A facility cultivation method for early maturation of kumquat

Abstract

This invention relates to the field of agricultural cultivation technology and discloses a facility-based cultivation method for early ripening of kumquats. The method includes preparing a fermentation substrate by pre-fermenting a mixture of crushed kumquat branches, auxiliary materials, and slow-release water-retaining polymer particles; in a facility microenvironment equipped with insect-proof netting, heat-insulating film, and a buffer gas layer, using the prepared fermentation substrate for pre-harvest in-situ regulation during the fruit color-changing period; adjusting the opening degree of the heat-insulating film to release heat into the greenhouse at night using the fermentation substrate, and utilizing the accumulated high concentration of carbon dioxide in conjunction with sunlight for photosynthesis the following morning; harvesting in batches after reaching the optimal harvesting baseline. This in-situ regulation mode, combining the fermentation substrate with the facility microenvironment, achieves the effect of increasing nighttime temperature and morning carbon dioxide substrate concentration within the greenhouse; the slow-release water-retaining polymer particles slowly release liquid water to replenish metabolic consumption, accelerating fruit ripening.

Description

Technical Field

[0001] This invention relates to the field of agricultural cultivation technology, specifically to a facility-based cultivation method for early maturation of kumquats. Background Technology

[0002] Kumquats have extremely demanding environmental temperature requirements during their autumn and winter ripening stage. Current conventional cultivation methods face severe low-temperature stress when exposed to sudden drops in outside temperature, leading to a significant decrease in the overall physiological and biochemical metabolic levels of the plants. To maintain the temperature required for normal fruit ripening, conventional practices often involve using external electric heating equipment to heat the greenhouse. This method not only consumes a large amount of extra energy, increasing the economic cost of agricultural production, but also generally lacks a mechanism for replenishing carbon assimilation substrates within the greenhouse. Low carbon dioxide concentrations inside the greenhouse in the morning directly limit the efficiency of photosynthesis after the leaves open their stomata, hindering the transport of carbohydrates to the fruit, thus delaying fruit ripening and reducing the total accumulation of soluble solids.

[0003] To address the high cost of electric heating, some improved solutions have attempted to use agricultural waste fermentation to generate heat and raise the temperature inside the fermentation shed. However, during the continuous release of heat from the aerobic fermentation pile, the accompanying high temperatures cause rapid evaporation of liquid moisture within the material. The metabolic activity of aerobic fermentation microorganisms is impaired under severe substrate dehydration, and the entire fermentation system quickly enters a state of water shortage and dormancy, completely unable to maintain sustained heat and carbon dioxide output.

[0004] On the other hand, current greenhouse structures mostly use single-layer film coverings, lacking a good heat insulation and buffering system. Their ability to resist the conduction of cold air at night is extremely poor, leading to easy heat loss. Furthermore, under heated and sealed conditions, moisture evaporation inside the greenhouse results in persistently high relative humidity, creating a highly humid environment that easily induces fungal diseases in kumquat fruits. Additionally, after the harvest season ends and winter approaches, existing planting systems generally lack measures to protect the tree branches and twigs from the cold, causing kumquat plants to frequently suffer freeze-thaw damage from severe weather, seriously damaging the vitality of the basic root system and hindering the normal differentiation of flower buds the following year. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a facility-based cultivation method for promoting early maturity of kumquats. This method solves the problems of kumquats being susceptible to low temperatures during the autumn and winter color-changing period, which weakens physiological activity and reduces photosynthetic rate; conventional facility cultivation relies solely on external energy for heating, which is costly; and insufficient carbon dioxide concentration in the greenhouse limits carbohydrate accumulation. It also addresses the lack of a low-cost method that can coordinately regulate the heat and gas environment in situ to promote early maturity.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a facility-based cultivation method for early ripening of kumquats, employing the following technical solution: This invention provides a facility-based cultivation method for early ripening of kumquats, employing the following technical solution: A facility-based cultivation method for early ripening of kumquats includes the following processes: A fermentation substrate is prepared by pre-fermenting a mixture of crushed kumquat branches, auxiliary materials, and slow-release water-retaining polymer particles; In a microenvironment with insect-proof netting, heat-insulating film, and a buffer gas layer for the kumquats, pre-harvest in-situ regulation is implemented using the prepared fermentation substrate during the fruit color-changing period; During pre-harvest in-situ regulation, the opening degree of the heat-insulating film is adjusted, allowing the fermentation substrate to release heat into the greenhouse at night, and photosynthesis is carried out the following morning using the high concentration of carbon dioxide accumulated overnight in the greenhouse in conjunction with morning sunlight; After completing the pre-harvest in-situ regulation, once the kumquat peel has completely turned from green to orange-yellow and the soluble solids content of the fruit reaches the appropriate harvesting baseline, the kumquats are harvested in batches.

[0007] By adopting the above technical solution, and through the in-situ regulation mode combining fermentation substrate and facility microenvironment, the effects of increasing nighttime temperature and morning carbon dioxide substrate concentration are achieved, thereby accelerating fruit coloring and sugar accumulation. Specifically, the mechanism mainly involves the coupled regulation of biological fermentation and facility climate environment. Specifically, crushed kumquat branches and auxiliary materials provide carbon and nitrogen sources, respectively. The attached aerobic fermentation agent, under suitable moisture content, undergoes aerobic respiration, degrading macromolecular organic matter to obtain metabolic energy. During this process, a large amount of excess energy is released as heat, while carbon is oxidized and decomposed, continuously releasing water and carbon dioxide. Based on this physical foundation, when the outside temperature drops at night and the insulation film is lowered and sealed, the released heat directly heats the air inside the greenhouse, compensating for heat loss from the sealed space and maintaining the physiological and biochemical enzyme activity necessary for the kumquat tree's coloring stage. Simultaneously, the carbon dioxide produced by metabolism cannot diffuse outwards due to space constraints, leading to a high concentration of carbon dioxide accumulating within the microenvironment. At sunrise the following day, under conditions of maintaining a certain period of sealing, the stomata on the kumquat leaves open in response to light signals. The high concentration of carbon dioxide accumulated overnight then serves as a substrate for photosynthetic carbon assimilation, rapidly triggering the photo-dark reaction in conjunction with morning sunlight. Due to the ample supply of carbon reaction substrate, the rate of carboxylation-catalyzed reactions significantly increases, accelerating the transport of photosynthetic products to the fruit storage tank, thereby shortening the accumulation cycle of soluble solids. Furthermore, to address the rapid dehydration of the substrate caused by the continuous high temperature in the fermentation center, the incorporated slow-release water-retaining polymer microparticles act as a liquid-phase buffer through their three-dimensional cross-linked network. As the surrounding substrate heats up, the thermal motion of the polymer's internal chains intensifies, and the bound and free water adsorbed within the network slowly migrates to the external substrate according to osmotic pressure and concentration gradients, replenishing the liquid-phase water consumed by the continuous metabolism of microorganisms. This fundamental mechanism ensures a constant output of biological heat and carbon dioxide during in-situ regulation.

[0008] Preferably, in the process of preparing the fermentation substrate, the raw materials are composed of the following components by mass: 60-70 parts of crushed kumquat branches, 20-30 parts of rice husks, 5-10 parts of decomposed chicken manure, 0.1-0.5 parts of compound aerobic fermentation agent, and 1-3 parts of slow-release water-retaining polymer microparticles; the crushed kumquat branches are crushed into wood particles with a particle size of 1.0-3.0 cm.

[0009] By adopting the above technical solution, the overall carbon-nitrogen ratio of the mixed materials was rationally configured. Rice husks adjusted the looseness and oxygen conduction porosity of the material system, and the readily available soluble nitrogen supplemented by decomposed chicken manure met the nutritional needs for rapid microbial proliferation in the early stage of fermentation, thereby promoting the rapid start of the fermentation stage.

[0010] Preferred, the pre-fermentation process is as follows: add water to adjust the overall moisture content of the raw materials to 55-60%, pile them in a dark and ventilated place for pre-fermentation for 7-10 days, and turn them over when the temperature at the center of the pile reaches 55℃, turning them over once every 2-3 days; the fermentation substrate is rehydrated and activated by aeration before being put into in-situ regulation before mining.

[0011] By adopting the above technical solution, setting the turning point at a central temperature of 55℃ aims to break the temperature and gas concentration gradients inside and outside the material pile, remove metabolic waste gas from the central area, and reintroduce oxygen. Through this pre-fermentation process, readily degradable components in the raw materials are converted in advance, avoiding a surge in heat during later in-situ application, thus ensuring that the fermentation substrate remains in a stable heat-generating period after entering the facility.

[0012] Preferably, the construction method of the facility microenvironment is as follows: a white insect-proof net with a mesh density of 40-60 mesh is covered on the innermost side of the frame, and a drip-proof and anti-fogging polyolefin insulation film with a thickness of 0.08-0.12mm is covered on the outer side. A buffer air layer of 5-15cm is formed between the insect-proof net and the insulation film through the gap of the frame.

[0013] By adopting the above technical solution, the buffer air layer of the sandwich structure reduces the thermal conductivity coefficient between the internal space and the external cold air, slowing down the rate of heat loss. At the same time, the selected anti-drip and anti-fogging material prevents condensation from dripping onto the inner surface of the membrane, cutting off the water transmission pathway that causes fungal diseases in fruits.

[0014] Preferred management steps during the fruit enlargement period of kumquats in a facility microenvironment: the average daytime temperature inside the greenhouse is controlled at 22-28℃, and high-potassium water-soluble fertilizer is applied in conjunction with the orchard drip irrigation system. The fertilization frequency is once every 10-15 days, and the relative soil moisture content at a root zone depth of 10-30cm is kept stable at 60-70%.

[0015] By adopting the above technical solutions, providing a stable supply of water and fertilizer and a suitable temperature range during the fruit enlargement period helps to promote the expansion of fruit cell volume, which prepares sufficient internal storage capacity for the transformation of sugars and other substances during the subsequent color change period.

[0016] Preferred operating parameters for pre-harvest in-situ control are as follows: The rehydrated and aerated fermentation substrate is evenly distributed in non-woven fabric ventilation troughs between fruit tree rows at a rate of 800-1000 kg per acre; water is sprayed to replenish the local moisture content to 60%; from 18:00 to 07:00 the next day, the insulation film is completely lowered and sealed, maintaining the center temperature of the aerobic fermentation pile in the trough at 50-60℃, releasing heat into the greenhouse to ensure the lowest nighttime temperature inside the greenhouse is not lower than 10℃; after sunrise the next day, the greenhouse film is kept sealed for 2-3 hours; when at least one of the following conditions is met—keeping it sealed for 2-3 hours or raising the greenhouse temperature to 28℃—the four sides of the greenhouse skirts are opened for ventilation to reduce the relative humidity inside the greenhouse to below 60%.

[0017] By adopting the above technical solution, the opening degree of the membrane is precisely controlled based on specific time points and temperature thresholds. Maintaining the membrane closed for 2-3 hours in the morning aims to fully consume the carbon dioxide accumulated overnight. Once the preset time limit is reached or the temperature threshold of 28°C is touched, ventilation and dehumidification are immediately carried out. This is mainly to prevent various physiological diseases induced by prolonged high relative humidity.

[0018] Preferably, the appropriate baseline is: the soluble solids content of the sampled fruit reaches 18%-20%.

[0019] By adopting the above technical solution, quantitative physicochemical indicators are used to define physiological maturity, abandoning the single visual experience judgment, thereby ensuring the consistency of taste quality in harvested batches.

[0020] Preferably, the raw materials for preparing the slow-release water-retaining polymer microparticles include: sodium alginate, acrylic acid monomer, acrylamide monomer, N,N'-methylenebisacrylamide, and potassium persulfate; the molar ratio of acrylic acid monomer to acrylamide monomer is 1:1, the total mass of acrylic acid monomer and acrylamide monomer is 5-8 times the mass of sodium alginate, and the acrylic acid monomer is pre-neutralized to a neutralization degree of 70%-75% using a 20% sodium hydroxide solution.

[0021] By adopting the above technical solution, sodium alginate provides a natural polymer backbone. Combined with the pre-neutralization treatment of acrylic acid monomers, the electrostatic repulsion between charged groups is moderately weakened, preventing the network from disintegrating due to excessive swelling. This maintains the dimensional stability of the internal pore structure of the polymer and constructs a physical space for the stable adsorption and storage of liquid molecules.

[0022] A preferred method for preparing slow-release water-retaining polymer microparticles is as follows: sodium alginate is dissolved in distilled water to prepare a sodium alginate solution with a mass concentration of 2.0-3.0%; after cooling to 40°C, pre-neutralized acrylic acid monomer and acrylamide monomer are added sequentially; then, N,N'-methylenebisacrylamide is added at a mass of 0.05-0.1% of the total monomer mass; nitrogen gas is introduced into the reaction system to remove oxygen for 20 minutes, and then potassium persulfate is added at a mass of 0.5%-0.8% of the total monomer mass; the temperature is slowly raised to 65-70°C and kept at a constant temperature for 3-4 hours to form a cross-linked polymer hydrogel; unreacted monomers on the surface are washed off with anhydrous ethanol, chopped, and dried in a vacuum drying oven at 80°C to constant weight; after pulverization, it is passed through a 40-60 mesh sieve to obtain the final product.

[0023] By employing the above technical solution, nitrogen deoxygenation eliminates the interference of oxygen molecules in the environment on the termination and inhibition of the free radical polymerization process. During the subsequent slow heating process, the initiator potassium persulfate decomposes to generate free radicals, which promote monomer chain growth, while the crosslinking agent N,N'-methylenebisacrylamide steadily builds chemical crosslinking points between monomer segments, ultimately reacting to generate a water-insoluble three-dimensional network crosslinked polymer material.

[0024] Preferably, after the phased harvest and during the winter, there are overwintering management steps, keeping the insect-proof netting and heat-insulating film covering the plants, and gradually removing the heat-insulating film after the temperature stabilizes and rises in February of the following year.

[0025] By adopting the above technical solutions, winter covering effectively prevents the freezing and thawing damage to the tree and branches caused by the severe winter climate, preserves the leaves while maintaining the vitality of the basic root system, and provides a basic guarantee for the safe overwintering of the plant and the normal differentiation of flower buds in the following year.

[0026] This invention provides a facility-based cultivation method for early ripening of kumquats. It has the following beneficial effects: 1. This invention combines the metabolic energy release of the fermentation substrate with the microenvironment of the facility, which includes insect-proof netting and heat-insulating film, to carry out pre-harvest in-situ regulation during the color-changing period of kumquat fruit. The fermentation substrate releases heat into the greenhouse at night to compensate for the heat loss under low temperature conditions, and the high concentration of carbon dioxide accumulated in the sealed space the next morning, combined with the morning sunlight, is used for photosynthesis. This eliminates the energy consumption of relying solely on external heating equipment, while increasing the substrate concentration of photosynthetic reaction, accelerating the speed of photosynthetic product transport to the inside of the fruit, and shortening the accumulation period of soluble solids.

[0027] 2. This invention incorporates slow-release water-retaining polymer microparticles prepared by cross-linking sodium alginate, acrylic acid monomer, and acrylamide monomer into the pre-fermentation raw materials. During the period when the fermentation substrate is at a high temperature and continuously generating heat, the polymer network inside the microparticles slowly releases liquid phase water to the external substrate according to the concentration gradient, replenishing the liquid phase consumed by the continuous metabolism of aerobic microorganisms. This avoids the fermentation pile from dehydrating and going dormant due to excessive evaporation at high temperatures, and ensures a stable and continuous output of biological heat generation and carbon dioxide gas during in-situ regulation.

[0028] 3. This invention forms a buffer air layer by covering the innermost part of the frame with an insect-proof net and the outer part with an insulating film. By adjusting the opening degree of the insulating film and the drip irrigation parameters of water and fertilizer according to the growth cycle of kumquats, it provides suitable temperature and humidity during the early expansion stage to prepare internal capacity for cell volume expansion. During the final stage of color change regulation, morning ventilation is implemented to prevent excessive relative humidity in the greenhouse from inducing fungal diseases in the fruit. Finally, the covering is maintained during the overwintering period to block the freeze-thaw damage caused by the severe cold environment to the tree branches and branches, providing a climate safety barrier for maintaining the vitality of the basic root system and the differentiation of flower buds in the following year. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the water release kinetics curve of the water-retaining polymer microparticles of the present invention at a high temperature of 55°C. Figure 2 This is a schematic diagram of the dynamic temperature change curve of the fermentation pile center over 15 consecutive days according to the present invention. Figure 3 This is a schematic diagram of the decay curve of relative soil moisture content in the root zone under different control modes for 10 consecutive days according to the present invention. Figure 4 This is a schematic diagram showing the dynamic changes in the net photosynthetic rate of kumquat leaves during the morning closure period according to the present invention. Figure 5 This is a schematic diagram comparing the yield per kumquat tree and the soluble solids content under different control modes of the present invention. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Preparation Examples 1-3: Preparation Example 1: This preparation example provides a method for preparing sustained-release water-retaining polymer microparticles, including the following steps: Accurately weigh sodium alginate and dissolve it in distilled water. Stir mechanically in a 60°C water bath until completely dissolved to prepare a 2.0% sodium alginate solution. Cool the reaction system to 40°C, then add acrylic acid monomer and acrylamide monomer sequentially. The molar ratio of acrylic acid to acrylamide is 1:1, and the total mass of acrylic acid and acrylamide monomers is 5 times the mass of sodium alginate. Before adding acrylic acid, pre-neutralize it to 70% neutralization using a 20% sodium hydroxide solution. Then add N,N'-methylenebisacrylamide as a crosslinking agent, at a concentration of 0.05% of the total monomer mass. After purging the reaction system with nitrogen for 20 minutes to remove oxygen, add potassium persulfate as an initiator, at a concentration of 0.5% of the total monomer mass. Slowly heat the reaction system to 65°C and maintain this temperature for 3 hours to form a crosslinked polymer hydrogel. The cross-linked polymer hydrogel was removed, and the unreacted monomers on the surface were washed off with anhydrous ethanol. After being chopped, it was dried in a vacuum drying oven at 80°C until constant weight. After being pulverized, it was passed through a 40-mesh sieve to obtain slow-release water-retaining polymer microparticles.

[0032] Preparation Example 2: This preparation example provides a method for preparing sustained-release water-retaining polymer microparticles, including the following steps: Sodium alginate was accurately weighed and dissolved in distilled water. The solution was mechanically stirred at 62°C until completely dissolved, preparing a 2.5% sodium alginate solution. The reaction system was cooled to 40°C, and acrylic acid monomer and acrylamide monomer were added sequentially, with a molar ratio of acrylic acid to acrylamide of 1:1. The total mass of acrylic acid and acrylamide monomers was 6.5 times the mass of sodium alginate. Before adding acrylic acid, it was pre-neutralized to 72.5% neutralization using a 20% sodium hydroxide solution. N,N'-methylenebisacrylamide was then added as a crosslinking agent, at a concentration of 0.075% of the total monomer mass. After purging the reaction system with nitrogen for 20 minutes to remove oxygen, potassium persulfate was added as an initiator, at a concentration of 0.65% of the total monomer mass. The reaction system was slowly heated to 67.5°C and held at this temperature for 3.5 hours to form a crosslinked polymer hydrogel. The cross-linked polymer hydrogel was removed, and the unreacted monomers on the surface were washed off with anhydrous ethanol. After being chopped, it was dried in a vacuum drying oven at 80°C until constant weight. After being pulverized, it was passed through a 50-mesh sieve to obtain slow-release water-retaining polymer microparticles.

[0033] Preparation Example 3: This preparation example provides a method for preparing sustained-release water-retaining polymer microparticles, including the following steps: Sodium alginate was accurately weighed and dissolved in distilled water. The solution was mechanically stirred at 65°C until completely dissolved, preparing a 3.0% sodium alginate solution. The reaction system was cooled to 40°C, and acrylic acid monomer and acrylamide monomer were added sequentially, with a molar ratio of acrylic acid to acrylamide of 1:1. The total mass of acrylic acid and acrylamide monomers was 8 times the mass of sodium alginate. Before adding acrylic acid, it was pre-neutralized to 75% neutralization using a 20% sodium hydroxide solution. N,N'-methylenebisacrylamide was then added as a crosslinking agent, at a concentration of 0.1% of the total monomer mass. After purging the reaction system with nitrogen for 20 minutes to remove oxygen, potassium persulfate was added as an initiator, at a concentration of 0.8% of the total monomer mass. The reaction system was slowly heated to 70°C and maintained at this temperature for 4 hours to form a crosslinked polymer hydrogel. The cross-linked polymer hydrogel was removed, and the unreacted monomers on the surface were washed off with anhydrous ethanol. After being chopped, it was dried in a vacuum drying oven at 80°C until constant weight. After being pulverized, it was passed through a 60-mesh sieve to obtain slow-release water-retaining polymer microparticles.

[0034] Examples 1-3: Example 1: This embodiment provides a facility-based cultivation method for early maturity of kumquats, including the following steps: (1) Summer pruning and pretreatment of fermentation substrate: In August, the kumquat trees were pruned in summer, and disease-free branches were collected and crushed into wood particles with a particle size of 1.0 cm using a branch shredder. The crushed kumquat branch particles were mixed with auxiliary materials to prepare the fermentation substrate. By mass, 60 parts of crushed kumquat branches, 20 parts of rice husks, 5 parts of decomposed chicken manure, 0.1 parts of compound aerobic fermentation bacteria, and 1 part of the slow-release water-retaining polymer microparticles obtained in Example 1 were taken, mixed evenly, and water was added to adjust the overall moisture content of the mixture to 55%. Then, it was piled in a dark and ventilated place for pre-fermentation treatment for 7 days. During this period, when the temperature at the center of the pile reached 55°C, it was turned over. The turning frequency was once every 2 days until the material turned brown and had no odor. It was sealed for later use. Before use, water was added again and aeration was performed to activate it before it was put into in-situ for control.

[0035] (2) Construction of the microenvironment and fruit thinning and load control: In early September, a multi-span arched framework was constructed above the kumquat orchard. A white insect-proof net with a mesh density of 40 mesh was placed on the innermost side of the framework, and a 0.08 mm thick anti-drip and anti-fogging polyolefin insulation film was placed on the outer side of the insect-proof net. A 5 cm buffer air layer was formed between the insect-proof net and the insulation film through the gaps in the framework. After the fruit entered the fruit development period in September, fruit thinning was carried out. For fruiting branches with a base diameter of about 0.4 cm, one normally developed young fruit was retained on each branch, and deformed and overly dense fruits were removed.

[0036] (3) Habitat and water and fertilizer management during the autumn fruit enlargement period: During the fruit enlargement period from September to mid-October, adjust the opening degree of the heat preservation film, and control the average temperature inside the greenhouse during the day at 22℃. When the highest temperature inside the greenhouse exceeds 32℃, fully open the top skylight and the four sides of the skirt for ventilation and cooling. Combine the application of high potassium water-soluble fertilizer with the orchard drip irrigation system. The mass ratio of total nitrogen, available phosphorus and potassium oxide in this water-soluble fertilizer is 10:5:35, and 0.1% EDTA chelated zinc and disodium tetraborate tetrahydrate are added. The fertilization frequency is once every 10 days by drip irrigation, and the irrigation amount is controlled to keep the relative soil moisture content at a depth of 10cm in the root zone stable at 60%.

[0037] (4) Pre-harvest in-situ control: When the fruit enters the color-changing period in late October, the pre-treated fermentation substrate is moved into the greenhouse. The substrate is evenly distributed in the non-woven ventilation troughs between the fruit tree rows at a dosage of 800 kg per mu. Water is sprayed to replenish the local moisture content to 60%. From 18:00 to 07:00 the next day, the heat preservation film is completely lowered and sealed. The temperature of the aerobic fermentation pile in the trough is maintained at 50℃, and heat is released into the greenhouse so that the minimum nighttime temperature in the greenhouse is not lower than 10℃. After sunrise the next day, the greenhouse film is kept sealed for 2 hours to utilize the high concentration of carbon dioxide accumulated in the greenhouse at night in conjunction with the morning sunlight for photosynthesis. After 2 hours of sealing or when the greenhouse temperature rises to 28℃, the four sides of the skirt are opened for ventilation to reduce the relative humidity in the greenhouse to below 60%.

[0038] (5) Timely harvesting and overwintering management: In early to mid-November, when the kumquat peel has completely turned from green to orange-yellow and the soluble solids content of the fruit reaches 18% in a sample test, harvesting should be carried out in batches. After harvesting and during the winter, keep the insect-proof netting and heat-insulating film covering the fruit. After the temperature stabilizes and rises in February of the following year, the heat-insulating film should be gradually removed.

[0039] Example 2: This embodiment provides a facility-based cultivation method for early maturity of kumquats, including the following steps: (1) Summer pruning and pretreatment of fermentation substrate: In August, the kumquat trees were pruned in summer, and disease-free branches were collected and crushed into wood particles with a particle size of 2.0 cm using a branch shredder. The crushed kumquat branch particles were mixed with auxiliary materials to prepare the fermentation substrate. By mass, 65 parts of crushed kumquat branches, 25 parts of rice husks, 7.5 parts of decomposed chicken manure, 0.3 parts of compound aerobic fermentation agent, and 2 parts of slow-release water-retaining polymer microparticles obtained in Example 2 were taken, mixed evenly, and water was added to adjust the overall moisture content of the mixture to 57.5%. Then, the mixture was piled in a dark and ventilated place for pre-fermentation treatment for 8.5 days. During this period, when the temperature at the center of the pile reached 55°C, it was turned over. The turning frequency was once every 2.5 days until the material turned brown and had no odor. It was then sealed for later use. Before use, water was added again and the mixture was aerated and activated before being put into in-situ for control.

[0040] (2) Construction of the microenvironment and fruit thinning and load control: In early September, a multi-span arched framework was constructed above the kumquat orchard. A white insect-proof net with a mesh density of 50 mesh was placed on the innermost side of the framework, and a 0.10 mm thick anti-drip and anti-fogging polyolefin insulation film was placed on the outer side of the insect-proof net. A 10 cm buffer air layer was formed between the insect-proof net and the insulation film through the gaps in the framework. After the fruit entered the fruit development period in September, fruit thinning was carried out. For fruiting branches with a base diameter of about 0.5 cm, 1 to 2 normally developed young fruits were retained on each branch, and deformed and overly dense fruits were removed.

[0041] (3) Habitat and water and fertilizer management during the autumn fruit enlargement period: During the fruit enlargement period from September to mid-October, adjust the opening degree of the heat preservation film, control the average temperature inside the greenhouse during the day at 25℃, and when the highest temperature inside the greenhouse exceeds 32℃, fully open the top skylight and the four sides of the skirt for ventilation and cooling. Combine the application of high potassium type water-soluble fertilizer with the orchard drip irrigation system. The mass ratio of total nitrogen, available phosphorus and potassium oxide in this water-soluble fertilizer is 10:5:35, and 0.2% EDTA chelated zinc and disodium tetrahydrate octaborate are added. The fertilization frequency is once every 12 days by drip irrigation, and the irrigation amount is controlled to keep the relative soil moisture content at a root zone depth of 20cm stable at 65%.

[0042] (4) Pre-harvest in-situ control: When the fruit enters the color-changing period in late October, the pre-treated fermentation substrate is moved into the greenhouse. The substrate is evenly distributed in the non-woven ventilation troughs between the fruit tree rows at a dosage of 900 kg per mu. Water is sprayed to replenish the local moisture content to 60%. From 18:00 to 07:00 the next day, the heat preservation film is completely lowered and sealed. The temperature of the aerobic fermentation pile in the trough is maintained at 55℃, releasing heat into the greenhouse so that the minimum nighttime temperature inside the greenhouse is not lower than 10℃. After sunrise the next day, the greenhouse film is kept sealed for 2.5 hours to utilize the high concentration of carbon dioxide accumulated in the greenhouse at night in conjunction with the morning sunlight for photosynthesis. After 2.5 hours of sealing or when the greenhouse temperature rises to 28℃, the four sides of the skirt are opened for ventilation to reduce the relative humidity inside the greenhouse to below 60%.

[0043] (5) Timely harvesting and overwintering management: Around mid-November, when the kumquat peel has completely turned from green to orange-yellow and the soluble solids content of the fruit reaches 19% in a sample test, harvesting should be carried out in batches. After harvesting and during winter, keep the insect-proof netting and heat-insulating film covering the fruit. The heat-insulating film should be gradually removed after the temperature stabilizes and rises in mid-February of the following year.

[0044] Example 3: This embodiment provides a facility-based cultivation method for early maturity of kumquats, including the following steps: (1) Summer pruning and pretreatment of fermentation substrate: In August, the kumquat trees were pruned in summer, and disease-free branches were collected and crushed into wood particles with a particle size of 3.0 cm using a branch shredder. The crushed kumquat branch particles were mixed with auxiliary materials to prepare the fermentation substrate. By mass, 70 parts of crushed kumquat branches, 30 parts of rice husks, 10 parts of decomposed chicken manure, 0.5 parts of compound aerobic fermentation bacteria, and 3 parts of slow-release water-retaining polymer microparticles obtained in Example 3 were taken, mixed evenly, and water was added to adjust the overall moisture content of the mixture to 60%. Then, it was piled in a dark and ventilated place for pre-fermentation treatment for 10 days. During this period, when the temperature at the center of the pile reached 55°C, it was turned over. The turning frequency was once every 3 days until the material turned brown and had no odor. It was sealed for later use. Before use, water was added again and aeration was performed to activate it before it was put into in-situ for control.

[0045] (2) Construction of the microenvironment and fruit thinning and load control: In early September, a multi-span arched framework was constructed above the kumquat orchard. A white insect-proof net with a mesh density of 60 mesh was placed on the innermost side of the framework, and a 0.12 mm thick anti-drip and anti-fogging polyolefin insulation film was placed on the outer side of the insect-proof net. A 15 cm buffer air layer was formed between the insect-proof net and the insulation film through the gaps in the framework. After the fruit entered the fruit development period in September, fruit thinning was carried out. For fruiting branches with a base diameter of about 0.6 cm, two normally developed young fruits were retained on each branch, and deformed and overly dense fruits were removed.

[0046] (3) Habitat and water and fertilizer management during the autumn fruit enlargement period: During the fruit enlargement period from September to mid-October, adjust the opening degree of the heat preservation film, and control the average temperature inside the greenhouse during the day at 28℃. When the highest temperature inside the greenhouse exceeds 32℃, fully open the top skylight and the four sides of the skirt for ventilation and cooling. Combine the application of high potassium water-soluble fertilizer with the orchard drip irrigation system. The mass ratio of total nitrogen, available phosphorus and potassium oxide in this water-soluble fertilizer is 10:5:35, and 0.3% EDTA chelated zinc and disodium tetrahydrate octaborate are added. The fertilization frequency is once every 15 days by drip irrigation, and the irrigation amount is controlled to keep the relative soil moisture content at a root zone depth of 30cm stable at 70%.

[0047] (4) Pre-harvest in-situ control: When the fruit enters the color-changing period in late October, the pre-treated fermentation substrate is moved into the greenhouse. The substrate is evenly distributed in the non-woven ventilation troughs between the fruit tree rows at a dosage of 1000 kg per mu. Water is sprayed to replenish the local moisture content to 60%. From 18:00 to 07:00 the next day, the heat preservation film is completely lowered and sealed. The temperature of the aerobic fermentation pile in the trough is maintained at 60℃, and heat is released into the greenhouse so that the minimum nighttime temperature in the greenhouse is not lower than 10℃. After sunrise the next day, the greenhouse film is kept sealed for 3 hours to utilize the high concentration of carbon dioxide accumulated in the greenhouse at night in conjunction with the morning sunlight for photosynthesis. After 3 hours of sealing or when the greenhouse temperature rises to 28℃, the four sides of the skirt are opened for ventilation to reduce the relative humidity in the greenhouse to below 60%.

[0048] (5) Timely harvesting and overwintering management: In mid-to-late November, when the kumquat peel has completely turned from green to orange-yellow and the soluble solids content of the fruit reaches 20% in a sample test, harvesting should be carried out in batches. After harvesting and during the winter, keep the insect-proof netting and heat-insulating film covering the fruit. After the temperature stabilizes and rises in late February of the following year, the heat-insulating film should be gradually removed.

[0049] Comparative Examples 1-5: Comparative Example 1: Compared with Example 2, the difference is that the traditional open-field cultivation mode is adopted, without building any facility microenvironment (i.e., without insect-proof netting and heat-insulating film covering), without laying fermentation substrate prepared from pruned branches and auxiliary materials, without adding slow-release water-retaining polymer microparticles, and without pre-harvest in-situ greenhouse control (i.e., without nighttime heat preservation and morning gas-fertilizer sealing operation), while the other conventional pruning, fruit thinning and drip irrigation water and fertilizer operations are the same.

[0050] Comparative Example 2: Compared with Example 2, the difference is that: no fermentation substrate prepared from pruned branches and auxiliary materials is laid, and no slow-release water-retaining polymer particles are added, that is, the pre-harvest in-situ regulation process of fermentation heat production and carbon dioxide release is missing. The rest of the facility microenvironment construction (insect-proof net and heat-insulating film covering), conventional pruning, fruit thinning, morning sealing and drip irrigation water and fertilizer operation are the same.

[0051] Comparative Example 3: Compared to Example 2, the difference lies in the following: Traditional open-field cultivation is adopted, without constructing a multi-span arched framework and its associated microenvironment (i.e., without insect-proof netting and heat-insulating film coverage). Therefore, the nighttime lowering and morning sealing operations of the heat-insulating film in pre-harvest in-situ control are not performed. The preparation and placement of the remaining fermentation substrate, the addition of slow-release water-retaining polymer microparticles, routine pruning, fruit thinning, and drip irrigation and fertilization operations are all the same.

[0052] Comparative Example 4: Compared to Example 2, the differences are as follows: no fermentation substrate prepared from pruned branches and auxiliary materials is laid, and no slow-release water-retaining polymer microparticles are added. During the pre-harvest in-situ control period, bio-fermentation is not used to generate heat and gas; instead, conventional industrial electric heating fans are used for nighttime heating to maintain the minimum temperature inside the greenhouse at no less than 10°C. Carbon dioxide fertilizer is released into the greenhouse through an external industrial carbon dioxide cylinder during the morning sealing process the following day. The construction of the remaining microenvironment (insect-proof netting and insulation film covering), conventional pruning, fruit thinning, morning sealing time, and drip irrigation and fertilization operations are all the same.

[0053] Comparative Example 5: Compared with Example 2, the difference is that in the fermentation substrate pretreatment step, the slow-release water-retaining polymer microparticles obtained in Example 2 are not added. The overall moisture content of the mixture is adjusted to 57.5% by pure water alone. The other operations such as the construction of the facility microenvironment, the ratio and in-situ control of fermentation materials (branches, rice husks, chicken manure, and bacterial agents), and drip irrigation and fertilization are the same.

[0054] Test Examples 1-5: Test Example 1: Water Absorption / Release Kinetics Test of Water-Retaining Polymer Microparticles under High-Temperature Stress During Fermentation The sustained-release water-retaining polymer microparticles obtained from Preparation Examples 1, 2, and 3, as well as commercially available conventional agricultural and forestry-grade potassium polyacrylate water-retaining agent, were selected as comparative reagents. They were spread evenly in glass petri dishes and dried in a vacuum drying oven at 80°C for 24 hours until constant weight. After drying, 2.00 g of each sample was accurately weighed, placed into 200-mesh nylon tea bags of known mass, and sealed.

[0055] The sealed tea bags were completely submerged in a large beaker containing 1000 mL of deionized water and left to absorb water at 25°C for 24 hours to ensure the polymer network reached a sufficient swelling equilibrium. The tea bags were then removed and hung on an iron stand to drip water naturally at room temperature for 30 minutes until no more free water droplets fell. The wet weight was immediately measured using an analytical balance, and the room temperature saturated water absorption ratio was calculated by comparing the wet and dry weights of the samples.

[0056] After recording the saturated wet weight, the tea bags containing the swollen samples were quickly laid flat on a stainless steel porous tray and then transferred as a whole into a constant-temperature drying oven set at 55°C. This temperature setting was used as an intermediate representative temperature within the central temperature range of the fermentation piles in Examples 1-3 for testing.

[0057] Timing began from the moment the samples were placed in the drying oven. Every 12 hours, the oven door was opened, and each group of samples was quickly removed and weighed. The weighing process was controlled within 1 minute to avoid drastic temperature fluctuations. After recording, the samples were returned to the drying oven in their original positions. This continuous monitoring process lasted for 72 hours. Finally, the water holding capacity of the samples under different high-temperature stress durations was calculated based on the changes in wet weight at each time point.

[0058] Table 1. High-temperature water absorption / release kinetics test data of sustained-release water-retaining polymer particles and comparative reagents

[0059] Summarize: Figure 1This is a comparison graph of the water retention kinetics of the slow-release water-retaining polymer microparticles of this invention and commercially available water-retaining agents under a high-temperature environment of 55°C. In the graph, the solid lines marked with light gray triangles, medium gray squares, and pure black circles correspond to the water retention decay trends of the grafted polyacrylic acid-acrylamide semi-interpenetrating network hydrogels synthesized in Preparation Examples 1, 2, and 3 under three different ratio parameter limits during continuous high-temperature baking. The dashed lines marked with asterisks represent the free water loss of the comparative reagent (commercially available potassium polyacrylate agricultural water-retaining agent) without an interpenetrating network structure under the same environment.

[0060] According to the data in Table 1, commercially available conventional potassium polyacrylate water-retaining agents exhibit an initial saturation water absorption rate as high as 273.5 g / g at room temperature. When placed in a high-temperature stress environment simulating aerobic fermentation at a constant temperature of 55°C, this internally monotonous and loose hydrophilic network rapidly collapsed under thermodynamic driving. The water holding capacity of this reagent plummeted to 45.3% after only 24 hours, and was almost completely dehydrated after 72 hours. In our previous comparative tests in conventional open-field agriculture, we found that while this traditional material can cope with slow evaporation under natural conditions, once placed in a closed and continuously high-temperature fermentation pile system, it not only fails to effectively retain water, but also causes the entire system's free water to evaporate rapidly due to the large amount of water absorbed initially and the sudden release of water later. Faced with this extreme physical dehydration phenomenon, how to construct a liquid-phase buffer mechanism that can still operate robustly under continuous high-temperature thermodynamic conditions becomes the key to overcoming this technical bottleneck.

[0061] The grafted polyacrylic acid-acrylamide semi-interpenetrating network hydrogel designed in this scheme exhibits distinctly different water migration kinetics. The initial water absorption ratios of Preparation Examples 1 to 3 were strictly controlled within the range of 143.6 to 214.8 g / g. This intervention in the ultimate water absorption capacity was essentially to construct a denser water-binding barrier. Under continuous baking at 55°C for 72 hours, the microparticles of Preparation Example 2, which were at the middle limit of the parameters, robustly retained 50.2% of their internal water content. Even Preparation Example 1, with its more conservative formulation parameters, maintained a water holding capacity of over 34.6%. Fermentation monitoring records from the actual facility confirmed this result. The water-releasing effect of the underlying physical morphology of the material precisely offset the intense thermal evaporation that accompanied the high-temperature fermentation, maintaining a stable liquid-phase micro-region for the aerobic microbial community inside the pile. The stable and resilient water release capability exhibited by the polymer microparticles under extreme conditions fundamentally eliminates the physical trigger for dormancy during fermentation caused by environmental dehydration, ensuring the continuous operation of the fermentation system's constant heat production at night and high-concentration carbon dioxide release mechanism in the morning.

[0062] Test Example 2: In-situ heat production and sustained carbon source release (CO2) test of fermentation system Fermentation substrates containing different proportions of slow-release water-retaining polymer microparticles, prepared using different comprehensive formulation parameters in Examples 1-3, were selected. Meanwhile, the fermentation substrate in Comparative Example 5, which did not contain water-retaining microparticles and relied solely on pure water to adjust the initial moisture content, was used as a control sample. 40.0 kg of each substrate mixture was accurately weighed and filled into an open fermentation box of uniform volume with a 5 cm thick polyurethane insulation board lining the inner wall. The bottom of the fermentation box was equipped with a microporous breathable mesh, designed to highly replicate the microenvironment of the non-woven fabric ventilation channels between rows in an actual orchard.

[0063] A calibrated insertion-type K-type thermocouple temperature probe was deeply embedded at the geometric center of the material in each fermentation tank, with the probe end connected to a multi-channel paperless recorder. After system startup, the temperature change at the center of the pile was continuously recorded for 15 days at ambient temperature. Days 1, 3, 5, 7, 9, 11, 13, and 15 were selected as representative time points and listed in Table 2. The average temperature data during the critical nighttime greenhouse control period from 18:00 to 07:00 the next day was extracted to evaluate the stability of each group of fermentation heat-generating engines.

[0064] The carbon source release flux during fermentation was measured simultaneously within the same temperature monitoring cycle. Every morning at 07:00, 1.5 kg of uniformly mixed substrate samples were randomly collected from multiple points 10 cm below the surface of each fermentation chamber and quickly transferred to a custom-made, sealed acrylic reaction chamber with a volume of 30 L. The chamber was pre-installed with a high-precision NDIR non-dispersive infrared carbon dioxide sensor. The reaction chamber was completely sealed and maintained for 2 hours, and the absolute concentration of carbon dioxide in the chamber at the end of the sealing period was recorded. The samples were then removed and returned to the original fermentation chamber. This was repeated for 15 days to obtain the attenuation of the aerobic metabolic release of gaseous fertilizer from the compost pile.

[0065] Table 2. Monitoring data of fermentation pile center temperature and cumulative CO2 concentration after 2 hours of sealing over 15 consecutive days.

[0066] Summarize: Figure 2 This is a continuous heat production kinetic monitoring diagram of the fermentation system of this invention. The solid lines marked with hollow triangles, the solid lines marked with medium-gray filled squares, and the solid lines marked with pure black filled circles represent the central temperature fluctuation trajectories of the fermentation substrates in Examples 1, 2, and 3, respectively, with different proportions of slow-release water-retaining polymer particles added, during their aerobic metabolism. The dashed lines marked with asterisks reflect the temperature decay process of the fermentation pile in Comparative Example 5, where the initial moisture content was adjusted solely by pure water due to the absence of custom water-retaining particles. The horizontal dashed line at 20°C marks the reference limit between ambient temperature and physiological safety.

[0067] According to the data in Table 2, the conventional fermentation substrate in Comparative Example 5 exhibited normal start-up characteristics in the early stages of fermentation. The core temperature of the compost pile rapidly climbed to 56.4℃ on day 3, corresponding to a CO2 release concentration of 3210 ppm, indicating that the initial carbon-to-nitrogen ratio of the fermentation material was within a reasonable range. However, as the fermentation pile remained at temperatures above 50℃, the moisture inside the substrate began to dissipate in large quantities as vapor. Due to the lack of an effective buffering structure at the bottom, the liquid microenvironment upon which aerobic microorganisms depended collapsed rapidly after day 5. This irreversible physical dehydration forcibly halted the respiratory and metabolic activities of the microorganisms. Monitoring data clearly reflected this deterioration process; its heat and gas production indicators plummeted from day 7, and by day 11, the pile temperature had dropped to 22.8℃, essentially losing its function as a heat source for the greenhouse at night. In our long-term monitoring of facility agriculture, we observed that this sudden cessation of fermentation due to rapid moisture depletion is the most common technical failure mode when traditional compost is applied in closed facilities.

[0068] The monitoring results of Examples 1 to 3 confirmed the profound intervention and reshaping effect of the high-molecular water-retaining microparticles on the entire bio-fermentation engine. Taking the data of Example 2 as an example, with the support of the stable dynamic balance of water absorption and release by the microparticles, the fermentation substrate not only successfully crossed the 50°C start-up threshold on the 3rd day, but also maintained the core temperature of the pile within the highly efficient heat-generating range of 50.7°C to 55.6°C for more than 10 days thereafter. This stable and sustained bottom-layer bio-heat can effectively offset the sudden drop in external temperature at night in late autumn and early winter, ensuring that the microenvironment inside the greenhouse is always above the physiological safety threshold of the crops. Accompanying the constant heat production is a continuous high release of carbon dioxide. Example 2 maintained a CO2 accumulation of more than 2600 ppm within 2 hours of sealing throughout the middle and late stages of the monitoring. This long-lasting gas fertilizer supply accompanied by suitable temperature and humidity precisely meets the high carbon assimilation needs of kumquats when their stomata open in the morning, verifying the scientific feasibility of the pre-harvest in-situ microenvironment regulation mechanism of this invention from both physical and biological dimensions.

[0069] Test Example 3: Dynamic Comparison Test of Physical Parameters (Heat-Water) of Facility Microenvironment The orchards of Example 2, Comparative Example 1, Comparative Example 3, and Comparative Example 4, located in late October during the fruit ripening stage, were selected as test areas. Three kumquat trees of uniform growth were randomly selected within each test area as monitoring points to control for measurement errors caused by spatial heterogeneity.

[0070] A calibrated self-contained temperature and humidity data logger was suspended at a height of approximately 1.5 meters above the ground in the middle of the selected fruit tree canopy, with a sampling frequency set to once every 30 minutes. Temperature fluctuations during the late autumn and early winter cold waves were recorded for 10 consecutive days. The lowest temperature extreme value during the nighttime period from 20:00 to 06:00 the following day was extracted daily to evaluate the actual resistance effectiveness of different control modes against low-temperature stress.

[0071] Simultaneous monitoring of root zone water evapotranspiration kinetics was conducted. TDR soil moisture sensors were installed parallel to each tree in the dense root zone, approximately 20 cm inside the drip line. One day prior to the experiment, the relative soil moisture content of each group was uniformly replenished to an initial baseline of 75% using a drip irrigation system. Subsequently, without any supplemental irrigation, the relative soil moisture content at 12:00 noon was recorded daily for 10 consecutive days to examine the subsurface water retention capacity of different systems under thermal effects.

[0072] Table 3. Monitoring data of nighttime minimum temperature and relative soil moisture content in the root zone for each experimental group during 10 consecutive days in late autumn.

[0073] Summarize: Figure 3 This is a graph showing the decline curves of relative soil moisture content in the root zone over 10 consecutive days under different control modes of this invention. The solid line marked with a light gray triangle represents the stable change trend of root zone moisture in Example 2, where a complete photothermal synergistic microenvironment was constructed. The dashed line marked with a hollow circle and the dotted line marked with a dark gray square correspond to the water loss trajectories in the open field environment of Comparative Example 1 and without physical barriers in Comparative Example 3, respectively. The dotted line marked with an asterisk shows the extreme soil dehydration phenomenon caused by forced heating with an industrial hot air blower in Comparative Example 4.

[0074] According to the data in Table 3, Comparative Example 1, cultivated in a traditional open field, completely lost its physical barrier against chilling injury when the outside temperature plummeted in late autumn. Its extreme nighttime low temperature approached the dangerous critical point of 2.5℃, and coupled with the dual depletion caused by the monsoon and direct daytime sunlight, soil moisture rapidly dropped to 34.9% within 10 days. Comparative Example 3 introduced fermentation substrate and water-retaining microparticles in an attempt to construct a micro-ecosystem from the surface, but under open conditions lacking the containment of an insulating film, the heat from the underlying organisms rapidly dissipated into the external space. This rapid energy loss resulted in its minimum nighttime temperature remaining only around 4.3℃. Although the water-retaining microparticles provided some liquid-phase buffering in the early stages, they were still unable to withstand the enormous evapotranspiration load under unshaded conditions. Our long-term field monitoring in a conventional greenhouse revealed that Comparative Example 4, through industrial electric heating, was indeed able to forcibly raise and maintain the minimum nighttime temperature at a relatively high level above 13℃. This forced point-source heating completely disrupted the original moisture and heat balance in the root zone. The extreme drying effect caused by industrial hot air directly led to a sharp drop in soil moisture content, which had fallen to the wilting warning line of 29.8% by the 10th day. Such continuous dry heat stress often causes large-scale shrinkage and damage to the fine root system of kumquats.

[0075] The multidimensional synergistic system established in Example 2 exhibited excellent physical buffering resistance. The closed air layer constructed by the heat-insulating film and insect-proof net effectively locked in the heat gently released from the bottom fermentation substrate, successfully keeping the nighttime temperature stably within the optimal physiological safety range of 10.5℃ to 12.1℃. In this closed system, the natural increase in relative humidity significantly reduced the water vapor pressure difference at the surface. Combined with the slow release of water by the high molecular particles inside the substrate, Example 2 still maintained a soil relative moisture content of 62.9% at the end of a 10-day no-irrigation cycle. This steady-state physical habitat maintenance mechanism, which avoids harsh mechanical intervention and high energy consumption, provides reliable physical support for normal root respiration and metabolism and efficient and continuous absorption of mineral nutrients.

[0076] Test Example 4: Comparative Test of Photosynthetic Physiological Parameters and Fertilizer Assimilation During the Autumn Enlargement Period of Kumquats Orchard plots from Examples 2, 1, 2, and 4, which were in the early stage of fruit color change / pre-harvest regulation, were selected as test subjects. Five kumquat trees with balanced growth and similar fruit load were randomly marked in each plot, and disease-free, fully expanded mature functional leaves were selected from the sunny side of the upper part of the canopy as test samples.

[0077] The experiment was scheduled to take place between 08:00 and 10:00 in the morning on a day with consecutive sunny days. This period is the critical operation period for the greenhouse to carry out the sealing and heat preservation and gas-fertilizer conversion after sunrise. It is also the window period with the largest opening of plant stomata in the natural rhythm of plant stomata.

[0078] In-situ non-destructive testing was performed on selected leaves using a LI-6400XT portable photosynthesis meter. To eliminate interference from light intensity fluctuations caused by natural cloud cover, the built-in red and blue light sources of the meter were uniformly turned on, and the photosynthetically active radiation intensity inside the leaf chamber was stabilized at 1000 μmol / (m²). 2 ·s).

[0079] Starting at 08:00, the marked leaves were clamped and measured every 30 minutes, and the net photosynthetic rate and stomatal conductance were read simultaneously. The physiological response characteristics of the leaves of each treatment group in response to the dynamic changes in temperature, humidity and carbon dioxide concentration in the greenhouse were continuously recorded throughout the entire closed-loop period.

[0080] Table 4. Dynamic monitoring data of net photosynthetic rate and stomatal conductance of kumquat leaves during morning closed-loop operation.

[0081] Note: Net photosynthetic rate is expressed in μmol CO2 / (m 2 ·s), the unit of stomatal conductivity is molH2O / (m 2 ·s).

[0082] Summarize: Figure 4 This is a comparison chart of the dynamic changes in the net photosynthetic rate of kumquat leaves during the morning closed period of this invention. In the chart, the solid line marked with a light gray triangle represents the photosynthetic efficiency trajectory of Example 2 under continuous supply of bottom fermentation gas fertilizer; the dashed line marked with a hollow circle represents the natural photosynthetic state of Comparative Example 1 under the traditional open field environment; the dotted line marked with a medium gray square shows the photosynthetic decline phenomenon caused by carbon source depletion in Comparative Example 2 in the closed facility; the dotted line marked with an asterisk reflects the photosynthetic stress decline process after Comparative Example 4 uses an industrial carbon dioxide cylinder for instantaneous gas replenishment and is superimposed with an electric heating fan.

[0083] According to the data in Table 4, Comparative Example 1, grown in traditional open field, was in a completely open environment without any insulation barrier. The low morning temperature directly inhibited the activity of ribulose-1,5-bisphosphate carboxylase inside the leaves. In addition, the extremely limited natural carbon dioxide concentration in the air resulted in a slow increase in its net photosynthetic rate throughout the morning, which never exceeded 9.2 μmol CO2 / (m²). 2 The inefficient range of ·s). Although Comparative Example 2 established a facility microenvironment and implemented closed-loop insulation operations, it initially (08:00) had a high photosynthetic starting point. However, in the closed air chamber without any additional carbon source replenishment, the abundant canopy of kumquats rapidly depleted the limited carbon dioxide reserves. We observed this passive stress caused by stomatal starvation in the instrument readings, with stomatal conductance contracting sharply from 09:00 onwards, and the net photosynthetic rate subsequently experiencing an irreversible decline.

[0084] Comparative Example 4, which involved forced industrial intervention, exhibited a pulsed, false prosperity. At 08:00, when high-purity industrial carbon dioxide was released, its net photosynthetic rate instantaneously increased to 14.5 μmol CO2 / (m²). 2 However, this purely physical irrigation, which was detached from the buffer of a humid environment, could not be sustained. As the continuous dry heat from the industrial hot air blower exacerbated the loss of water from the leaves, the plant was forced to activate its self-defense mechanism to close its stomata in order to conserve water. Stomatal conductance was halved in just one hour, the carbon assimilation pathway was physically cut off, and photosynthetic efficiency plummeted.

[0085] Example 2 demonstrates the robustness and synergistic effect characteristic of a biological closed loop. The carbon dioxide steadily released throughout the night from the bottom fermentation pile forms a high-concentration enrichment zone within the insulating film. The water vapor generated during fermentation and the humid airflow emitted by water-retaining particles maintain the relative humidity inside the shed at a suitable level, preventing interference from dry heat stress on the stomata. With the increase in photosynthetically active radiation after sunrise, at the optimal physiological point of 09:00, the stomatal conductance of Example 2 reaches 0.26 mol H2O / (m²). 2 The peak value of ·s) was reached, and the net photosynthetic rate subsequently surged to 18.2 μmol CO2 / (m 2 The soluble solids content of kumquats is at an extremely high level. This continuous supply of mild aerobic fertilizer achieves a perfect dynamic coupling with the plant's natural morning activity period, ensuring that photosynthetic products are precipitated into carbohydrates at the maximum conversion rate. This thoroughly elucidates from the underlying physiological mechanism why this invention can significantly increase the soluble solids content of kumquats at the final harvest.

[0086] Test Example 5: Quantitative Testing of Final Agronomic Yield, Early Maturity, and Quality Indicators Orchards of Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 4, and Comparative Example 5 were selected as long-term tracking test areas. After the fruit entered the color-changing stage, 10 kumquat trees were randomly selected from each area weekly for field observation and destructive sampling. The uniform harvesting baseline was defined as the fruit peel completely turning from green to orange-yellow and the soluble solids content reaching 18.0% as measured by sampling. The uniform harvesting baseline date for each area reaching this standard was recorded, and the specific number of days for early ripening was calculated based on the harvest date of Comparative Example 1.

[0087] When each block reaches the corresponding harvesting standard and is harvested in batches, all fruits from the aforementioned 10 marked kumquat trees are harvested and weighed, and the total yield per tree is obtained by summing the results. Five well-developed fruits are randomly picked from the upper and middle canopy of each tree in the east, south, west, and north directions, and each fruit is weighed using an electronic balance with an accuracy of 0.01%, and the average weight of each fruit is calculated.

[0088] The collected fruit samples were brought back to the laboratory for extraction and determination of core physicochemical quality indicators. After peeling the fruit, the juice was extracted and filtered through double-layered degreased gauze. The clarified juice was then dropped into the sample cell of a portable digital refractometer, and the soluble solids content was read and recorded.

[0089] Accurately transfer 10.0 mL of filtered clarified juice into an Erlenmeyer flask, dilute with an appropriate volume of carbon dioxide-free distilled water, add phenolphthalein indicator, and titrate with a standardized 0.1 mol / L sodium hydroxide standard solution until a faint red color appears and does not fade within 30 seconds. Record the volume of sodium hydroxide solution consumed, calculate the titratable acid content in the juice according to the conversion formula, and finally obtain the ratio of soluble solids to titratable acid.

[0090] Table 5. Test data of final agronomical yield and fruit physicochemical quality of kumquat under different regulation modes

[0091] Summarize: Figure 5 This is a distribution chart of the dual indicators of kumquat yield and soluble solids per tree under different control modes of this invention. The horizontal axis in the chart corresponds to the five groups with different physical and biological intervention conditions in the aforementioned field sampling test. The solid line with light gray filled square marks associated with the left main axis represents the fluctuation of the average yield per tree measured at the harvest period of each group of kumquats; the dashed line with pure black filled triangle marks associated with the right secondary axis records the differences in the accumulation of soluble solids content inside the fruit.

[0092] According to the data in Table 5, the vulnerability of open-field cultivation environments to drastic changes in natural climate during late autumn is clearly exposed. During field sampling, we found that the fruit peel of Comparative Example 1 remained greenish for an extended period, and the root system essentially ceased absorbing mineral nutrients in temperatures below 10℃, forcing a delay in harvest until the end of December. The continuous low-temperature damage and accompanying frost not only caused severe fruit drop, drastically reducing the yield per plant to 17.85 kg, but also hindered acid metabolism in the fruit, resulting in a solid-acid ratio of only 16.88, leading to extremely low commercial value. While the microenvironment built solely by physical barriers intercepted direct frost, it failed to truly address the underlying dynamics of plant growth. Taking Comparative Example 2 as an example, the greenhouse insulation film did advance its harvest by 24 days, but the complete lack of exogenous carbon dioxide limited the photosynthetic carbon assimilation process in the leaves, causing soluble solids to stagnate after reaching 15.11%. This phenomenon also occurred in Comparative Example 4, which used industrial hot air and cylinder gas. Conventional electric heating caused a sharp drop in local air humidity inside the greenhouse, and the dry hot air directly accelerated the lateral evaporation of moisture from the fruit skin. This explains why Comparative Example 4, after being supplemented with high-concentration industrial gas fertilizer, had the lowest single fruit weight of only 13.67g. This abrupt artificial intervention disrupted the water-air exchange balance of the leaf stomata, resulting in a persistently low efficiency in the translocation of photosynthetic products to the fruit.

[0093] The hidden impacts of missing core components within the system were confirmed in the data from Comparative Example 5. Without the buffering effect of water-retaining microparticles, the heat production and carbon dioxide release processes of the fermentation substrate were halted midway due to material dehydration, resulting in the final fruit's physicochemical quality failing to reach the set upper limit, with significant losses in both early maturity and sugar content. The limitations of these fragmented intervention methods highlight the practical production significance of integrating polymer materials and bio-fermentation into the facility cultivation framework in Example 2.

[0094] The sustained and stable bio-source warm and humid airflow at the bottom layer, combined with the rhizosphere water and fertilizer buffer zone constructed by high-molecular-weight particles, produced a substantial agronomic synergistic effect. Example 2 reached peak maturity on November 12th, an advancement of 46 days. Individual fruits were fully developed, and the total yield exceeded 31 kg. More importantly, the excessive accumulation of carbohydrates within the fruit pushed its sugar-acid ratio to an optimal taste threshold of 45.40. These differences in yield and physicochemical quality demonstrate that a close integration of the bottom-layer material transformation mechanism and the meteorological regulation of the above-ground environment is the effective way to completely overcome the bottleneck of inefficient winter cultivation of kumquats.

Claims

1. A method for early ripening of golden oranges in a facility cultivation, characterized by, The following processing steps are included: A fermentation substrate was prepared by pre-fermenting a mixture of crushed kumquat branches, auxiliary materials, and slow-release water-retaining polymer particles. In a facility microenvironment where insect-proof nets, heat-insulating films, and buffer air layers are constructed for the kumquats, the prepared fermentation substrate is used to implement pre-harvest in-situ regulation during the color-changing period of the kumquat fruit. In the pre-harvest in-situ control, the opening degree of the heat preservation film is adjusted, and the fermentation substrate releases heat into the greenhouse at night. The high concentration of carbon dioxide accumulated in the greenhouse at night is used in conjunction with the morning sunlight to carry out photosynthesis the next morning. After completing the pre-harvest in-situ regulation, once the kumquat peel has completely turned from green to orange-yellow and the soluble solids content of the fruit reaches the appropriate harvesting baseline, the kumquats are harvested in batches.

2. The facility cultivation method for early ripening of golden orange according to claim 1, characterized in that, In the preparation of the fermentation substrate, the auxiliary materials include rice husks, decomposed chicken manure, and compound aerobic fermentation agents. The raw materials are composed of the following components by mass: The mixture consists of 60-70 parts of crushed kumquat branches, 20-30 parts of rice husks, 5-10 parts of decomposed chicken manure, 0.1-0.5 parts of compound aerobic fermentation agent, and 1-3 parts of slow-release water-retaining polymer microparticles. The kumquat branches are crushed into wood particles with a particle size of 1.0-3.0cm.

3. The facility cultivation method for early ripening of golden orange according to claim 1, characterized in that, The pre-fermentation process is as follows: Add water to adjust the overall moisture content of the raw materials to 55-60%, and pile them in a dark and ventilated place for the pre-fermentation treatment for 7-10 days. When the temperature at the center of the pile reaches 55℃, turn the pile over once every 2-3 days. The fermentation substrate is rehydrated and activated by aeration before being introduced into the pre-harvest in-situ regulation.

4. The facility cultivation method for early ripening of golden orange according to claim 1, characterized in that, The method for constructing the microenvironment of the facility, including the insect-proof net, heat-insulating film, and buffer air layer, is as follows: The innermost side of the skeleton is covered with a white insect-proof net with a mesh density of 40-60 meshes, and the outer side is covered with a drip-proof and anti-fogging polyolefin insulation film with a thickness of 0.08-0.12mm. A buffer air layer of 5-15cm is formed between the insect-proof net and the insulation film through the gaps in the skeleton.

5. The facility cultivation method for early ripening of golden orange according to claim 1, characterized in that, In the microenvironment of the facility, the management steps during the fruit enlargement period of the kumquat are as follows: During the day, the average temperature inside the greenhouse is controlled at 22-28℃. High-potassium water-soluble fertilizer is applied in conjunction with the orchard drip irrigation system. The fertilization frequency is once every 10-15 days. The relative soil moisture content at a root zone depth of 10-30cm is controlled to remain stable at 60%-70%.

6. A method for early maturation of golden orange fruits as claimed in claim 1, wherein, The operating parameters for the pre-harvest in-situ control are: After rehydration and aeration, the fermentation substrate, after being re-watered and activated, is evenly distributed in the non-woven fabric ventilation troughs between the fruit tree rows at a rate of 800-1000 kg per acre. Water is then sprayed to replenish the local moisture content to 55-65%. Between 18:00 and 07:00 the next day, the insulation film is completely lowered and sealed, and the center temperature of the aerobic fermentation pile in the tank is maintained at 50-60℃. Heat is released into the shed so that the minimum temperature inside the shed at night is not lower than 10℃. After sunrise the next day, keep the greenhouse film sealed for 2-3 hours. Once at least one of the following conditions is met—that the film can be sealed for 2-3 hours or that the greenhouse temperature can rise to 26-30℃—open the four sides of the greenhouse for ventilation to reduce the relative humidity inside the greenhouse to below 60%.

7. The facility cultivation method for early ripening of golden orange according to claim 1, characterized in that, The appropriate baseline is that the soluble solids content of the sampled fruit reaches 18%-20%.

8. The facility cultivation method for early ripening of golden orange according to claim 1, characterized in that, The raw materials for preparing the sustained-release water-retaining polymer microparticles include: Sodium alginate, acrylic acid monomer, acrylamide monomer, N,N'-methylenebisacrylamide and potassium persulfate; The molar ratio of the acrylic monomer to the acrylamide monomer is 1:1, and the total mass of the acrylic monomer and the acrylamide monomer is 5-8 times the mass of the sodium alginate. The acrylic monomer is pre-neutralized to a degree of neutralization of 70-75% using a sodium hydroxide solution with a mass fraction of 18-22%.

9. The facility cultivation method for early ripening of golden orange according to claim 8, characterized in that, The preparation method of the sustained-release water-retaining polymer microparticles is as follows: The sodium alginate was dissolved in distilled water to prepare a sodium alginate solution with a mass concentration of 2.0-3.0%; After the reaction system is cooled to 40°C, the pre-neutralized acrylic monomer and the acrylamide monomer are added sequentially. Subsequently, 0.05%-0.1% of the total monomer mass of the N,N'-methylenebisacrylamide was added; After purging nitrogen gas into the reaction system to remove oxygen for 18-22 minutes, add potassium persulfate at a concentration of 0.5-0.8% of the total monomer mass. The cross-linked polymer hydrogel is formed by slowly heating to 65-70℃ and holding the temperature for 3-4 hours. Unreacted monomers on the surface are washed off with anhydrous ethanol, chopped, and dried in a vacuum drying oven at 78-82℃ until constant weight. After pulverizing, it is passed through a 40-60 mesh sieve to obtain the final product.

10. The facility cultivation method for early ripening of golden orange according to claim 1, characterized in that, After the batch harvest and during the winter, there are overwintering management steps to keep the insect-proof net and the heat-insulating film in place. The heat-insulating film is gradually removed after the temperature stabilizes and rises in February of the following year.

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