Four-year cycle fish and plant wheel breeding green ecological breeding system

Abstract

The application discloses a four-year period fish and lotus root combined rotation green ecological breeding system, and relates to the technical field of ecological agricultural circulation breeding, which comprises successively connected fresh carp ecological purification breeding modules, grass carp and crucian carp high-yield antibiotic-free breeding modules and lotus root re-cultivation and waste resource utilization modules; the fresh carp ecological purification breeding module is a first year breeding unit, a freshwater pond after lotus root harvesting is adopted, lotus root residual roots, organic debris and natural plankton in the pond are reserved, and fresh carp fry is put into the pond; the grass carp and crucian carp high-yield antibiotic-free breeding module is a second year breeding unit and a third year breeding unit, and grass carp and crucian carp fry is put into the pond; the lotus root re-cultivation and waste resource utilization module is a fourth year breeding unit; the system realizes pond ecological self-purification, efficient organic matter conversion and full utilization of waste resources through the construction of a four-year closed loop system, and does not add antibiotics, chemical disinfectants, chemical fertilizers and pesticides in the whole process, and the comprehensive yield per mu is significantly improved compared with the traditional mode, and the system can be popularized on a large scale.

Description

Technical Field

[0001] This invention relates to the field of ecological agricultural circular farming technology, specifically to a four-year cycle fish and lotus root rotation green ecological farming system. Background Technology

[0002] Freshwater pond aquaculture has long relied on monoculture of lotus root, monoculture of fish, or simultaneous intercropping of fish and lotus root. This approach is characterized by a lack of technological sophistication, low resource utilization, significant non-point source pollution, and low overall economic benefits. Monoculture of lotus root year after year easily leads to thickened pond bottom silt, enrichment of organic matter, excessive nitrogen and phosphorus levels in the water, and frequent disease outbreaks. The indiscriminate disposal of inferior lotus roots and straw waste wastes resources and pollutes the environment. Monoculture of aquatic products heavily relies on formulated feeds, antibiotics, and chemical disinfectants, resulting in drug residues, heavy metal accumulation, blackened and foul-smelling bottom mud, declining aquatic product quality, high food safety risks, and continuously rising ecological costs. While simultaneous intercropping of fish and lotus root achieves spatial overlap, the shading effect of lotus leaves leads to insufficient dissolved oxygen in the water, restricts fish growth, results in low utilization of fish excrement, lacks a clear purification cycle, and lacks closed-loop waste utilization, making it difficult to achieve antibiotic-free practices and stable quality, thus limiting the overall improvement in economic benefits.

[0003] Current fish and lotus root farming generally lacks scientific long-term cycle design, and most of them are short-term symbiosis or simple polyculture. They cannot build a pond ecological self-purification and organic matter efficient conversion mechanism, and it is difficult to take into account ecological protection, green antibiotic-free production and efficient resource recycling. This leads to drug dependence, resource waste, pollution accumulation and low efficiency in the farming process, which restricts the high-quality and sustainable development of freshwater pond ecological farming industry. Summary of the Invention

[0004] The purpose of this invention is to provide a four-year cycle fish and lotus root rotation green ecological farming system to solve the problem that existing fish and lotus root farming models lack scientific long-term cycles.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A four-year cycle fish and lotus root rotation green ecological farming system includes a sequentially connected lotus and grass carp ecological purification farming module, a grass carp and crucian carp high-yield antibiotic-free farming module, and a lotus root replanting and waste resource utilization module, with a four-year cycle as a complete farming cycle.

[0007] The lotus-fresh grass carp ecological purification and aquaculture module is the first-year planting and breeding unit. It uses freshwater ponds after lotus root harvesting, retains lotus root residues, organic debris and natural plankton in the pond, and introduces lotus-fresh grass carp fry. No artificial feed is fed, and no antibiotics or chemical disinfectants are used throughout the process to achieve ecological purification of the pond.

[0008] The high-yield antibiotic-free grass carp and crucian carp farming module is a second-year and third-year farming unit. Grass carp and crucian carp fry are introduced. No antibiotics, chemical disinfectants and fertilizers are used throughout the process. Relying on natural bait in the pond and supplemented with a small amount of ecological feed, green and high-yield farming is achieved and fish excrement is accumulated as organic fertilizer.

[0009] The lotus root replanting and waste resource utilization module is the fourth-year planting and breeding unit. Aquaculture is stopped, and after the pond is dried, shallow-water lotus roots are planted using organic fertilizer from fish excrement in the pond. No chemical fertilizers or pesticides are used throughout the process. Lotus tips, lotus seeds and lotus roots are harvested simultaneously. Secondary lotus roots and lotus stalks are crushed and fermented into biological feed for the next cycle of fish farming, forming a closed-loop planting and breeding cycle.

[0010] Furthermore, in the first year, the size of fresh grass carp fry is 180–220g / fish, and the stocking density is 80–120 fish / mu; silver carp and bighead carp are selected and matched, with a size of 100–150g / fish and a density of 20–30 fish / mu.

[0011] Furthermore, in the second and third years, the stocking size of grass carp fry is 150–200g / fish, and the stocking size of crucian carp fry is 50–80g / fish; the stocking density of grass carp is 200–250 fish / mu, and the stocking density of crucian carp is 300–350 fish / mu.

[0012] Furthermore, during the second and third years of aquaculture, the proportion of supplemental ecological feed to the total feed intake of fish shall not exceed 15%, and the ecological feed shall be at least one of fermented wheat bran, soybean meal, and green grass.

[0013] Furthermore, in the fourth year, shallow-water high-yield varieties of lotus root are selected for planting. The seed lotus root specifications are 2-3 buds, with a single section weighing ≥150g. The planting density is 1200-1500 plants / mu, with a row spacing of 1.5-1.8m and a plant spacing of 0.4-0.5m.

[0014] Furthermore, the method for preparing the biological feed includes the following steps:

[0015] S1. Crush the lotus root and lotus stalks to 2-5cm;

[0016] S2. Take 83%–89% of the crushed material, 1%–2% of the probiotic starter, and 10%–15% of the wheat bran by weight, and mix them evenly.

[0017] S3. Adjust the moisture content of the mixture to 55%–60%;

[0018] S4. After sealing, anaerobic fermentation is carried out for 7–10 days to obtain biological feed.

[0019] Furthermore, the biological feed is circulated to supply the fresh grass carp ecological purification aquaculture module and the high-yield antibiotic-free aquaculture module for crucian carp.

[0020] Furthermore, the lotus-fish ecological purification aquaculture module, the grass carp high-yield antibiotic-free aquaculture module, and the lotus root replanting and waste resource utilization module share the same freshwater pond and are used in rotation on an annual basis.

[0021] Compared with existing technologies, the present invention provides a four-year cycle fish and lotus root rotation green ecological farming system. By constructing a four-year closed-loop cycle system, it realizes the ecological self-purification of the pond, the efficient conversion of organic matter, and the full utilization of waste resources. No antibiotics, chemical disinfectants, fertilizers and pesticides are added throughout the process. The aquatic products have no drug residues, the lotus roots are of excellent quality, and the lotus tips and lotus seeds generate additional income. The overall yield per mu is significantly improved compared with the traditional model. It has strong adaptability and can be promoted on a large scale. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0023] Figure 1 This is a schematic diagram of a four-year cycle fish and lotus root rotation system. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] As attached Figure 1 As shown, this invention provides a four-year cycle fish and lotus root rotation green ecological farming system. It utilizes a single freshwater pond, implementing ecological purification farming of lotus and grass carp, high-yield antibiotic-free farming of crucian carp, and lotus root replanting along with waste resource utilization in a four-year cycle, forming a closed-loop cycle. The pond area is suitable for 1–50 mu (approximately 0.8–0.7 hectares), the water depth can be controlled at 0.5–1.5 m, the silt thickness is 15–25 cm, the water source is sufficient, the water quality meets freshwater aquaculture standards, the pond banks are reinforced to prevent seepage, water inlet and outlet are convenient, and basic aeration equipment is provided, eliminating the need for complex specialized facilities.

[0026] Example 1: Standard-scale four-year cycle fish and lotus root rotation farming (10 mu conventional pond)

[0027] This embodiment uses a conventional freshwater pond with an area of ​​10 mu (approximately 667 square meters), an average water depth of 0.9–1.0 m, and a silt thickness of 18–20 cm. The water source is surface water with a transparency of 35–45 cm. The pond can be naturally replenished and drained throughout the year. The pond embankment is 1.8 m high with a slope ratio of 1:2.5. The bottom of the pond is flat with a slope of less than 2%, making it suitable for promotion and application in most rural areas. It takes into account ecological purification, high-yield aquaculture, high-quality lotus roots, and resource recycling.

[0028] Year 1: The ecological purification ponds for lotus root and grass carp farming are idle ponds after lotus root harvesting. No pond cleaning, disinfection, or fertilization is required. Only large debris such as branches, plastic bags, and weed roots are manually removed. The ponds naturally retain lotus root remnants, nodes, organic debris, phytoplankton, zooplankton, and benthic organisms such as midge larvae and snails, forming a natural composite food layer. Select healthy, disease-free, and agile grass carp fry (180-200g / fish, 20-24cm in length, with intact scales) at a stocking density of 80-100 fish / acre. Supplement with 20-25 silver carp (100-120g / fish, with a symmetrical body shape and silvery-white color) per acre to help regulate water quality and suppress blue-green algae blooms. The breeding cycle is 12 months. No artificial feed, antibiotics, chemical disinfectants, or water conditioners are used throughout the entire process. The water is not changed or fertilized. The grass carp rely on the pond to feed on the remaining lotus roots, organic debris, algae, plankton, and benthic organisms. The pond is inspected twice a day to observe the water color, fish activity, and dissolved oxygen changes. In hot and low-pressure weather (water temperature ≥32℃, air pressure <1000hPa), the aerator is turned on for 1.5–2 hours each at noon and at night to maintain dissolved oxygen ≥4mg / L. In November, the ponds were drained and harvested. The average weight of the fresh grass carp was 1.5–1.6 kg, with a yield of about 140–160 kg per mu. The fish were uniform in size, with firm flesh and no muddy smell. Tests showed that the thickness of the silt at the bottom of the pond was reduced by about 2–3 cm, the ammonia nitrogen and nitrite content in the water was reduced by about 30%–35%, the transparency was increased to more than 50 cm, the water quality was clear, the bottom was loose, and there was no blackening or foul smell. The ecological purification and restoration of the pond was completed.

[0029] Year Two: High-Yield, Antibiotic-Free Aquaculture of Grass Carp and Crucian Carp. The ponds purified in the first year are used, requiring no pond cleaning or disinfection. Water is introduced to a depth of 1.1–1.2m to maintain the original aquatic microbial community and natural food resources. Grass carp fry (150–180g / fish, 18–22cm in length, healthy, disease-free, with glossy scales, and fast growth rate) are selected and stocked at a density of 200–220 fish / acre. This is supplemented with crucian carp fry (50–60g / fish, laterally compressed body, highly adaptable, tolerant of low oxygen levels, and with tender flesh) at a stocking density of 280–320 fish / acre. A small number of bream (120–150g / fish) and silver carp (15–20 fish / acre) are also added to optimize the population structure. The breeding cycle is 12 months, during which no antibiotics, chemical disinfectants, or fertilizers are used, and the water is not changed. The main food sources are natural aquatic plants, organic debris, plankton, microbial film, and benthic organisms in the pond. Only a small amount of ecological feed is supplemented during the summer and autumn when food is scarce. Fresh ryegrass, Sudan grass, and fermented bran are selected and fed once a day. The amount of feed should be such that it can be consumed within 2 hours, and the supplementary amount should not exceed 10% of the total food intake of the fish to avoid overfeeding and water pollution. The pond is inspected 3 times a day to monitor water quality, dissolved oxygen, and water temperature. During the high-temperature season (June-September), the aerator is turned on for 3-4 hours a day. After heavy rain, surface rainwater is promptly drained to prevent water stratification. In November, the fish were caught in batches by net. The grass carp had an average weight of 0.9–1.0 kg per fish and a yield of about 200–220 kg per mu. The crucian carp had an average weight of 0.35–0.38 kg per fish and a yield of about 100–110 kg per mu. The fish had no drug residues, delicious meat, and met the standards for pollution-free agricultural products. During the breeding process, fish excrement continuously accumulated at the bottom of the pond, forming loose and fertile organic bottom mud with a thickness of about 2–2.5 cm and an organic matter content of 7%–9%, ​​which accumulated sufficient high-quality organic fertilizer for the subsequent lotus root planting.

[0030] Year Three: The second year's farming model was maintained, with grass carp and crucian carp continuing to be raised and organic fertilizers accumulated. The pond water depth was kept at 1.2–1.4m without any additional modifications. At the beginning of the year, based on the stock and growth size of the fish, an appropriate amount of grass carp (180–200g / fish) was added per mu (approximately 0.067 hectares), and crucian carp (60–70g / fish) were added per mu to maintain a reasonable stocking density and ensure uniform growth. Farming management continued according to the second year's standards, with no drugs or fertilizers used throughout the entire process, and ecological feeding. The proportion of ecological feed was controlled below 12%, mainly consisting of fresh grass and fermented soybean meal. Emphasis was placed on water quality control and dissolved oxygen management, and floating debris was regularly removed from the water surface to reduce disease occurrence. Daily disease prevention was strengthened, and the aquatic microecological balance was maintained through biological regulation, resulting in no outbreaks of disease throughout the year. The fish are harvested in November at the end of the year. The grass carp have an average weight of 1.1-1.2 kg per fish and a yield of about 230-250 kg per mu. The crucian carp have an average weight of 0.40-0.42 kg per fish and a yield of about 120-130 kg per mu. The yield is stable and the quality is excellent. After two years of grass carp and crucian carp farming, the total thickness of organic fertilizer at the bottom of the pond reaches 5-7 cm, with an organic matter content of 10%-12%. The nitrogen, phosphorus, potassium and trace elements are balanced, which fully meets the growth needs of lotus roots throughout the entire growth period, and no additional chemical fertilizers are required.

[0031] Year Four: Lotus Root Cultivation and Waste Resource Utilization. After the third year of cultivation, drain the pond water and expose it to the open air for 15-18 days. During this period, till the pond bottom once to a depth of 12-15cm to promote the maturation, loosening, and aeration of the pond bottom silt, and to kill harmful bacteria, parasite eggs, and weed seeds. After the pond is exposed to the air, fill it with water to a depth of 0.25-0.3m. Select the E'lian No. 6 variety, which is shallow-water, high-yielding, adaptable, with crisp and sweet lotus flesh and moderate starch content. Select main lotus roots with 2-3 plump buds, a single section weight ≥140g, a length of 25-35cm, no rot, no damage, strong buds, and no pests or diseases. Plant them at a row spacing of 1.5-1.6m and a plant spacing of 0.4-0.45m, with a planting density of 1200-1300 plants / mu and a planting depth of 8-12cm, ensuring that the buds face upwards, are firmly rooted, and do not float. Lotus roots are grown without chemical fertilizers, pesticides, or herbicides, relying on the organic fertilizer from fish excrement at the bottom of the pond for natural growth. During the growing season (April-May), the water level is kept shallow at 0.2-0.3m to promote budding and growth. During the high-temperature season (June-August), the water level is appropriately deepened to 0.4-0.5m to lower the water temperature and promote tuber formation. Weeds are removed manually 2-3 times a day to avoid chemical pollution. Any pests found are dealt with by manual capture. Lotus tips are harvested from May to July, every 7 to 10 days, yielding approximately 150-180 kg per mu (667 square meters). They are tender, crisp, fibrous, and have high added value. Lotus seeds are harvested from July to September, with mature lotus pods picked in batches, yielding approximately 60-70 kg per mu. The seeds are plump, sweet, and have a slightly bitter heart. Mature lotus roots are harvested from October to November, manually dug to avoid damaging the roots, yielding approximately 1800-2000 kg per mu. The roots are regular in shape, smooth in skin, and of excellent quality. Tests have shown no heavy metals or pesticide residues, meeting the standards for pollution-free agricultural products. After lotus root harvesting, collect inferior, small, and damaged lotus roots, along with lotus stalks and leaves. Remove soil and impurities, then crush the material to approximately 2-3 cm using a straw crusher. Take 85 parts by weight of the crushed material, 1.2 parts by weight of Bacillus subtilis compound probiotic fermentation agent, and 13.8 parts by weight of wheat bran, and mix thoroughly in a mixer. Adjust the moisture content of the material to 55%-58%; it should be able to form a clump when squeezed but crumble easily when released, without dripping water. Pack the mixture into a sealed fermentation tank, compacting it in layers, and then cover it tightly with a plastic film. The material is sealed and anaerobic fermented at room temperature (20–30℃) for 7–8 days. During the fermentation process, the material temperature naturally rises to 45–50℃, with no foul odor and strong bacterial activity. After fermentation, the material is brownish-brown, soft in texture, fragrant, and rich in nutrients, producing about 12–14 tons of biological feed with a crude protein content of 16%–18%. It can be directly used for the next cycle of grass carp and crucian carp farming, with good palatability and high digestibility and absorption rate, realizing closed-loop utilization of waste and planting and breeding cycle.

[0032] In this embodiment, the entire planting and breeding process is ecological and pollution-free. The aquatic products and lotus roots meet the pollution-free standards, and the lotus tips and lotus seeds provide additional income. The overall yield per mu is about 2,200-2,500 yuan higher than that of traditional single planting and breeding. The input-output ratio is reasonable, and the ecological and economic benefits are balanced.

[0033] Example 2: Refined aquaculture in shallow water ponds (8 mu, water depth 0.7–0.8 m)

[0034] This embodiment selects a shallow pond with an area of ​​8 mu, an average water depth of 0.7–0.8 m, a silt thickness of 15–18 cm, and abundant natural aquatic plants. The pond bottom is loam with good water retention. The water source is clean mountain spring water that flows all year round, with fresh water quality and a transparency of 50–60 cm. It is suitable for refined management and high-quality ecological output, with a focus on improving the meat flavor of aquatic products and the crispness of lotus root.

[0035] Year 1: The lotus root and fresh grass carp ecological purification aquaculture ponds are idle ponds after lotus root harvesting, preserving complete lotus root remnants, nodes, aquatic plant roots, and organic debris to naturally construct a natural food bed. Selected fresh grass carp fry (170–190g / fish, 19–23cm in length, vigorous, bright blue-green in color, and free of parasites) are stocked at a density of 90–110 fish / acre; 22–28 silver carp (90–110g / fish, slender body, tightly scaled) are stocked at a density to enhance algae control. The aquaculture cycle is 12 months, with zero feed, zero drugs, and zero water changes throughout the entire process, relying entirely on the fresh grass carp to feed on the natural organic matter, tender aquatic plant shoots, and plankton in the pond. Daily pond inspections are conducted twice daily to observe water color and fish activity. During high-temperature periods (water temperature ≥31℃), aerators are turned on for 1–1.5 hours each night to maintain dissolved oxygen ≥4.5mg / L. At the end of the year, the ponds are drained for harvesting. The average weight of fresh grass carp is 1.4-1.5 kg, and the yield is about 130-150 kg per mu. The meat is tender, without muddy taste, and has a sweet taste. The thickness of the silt at the bottom of the pond is reduced by 2-2.5 cm, and the ammonia nitrogen and nitrite in the water are reduced by 32%-38%. The water is clear and the bottom is loose and breathable, with excellent ecological purification effect.

[0036] Year Two: High-yield, antibiotic-free aquaculture of grass carp and crucian carp continues in the purified pond, with water level increased to 0.9–1.0m, preserving the original aquatic plant community and microbial system. Healthy, active, and fast-growing grass carp fingerlings (140–160g / fish, 17–21cm in length) are selected and stocked at a density of 210–230 fish / acre; crucian carp fingerlings (45–55g / fish, rounded body, tender flesh, and tolerance to low oxygen levels) are stocked at a density of 300–330 fish / acre; a small number of bream (110–140g / fish, 20–25 fish / acre) are also added to optimize feed utilization. The aquaculture cycle is 12 months, with no antibiotics, disinfectants, or chemical fertilizers used throughout. The main diet consists of natural aquatic plants, organic detritus, and plankton; only a small amount of fresh ryegrass and fermented bran is supplemented during the summer and autumn when aquatic plants are insufficient. Feeding is done once daily, with the amount controlled to within 8% of the fish's total food intake to prevent eutrophication. Strengthen daily water quality monitoring, promptly drain water after heavy rain to prevent overflow, and run aerators for 2-3 hours daily during the high-temperature season. Conduct net fishing at the end of the year. Grass carp average weight 0.85-0.95 kg per fish, yield approximately 190-210 kg per mu; crucian carp average weight 0.32-0.36 kg per fish, yield approximately 95-105 kg per mu. The fish have firm flesh, pure flavor, and no drug residues. The pond bottom has a 2-2.5 cm thick layer of organic fertilizer with an organic matter content of 8%-10%, providing balanced nutrients and long-lasting fertility.

[0037] Year Three: Continued rearing of grass carp and crucian carp, along with the accumulation of organic fertilizer, maintains a shallow-water aquaculture model with a water depth of 1.0–1.2m. Aquatic plants grow naturally, continuously providing natural food. At the beginning of the year, supplement with 20–25 grass carp (160–180g / fish) per mu and 30–35 crucian carp (55–65g / fish) per mu to maintain a reasonable density and promote uniform growth. The entire aquaculture management process is ecological, with no medication or fertilizer used. Supplementation with green grass and fermented soybean meal does not exceed 10%. Emphasis is placed on aquatic plant maintenance, with regular removal of aging plants to maintain the ecological balance of the aquatic body. Daily biological control of diseases is strengthened, ensuring no disease occurrence and healthy growth throughout the year. At the end of the year, the fish are harvested. The grass carp have an average weight of 1.05-1.15 kg per tail and a yield of about 220-240 kg per mu. The crucian carp have an average weight of 0.38-0.40 kg per tail and a yield of about 115-125 kg per mu. They are of excellent quality and have high commercial value. After two years of cultivation, the total thickness of organic fertilizer at the bottom of the pond reaches 5-6.5 cm, with an organic matter content of 11%-14%. It is loose, fertile, and well-aerated, which fully meets the growth requirements of lotus roots.

[0038] Year 4: Lotus root cultivation and waste resource utilization. Dry the pond for 14–16 days, tilling the bottom once to a depth of 10–12 cm to promote sludge decomposition and kill harmful organisms. Fill the pond to a depth of 0.2–0.25 m. Select the crisp and tender shallow-water lotus variety, Su'ou No. 5. Choose main rhizomes with two plump buds, each section weighing ≥130g, undamaged, and with fresh buds. Plant at a row spacing of 1.4–1.5 m and a plant spacing of 0.35–0.4 m, with a planting density of 1350–1450 plants / mu. Plant at a depth of 7–10 cm, ensuring the buds face upwards and the roots are firmly established. The lotus roots are grown without fertilizer, pesticides, or herbicides throughout their entire growth period, relying on the organic fertilizer at the bottom of the pond for natural growth. During the growing season, the water level is maintained at a shallow depth of 0.2–0.3m to promote early vegetative growth and tuber formation. During periods of high temperature, the depth is increased to 0.4–0.45m to regulate water temperature and enhance crispness. Weeding is done twice manually for ecological pest control. Lotus tips are harvested from May to July, yielding approximately 160–190 kg per mu (approximately 0.067 hectares), which are crisp, tender, and sweet. Lotus seeds are harvested from July to September, yielding approximately 65–75 kg per mu (approximately 0.067 hectares), which are plump, fragrant, and sweet. Lotus roots are harvested from October to November, yielding approximately 1750–1950 kg per mu (approximately 0.067 hectares), with slender bodies, white and tender skin, crisp and sweet flesh, and superior quality. After harvesting, collect the secondary lotus roots and lotus stalks, and crush them to 2–2.5 cm. Take 86 parts of the crushed material, 1.0 part of compound probiotics, and 13 parts of wheat bran by weight, and mix them evenly. Adjust the moisture content to 54%–56%, and seal for anaerobic fermentation for 6–7 days. After fermentation, about 9–11 tons of biological feed are produced. The feed has a fine texture, balanced nutrition, and good palatability, and can be directly used for the next breeding cycle.

[0039] This embodiment features ecological and meticulous farming practices throughout the entire process, resulting in aquatic products with excellent meat quality and flavor, lotus roots with high crispness and tenderness, and lotus tips and seeds with significant added value. The overall yield per mu is increased by approximately 2,300–2,600 yuan, making it suitable for the production of high-end ecological agricultural products.

[0040] Example 3: High-yield aquaculture in fertile ponds with thick mud (15 mu, 22-25cm silt)

[0041] This embodiment selects a fertile pond with an area of ​​15 mu, an average water depth of 1.1–1.2 m, a silt thickness of 22–25 cm, high organic matter content, and sufficient fertility. The pond bottom is made of clay loam soil with good fertilizer retention. The water source is sufficient and the drainage and irrigation are convenient, making it suitable for high-yield and high-efficiency farming. The focus is on increasing fish and lotus root production, reducing production costs, and achieving large-scale benefits.

[0042] Year 1: The lotus root and fresh grass carp ecological purification aquaculture ponds are idle ponds after lotus root harvesting, with deep silt, rich organic matter, and retaining a large amount of lotus root residue, organic debris, plankton, and benthic organisms, providing ample natural food. Select robust, fast-growing, and fertile-water-tolerant lotus root and fresh grass carp fingerlings (190–210g / fish, 21–25cm in length) at a stocking density of 75–90 fish / acre; supplement with 18–22 large-bodied, filter-feeding silver carp (110–130g / fish) at a density to enhance water purification and control algae. The aquaculture cycle is 12 months, with zero feed, zero drugs, and zero water changes throughout the entire process. The lotus root and fresh grass carp feed on the abundant organic matter, lotus root residue, algae, and plankton in the pond, resulting in rapid growth. Daily pond inspections are conducted twice daily to observe water color and fish activity. During hot and humid weather, aerators are run for 2–2.5 hours daily to maintain dissolved oxygen ≥4mg / L. At the end of the year, the ponds are drained for harvesting. The average weight of fresh grass carp is 1.6-1.7 kg, and the yield is about 150-170 kg per mu. They grow quickly, are plump, and have firm flesh. The thickness of the silt at the bottom of the pond is reduced by 3-3.5 cm, and the ammonia nitrogen and nitrite in the water are reduced by 35%-40%. The water quality is significantly improved, the bottom is loose, and the fertility is moderate, thus completing the ecological purification.

[0043] Year Two: High-Yield, Antibiotic-Free Aquaculture of Grass Carp and Crucian Carp Continues with Purified, Fertilized Ponds. Water is filled to a depth of 1.2–1.3m, ensuring ample fertility and abundant natural food. Grass carp fry (170–190g / fish, 20–24cm in length, tolerant of fertilizer, rapid growth, and strong disease resistance) are selected and stocked at a density of 190–210 fish / acre. These are stocked with robust crucian carp fry (60–70g / fish), tolerant of fertilizer, and high-yielding, at a density of 270–310 fish / acre. A small number of bream (140–160g / fish, 25–35 fish / acre) and silver carp (20–25 fish / acre) are also added to fully utilize the water space and maximize yield. The aquaculture cycle is 12 months, with no antibiotics, disinfectants, or chemical fertilizers used throughout. Growth relies on abundant natural food in the pond. Only a small amount of fermented bran and soybean meal is supplemented during winter when food is scarce, with the feeding amount controlled to within 12% of the fish's total food intake to avoid water pollution. Strengthen daily water quality management, run aerators for 3-4 hours daily during the high-temperature season, and regularly remove floating debris from the water surface. At the end of the year, conduct net fishing. Grass carp average weight 1.0-1.1 kg per fish, with a yield of about 210-230 kg per mu; crucian carp average weight 0.38-0.40 kg per fish, with a yield of about 110-120 kg per mu. The yield is high, the fish are large, and the commercial value is high. The pond bottom has a layer of organic fertilizer about 2.5-3 cm thick, with an organic matter content of 9%-11%, which is fertile and nutrient-rich.

[0044] Year Three: Continued rearing of grass carp and crucian carp, along with the accumulation of organic fertilizer, maintains a deep, fertile water environment at a depth of 1.3–1.5m, ensuring sustained fertility and ample feed. At the beginning of the year, supplement with 25–35 grass carp (190–210g / fish) per mu and 40–55 crucian carp (65–75g / fish) per mu to maintain a reasonable density and promote high yields. The entire aquaculture management process is ecological, with no medication or fertilizer used. The proportion of supplementary ecological feed is controlled below 13%, primarily consisting of fermented soybean meal and green grass. Emphasis is placed on water quality management to prevent eutrophication. Daily disease prevention is strengthened, and biological regulation maintains water balance, ensuring vigorous growth and disease-free conditions throughout the year. At the end of the year, the fish are harvested. Grass carp have an average weight of 1.2-1.3 kg per tail and a yield of about 240-260 kg per mu. Crucian carp have an average weight of 0.43-0.46 kg per tail and a yield of about 130-140 kg per mu. The yield is outstanding and the economic benefits are significant. After two years of cultivation, the total thickness of organic fertilizer at the bottom of the pond reaches 6.5-8 cm, with an organic matter content of 12%-15%. The fertilizer is extremely strong and the nutrients are balanced, providing sufficient nutrients for the high yield of lotus root.

[0045] Year Four: Lotus Root Planting and Waste Resource Utilization. Dry the pond for 18-20 days, then till the bottom once to a depth of 15-18cm to promote silt decomposition and improve aeration. Fill the pond to a depth of 0.3-0.35m. Select the high-yield, fertilizer-tolerant, shallow-water lotus variety, E'lian No. 7. Choose main rhizomes with 3 plump buds, each segment weighing ≥150g, robust and full, and free from pests and diseases. Planting density is 1150-1250 plants / acre, with row spacing of 1.6-1.7m and plant spacing of 0.45-0.5m. Planting depth is 10-14cm to ensure strong rooting and vigorous growth. The lotus root is grown without fertilizer, pesticides, or herbicides throughout its entire growth period, relying on the high fertility of the organic fertilizer at the bottom of the pond for rapid growth. During the growing season, the water level is maintained at a shallow depth of 0.3–0.4m to promote early branching and tuber formation. During periods of high temperature, the water depth is increased to 0.5–0.55m to promote tuber enlargement and increase yield. Weeding is done manually 2–3 times for ecological pest control. The lotus tips are harvested from May to July, yielding approximately 140–170 kg per mu (approximately 0.067 hectares), which are tender, plump, and have a good taste. Lotus seeds are harvested from July to September, yielding approximately 55–70 kg per mu (approximately 0.067 hectares), which are large and high-yielding. The lotus roots are harvested from October to November, yielding approximately 1900–2100 kg per mu (approximately 0.067 hectares), which are robust, high-yielding, and of excellent quality. After harvesting, collect the secondary lotus roots and lotus stalks, and crush them to 3-4 cm. Take 84 parts of the crushed material, 1.5 parts of compound probiotics, and 14.5 parts of wheat bran by weight, and mix them evenly. Adjust the moisture content to 57%-59%, and seal for anaerobic fermentation for 8-9 days. After fermentation, about 15-17 tons of biological feed is produced, which is nutritious, high-yield, and low-cost, and can be used for large-scale recycling in the next breeding cycle.

[0046] This embodiment of the farming method is highly efficient, low-cost, and profitable, with outstanding fish and lotus root yields and high waste utilization rate. The overall yield per mu (unit of land area) increases income by approximately 2100–2400 yuan, making it suitable for large-scale and industrialized promotion.

[0047] Example 4: Standardized Aquaculture in Newly Renovated Ponds (20 mu, newly built ponds)

[0048] This embodiment selects a standardized pond with an area of ​​20 mu (approximately 3.3 hectares), newly excavated and renovated, with a flat bottom, silt thickness of 14-16 cm, high-quality water source, and complete drainage and irrigation facilities. The pond embankment is sturdy, the slope is regular, the inlet and outlet are independent, and it is equipped with standardized aeration equipment. It is suitable for standardization, normalization, and replication and promotion, and focuses on achieving standardization of the model, normalization of management, and stability of benefits.

[0049] Year 1: The lotus root and grass carp ecological purification aquaculture ponds are newly renovated ponds. After the lotus root harvest in the first year, a 14-16cm thick layer of organic silt forms at the bottom of the pond, retaining lotus root remnants, organic debris, and plankton to construct a basic feed system. Select healthy, disease-free, and uniformly sized grass carp (180-200g / fish, 20-24cm in length) at a stocking density of 80-100 fish / acre; and supplement with 20-25 uniformly sized, healthy, and active silver carp (100-120g / fish) per acre, ensuring standardized stocking and even distribution. The aquaculture cycle is 12 months, with zero feed, zero medication, and zero water changes throughout the entire process, following standardized ecological aquaculture. Daily pond inspections are conducted twice a day, recording water color, temperature, and dissolved oxygen. During high-temperature periods, aerators are operated in a standardized manner to maintain dissolved oxygen ≥4mg / L. At the end of the year, the ponds were drained for harvesting. The fresh grass carp were of uniform size, with an average tail weight of 1.5-1.6 kg and a yield of about 140-160 kg per mu. The quality was stable and the product was consistent. The thickness of the silt at the bottom of the pond was reduced by 2-3 cm. The water quality indicators met the standards, the water was clear, and the bottom was loose, thus completing the standardized ecological purification.

[0050] Year Two: High-yield, antibiotic-free aquaculture of grass carp and crucian carp continues in purified, standardized ponds with a water depth of 1.1–1.2m, a flat bottom, and stable water quality. Grass carp fingerlings of uniform size (150–180g / fish), healthy and disease-free, are selected and stocked at a density of 200–220 fish / acre; crucian carp fingerlings of uniform size (50–60g / fish), with strong adaptability, are stocked at a density of 280–320 fish / acre; bream and silver carp are also stocked in a standardized manner, with densities controlled within 40–50 fish / acre to achieve standardized population structure. The aquaculture cycle is 12 months, with no antibiotics, disinfectants, or chemical fertilizers used throughout, and standardized ecological management is implemented; the proportion of supplementary ecological feed is controlled within 10%, with fermented bran and green grass fed uniformly, at fixed times and in fixed quantities, using standardized operations. Daily standardized monitoring of water quality, dissolved oxygen, and water temperature is conducted; aerators are operated in a standardized manner during high-temperature seasons; and standardized drainage is implemented after heavy rains to prevent overflow. At the end of the year, the net fishing yielded grass carp and crucian carp of uniform size, stable quality, and up to standard. The yield of grass carp was about 200-220 kg per mu, and the yield of crucian carp was about 100-110 kg per mu. The products were of good consistency and had high market acceptance. The organic fertilizer deposited at the bottom of the pond was about 2-2.5 cm thick, with organic matter content meeting the standard and balanced fertility.

[0051] Year Three: The standardized aquaculture model is maintained through continuous rearing of grass carp and crucian carp, and the accumulation of organic fertilizer. The water depth is 1.2–1.4m, with standardized management and standardized operations. At the beginning of the year, fish fry are replenished in a standardized manner to maintain a reasonable density and ensure uniform size. The entire aquaculture management process is standardized, with no drugs or fertilizers used, and ecological feeding. The proportion of supplementary feed is controlled within 12%, with unified formula, unified feeding, and unified management. Daily standardized pond inspections, recording, and monitoring are conducted, along with biological disease control and maintenance of the aquatic ecological balance, ensuring healthy growth and uniform size throughout the year. At the end of the year, adult fish are harvested, with stable yields, excellent quality, and uniform size for both grass carp and crucian carp. The yield is approximately 230–250 kg per mu for grass carp and approximately 120–130 kg per mu for crucian carp. After two years of aquaculture, the thickness of organic fertilizer at the bottom of the pond meets the standards, and the nutrients are balanced, fully meeting the requirements for standardized lotus root cultivation.

[0052] Year Four: Standardized lotus root cultivation and waste resource utilization. The pond is drained and sun-dried for 15-18 days, the pond bottom is tilled, and standardized land preparation is carried out to ensure a level pond bottom. Standardized water filling to a depth of 0.25-0.3m is used, selecting standardized shallow-water lotus root varieties with uniform seed rhizomes, robust buds, and no pests or diseases. Standardized planting is implemented with row spacing of 1.5-1.6m, plant spacing of 0.4-0.45m, a density of 1200-1300 plants / acre, and consistent planting depth to ensure uniform growth and consistent size. Standardized management is applied throughout the lotus root growth period, with no fertilizers, pesticides, or herbicides used. Standardized water level control, standardized manual weeding, and standardized ecological pest control are employed. Standardized harvesting of lotus tips, lotus seeds, and lotus roots is implemented, with yields of approximately 150-180 kg / acre for lotus tips, approximately 60-70 kg / acre for lotus seeds, and approximately 1800-2000 kg / acre for lotus roots, ensuring stable yields, excellent quality, and uniform size. After harvesting, secondary lotus roots and lotus stalks are collected in a standardized manner, crushed to 2-3cm in a standardized manner, and then mixed, with the moisture content adjusted to 55%-58% in a standardized manner. After anaerobic fermentation for 7-8 days in a standardized manner, approximately 18-22 tons of biological feed are produced, which meets nutritional standards, has stable quality, and can be recycled for the next cycle of standardized breeding.

[0053] This embodiment of the cultivation and breeding is standardized, regulated, and replicable. The yield of fish and lotus root is stable, the quality is excellent, and the waste utilization rate is high. The comprehensive increase in income per mu is about 2,200-2,500 yuan, which is suitable for large-scale promotion and industrial development.

[0054] The data comparison of the four sets of examples is shown in the table below:

[0055] Area / Depth 10 mu / 0.9–1.0 m 8 mu / 0.7–0.8 m 15 mu / 1.1–1.2 m 20 mu / 1.0–1.2m Lotus fresh grass carp yield per mu 140–160kg 130–150kg 150–170kg 140–160kg Total yield per mu of grass carp 430–470kg 410–450kg 450–490kg 430–470kg Total yield of crucian carp per mu 220–240kg 210–230kg 240–260kg 220–240kg lotus root tip yield per mu 150–180kg 160–190kg 140–170kg 150–180kg Lotus seed yield per mu 60–70kg 65–75kg 55–70kg 60–70kg Lotus root yield per mu 1800–2000kg 1750–1950kg 1900–2100kg 1800–2000kg Increased income per mu 2200–2500 yuan 2300–2600 yuan 2100–2400 yuan 2200–2500 yuan

[0056] The four-year cycle fish and lotus rotation green ecological farming system provided by this invention has verified its universality, stability and scalability through four typical embodiments.

[0057] Example 1 is a standard conventional pond model, with balanced parameters and stable returns, suitable for most rural ponds; Example 2 is a shallow-water, grass-fed pond model, relying on natural aquatic plant resources, resulting in outstanding flavor of aquatic products and crispness of lotus roots, suitable for high-end ecological agricultural product production; Example 3 is a thick-mud, fertile pond model, making full use of highly fertile bottom mud, resulting in significant advantages in fish and lotus root yields, suitable for large-scale, high-yield farming; Example 4 is a newly renovated standardized pond model, with standardized processes, unified management, and strong replicability, suitable for large-scale industrial promotion. These four examples cover different pond conditions, and the system demonstrates consistent performance in ecological purification, antibiotic-free production, resource recycling, and economic benefits, possessing broad application value.

[0058] This invention constructs a four-year cycle closed-loop ecological farming system for fish and lotus root rotation. Through the orderly connection of lotus-fresh grass carp ecological purification, antibiotic-free crucian carp farming, lotus root organic fertilizer planting, and waste resource utilization, it achieves natural restoration of pond water quality and bottom sediment, efficient conversion and recycling of organic matter, and eliminates the need for antibiotics, chemical disinfectants, fertilizers, and pesticides throughout the entire process, fundamentally preventing agricultural non-point source pollution and significantly improving the aquatic ecological environment. The green and antibiotic-free production mode ensures that the aquatic products have firm flesh, pure flavor, and no drug residues, and that the lotus roots are crisp, sweet, and of excellent quality. The additional products such as lotus root tips and lotus seeds further enhance the overall income. At the same time, secondary lotus roots and lotus root stalks are fermented into biological feed, and fish excrement is converted into natural organic fertilizer, achieving zero discharge of farming waste and efficient resource recycling, and significantly reducing production costs. This system is suitable for various types of freshwater ponds, is easy to operate, and is easy to replicate and promote. The overall yield per mu is 2100-2600 yuan higher than the traditional model, and it has excellent ecological, social, and economic benefits, providing a green development solution that can be applied on a large scale for freshwater pond ecological farming.

[0059] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A four-year cycle fish and lotus root rotation green ecological farming system, characterized in that, It includes sequentially connected modules such as the ecological purification and aquaculture of fresh grass carp, the high-yield antibiotic-free aquaculture of crucian carp, and the replanting of lotus roots and the resource utilization of waste, with a complete planting and breeding cycle of four years. The lotus fresh grass carp ecological purification and aquaculture module is the first year of planting and breeding unit. It uses freshwater ponds after lotus root harvesting, retains lotus root residues, organic debris and natural plankton in the pond, and introduces lotus fresh grass carp fry. No artificial compound feed, antibiotics and chemical disinfectants are used throughout the process. The high-yield, antibiotic-free grass carp and crucian carp farming module is a second-year and third-year farming unit. Grass carp and crucian carp fry are introduced, and no antibiotics, chemical disinfectants or fertilizers are used throughout the process. The farming relies on natural bait in the pond and is supplemented with a small amount of ecological feed. The lotus root replanting and waste resource utilization module is the fourth-year planting and breeding unit. Aquaculture is stopped, and after the pond is dried, the organic fertilizer from the fish excrement in the pond is used to plant shallow-water lotus roots. No chemical fertilizers or pesticides are used. The lotus tips, lotus seeds and lotus roots are harvested at the same time. The secondary lotus roots and lotus stalks are crushed and fermented into biological feed for the next cycle of fish farming, forming a closed-loop planting and breeding cycle.

2. The four-year cycle fish and lotus root rotation green ecological farming system according to claim 1, characterized in that, In the first year, the size of fresh grass carp fry is 180–220g / fish, and the stocking density is 80–120 fish / mu; silver carp and bighead carp are selected and matched, with a size of 100–150g / fish and a stocking density of 20–30 fish / mu.

3. The four-year cycle fish and lotus root rotation green ecological farming system according to claim 2, characterized in that, In the second and third years, the stocking size for grass carp fry is 150–200g / fish, and the stocking size for crucian carp fry is 50–80g / fish; the stocking density for grass carp is 200–250 fish / mu, and the stocking density for crucian carp is 300–350 fish / mu.

4. The four-year cycle fish and lotus root rotation green ecological farming system according to claim 1, characterized in that, During the second and third years of aquaculture, the proportion of supplemental ecological feed in the total feed intake of fish shall not exceed 15%, and the ecological feed shall be at least one of fermented wheat bran, soybean meal, and green grass.

5. The four-year cycle fish and lotus root rotation green ecological farming system according to claim 1, characterized in that, In the fourth year, shallow-water, high-yield varieties of lotus root are selected. The seed tubers are 2-3 buds with a single section weighing ≥150g. The planting density is 1200-1500 plants / mu, with a row spacing of 1.5-1.8m and a plant spacing of 0.4-0.5m.

6. The four-year cycle fish and lotus root rotation green ecological farming system according to claim 1, characterized in that, The method for preparing the biological feed includes the following steps: S1. Crush the lotus root and lotus stalks to 2-5cm; S2. Take 83%–89% of the crushed material, 1%–2% of the probiotic starter, and 10%–15% of the wheat bran by weight, and mix them evenly. S3. Adjust the moisture content of the mixture to 55%–60%; S4. After sealing, anaerobic fermentation is carried out for 7–10 days to obtain biological feed.

7. A four-year cycle fish and lotus root rotation green ecological farming system according to claim 6, characterized in that, The biological feed is circulated and supplied to the ecological purification and aquaculture module for fresh grass carp and the high-yield antibiotic-free aquaculture module for crucian carp.

8. The four-year cycle fish and lotus rotation green ecological farming system according to claim 1, characterized in that, The ecological purification and aquaculture module for fresh grass carp, the high-yield antibiotic-free aquaculture module for crucian carp, and the module for lotus root replanting and waste resource utilization share the same freshwater pond and are used in rotation on an annual basis.

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