Fish-meat coexistence substrate, laying structure and system

Abstract

The application discloses a fish-vegetable symbiosis substrate, a laying structure and a system, and belongs to the technical field of fish-vegetable symbiosis cultivation.The fish-vegetable symbiosis special substrate comprises, by volume ratio, 55% to 65% of coconut bran, 20% to 30% of coal cinder, 10% to 12% of broken brick, 2% to 3% of wood ash, 0 to 2% of vermiculite and 0 to 1% of perlite, and is divided into three types of general type, leaf vegetable special type and fruit and vegetable special type.The layered laying structure is composed of a bottom layer of broken brick plus 40-mesh water-permeable net, a middle layer of mixed substrate and a surface layer of fine coconut bran plus thick coconut shell.The pretreatment method is used to respectively perform soaking, acid adjusting, cleaning and disinfection and other treatments on the coconut bran, the coal cinder, the broken brick and the wood ash.A 7-day rapid starting method is used to complete system starting and fish releasing within 7 days through the steps of laying, nitrobacteria adding, small amount of bait adding and water quality detection.The application realizes the rapid starting, water quality stabilization and long-term easy maintenance of the fish-vegetable symbiosis system through precise volume ratio, three-layered structure, standardized pretreatment and 7-day bacteria cultivation process, and is suitable for the cultivation of leaf vegetables, fruit and vegetables and general crops.

Description

Technical Field

[0001] This invention belongs to the field of facility agriculture and ecological farming technology, and in particular relates to an aquaponics substrate, laying structure and system. Background Technology

[0002] Aquaponics is a novel integrated farming system that combines aquaculture and hydroponics. Ammonia nitrogen produced by fish metabolism is converted into nitrates by nitrifying bacteria, providing nutrients for plant growth. Simultaneously, plant roots absorb and purify the aquaculture water, creating an ecological cycle of "raising fish without changing the water and growing vegetables without applying fertilizer." This system possesses dual value in agricultural production and environmental protection, and has gained widespread attention in recent years in the fields of facility agriculture, urban agriculture, and recirculating aquaculture.

[0003] In aquaponics systems, the cultivation substrate is not only a carrier for plant roots to anchor, but also the main site for nitrifying bacteria to attach and reproduce. Its physicochemical properties directly affect the water purification efficiency and crop growth. Currently, commonly used substrates in existing technologies mainly include single or simple mixtures of materials such as expanded clay, rock wool, perlite, vermiculite, and coconut coir. Among them, expanded clay, although having good air permeability and chemical stability, is expensive and heavy, increasing the system's load-bearing capacity and transportation burden; rock wool has excellent water and fertilizer retention properties, but it is not biodegradable, posing a potential environmental pollution hazard after disposal, and its fiber dust can easily clog waterways; perlite and vermiculite, when used alone, have insufficient water retention capacity and need to be used in combination with organic substrates; coconut coir, as a natural organic substrate, has good water retention and air permeability, but its electrical conductivity (EC) is high when untreated, and its initial pH is acidic, which can easily lead to fluctuations in the chemical properties of the water when used directly in aquaponics systems, affecting fish survival.

[0004] Furthermore, existing technologies have reported the use of solid wastes such as coal ash and broken bricks as cultivation substrates or water filtration materials. Coal ash possesses a certain porous structure and mineral nutrients, while broken bricks provide support and permeability. However, if these materials are used directly in aquaponics systems without strict pretreatment, several technical drawbacks exist: First, coal ash is highly alkaline and may contain harmful impurities such as heavy metals, leading to a sharp increase in water pH and potential pollution risks if directly introduced into the water. Second, dust and fine particles on the surface of broken bricks easily accumulate in pipes or aquaculture areas, causing system blockages. Third, the direct introduction of alkaline materials such as wood ash into the water will cause drastic pH fluctuations, threatening fish health. Existing technologies have failed to address the issue of the safe and stable utilization of these wastes in the unique aquatic environment of aquaponics, simultaneously meeting the needs of both fish and plants.

[0005] In terms of system structure, existing aquaponics planting troughs mostly adopt a single substrate laid flat or a simple upper and lower layer filling method, lacking an effective physical isolation design. The large-diameter support material at the bottom layer is prone to problems such as fine particle migration and dust settling between it and the upper cultivation substrate. After long-term use, this leads to blockage of the bottom layer pores, increased water circulation resistance, and insufficient root oxygen supply, which in turn affects nitrification efficiency and crop yield.

[0006] In terms of system startup, aquaponics systems rely on nitrifying bacteria to gradually convert toxic ammonia nitrogen into nitrite and nitrate. Under natural conditions, the establishment of nitrifying bacteria typically takes 4 to 8 weeks or even longer. During this period, if fish are directly introduced and fed normally, the concentrations of ammonia nitrogen and nitrite accumulate rapidly, easily causing fish poisoning and death. Using external biological filters or frequent large-volume water changes to shorten the startup period increases equipment investment, energy consumption, and water resource consumption, and is also complex to operate, hindering the widespread application of small-scale or home-based aquaponics systems. Therefore, developing a startup method that requires no additional biological filters, relies solely on the nitrifying bacteria within the substrate for rapid establishment, and can achieve water quality standards within 7 days has become a pressing technical problem to be solved in this field.

[0007] In summary, existing aquaponics technologies still have significant shortcomings in areas such as low-cost and environmentally friendly formulations of cultivation substrates, safe pretreatment and utilization of solid waste, anti-clogging layered laying structure design, and rapid system start-up and water quality control. There is an urgent need for a comprehensive technical solution that can take into account fish health, crop growth, system stability, and economic benefits. Summary of the Invention

[0008] In a first aspect, the present invention provides a substrate specifically for aquaponics, comprising the following components by volume ratio:

[0009] 55–65% coconut coir, 20–30% coal ash, 10–12% crushed bricks, 2–3% wood ash, 0–2% vermiculite, and 0–1% perlite.

[0010] In one embodiment of the present invention, the matrix is ​​one of the following three types:

[0011] (1) General type: 60% coconut coir, 25% coal ash, 10% crushed bricks, 3% wood ash, 2% vermiculite;

[0012] (2) Leafy vegetable special type: 65% coconut coir, 20% coal ash, 10% crushed bricks, 3% wood ash, 2% vermiculite;

[0013] (3) Fruit and vegetable special type: 55% coconut coir, 30% coal ash, 12% crushed brick, 2% wood ash, 1% perlite.

[0014] One embodiment of the present invention further includes the following preprocessing steps:

[0015] Soak coconut coir for 24 hours, changing the water 2–3 times, controlling EC < 0.4, and adjust the pH to 6.0–6.5 with quicklime;

[0016] Crush the coal slag to 3–6 mm, soak it in 5% acetic acid for 12 hours, rinse it until neutral, and sterilize it at high temperature.

[0017] Clean the broken bricks to remove dust, soak them for 48 hours, and then expose them to the sun for 3 days.

[0018] After sieving, only the leachate is used, and the amount used does not exceed 3% of the total volume.

[0019] In one embodiment of the present invention, the coal slag is non-industrial coal slag, and the wood ash is not directly added to water bodies.

[0020] Secondly, the present invention provides a layered laying structure for an aquaponics system, comprising:

[0021] S1 bottom layer: crushed bricks with a particle size of 10–20mm and a thickness of 8–10cm, with a 40-mesh permeable mesh laid on top of the bottom layer;

[0022] S2 middle layer: a mixed matrix as described above, with a thickness of 18–22 cm;

[0023] S3 Surface Layer: 2cm of fine coconut coir + 1cm of coarse coconut husk.

[0024] In one embodiment of the present invention, a permeable mesh dust-proof layer is provided between the bottom layer and the middle layer to prevent dust from settling and clogging the water body.

[0025] Thirdly, the present invention provides a 7-day rapid start-up method for an aquaponics system, employing the substrate and the layered laying structure described above, and proceeding according to the following steps:

[0026] Day 1: Lay the substrate and permeable net, pour in clean water, add nitrifying bacteria, do not put in fish or feed;

[0027] Days 2-3: Circulate water, monitor pH, do not feed;

[0028] Day 4: Feed 1 / 5 of the normal amount of food;

[0029] Day 5: Test ammonia nitrogen and nitrite. If they exceed the standard, change 1 / 4 of the water.

[0030] Day 6: Feed small amounts of food to stabilize pH;

[0031] Day 7: Release the fish after the water quality meets the standards.

[0032] In one embodiment of the present invention, the water quality standards are: ammonia nitrogen < 0.2 mg / L, nitrite < 0.1 mg / L, and the water pH is maintained at 6.6–6.8.

[0033] Fourthly, the present invention provides the application of the aquaponics-specific substrate or the layered laying structure described above in an aquaponics system for the cultivation of leafy vegetables, fruit vegetables, or general-purpose crops.

[0034] Fifthly, the present invention provides an aquaponics system, comprising:

[0035] Planting trough box body;

[0036] The water layer located at the bottom of the tank;

[0037] The layered laying structure described above is installed above the water layer;

[0038] Cultivated crops placed on top of the layered paving structure;

[0039] A return water pipe or water distribution system connected to the planting trough;

[0040] Nitrifying bacteria start-up and water quality control system operating according to the method described. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the system structure of this application. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0043] Example 1

[0044] Taking an aquaponics system established by an ecological farm as an example, a general-purpose substrate ratio was used for laying the planting troughs and starting the system. The substrate was prepared by volume ratio: 60% coconut coir, 25% cinder, 10% crushed brick, 3% wood ash, and 2% vermiculite. Before preparation, all raw materials were treated according to pretreatment requirements: coconut coir was soaked for 24 hours with three water changes during this period, and the EC value was measured to be 0.38 using a conductivity meter, which meets the requirement of less than 0.4. Then, quicklime was added to adjust the pH to 6.2; cinder was crushed to a particle size of about 4mm, soaked in 5% acetic acid for 12 hours, rinsed repeatedly until neutral, and then sterilized by high-temperature steam for 30 minutes; crushed brick was repeatedly rinsed with clean water to remove surface dust and then soaked for 48 hours, then taken out and spread out to dry in the sun for 3 days; wood ash was sieved through an 80-mesh sieve and the leachate was reserved for later use. Solid wood ash was not directly mixed into the substrate.

[0045] The planting trough is a PVC box measuring 2m long, 0.8m wide, and 0.5m high, with a pre-installed return water pipe interface at the bottom. During installation, first lay a layer of broken bricks, approximately 9cm thick, at the bottom of the box. The brick particle size should be controlled between 10 and 20mm. After leveling the bricks, cover them with a 40-mesh permeable mesh, folding the edges upwards about 5cm and securing it to the inner wall of the box to prevent dust from the substrate from settling and clogging the water channels. Fill the permeable mesh with a well-mixed intermediate substrate, approximately 20cm thick, gently compacting it without over-tamping to maintain a loose texture. First, lay a 2cm thick layer of fine coconut coir on the surface, then sprinkle a 1cm thick layer of coarse coconut husks, approximately 1 to 2cm in diameter, on top of the fine coconut coir.

[0046] The system was started using a 7-day rapid bacterial culture process. On day 1, clean water was slowly poured into the planting tank, the water level just submerged the bottom broken bricks and the water surface reaching below the permeable net. Then, commercially available compound nitrifying bacteria powder was added at a dosage of 20g per cubic meter of water. No fish were introduced or any feed was given at this time. On days 2 and 3, the water circulation system was kept running 24 hours a day, and the pH value was measured twice daily, morning and evening. The pH remained stable between 6.5 and 6.7, and no adjustments were made. On day 4, small amounts of feed were introduced, calculated at one-fifth of the normal stocking amount, approximately 2g of fish food per day. On day 5, a rapid testing kit showed ammonia nitrogen of 0.25mg / L and nitrite of 0.12mg / L, slightly higher than the fish stocking standard. One-quarter of the water was then replaced, and an equal amount of clean water was added. On day 6, small amounts of feed continued, and the pH was slightly adjusted to 6.7 using quicklime water. On the 7th day, the water quality was tested again. Ammonia nitrogen had decreased to 0.15 mg / L, nitrite to 0.08 mg / L, and the pH value stabilized at 6.7. Meeting the fish stocking criteria, 20 tilapia fry were released, and pre-grown lettuce seedlings were transplanted simultaneously. After four months of system operation, the soil was loosened, and holes were evenly punched in the substrate surface with a fine stick to increase aeration. After 12 months of operation, one-third of the top and middle layers of substrate were replaced. No root rot occurred throughout the entire operation period, the fish survival rate was over 95%, and the lettuce growth cycle was shortened by approximately 4 days compared to traditional hydroponics.

[0047] Example 2

[0048] To address the cultivation needs of leafy vegetables, a small-scale aquaponics system was built on a home balcony, using a substrate specifically formulated for leafy vegetables. The planting box measures 60cm × 40cm × 35cm, and the substrate is prepared by volume as follows: 65% coconut coir, 20% cinder, 10% crushed bricks, 3% wood ash, and 2% vermiculite. Compared to general-purpose systems, the increased proportion of coconut coir reduces moisture evaporation and maintains substrate moisture.

[0049] The pretreatment process was basically the same as in Example 1, but the EC value of the coconut coir after soaking was controlled below 0.35, and the amount of wood ash leachate was strictly controlled within 3% of the total volume of the substrate, which did not exceed the limit. The layered laying structure also adopted the method of bottom broken bricks plus permeable net. Due to the small height of the planting box, the thickness of the bottom broken bricks was adjusted to 8cm, the thickness of the middle substrate was controlled at 18cm, and the surface layer was still 2cm of fine coconut coir plus 1cm of coarse coconut husk.

[0050] During the 7-day rapid bacterial culture process, on day 5, ammonia nitrogen was measured at 0.18 mg / L and nitrite at 0.09 mg / L, close to the standard requirements. No water change was performed; only the water circulation frequency was increased. On day 7, ammonia nitrogen was measured at 0.12 mg / L and nitrite at 0.05 mg / L. After the water quality met the standards, six goldfish were introduced, and three each of bok choy and spinach seedlings were transplanted. During operation, it was found that leafy vegetables have higher water requirements, and the surface of the coarse coconut husk evaporated quickly in the high summer temperatures. In week 8, an additional layer of damp non-woven fabric was placed on top of the coarse coconut husk to reduce evaporation, with good results. After three months of operation, the average weight of each bok choy seedling was approximately 150g, and the spinach leaves were thick, dark green, with no yellowing or root rot. Throughout the system's operation, ammonia nitrogen remained below 0.2 mg / L, nitrite did not exceed 0.1 mg / L, and the pH value remained stable between 6.6 and 6.8.

[0051] Example 3

[0052] A specialized aquaponics system for fruits and vegetables was established within a large-scale greenhouse. The planting troughs, totaling 20 meters in length, are 0.6 meters wide and 0.5 meters high in each section, connected in series and sharing a common circulating water system. The substrate was prepared according to a special formula for fruits and vegetables: 55% coconut coir, 30% cinder, 12% crushed bricks, 2% wood ash, and 1% perlite. The proportion of cinder was increased by 5% compared to the general formula to enhance aeration, while the addition of perlite further improved drainage, meeting the high-oxygen environment required by the roots of fruits and vegetables such as tomatoes and cucumbers.

[0053] The pretreatment of coal ash is particularly stringent because fruit vegetables are sensitive to heavy metals. After neutralization by soaking in acetic acid, an additional EDTA solution soaking step is added to ensure that heavy metal residues meet standards. Larger-sized crushed bricks (15-20mm) are selected to increase the porosity of the bottom layer. When laying in layers, the thickness of the bottom layer of crushed bricks is increased to 10cm, the thickness of the middle layer substrate is increased to 22cm to provide more space for the fruit and vegetable roots, and the surface layer remains 2cm of fine coconut coir plus 1cm of coarse coconut husk.

[0054] After a 7-day rapid bacterial culture process, fish were introduced once the water quality met standards. Tilapia and koi were used for mixed breeding. Five seedlings each of tomato, cucumber, and pepper were selected, ensuring the roots were completely buried in the middle layer of substrate during transplanting to avoid exposure. Since the flowering and fruiting stages of the fruits and vegetables require a high amount of iron, chelated iron was supplemented on the 25th day of system operation at a concentration of 1.0 mg per liter of water, and thereafter every 25 days. During operation, vigorous growth of tomato plants was observed, with fruiting beginning on the 45th day and the first batch of fruits ripening on the 70th day. The yield per tomato plant was approximately 2.5 kg, an increase of about 15% compared to traditional substrate cultivation in the same greenhouse. Cucumber vines grew rapidly, requiring additional support. Peppers had a high fruit density and bright fruit color. No iron deficiency yellowing or root rot was observed throughout the entire fruit and vegetable growth cycle. After 8 months of continuous system operation, ammonia nitrogen and nitrite levels remained within controlled ranges. Only in the 6th month of operation was the top third of the fine coconut coir replaced to maintain substrate activity.

[0055] Example 4

[0056] To verify the effectiveness of the proposed 7-day rapid bacterial cultivation process, a comparative experiment was conducted. The experiment was carried out under the same environmental conditions, using two identical planting troughs and the same proportion of general-purpose substrate, both laid out in a three-layer structure. The experimental group used the proposed 7-day rapid bacterial cultivation process, while the control group used the traditional natural bacterial cultivation method, which involved directly adding water after laying the substrate, introducing a small number of fish, and relying on fish excrement to naturally cultivate nitrifying bacteria, without adding additional nitrifying bacteria or following a specific number of days.

[0057] Water quality indicators for both groups were monitored daily after the experiment began. In the experimental group, ammonia nitrogen concentration began to decrease on day 3, and a visible nitrifying bacteria biofilm appeared on the surface of the broken bricks on day 5. By day 7, ammonia nitrogen had dropped to 0.15 mg / L and nitrite to 0.08 mg / L, meeting the fish stocking standard. In the control group, ammonia nitrogen rose to 0.45 mg / L on day 5 and to 0.62 mg / L on day 7. Nitrite reached a significant peak at 0.35 mg / L on day 9. In the control group, ammonia nitrogen did not drop below 0.2 mg / L until day 18, and nitrite did not drop below 0.1 mg / L until day 22. The entire start-up process took approximately 21 to 25 days before safe fish stocking. Regarding the formation time of the nitrifying bacteria biofilm, a noticeable brown biofilm was observed in the experimental group on days 5 to 6, while it appeared in the control group on days 12 to 15. Experimental results show that the 7-day rapid bacterial culture process proposed in this invention can shorten the system start-up time by 14 to 18 days, significantly reduce the risk of toxicity to fish caused by high concentrations of ammonia nitrogen and nitrite, and at the same time, the broken brick layer provides sufficient attachment area for nitrifying bacteria, accelerating the establishment of biofilm.

[0058] Example 5

[0059] To verify the advantages of the three-layer structure of this invention, a comparative experiment was also conducted. The experimental group used a three-layer structure consisting of a bottom layer of broken bricks and a 40-mesh permeable mesh, a middle layer of mixed substrate, and a top layer of fine coconut coir and coarse coconut husk. The control group used a single mixed substrate directly to fill the planting trough, without the bottom layer of broken bricks and permeable mesh, and without any surface covering structure; the total substrate thickness was the same as the experimental group. Both groups used a general-purpose substrate ratio and the same 7-day rapid incubation process, and the cultivated crop was Chinese cabbage.

[0060] On day 15 of the experiment, the experimental group of bok choy had clean, white roots with abundant fibrous roots, and the surface of the substrate remained moist, with clear, sand-free water flowing from the drainage outlet. In the control group, the roots began to show browning, some root tips showed signs of rotting, the substrate surface became compacted, water seeped in slowly after watering, and initially, a large amount of turbid dust was discharged from the drainage outlet. On day 30, the substrate was excavated for observation. The experimental group's broken brick layer was covered with a uniform brown biofilm, the middle substrate was loose and water-free, and the surface layer of coarse coconut husks and fine coconut coir maintained a good structure. The control group had significant water accumulation at the bottom, the substrate was muddy, accompanied by a slight odor, and the browning of the roots had expanded. The experiment also found that due to the isolation effect of the permeable net, the broken brick layer in the experimental group was almost unaffected by dust, while the bottom blockage in the control group became increasingly severe with prolonged operation. A comprehensive comparison shows that the three-layer structure of this invention effectively solves the problem of water accumulation and root rot, maintains the long-term air permeability and water permeability of the substrate, prevents dust from settling and clogging, provides an additional attachment surface for nitrifying bacteria, and reduces water evaporation and surface hardening. The synergistic effect of the entire structure is significantly better than that of a single substrate filling method.

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A special substrate for aquaponics, characterized in that, The following components are included by volume ratio: 55–65% coconut coir, 20–30% coal ash, 10–12% crushed bricks, 2–3% wood ash, 0–2% vermiculite, and 0–1% perlite.

2. The aquaponics substrate according to claim 1, characterized in that, The matrix is ​​one of the following three types: (1) General type: 60% coconut coir, 25% coal ash, 10% crushed bricks, 3% wood ash, 2% vermiculite; (2) Leafy vegetable type: 65% coconut coir, 20% coal ash, 10% crushed bricks, 3% wood ash, 2% vermiculite; (3) Fruit and vegetable special type: 55% coconut coir, 30% coal ash, 12% crushed brick, 2% wood ash, 1% perlite.

3. The aquaponics substrate according to claim 1 or 2, characterized in that, It also includes the following preprocessing steps: Soak coconut coir for 24 hours, changing the water 2–3 times, controlling EC < 0.4, and adjust the pH to 6.0–6.5 with quicklime; Crush the coal slag to 3–6 mm, soak it in 5% acetic acid for 12 hours, rinse it until neutral, and sterilize it at high temperature. Clean the broken bricks to remove dust, soak them for 48 hours, and then expose them to the sun for 3 days. After sieving, only the leachate is used, and the amount used does not exceed 3% of the total volume.

4. The aquaponics substrate according to claim 3, characterized in that, The coal slag is from non-industrial sources, and the wood ash is not directly added to water bodies.

5. A layered laying structure for an aquaponics system, characterized in that, include: S1 bottom layer: crushed bricks with a particle size of 10–20mm and a thickness of 8–10cm, with a 40-mesh permeable mesh laid on top of the bottom layer; S2 middle layer: the mixed matrix as described in claim 1 or 2, with a thickness of 18–22 cm; S3 Surface Layer: 2cm of fine coconut coir + 1cm of coarse coconut husk.

6. The layered laying structure according to claim 5, characterized in that, A permeable mesh dust-proof layer is provided between the bottom layer and the middle layer to prevent dust from settling and clogging the water body.

7. A 7-day rapid start-up method for an aquaponics system, characterized in that, The substrate as described in claim 1 or 2, the layered layup structure as described in claim 5 or 6, and the following steps are performed: Day 1: Lay the substrate and permeable net, pour in clean water, add nitrifying bacteria, do not put in fish or feed; Days 2-3: Circulate water, monitor pH, do not feed; Day 4: Feed 1 / 5 of the normal amount of food; Day 5: Test ammonia nitrogen and nitrite. If they exceed the standard, change 1 / 4 of the water. Day 6: Feed small amounts of food to stabilize pH; Day 7: Release the fish after the water quality meets the standards.

8. The 7-day rapid start-up method according to claim 7, characterized in that, The water quality standards are: ammonia nitrogen < 0.2 mg / L, nitrite < 0.1 mg / L, and water pH maintained at 6.6–6.

8.

9. The application of the aquaponics substrate according to claim 1 or 2 or the layered laying structure according to claim 5 or 6 in an aquaponics system, characterized in that, Used for the cultivation of leafy vegetables, fruit vegetables, or general-purpose crops.

10. An aquaponics system, characterized in that, include: Planting trough box body; The water layer located at the bottom of the tank; The layered laying structure as described in claim 5 or 6, disposed above the water layer; Cultivated crops placed on top of the layered paving structure; A return water pipe or water distribution system connected to the planting trough; A nitrifying bacteria start-up and water quality control system operating according to the method of claim 7 or 8.

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