the flying birds are prevented mainly by the defense device, the flying birds need a certain piercing or buffering distance in the take-off and landing processes, and the cultured area can not meet the landing and take-off conditions of the natural enemies of the flying birds by pre-buried defense lines with the spacing of 100com, so that the cultured crabs can be effectively protected.

4. The rice-crab symbiotic large-size crab culture method is characterized in that the soft net pipes can meet sequencing requirements and prevent cultured crabs from entering a pipeline, the height of a pipe orifice is adjusted and controlled in a manual gate valve lifting adjusting mode to meet the water level difference drainage controllable condition, and drainage is stopped when the water level is lower than the pipe orifice.

5. The method for breeding the large-size crabs is characterized in that excrement of the crabs bred in a breeding pond (3) enters a rice field (1) through a water inlet pipe (5), the excrement can be absorbed as fertilizer of the rice field, weeds in the rice field (1), pests can be used as the crabs bred in the rice field (1), part of the weeds can circulate to a large ditch along with water flow, and water in the large ditch circulates back to the breeding pond (3) after being recycled.

6. The method for culturing the large-size symbiotic rice and crabs is characterized in that when water circulation is carried out by utilizing the water level difference, the water level gradually becomes lower, and a water pump is needed to raise the water level to enable the water to return to a high water level.

7. The defense device for the symbiotic large-size rice and crab cultivation is characterized by comprising a lead pile and a line pile;

a lead pile; the wire leading pile comprises a first ground nail (6), a winch (7) is fixedly mounted at the top of the first ground nail (6), a wire pipe (8) is fixedly mounted at the top of the winch (7), a rotatable rotating shaft (9) is mounted inside the wire pipe (8), an iron head (10) is movably mounted at the top of the wire pipe (8), a rotatable fixed shaft (19) is mounted on the left side wall of the winch (7), a wire coil (18) is fixedly mounted on the outer side of the fixed shaft (19), a rotatable screw rod (12) is mounted on the right side wall of the winch (7), the left end of the screw rod (12) is rotatably connected with the fixed shaft (19), a brake disc (21) is connected to the outer side of the screw rod (12) in a threaded manner, and the right side of the brake disc (21) is fixedly connected with the right side wall of the winch (7) through a telescopic rod (20);

pile alignment; the alignment pile comprises a second ground nail (14), a pile (15) is fixedly mounted at the top of the second ground nail (14), a clamping groove (16) is formed in the top of the pile (15), and a top cover (17) is connected to the inner thread of the clamping groove (16).

8. The utility model provides a rice crab intergrowth big specification crab breeding's defense device which characterized in that, pass through the defense line between drum (18) and iron head (10) and be connected, the diameter of iron head (10) is greater than draw-in groove (16) width.

9. The rice-crab symbiotic large-size crab culture defense device is characterized in that a crab escape preventing net is tied outside first ground nails (6) through iron wires or nylon ropes, and the first ground nails (6) are arranged at the top of a pool dike (4).