JP2009011271A - Feed conversion method for benthic organism, method for cleaning culture pond of tiger shrimp, and feed conversion agent for benthic organism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming, maintaining and recovering the medium function (soil fertility) of microbial reaction of the bottom mud of a tiger shrimp culture pond, and effective for remarkably improving a culture pond having low productivity, preventing injury by continuous culture, recovering a pond lost its culture potential by continuous culture and improving tidal land environment deteriorated by organic matter loading. <P>SOLUTION: A method for converts either one or both of organic matters deposited on the bottom of a tiger shrimp culture pond and organic matters in the soil of the pond, concretely. The method provides a feed conversion method for benthic organism and a cleaning method for a culture pond or a tidal land by mixing or scattering amorphous hydrous iron oxide to the bottom. Further, a feed conversion agent for benthic organism, containing amorphous hydrous iron oxide and usable in the feed conversion method for benthic organism, is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention improves a biological soil environment such as an aquaculture pond or a tidal flat, and can solve a natural environment destruction problem associated with a shrimp aquaculture business that has been particularly raised worldwide. Alternatively, the present invention relates to a feed conversion method for benthic shallow mud benthic organisms, a method for purifying shallow ponds or tidal flats, and a benthic feed conversion agent.

The world's history of shrimp farming is also the process of relocation of production areas with the destruction of the natural environment. Black tiger shrimps are the mainstream of shrimp farming, and have been cultivated mainly by developing and creating ponds in the sedimentary soil of tropical and subtropical brackish waters. The disadvantage of this aquaculture is that it shows high productivity immediately after the cultivation pond is established, but the productivity decreases with continued use, eventually the shrimp can no longer be produced and the pond is abandoned as worn out, and the next sedimentary soil area As a result, the natural environment destruction has been expanded. The above-mentioned deterioration of the aquaculture pond has occurred in 2 years at the earliest and about 5 years at the latest, and has been regarded as a problem that cannot be solved as a continuous cropping disorder of unknown cause.
Thus, as a result of studying the cause of continuous cropping disorder, the present inventor has obtained the following knowledge.

  In the cultivation of black tiger shrimp, which is the core of shrimp farming, the geological strength of the pond is an essential condition. The role of geopower is the culture medium of microbial reaction, and when it stops working as a culture medium, shrimp cannot be trained. In other words, the microbial reaction of the geological force has the effect of maintaining the biological environment by decomposing sediment such as residual food of shrimp training feed, excrement of shrimp, organic matter produced by the pond, and consuming the organic sediment. Combined with the action of converting to shrimp effective prey. The action of these two pond bottom soils is necessary, and when the action is lost or lowered, the pond has been discarded because shrimp can no longer be done for unknown reasons (occurrence of continuous cropping failure).

  In response to the above problems in shrimp aquaculture business, by installing a water flow device in the shrimp cultivation pond, organic matter accumulated in the non-water basin of the aquaculture pond is discharged as sludge by circulating the water in the pond, There is an example in which the solid chlorine tablet is decomposed while being deposited (see Patent Document 1). However, in the case of this method, although the oxygen consumption of the accumulated bottom mud is reduced and the ammonia is reduced, the accumulated organic matter is not actively used as a feed and is insufficient. In addition, there is an example in which plankton is propagated by spraying a specific solution of plankton breeding to feed floating or precipitated organic matter (see Patent Document 2). However, this method uses a specific extract extracted from the fermented product and has nothing to do with the feed conversion of the deposited organic matter by amorphous hydrous iron oxide, which is the technical field of the present invention. In addition, there is a technology for cultivating fry and the like by spraying chlorella by installing members that block tidal currents at intervals on the seabed, closing the entire space with a net, making the closed space a culture area, and spraying chlorella (Patent Document 3). reference). However, this technology prevents the outflow of fry and chlorella due to tidal currents, and does not improve the deterioration of bottom mud due to dung or residual food. Moreover, there exists a technique which makes a specific bacterium act on seaweed and uses it as a feed (refer patent document 4). Furthermore, there is a description of supplying a specific bait to the bivalve detoxification method (see Patent Document 5). However, these techniques do not use sediment as a microbial medium to convert sedimentary organic matter into feed.

  There is a description of changing the iron content dissolved by aeration to amorphous hydrous ferric oxide and removing the iron content for water treatment (see Patent Document 6). In addition, as an adsorbent or deodorant for sulfur oxides, hydrogen sulfide, nitrogen oxides, etc. in the atmosphere or gas, air is blown into a sulfate aqueous solution of ferrous sulfate and alkali metal to produce amorphous hydrous oxide. There is description which obtains ferric iron (refer to patent documents 7). In addition, there is a description of obtaining hydrous ferric oxide for magnetic recording by aeration of a mixed solution of a ferrous salt aqueous solution and an alkaline aqueous solution (see Patent Document 8). However, in these documents, there is a description that ferrous chloride or ferrous sulfate is dissolved in seawater or salt-added water, and aerated to separate flocked precipitates to produce amorphous hydrous iron oxide. Absent. The amorphous hydrous iron oxides in these documents are hydrous ferric oxides for water treatment, gas treatment and magnetic recording, and do not modify the bottom mud of aquaculture ponds. Is different.

  The cultivation of black tiger shrimp cultivated in tropical or subtropical areas depends on the geological power of the cultivation pond, and there is no effective means for continuous cropping damage that occurs after exhausting the geological power.

JP-A-8-298894 JP-A-6-296444 JP 11-289903 A Japanese Patent No. 2772772 Japanese Patent Laid-Open No. 11-46617 JP-A-6-114385 JP-A-6-122519 JP-A-9-71422

  The present invention relates to a method capable of forming, maintaining, and recovering a culture function (geopower) of a microbial reaction in a shallow basin mud of a culture pond or tidal flat, which significantly improves a low productivity shrimp culture pond. The objectives of this project are to prevent continuous cropping failures, to recover ponds that are no longer able to shrimp due to continuous cropping failures, and to improve the tidal flat environment that has deteriorated due to organic load.

Means for solving the above-described problems are as follows.
(1) A method of converting at least one of organic matter deposited in the bottom of a shallow basin of an aquaculture pond or tidal flat and organic matter contained in soil into feed for benthic organisms, which is amorphous with respect to the bottom. A feed conversion method for benthic organisms, characterized by mixing or spraying iron oxide.
(2) At least one of the organic matter deposited in the bottom of the shallow water of the culture pond or tidal flat and the organic matter contained in the soil is converted into benthic feed, and the shallow water of the culture pond or tidal flat is improved by improving the biological environment. A method for purification, comprising mixing or spraying amorphous hydrous iron oxide on the bottom surface, wherein the method is a method for purifying the shallow water of an aquaculture pond or tidal flat.
(3) The feed conversion method for benthic organisms according to (1) above, wherein the aeration is performed from the bottom of the shallow pond of the culture pond or tidal flat.
(4) A benthos feed conversion agent which is used in the benthos feed conversion method described in (1) above and contains amorphous hydrous iron oxide.
(5) Described in (4) above, wherein at least one of ferrous chloride and ferrous sulfate is dissolved in seawater or salt-added water to obtain a solution, and the solution is aerated to cause flocking and precipitation separation. It is a feed conversion agent for benthos.

  In addition to significantly improving low-productivity shrimp ponds in relation to the method of forming, maintaining and recovering the culture function (geopower) of microbial reactions in cultured pond bottom mud or tidal flat shallow water soil, Provide a method to recover the pond where shrimp can no longer be produced due to continuous cropping failure, and a method to improve the tidal flat environment that has deteriorated due to organic load.

The present invention was made by investigating the cause of the above-mentioned shrimp pond continuous cropping failure. In addition to preventing the continuous cropping failure, the present invention also provides a method for remarkably improving the productivity even in shrimp ponds that were originally low in productivity. To do. For the time being, it is also a means to solve the natural environment destruction problems associated with shrimp farming.
The problem of shrimp ponds is the problem of organic load and the management of soil and water quality. The technology of the present invention is an effective means for improving the tidal flat environment.
Using amorphous hydrous iron oxide administered to soil as in the present invention, precipitating organic matter is positively converted to benthic feed, and water quality and bottom mud biological environment with the progress of aquaculture are maintained and improved. There was no technology. There is no technology other than the present invention that meets the above-mentioned problems.

<Forage conversion of aquaculture ponds or tidal flats>
A first aspect of the present invention is a method of converting at least one of organic matter deposited on the bottom of a shallow basin of an aquaculture pond or tidal flat and organic matter contained in soil into feed for benthic organisms, A feed conversion method for benthic organisms, characterized by mixing or spraying crystalline hydrous iron oxide.
An aquaculture pond refers to a pond used for the cultivation of shrimp, crab shellfish, fish, or similar shellfish. The culture pond may be either artificial or natural. The benthic feed refers to the feed of crustaceans such as shrimp and crab, fish or similar fish and shellfish that live near the bottom. Amorphous hydrous iron oxide is ferrous oxide which is amorphous and contains crystal water. Here, administration refers to mixing or dispersing amorphous hydrous iron oxide on the bottom surface. As a method of administration, for example, a method in which water is reduced with a dehydrator or amorphous hydrous iron oxide suspended in water is poured into the bottom or top surface of a pond through a pipe by a pump or by natural fall There is.

The present invention is based on the knowledge that the bottom mud improving microorganisms of the pond bottom are propagated by administering amorphous hydrous iron oxide at each of the initial stage immediately after the formation of the training pond, the subsequent middle stage, and the final stage. By decomposing the organic matter deposited on the bottom, the organic matter deposited on the shallow soil surface of the culture pond or tidal flat or the organic matter contained in the soil is fed.
The present inventor initially administered amorphous hydrous iron oxide in the 3 mm of the bottom mud surface at each of the initial, middle and final stages of the shrimp aquaculture pond that was exhausted after showing a certain degree of productivity. As a result of keeping the concentration of high quality hydrous iron oxide to 0.25%, we were able to secure higher productivity and shrimp size than before the aquaculture pond was exhausted, and the knowledge that the amount of food required was reduced Obtained.
Since amorphous hydrous iron oxide can be easily used as soluble iron by microorganisms, its administration will maintain the microbial flora in a healthy manner, and the remaining feed of shrimp training feed, excrement of shrimp, ponds The organic matter and other sediments produced are decomposed and converted into prey that is effective for shrimp, resulting in an improved biological environment. Even in poorly productive ponds, the productivity of shrimp ponds can be improved by administering amorphous hydrous iron oxide and managing its concentration in the soil. This principle is the same in tidal flats and can be applied.
The process of feeding is not clear, but feces, residual food, plankton and other organic matter are settled and deposited on the pond bottom. Amorphous hydrous iron oxide is mixed or sprayed on the pond bottom soil. It is possible to reduce ammonia and increase the redox potential. It is thought that the decomposition of organic matter that promotes the feeding of organic matter by bacteria was promoted.

<Purification of shallow water in aquaculture pond or tidal flat>
The second aspect of the present invention is to convert at least one of organic matter deposited on the bottom of the shallow basin of the culture pond or tidal flat and organic matter contained in the soil into feed for benthic organisms, thereby improving the biological environment. A method for purifying the shallow sea of a tidal flat, wherein amorphous hydrous iron oxide is mixed or sprayed on the bottom surface.
Purification refers to improving the bottom soil and water quality by improving the redox potential of the bottom soil of the aquaculture pond or tidal flat and decreasing the soil ammonia concentration, thus improving the biological environment.

  In aquaculture ponds, dung and residual food accumulate in the bottom mud, while in tidal flats, the increase in organic load increases oxygen consumption in the water and bottom mud, resulting in frequent oxygen shortages. Furthermore, with the progress of the reducing environment, the oxidative decomposition of organic matter stagnates, ammonia damage occurs, and the properties of soil and water quality such as aquaculture ponds and tidal flats deteriorate. In the present invention, by administering amorphous hydrous iron oxide, it was possible to increase the redox potential of the bottom mud and decrease the soil ammonia concentration, confirming the improvement of the biological environment and the purification of water quality.

<Forage conversion of aquatic ponds or tidal flat shallow benthic organisms by aeration from the bottom>
A third aspect of the present invention is a benthos feed conversion method according to the first aspect of the present invention, wherein the aeration is performed from the bottom of the shallow sea of the culture pond or the tidal flat.
Aeration refers to directing air into a shallow water solution in an aquaculture pond or tidal flat. As a method for introducing air, for example, there is a method in which air pressurized by a blower is guided to a pond bottom through a pipe, and air is blown into a solution from an outlet of a pipe pipe with an aeration nozzle laid on the pond bottom facing upward. .
The present invention can further improve the effects of the first invention. In the supply of oxygen to the aquaculture pond water, the aeration method is more efficient and energy-efficient than the conventional water wheel method, but it also supplies dissolved oxygen into seawater. I found that the effect of the flow was great. By aeration during the day, a vertical circulation flow was formed, and photosynthesis in seawater was promoted sterically, and the dissolved oxygen concentration showed a supersaturation of 200% by aeration for about 3 hours during sunshine. In aquaculture ponds without vertical circulation flow, combined with high plankton concentration, effective photosynthesis depth is about 50cm from the surface, and in general the cultivation pond is about 1.2m deep. Dissolved oxygen concentration shows only supersaturation of pond water average 120% at maximum. Moreover, the oxygen concentration at the bottom of the pond is low, which is no longer desirable as a biological environment.
Since this method can maintain a uniform and high concentration of oxygen up to the bottom pond water, it can supply a large amount of oxygen to the bottom mud, and in combination with the method of the first invention, a healthy microflora can be efficiently produced. Can be formed.

  In addition, the effect of uniform agitation at high oxygen concentration is great due to aeration, and the decomposition of suspended organic matter is promoted, so that the water quality is purified, and new plankton is produced in large quantities by the decomposed inorganic matter. Since the planktons and suspended suspensions coagulate and settle due to the agglomeration effect, the raw material for shrimp feed can be supplied to the microbial medium at the bottom of the pond. What the feed has become a benthic organism in the bottom mud microbial medium is usually called detritus. This stirring and coagulating sedimentation effect becomes even more effective by combining a water wheel that creates a horizontal circulation flow.

<Feed conversion agent of benthic organisms characterized by containing amorphous hydrous iron oxide>
A fourth aspect of the present invention is a benthos feed conversion agent which is used in the benthos feed conversion method described in the first aspect of the present invention and contains amorphous hydrous iron oxide. .
According to a fifth aspect of the present invention, at least one of ferrous chloride and ferrous sulfate is dissolved in seawater or salt-added water to obtain a solution, and the solution is aerated to obtain a flocked precipitate. A feed conversion agent for benthic organisms according to the fourth invention.
Here, the feed conversion agent for benthic organisms contains amorphous hydrous iron oxide, and may be, for example, one that has been dehydrated or suspended in water.
Amorphous hydrous iron oxide is an economically superior method for producing amorphous hydrous iron oxide using ferrous chloride (FeCl ₂ ) and / or ferrous sulfate (FeSO ₄ ) as a raw material. is there. It is possible to manufacture with ferric chloride or ferric sulfate, but the material is expensive and not suitable.
An example of the method for producing amorphous hydrous iron oxide according to the present invention will be described below. That is, ferrous chloride or ferrous sulfate is administered and dissolved in seawater or NaCl-dissolved water, and aeration is added thereto to produce amorphous hydrous iron oxide (ferric hydroxide). Since the produced amorphous hydrous iron oxide is positively charged, it does not settle due to charge repulsion when it is produced in normal fresh water, but seawater or NaCl-dissolved water has high electrical conductivity. From the above, it was found that electroneutralization can easily proceed to achieve coagulation precipitation separation. Usually, the amount of amorphous hydrous iron oxide required for shrimp training is small, so there is little ferrous chloride or ferrous sulfate to be administered, so that the pH of the pond affects shrimp training. Since it does not become acidic, it is possible to administer it directly to a shrimp pond and precipitate the amorphous hydrous iron oxide produced on the pond bottom soil. It is not preferable for shrimp breeding because it is clogged with the shrimp of the shrimp being trained. The inventor has confirmed that administration of amorphous hydrous iron oxide precipitated as a floc at one end does not cause this problem and can be smoothly administered.

  Hereinafter, examples will be shown, but the present invention is not limited to these examples.

<Hydrogenated iron administration to aquaculture pond and shrimp FCR>
The relationship between the administration of hydrous iron oxide to the aquaculture pond and the FCR of shrimp is shown in FIG. Condition A was an example in which no hydrous iron oxide was administered to the culture pond, and condition B was an example in which the hydrous iron oxide was administered, and the culture was performed for a period of 120 to 135 days. Condition A is the average value of n = 15 and condition B is the average value of n = 8. The horizontal axis of FIG. 1 shows the concentration of amorphous hydrous iron oxide in the ground mud. The average value of the condition B in which the administration was performed was 0.04%, whereas the average value of the condition B in which the administration was not performed was 0.25. Rose to%. The FCR (Feed Conversion Ratio) on the vertical axis is the weight of bait used to make 1 kg of shrimp body weight, and is generally called the increase coefficient in Japan. FCR = used feed weight / trained shrimp weight. The FCR during the period A is 1.75, while the FCR during the period B is reduced to 1.50, and the required amount of food is decreased. It shows that plankton, residual food and other organic matter in the ground mud are effectively fed into the pond ecosystem.

<Amorphous hydrous iron oxide administration and shrimp production>
FIG. 2 shows a comparison of the shrimp weights of the investigated conditions A and B. An increase in the weight per fish has a great economic effect. Large amounts of shrimp can be trained by administration of amorphous hydrous iron oxide.
FIG. 3 shows long-term changes in shrimp productivity of the culture pond used in the present application test. The aquaculture pond used in the test of the present application was initially highly productive (Group A), but then the main pond was exhausted and the productivity decreased (□ in Group B). Shrimp productivity was improved by administration of amorphous hydrous iron oxide (group C ■ mark).
As the amorphous iron hydroxide concentration, iron extraction by EDTA was used. The amount of amorphous hydrous iron oxide in the pond bottom soil was determined by quantifying the extracted iron by phenanthroline colorimetric method (Soil Nutrient Analysis, Yokendo (2002) 15th edition, p301-p302). . A calibration curve was obtained from the developed iron standard solution and colorimetrically determined with 510 nm (absorptiometer: Spectrophotometer U-1500 manufactured by Hitachi, Ltd.) to determine the iron concentration (mg / L) of the EDTA extract.

<Collecting pond bottom soil>
A cylindrical transparent container (diameter 5.5 cm, height 12 cm) was inserted into the shrimp cultivation pond bottom soil (5 spots / ha). The container was covered, and the container was slowly pulled up so that the soil did not come off. By this method, soil can be collected without destroying the state of the pond bottom. The collected soil is separated into a surface layer and a lower layer according to soil color, and the surface layer soil is filled in a small container (diameter 1.5 cm, height 9.5 cm) so that air does not enter. This soil was used for each analysis.

<Measurement of oxidation-reduction potential, ammonia concentration and bottom mud oxygen consumption by administration of amorphous hydrous iron oxide>
FIG. 4 shows the improvement in redox potential and the decrease in soil ammonia concentration when amorphous hydrous iron oxide is administered, and FIG. 5 shows the effect of reducing the oxygen consumption of the bottom mud. In both cases, during the training of shrimp, the amorphous hydrous iron oxide produced by the method described later is administered, administered, and administered on a basis of 0.2% by weight relative to the soil thickness of 3 mm on the surface of the pond bottom. It is the data which shows the improvement of the biological environment obtained.
As shown in FIG. 4, the biological environment of the pond was almost before the cultivation limit before the administration at the 120th day of the cultivation, but the environment was recovered by the administration, and it was able to be harvested after a predetermined cultivation period. FIG. 5 shows an example in which the oxygen consumption of the pond bottom soil is intense and the oxygen concentration at night is 0.3 ppm which is the training limit.
Here, the measuring method of oxidation-reduction potential, ammonia concentration and bottom mud oxygen consumption is as follows.

  The redox potential was measured by measuring the ORP of the surface soil sampled by the soil sampling method. A small container filled with soil is filled with oxygen-free water, and an ORP electrode (Model number: INLAB501 REDOX (PLATINUM) manufactured by METLER TOLEDO) is inserted 2 cm into the soil. Five hours after the insertion, the ORP value was measured with an ORP meter (model number: MultiLine P4 manufactured by WTW) (Soil Nutrient Analysis Method Yokendo (2002), 15th edition, p53-p69).

The soil ammonia concentration was measured by potassium chloride solution leaching-indophenol blue absorptiometry (Soil environmental analysis method Hirotomo (2000) 2nd edition p241-p245) Surface layer collected by the soil sampling method Ammonium ions are eluted from 2cm soil (wet soil) by leaching potassium chloride solution. The amount of ammonium ions was quantified by indophenol blue spectrophotometry and measured as the amount of soil ammonia.

The bottom mud oxygen consumption is measured by culturing the collected pond bottom mud together with the aquaculture pond seawater in a brown glass bottle and measuring the amount of dissolved oxygen in the seawater consumed to measure the bottom mud oxygen consumption. It was a method. That is, 4 g (wet earth) of the collected 1 mm surface layer of soil is placed in a 530 ml brown glass bottle, seawater is poured into this bottle, a magnetic stirrer is placed, and a dissolved oxygen concentration meter electrode (model number: CellOx 325 manufactured by WTW) is inserted. did. The dissolved oxygen concentration (mgO2 / L) in the brown glass bottle is measured with a dissolved oxygen meter (manufactured by WTW, model number: Oxi330i). The seawater in the brown glass bottle was left in a warmer (dark place) adjusted to 28 ° C. while gently stirring (60 rpm). Initially, the dissolved oxygen concentration in the brown glass bottle after 2 hours, 4 hours, and 6 hours is measured. Separately, a blank brown glass bottle containing only seawater to which no soil was added was prepared, and the dissolved oxygen concentration was measured in the same manner. From the measured dissolved oxygen concentration in the brown glass bottle at each time and the dissolved oxygen concentration in the blank brown glass bottle containing only seawater, the dissolved oxygen consumption by the added soil per hour was calculated (mgO2 / h). From the obtained value, the soil surface 1mm, soil of 1mm layer × 1 m ² than using the soil weight 4g (specific gravity 1.5, Shimedo 1,500g equivalent) sediment oxygen consumption by converting the (MgO2 / m ² mm · h).

<Photosynthesis efficiency by aeration>
FIG. 6 shows an example of dissolved oxygen concentration transition with and without aeration. For aeration, a roots blower was used, and a pipe with an aeration nozzle facing upward was laid on the bottom of the pond, and the culture was performed at 0.5 L / m ² · min. The aeration arrangement is shown in FIG. When aeration is not performed, the dissolved oxygen concentration on the pond surface shows a relatively high value due to the photosynthetic effect, but the pond bottom does not advance light transmission and the dissolved oxygen concentration is small. When aeration is applied, the concentration of dissolved oxygen in the entire pond water increases, indicating that the photosynthetic effect is large. Aeration supplies oxygen to the bottom of the pond, which is effective in improving the environment of the bottom mud.
Here, the dissolved oxygen concentration was measured with the dissolved oxygen meter (manufactured by WTW, model number: Oxi330i).

<Measurement of the amount of detritus produced by aeration>
FIG. 7 shows the amount of detritus generated by aeration. Due to aeration, the production of detritus, which is a feed for shrimp, is increasing.
Here, for the measurement of detritus, the amount of detritus produced was determined by installing a collection bottle at the bottom of the pond and collecting the precipitated aggregate.

<Amorphous hydrous iron oxide produced by dissolving ferrous sulfate heptahydrate in seawater or salt-added water, aerated and separated into flocs and precipitates>
500 mL of 3.5% NaCl seawater was placed in a 500 mL beaker, ferrous sulfate heptahydrate was added to 500 ppm of iron, air was blown in, aerated, and the sedimentation rate of the ferric hydroxide floc produced was measured. Instead of 3.5% NaCl water, 1.0% NaCl diluted seawater, 3.5% NaCl salt water, 1.0% NaCl salt water and fresh water are aerated in the same manner, and the ferric hydroxide flock that is generated is settled. The speed was measured. The results are shown in FIG.
By dissolving ferrous sulfate heptahydrate in seawater or salt-added water and aeration, amorphous hydrous iron oxide flock that precipitates can be precipitated easily and efficiently. The obtained amorphous hydrous iron oxide floc settles on the bottom of the pond, thereby improving the environment of the bottom mud.

  Here, the method for measuring the sedimentation rate of amorphous hydrous iron oxide was to collect a 5 cm solvent below the surface after aeration, and the absorbance of the collected solvent at 720 nm (Absorptiometer: Spectrophotometer U-1500 manufactured by Hitachi, Ltd.) Was measured, and the time until the absorbance value reached 0.1 was measured, and the hydrous iron oxide precipitation rate (cm / h) of the produced amorphous per hour was calculated from the measured time.

  The present invention forms, maintains and restores the culture function (geopower) of the microbial reaction of the shallow mud in the shallow pond of the aquaculture pond or tidal flat, and prevents the continuous cropping failure in addition to remarkably improving the low productivity aquaculture pond. It is possible to restore ponds that cannot be cultivated due to continuous cropping failure, and to improve the tidal flat environment that has deteriorated due to organic load.

FIG. 1 is a diagram showing improvement of FCR by administration of amorphous hydrous iron oxide. FIG. 2 is a diagram showing improvement in shrimp size by administration of amorphous hydrous iron oxide. FIG. 3 is a graph showing changes in amorphous hydrous iron oxide concentration and shrimp productivity. FIG. 4 is a diagram showing an improvement in redox potential and a decrease in ammonia concentration by administration of amorphous hydrous iron oxide. FIG. 5 is a diagram showing the effect of reducing the oxygen consumption of cultured pond bottom mud by administration of amorphous hydrous iron oxide. FIG. 6 is a diagram showing an improvement in the photosynthesis rate by aeration. FIG. 7 is a diagram illustrating an improvement in detritus productivity by aeration. FIG. 8 is a diagram showing the sedimentation rate of ferric hydroxide in seawater, saline and fresh water. FIG. 9 is a layout diagram of aeration.

Claims (5)

  A method of converting at least one of organic matter deposited in the bottom of a shallow basin of an aquaculture pond or tidal flat and organic matter contained in soil into feed for benthic organisms, wherein amorphous hydrous iron oxide is added to the bottom. A feed conversion method for benthic organisms, comprising mixing or spraying.   A method of purifying the shallow water of a culture pond or tidal flat by converting the organic matter accumulated in the bottom of the shallow water of the culture pond or tidal flat and the organic matter contained in the soil into feed for benthic organisms and improving the biological environment A method for purifying a shallow basin of an aquaculture pond or tidal flat, wherein amorphous hydrous iron oxide is mixed or dispersed on the bottom surface.   The feed conversion method for benthic organisms according to claim 1, wherein the aeration is performed from the bottom of the shallow water of the culture pond or tidal flat.   A benthos feed conversion agent, which is used in the benthos feed conversion method according to claim 1 and contains amorphous hydrous iron oxide.   The benthic organism according to claim 4, which is obtained by dissolving at least one of ferrous chloride and ferrous sulfate in seawater or salt-added water to obtain a solution, and aeration of the solution to cause flocking and precipitation separation. Feed conversion agent.