A special fertilizer for promoting rice-crab symbiosis and its preparation method

Abstract

The present invention discloses a special fertilizer for promoting rice-crab symbiosis and a preparation method thereof, belonging to the technical fields of plant cultivation and aquaculture. The special fertilizer for promoting rice-crab symbiosis comprises the following raw materials in parts by mass: 60-80 parts of calcite, 20-30 parts of plagioclase, 30-40 parts of animal manure, 20-30 parts of straw, 10-12 parts of urea, 5-6 parts of potassium chloride, 3-5 parts of manganese sulfate, 2-3 parts of zinc sulfate, 2-3 parts of copper sulfate, 12-15 parts of humic acid, 2-3 parts of compound microorganisms, 0.5-0.8 parts of nitrifying bacteria, 5-6 parts of soybean meal, 5-6 parts of carbon powder and 5-8 parts of montmorillonite. The special fertilizer of the present invention can avoid the problem that the water quality deteriorates caused by fertilization and thus affects the growth of crabs, and at the same time can reduce the number of fertilization times and improve the utilization rate of the fertilizer.

Description

Technical Field

[0001] The present invention relates to the technical fields of plant cultivation and aquaculture, and particularly relates to a special fertilizer for promoting rice-crab symbiosis and a preparation method thereof. Background Art

[0002] Integrated rice-fish farming is a new type of compound three-dimensional arable land ecosystem and a typical ecological green circular agriculture. It organically combines the growth of rice with the growth of aquatic animals, can effectively develop the shallow water area environment in the paddy field, and brings a better living environment for the growth and development environment of aquatic animals, thus forming a new complex three-dimensional paddy field aquaculture technology of rice-fish symbiosis. Integrated rice-fish farming includes many types, such as rice-fish mode, rice-shrimp mode, rice-crab mode, rice-loach mode, rice-duck mode, rice-loach mode, rice-frog mode, etc. Currently, the integrated rice-fish farming is mainly based on the rice-crab mode. The paddy field provides good water quality for the habitat of river crabs, and the river crabs provide natural green organic fertilizers for the paddy field. The two benefit from each other and jointly build a paddy field green ecological system, forming a benign ecological cycle. Research has found that in the paddy field, river crabs can use their hidden environment to avoid natural enemies, and they can also use the shelter provided by the rice paddy to obtain sufficient nutrients, thereby promoting their molting and growth; river crabs can plow and loosen the soil, which is beneficial to the absorption of nutrients by rice; river crabs can prey on weeds and pests, reducing the incidence of diseases, pests and weeds in the paddy field. In addition, the excrement and residual bait of river crabs provide rich nutrients for the growth of rice, and these nutrients are absorbed by rice, which can promote the growth of rice and increase the rice yield. However, a large amount of chemical fertilizers need to be used in the initial stage of rice growth, and the application of chemical fertilizers affects the water quality and dissolved oxygen content of the paddy field (the fermentation and decomposition of fertilizers consume a large amount of oxygen, resulting in a decrease in dissolved oxygen in the water body), thus affecting the quality of rice and river crabs. Summary of the Invention

[0003] The purpose of the present invention is to provide a special fertilizer for promoting rice-crab symbiosis and a preparation method thereof to solve the problems existing in the above-mentioned prior art.

[0004] To achieve the above purpose, the present invention provides the following solutions:

[0005] One of the technical solutions of the present invention: A special fertilizer for promoting rice-crab symbiosis, comprising the following raw materials in parts by mass: 60-80 parts of calcite, 20-30 parts of plagioclase, 30-40 parts of animal feces, 20-30 parts of straw, 10-12 parts of urea, 5-6 parts of potassium chloride, 3-5 parts of manganese sulfate, 2-3 parts of zinc sulfate, 2-3 parts of copper sulfate, 12-15 parts of humic acid, 2-3 parts of compound microorganisms, 0.5-0.8 parts of nitrifying bacteria, 5-6 parts of soybean meal, 5-6 parts of carbon powder, and 5-8 parts of montmorillonite.

[0006] Further, the composite microorganism includes the following components in parts by mass:

[0007] 10 - 15 parts of iron bacteria, 5 - 8 parts of Rhodococcus coprophilus, 4 - 6 parts of Rhodopseudomonas palustris, 3 - 5 parts of Azotobacter chroococcum, 4 - 7 parts of Bacillus licheniformis, 4 - 6 parts of lactic acid bacteria, and 2 - 4 parts of Bacillus subtilis.

[0008] Further, the nitrifying bacteria are composed of nitrite bacteria and nitrate bacteria with a mass ratio of 1:1.

[0009] The iron bacteria, Rhodococcus coprophilus, and Rhodopseudomonas palustris in the composite microorganism can increase the oxygen content in the water body, avoiding the stress response caused by oxygen deficiency during the crab farming process (such as climbing out of the water surface or escaping from the original hiding places (such as fleeing to the rice roots, damaging the rice roots, and affecting the growth of rice)).

[0010] The Azotobacter chroococcum, Bacillus licheniformis, lactic acid bacteria, and Bacillus subtilis in the composite microorganism can regulate the physical and chemical properties of the soil, improve the soil permeability, and then increase the dissolved oxygen content, ensuring the symbiotic farming effect of rice and crabs.

[0011] The combined action of various microorganisms in the composite microorganism can not only keep the water quality fresh and the dissolved oxygen content in the water, but also improve the disease resistance of rice and crabs, and then increase the yields of rice and crabs.

[0012] The second technical solution of the present invention: A preparation method of a special fertilizer for promoting the symbiosis of rice and crabs, comprising the following steps:

[0013] Step (1): Dry and crush animal feces and straw, then mix them evenly with the composite microorganism, stack and ferment to obtain fermented fertilizer;

[0014] Step (2): Mix calcite, plagioclase, urea, potassium chloride, manganese sulfate, zinc sulfate, copper sulfate, nitrifying bacteria, and soybean meal evenly, spray starch solution, and granulate at low temperature to obtain fertilizer particles;

[0015] Step (3): Crush humic acid, carbon powder, and montmorillonite and mix them evenly with the fermented fertilizer, then coat them on the surface of the fertilizer particles to obtain composite fertilizer particles;

[0016] Step (4): Spray coating solution on the surface of the composite fertilizer particles, and dry at low temperature to obtain the special fertilizer for promoting the symbiosis of rice and crabs.

[0017] The soybean meal in the fertilizer particles can provide nutrients for nitrifying bacteria, promoting the growth and reproduction of nitrifying bacteria; a large number of nitrifying bacteria produced can continuously decompose calcite and plagioclase, providing a calcium source that can be absorbed and utilized by rice and crabs.

[0018] Calcium source is one of the important components in plant cell walls. By binding to polysaccharides such as pectin, it participates in the formation of intercellular and intracellular structures of the cell wall, helps enhance the mechanical stability of cells, and promotes cell growth and division; calcium can maintain the structural stability of the plant cell wall, protect the integrity of the plant cell membrane, and promote root and stem development; calcium can significantly improve the photosynthesis efficiency and stress resistance of crops, and help plants cope with various environmental stresses.

[0019] Crabs will undergo molting many times during their growth process. Calcium helps in the formation and hardening of the new shell. When the calcium content is sufficient, the molting speed and success rate of crabs will increase, and at the same time, the individuals after molting will be larger; crabs with sufficient calcium have stronger disease resistance and can better resist various diseases and stress responses; supplementing calcium can effectively improve the growth rate and health status of crabs, thereby improving the breeding efficiency and product quality.

[0020] The density of calcite and plagioclase is greater than that of water. Adding them to fertilizers can make the fertilizers stably deposit at the bottom of the water, avoiding the problem that fertilizers float on the water surface and cannot be fully utilized.

[0021] Further, in step (1), the crushing is to crush to a particle size of 50 - 100 mesh; the temperature of the stacking fermentation is 35 - 45 °C, the time is 25 - 30 days, and the moisture content is 50 - 55%; the pile is turned over every 5 days during the stacking fermentation.

[0022] Further, in step (2), the concentration of the starch solution is 5 wt.%; the temperature of the low-temperature granulation is 30 - 40 °C; the particle size of the fertilizer particles is 4 - 5 mm.

[0023] Further, in step (3), the crushing is to crush to a particle size of 50 - 100 mesh; the binder used in the preparation of the compound fertilizer particles is sodium lignosulfonate.

[0024] Further, in step (4), the preparation method of the coating solution includes the following steps:

[0025] Add cetyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether, and acrylamide to water, after high-pressure homogenization, add azobisisobutyramidine hydrochloride, and under nitrogen protection, heat and react to obtain the coating solution.

[0026] Further, the mass ratio of cetyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether, and acrylamide is 1:0.5:3; the dosage of azobisisobutyramidine hydrochloride is 25% of the mass of acrylamide;

[0027] The temperature of the heating reaction is 70 - 75 °C, and the time is 2 - 3 h.

[0028] Wrap humic acid, carbon powder, montmorillonite, and fermented fertilizer on the surface of fertilizer granules containing calcite, plagioclase, urea, potassium chloride, manganese sulfate, zinc sulfate, copper sulfate, nitrifying bacteria, and soybean meal, and wrap a coating material on the surface of the obtained compound fertilizer granules, which can slow down the release of nutrients in the fertilizer, avoid the decline in water quality caused by the large release of fertilizer nutrients, thereby affecting the growth of crabs and causing crabs to damage rice. At the same time, it can reduce the number of fertilizations and improve the utilization rate of fertilizers.

[0029] The third aspect of the technical solution of the present invention: An application of the above special fertilizer in rice-crab co-culture.

[0030] The present invention discloses the following technical effects:

[0031] The special fertilizer of the present invention can avoid the problem that the water quality deteriorates due to fertilization and then affects the growth of crabs. At the same time, it can reduce the number of fertilizations and improve the utilization rate of fertilizers.

[0032] The special fertilizer of the present invention can improve the water quality and avoid the problem that crabs damage rice due to poor water quality, resulting in a reduction in rice yield.

[0033] The special fertilizer of the present invention can increase the yield of rice and improve the symbiotic effect of crabs and rice. Detailed implementation manners

[0034] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0035] It should be understood that the terms described in the present invention are only for describing particular implementation manners and are not used to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0036] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0037] Without departing from the scope or spirit of the present invention, various modifications and variations can be made to the specific embodiments of the description of the present invention, which are obvious to those skilled in the art. Other embodiments obtained from the description of the present invention are obvious to those skilled in the art. The description and examples of the present invention are merely exemplary.

[0038] Regarding "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0039] All "parts" mentioned in the following examples are "parts by mass".

[0040] The iron bacteria, Rhodococcus coprophilus, Rhodopseudomonas palustris, Azotobacter chroococcum, Bacillus licheniformis, lactic acid bacteria, Bacillus subtilis, nitrite bacteria, nitrate bacteria, and cyanobacteria used in the present invention are all commercially available. Among them, the effective viable count of iron bacteria is 1.0×10 7 cfu / g, the effective viable count of Rhodococcus coprophilus is 2.0×10 9 cfu / g, the effective viable count of Rhodopseudomonas palustris is 1.0×10 9 cfu / g, the effective viable count of Azotobacter chroococcum is 2.0×10 9 cfu / g, the effective viable count of Bacillus licheniformis is 1.0×10 9 cfu / g, the effective viable count of lactic acid bacteria is 5.0×10 9 cfu / g, the effective viable count of Bacillus subtilis is 2.0×10 9 cfu / g, the effective viable count of nitrite bacteria is 5.0×10 8 cfu / g, nitrate bacteria 1.0×10 7 cfu / g, and the effective viable count of cyanobacteria is 1.0×10 8 cfu / g.

[0041] Example 1

[0042] (1) The special fertilizer for promoting rice-crab symbiosis is composed of the following raw materials in parts by mass: calcite 70 parts, plagioclase 25 parts, animal manure (chicken manure) 40 parts, straw (corn straw) 30 parts, urea 12 parts, potassium chloride 5.5 parts, manganese sulfate 5 parts, zinc sulfate 2.5 parts, copper sulfate 3 parts, humic acid 15 parts, compound microorganisms 2.5 parts, nitrifying bacteria 0.8 part, soybean meal 6 parts, carbon powder 6 parts, and montmorillonite 6 parts.

[0043] Among them, the compound microorganisms are composed of the following components in parts by mass: iron bacteria 12 parts, Rhodococcus coprophilus 6 parts, Rhodopseudomonas palustris 5 parts, Azotobacter chroococcum 5 parts, Bacillus licheniformis 6 parts, lactic acid bacteria 4 parts, and Bacillus subtilis 2.5 parts.

[0044] The nitrifying bacteria are composed of nitrite bacteria and nitrate bacteria with a mass ratio of 1:1.

[0045] (2) Dry and crush animal feces and straw to 80 mesh, then mix them evenly with the composite microorganisms, adjust the moisture content to 55%, and stack them into a fermentation pile with a length, width, and height of 1 m for fermentation (the fermentation temperature is 40 °C and the time is 30 days). Turn the pile once every 5 days during fermentation. After fermentation, the fermented fertilizer is obtained.

[0046] (3) Crush calcite, plagioclase, urea, potassium chloride, manganese sulfate, zinc sulfate, copper sulfate, nitrifying bacteria, and soybean meal to 100 mesh, add them to a granulator, mix them evenly, and then spray an aqueous starch solution with a concentration of 5 wt.%, and granulate at low temperature (30 °C) to obtain fertilizer particles with a particle size of 5 mm.

[0047] (4) Add the fertilizer particles to a granulator, and while spraying an aqueous sodium lignosulfonate solution with a concentration of 6 wt.%, add a mixture of humic acid, carbon powder, montmorillonite, and fermented fertilizer to wrap the mixture on the surface of the fertilizer particles to obtain composite fertilizer particles.

[0048] The preparation method of the mixture of humic acid, carbon powder, montmorillonite, and fermented fertilizer is as follows: Crush humic acid, carbon powder, and montmorillonite (particle size is 100 mesh) and mix them evenly with the fermented fertilizer to obtain the mixture.

[0049] (5) Spray a coating solution on the surface of the composite fertilizer particles (the mass / volume ratio of the composite fertilizer particles to the coating solution is 10 g:1.5 mL), and dry at low temperature (35 °C) to obtain a special fertilizer for promoting the symbiosis of rice and crabs.

[0050] Among them, the preparation method of the coating solution is as follows:

[0051] Add cetyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether, and acrylamide to water (the mass ratio of cetyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether, acrylamide, and water is 1:0.5:3:50), perform high-pressure homogenization, then add 2,2'-azobis(2-methylpropionamidine) dihydrochloride (the dosage of 2,2'-azobis(2-methylpropionamidine) dihydrochloride is 25% of the mass of acrylamide), and under nitrogen protection, heat and react (the temperature is 75 °C and the time is 2.5 h) to obtain the coating solution.

[0052] Example 2

[0053] (1) Special fertilizer for promoting rice-crab symbiosis, consisting of raw materials in the following parts by mass: 60 parts of calcite, 30 parts of plagioclase, 35 parts of animal manure (chicken manure), 20 parts of straw (corn straw), 10 parts of urea, 5 parts of potassium chloride, 4 parts of manganese sulfate, 2 parts of zinc sulfate, 3 parts of copper sulfate, 12 parts of humic acid, 3 parts of compound microorganisms, 0.6 part of nitrifying bacteria, 6 parts of soybean meal, 5 parts of carbon powder and 5 parts of montmorillonite.

[0054] Among them, the compound microorganisms consist of the following components in parts by mass: 10 parts of iron bacteria, 5 parts of Rhodococcus coprophilus, 6 parts of Rhodopseudomonas palustris, 3 parts of Azotobacter chroococcum, 7 parts of Bacillus licheniformis, 5 parts of lactic acid bacteria and 3 parts of Bacillus subtilis.

[0055] The nitrifying bacteria are composed of nitrite bacteria and nitrate bacteria with a mass ratio of 1:1.

[0056] (2) Dry the animal manure and straw, then crush them to 100 meshes, and then mix them evenly with the compound microorganisms, adjust the moisture content to 50%, stack them into a fermentation pile with a length, width and height of 1 m for fermentation (the fermentation temperature is 45 °C and the time is 30 days), turn the pile once every 5 days during fermentation, and obtain fermented fertilizer after fermentation.

[0057] (3) Crush calcite, plagioclase, urea, potassium chloride, manganese sulfate, zinc sulfate, copper sulfate, nitrifying bacteria and soybean meal to 100 meshes, mix them evenly, spray a 5 wt.% starch aqueous solution, and granulate at low temperature (40 °C) to obtain fertilizer particles with a particle size of 4 mm.

[0058] (4) Add the fertilizer particles into a granulator, and while spraying a 6 wt.% sodium lignosulfonate aqueous solution, add a mixture of humic acid, carbon powder, montmorillonite and fermented fertilizer, so that the mixture wraps around the surface of the fertilizer particles to obtain compound fertilizer particles.

[0059] The preparation method of the mixture of humic acid, carbon powder, montmorillonite and fermented fertilizer is: crush humic acid, carbon powder and montmorillonite (particle size is 50 meshes) and mix them evenly with the fermented fertilizer to obtain the mixture.

[0060] (5) Spray a coating solution on the surface of the compound fertilizer particles (the mass / volume ratio of the compound fertilizer particles to the coating solution is 10 g:1.5 mL), and dry at low temperature (35 °C) to obtain the special fertilizer for promoting rice-crab symbiosis.

[0061] Among them, the preparation method of the coating solution is:

[0062] Cetyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether and acrylamide were added to water (the mass ratio of cetyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether, acrylamide and water was 1:0.5:3:50). After high-pressure homogenization, azodiisobutyramidine hydrochloride was added (the dosage of azodiisobutyramidine hydrochloride was 25% of the mass of acrylamide). Under nitrogen protection, heating reaction was carried out (the temperature was 70 °C and the time was 2 h) to obtain the coating solution.

[0063] Example 3

[0064] (1) The special fertilizer for promoting rice-crab symbiosis is composed of the following raw materials in parts by mass: 80 parts of calcite, 20 parts of plagioclase, 30 parts of animal manure (chicken manure), 25 parts of straw (corn straw), 12 parts of urea, 6 parts of potassium chloride, 3 parts of manganese sulfate, 3 parts of zinc sulfate, 2 parts of copper sulfate, 15 parts of humic acid, 2 parts of compound microorganisms, 0.5 part of nitrifying bacteria, 5 parts of soybean meal, 5.5 parts of carbon powder and 8 parts of montmorillonite.

[0065] Among them, the compound microorganisms are composed of the following components in parts by mass: 15 parts of iron bacteria, 8 parts of Rhodococcus coprophilus, 4 parts of Rhodopseudomonas palustris, 5 parts of Azotobacter chroococcum, 4 parts of Bacillus licheniformis, 6 parts of lactic acid bacteria and 4 parts of Bacillus subtilis.

[0066] The nitrifying bacteria are composed of nitrite bacteria and nitrate bacteria with a mass ratio of 1:1.

[0067] (2) The animal manure and straw were dried and then crushed to 50 mesh, and then mixed evenly with the compound microorganisms. The moisture content was adjusted to 55%, and a fermentation pile with a length, width and height of 1 m was piled up for fermentation (the fermentation temperature was 35 °C and the time was 25 days). The pile was turned over every 5 days during fermentation. After fermentation, the fermented fertilizer was obtained.

[0068] (3) The calcite, plagioclase, urea, potassium chloride, manganese sulfate, zinc sulfate, copper sulfate, nitrifying bacteria and soybean meal were crushed to 100 mesh. After mixing evenly, a 5 wt.% aqueous starch solution was sprayed, and granulation was carried out at low temperature (40 °C) to obtain fertilizer particles with a particle size of 4.5 mm.

[0069] (4) The fertilizer particles were added to a granulator, and while spraying a 6 wt.% aqueous sodium lignosulfonate solution, a mixture of humic acid, carbon powder, montmorillonite and fermented fertilizer was added, so that the mixture was wrapped on the surface of the fertilizer particles to obtain composite fertilizer particles.

[0070] The preparation method of the mixture of humic acid, carbon powder, montmorillonite and fermented fertilizer is: the humic acid, carbon powder and montmorillonite were crushed (the particle size was 80 mesh) and mixed evenly with the fermented fertilizer to obtain the mixture.

[0071] (5) Spray the coating solution on the surface of the compound fertilizer granules (the mass / volume ratio of the compound fertilizer granules to the coating solution is 10 g: 1.5 mL), and obtain the special fertilizer for promoting the symbiosis of rice and crabs after drying at low temperature (35 °C).

[0072] Among them, the preparation method of the coating solution is as follows:

[0073] Add cetyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether and acrylamide to water (the mass ratio of cetyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether, acrylamide to water is 1: 0.5: 3: 50), after high-pressure homogenization, add azodiisobutyramidine hydrochloride (the dosage of azodiisobutyramidine hydrochloride is 25% of the mass of acrylamide), under nitrogen protection, heat and react (temperature is 75 °C, time is 3 h) to obtain the coating solution.

[0074] Comparative Example 1

[0075] Same as Example 1, the difference is only that the special fertilizer for promoting the symbiosis of rice and crabs does not contain nitrifying bacteria.

[0076] Comparative Example 2

[0077] Same as Example 1, the difference is only that the iron bacteria, Rhodococcus coprophilus and Rhodopseudomonas palustris in the complex microorganism are replaced with cyanobacteria of equal mass.

[0078] Comparative Example 3

[0079] Same as Example 1, the difference is only that the special fertilizer for promoting the symbiosis of rice and crabs does not contain soybean meal.

[0080] Comparative Example 4

[0081] Same as Example 1, the difference is only that the nitrifying bacteria in step (3) are added to step (2) and fermented together with animal manure, straw and complex microorganisms.

[0082] Comparative Example 5

[0083] Same as Example 1, the difference is only that the special fertilizer for promoting the symbiosis of rice and crabs does not contain carbon powder and montmorillonite.

[0084] Comparative Example 6

[0085] Same as Example 1, the difference is only that the coating solution does not contain cetyltrimethylammonium chloride and fatty alcohol polyoxyethylene ether.

[0086] Effect Example 1

[0087] A method for promoting the symbiosis of rice and crabs:

[0088] (1) Cultivation paddy field: Divide the paddy field into several non-connected small areas, each small area is 300 m 2;

[0089] A ditch with a depth of 50 cm and a width of 150 cm is set along the inner wall of the paddy field ridge. Then, a plurality of flow-through ditches with a depth of 70 cm and a width of 15 cm are evenly dug in the paddy field. The plurality of flow-through ditches form a grid pattern, and the area of the flow-through ditches accounts for 15% of the paddy field area. A water inlet is opened on the ditch, and a diversion pipe for water to flow out of the paddy field is provided between adjacent flow-through ditches. A separation net for preventing crabs from escaping is provided on the diversion pipe, and a separation fence for preventing crabs from escaping is provided on the ditch.

[0090] Before transplanting rice seedlings, quicklime is spread on the surface of the paddy field at a dosage of 40 kg / mu. After 15 days of spreading quicklime, 500 kg of the special fertilizers prepared in the examples and comparative examples is applied to the paddy field (repeated 3 times, that is, each fertilizer is treated in 3 plots), and the soil is plowed (the plowing depth is 10 cm) and harrowed flat.

[0091] (2) Rice planting: Rice (Nanjing 5718) seedlings are transplanted in the paddy field, and the transplanting density is 15,000 holes / mu, with 2 - 3 plants per hole.

[0092] (3) Releasing juvenile crabs: Crab seedlings (Eriocheir sinensis, with a specification of 200 per kilogram) are released one week after rice planting, and the stocking density is 2 kg / mu. The water depth is controlled at about 10 cm, and as the rice and juvenile crabs grow, the water depth increases to 25 - 30 cm.

[0093] (4) Conduct regular feeding and field management, during which no additional fertilization, water change, or oxygenation is carried out.

[0094] (5) Catch the river crabs before the rice is mature, and then harvest the rice. Calculate the per-mu yields of the rice and river crabs, and the results are shown in Table 1.

[0095] Table 1 Per-mu yields of rice and river crabs

[0096] Grouping Yield per mu of rice (kg) Yield per mu of river crabs (kg) Example 1 801.5 32.3 Example 2 795.8 31.6 Example 3 798.4 31.8 Comparative Example 1 752.1 22.1 Comparative Example 2 771.2 27.4 Comparative Example 3 770.9 26.1 Comparative Example 4 782.7 29.6 Comparative Example 5 783.1 29.9 Comparative Example 6 761.4 24.5

[0097] As can be seen from Table 1, the special fertilizers prepared in the examples of the present invention can obtain higher yields of rice and crabs.

[0098] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A special fertilizer for promoting rice-crab symbiosis, characterized in that: The invention comprises the following raw materials in parts by weight: 60-80 parts of calcite, 20-30 parts of plagioclase, 30-40 parts of animal manure, 20-30 parts of straw, 10-12 parts of urea, 5-6 parts of potassium chloride, 3-5 parts of manganese sulfate, 2-3 parts of zinc sulfate, 2-3 parts of copper sulfate, 12-15 parts of humic acid, 2-3 parts of composite microorganisms, 0.5-0.8 parts of nitrifying bacteria, 5-6 parts of soybean meal, 5-6 parts of carbon powder and 5-8 parts of montmorillonite; The composite microorganism comprises the following components in parts by weight: 10-15 parts of iron bacteria, 5-8 parts of coprophilic rhodococcus, 4-6 parts of Rhodopseudomonas palustris, 3-5 parts of round brown nitrogen-fixing bacteria, 4-7 parts of Bacillus licheniformis, 4-6 parts of lactic acid bacteria and 2-4 parts of Bacillus subtilis; The nitrifying bacteria are composed of nitrite bacteria and nitrate bacteria in a mass ratio of 1:1; The method for preparing the special fertilizer for promoting rice-crab symbiosis comprises the following steps: Step (1) drying and crushing animal excrement and straw, then mixing them evenly with composite microorganisms, piling and fermenting them to obtain fermented fertilizer; Step (2) mixing calcite, plagioclase, urea, potassium chloride, manganese sulfate, zinc sulfate, copper sulfate, nitrifying bacteria and soybean meal uniformly, spraying starch solution, and granulating at low temperature to obtain fertilizer granules; Step (3) crushing humic acid, carbon powder and montmorillonite and mixing them evenly with the fermented fertilizer, and then coating them on the surface of fertilizer particles to obtain composite fertilizer particles; Step (4) sprays the coating solution on the surface of the composite fertilizer particles, and obtains the special fertilizer for promoting rice-crab symbiosis after low-temperature drying.

2. The special fertilizer for promoting rice-crab symbiosis according to claim 1, characterized in that: In step (1), the crushing is to crush to a particle size of 50-100 mesh; the temperature of the pile fermentation is 35-45° C., the time is 25-30 days, and the moisture content is 50-55%; the pile is turned once every 5 days during the pile fermentation.

3. The special fertilizer for promoting rice-crab symbiosis according to claim 1, characterized in that: In step (2), the concentration of the starch solution is 5 wt.%; the temperature of the low-temperature granulation is 30-40° C.; and the particle size of the fertilizer particles is 4-5 mm.

4. The special fertilizer for promoting rice-crab symbiosis according to claim 1, characterized in that: In step (3), the pulverization is pulverization to a particle size of 50 to 100 meshes; and the binder used in the preparation of the composite fertilizer particles is sodium lignin sulfonate.

5. The special fertilizer for promoting rice-crab symbiosis according to claim 1, characterized in that: In step (4), the method for preparing the coating solution comprises the following steps: Hexadecyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether and acrylamide are added into water, and after high pressure homogenization, azobisisobutylamidine hydrochloride is added thereto, and the mixture is heated for reaction under nitrogen protection to obtain the coating solution.

6. The special fertilizer for promoting rice-crab symbiosis according to claim 5, characterized in that: The mass ratio of hexadecyltrimethylammonium chloride, fatty alcohol polyoxyethylene ether and acrylamide is 1:0.5:3; the amount of azobisisobutylamidine hydrochloride is 25% of the mass of acrylamide; The temperature of the heating reaction is 70-75° C. and the time is 2-3 hours.

7. Use of the special fertilizer according to any one of claims 1 to 6 in rice-crab co-culture.