An optimized cultivation method of immature fructus aurantii

Abstract

The application provides an optimized cultivation method of immature fructus aurantii, and relates to the technical field of traditional Chinese medicine planting, which comprises the following steps: collecting mature fructus aurantii fruits to obtain seeds, mixing the seeds with wet sand after rinsing and disinfecting for temperature-variable sand storage and stratification treatment, and preparing for sowing when the seed white rate is more than 70%. A seedling raising substrate is prepared and loaded into a seedling raising container, the white seeds are sowed, the environmental temperature and humidity are controlled, and the seedlings are cultivated until multiple true leaves grow. Suitable nursery land is selected, the land is prepared and fertilized, the seedlings are transplanted with complete substrate soil mass, and root fixing water is poured. Water and fertilizer management is implemented in stages during the slow seedling period, the sprouting period and the lignification period. When the seedlings grow to the fixed height, the main branches are selected and pruned, and the disease and pest control is simultaneously performed. When the seedling ground diameter and the plant height meet the nursery standard, the seedlings are transplanted, the soil ball is reserved, the root is dipped in the moisturizing slurry, and the seedling cultivation is completed. The application improves the immature fructus aurantii seedling and the qualified rate of nursery by the temperature-variable sand storage and stratification treatment and the substrate improvement.

Description

Technical Field

[0001] This invention relates to the field of traditional Chinese medicine cultivation technology, specifically to an optimized cultivation method for Citrus aurantium seedlings. Background Technology

[0002] Citrus aurantium, or bitter orange peel, is the dried, immature fruit of Citrus aurantium and its cultivated varieties, belonging to the Rutaceae family. It has medicinal properties of regulating qi, relieving chest congestion, and alleviating bloating, and is a commonly used traditional Chinese medicine. In addition to its stable medicinal market demand, its seedlings can also serve as high-quality rootstock for citrus grafting, giving it significant value for industrial cultivation.

[0003] Currently, cultivation techniques related to trifoliate orange (Citrus trifoliata) have been publicly disclosed in the industry. For example, CN107896774A describes a method for planting trifoliate orange, but it has the following problems: 1. The seeds of Citrus aurantium have a certain dormancy characteristic. They are simply buried in sand pits with mixed sand. The variable temperature stratification process is not disclosed. The seeds rely on the natural environment to break dormancy. The seeds germinate slowly and have a long germination cycle.

[0004] 2. Direct field sowing and seedling raising lacks a suitable seedling substrate for the growth of trifoliate orange seedlings. The physical and chemical properties of the field soil are unstable, and the aeration, water retention and nutrient supply capacity are difficult to control. The risk of soil-borne diseases is high, and problems such as uneven emergence and weak seedling root development are likely to occur. The quality of seedlings is poorly controllable, which is not conducive to subsequent transplanting survival. Summary of the Invention

[0005] This invention provides an optimized cultivation method for trifoliate orange seedlings to solve at least one of the technical problems mentioned in the background section.

[0006] To solve the above-mentioned technical problems, this invention discloses an optimized cultivation method for trifoliate orange seedlings, comprising: S1: Collect mature trifoliate orange fruits, remove the seeds and rinse and disinfect them. After disinfection, mix them with wet sand for variable temperature sand stratification. When the white sprouting rate of the trifoliate orange seeds reaches more than 65%, prepare for sowing. S2: Prepare the seedling substrate and fill it into the seedling container. Sow the white-tipped trifoliate orange seeds in the seedling substrate, regulate the temperature and humidity of the seedling environment, and cultivate until the trifoliate orange seedlings grow multiple true leaves. S3: Select a suitable nursery site for the cultivation of trifoliate orange seedlings, prepare the soil in the nursery site, apply fertilizer, transplant the trifoliate orange seedlings along with the complete substrate soil ball to the nursery site, and water them after transplanting; S4: Water and fertilizer management should be carried out in three stages: seedling establishment period, shoot emergence period, and lignification period; S5: After the seedlings reach the required height, select the main branches for shaping and carry out pest and disease control. S6: After the seedlings reach the required diameter and height for sale, lift them up, keeping the root ball intact, and dip the roots in moisturizing mud.

[0007] Preferably, in step S1, the unqualified bitter orange seeds are removed, and the qualified bitter orange seeds are then rinsed and disinfected. The disinfection is carried out by placing the rinsed bitter orange seeds in a 0.3%-0.5% potassium permanganate solution and soaking for 15-20 minutes. After soaking, the bitter orange seeds are taken out and rinsed with clean water.

[0008] Preferably, the variable-temperature sand stratification is performed as follows: sterilized trifoliate orange seeds are mixed with moist river sand at a volume ratio of 1:3-4. During sand stratification, the seeds are laid in alternating layers, with one layer of river sand followed by one layer of trifoliate orange seeds. After stratification, the seeds are first placed in an environment of 4-6℃ for 30-35 days, then buffered in an environment of 8-10℃ for 3-5 days, and finally transferred to an environment of 12-15℃ for 10-15 days. The seeds are turned over and inspected regularly to prevent mold growth.

[0009] Preferably, the preparation process of the seedling substrate includes: mixing the substrate raw materials, disinfecting the substrate raw materials after mixing, cooling to room temperature and adjusting the pH value of the substrate to 5.5-6.5; by weight, the substrate raw materials include: 28-38 parts of decomposed trifoliate orange peel branches, 18-26 parts of peat moss, 20-30 parts of decomposed edible mushroom residue, 4-7 parts of perlite, 5-9 parts of vermiculite, and 3-6 parts of calcium magnesium phosphate fertilizer.

[0010] Preferably, the preparation process of the decomposed bitter orange peel branches includes: collecting disease-free bitter orange peel branches and crushing them; passing the crushed material through an 18mm sieve and a 12mm sieve in sequence, retaining bitter orange peel branches in the 12-18mm range; adjusting the carbon-nitrogen ratio of the bitter orange peel branches to 25-30:1 and the moisture content to 55-65%; subjecting the adjusted bitter orange peel branches to aerobic composting; maintaining the core temperature at 55-65℃ for a cumulative period of 15-20 days after the core temperature reaches 55-65℃; turning the pile regularly; and sieving the material after it has cooled to ambient temperature to obtain decomposed bitter orange peel branches; the pile height is 1.1-1.3m and the bottom width is 1.2-2.0m.

[0011] Preferably, after adjusting the pH of the substrate to 5.5-6.5, Bacillus subtilis is mixed in when filling the seedling container with the seedling substrate; Bacillus subtilis is added at 0.5%-1.0% of the total mass of the seedling substrate.

[0012] Preferably, the preparation process of the seedling substrate includes: S21: Premix well-rotted trifoliate orange peel branches, peat moss, and well-rotted edible mushroom residue to obtain a premixed material; S22: Adjust the moisture content of the premixed materials to 48%-52%, stack the premixed materials in layers to the preset stacking thickness, cover with a film to keep warm and stand for 48-72 hours for disinfection, and after disinfection, allow it to cool naturally to room temperature and complete the pH adjustment to 5-5.8; the preset stacking thickness is 1.0-1.3m; S23: Add perlite and vermiculite to the material obtained in S22 and mix them; S24: Add calcium magnesium phosphate fertilizer to the material obtained in S23 and mix. S25: Adjust the pH of the material obtained in S24 to 5.5-6.5.

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention employs a three-stage gradient temperature stratification process: "low-temperature after-ripening - medium-temperature buffering - high-temperature germination." It also utilizes a stratification method that alternates between layering seeds and moist substrate to prevent seed clumping and ensures that each seed is evenly exposed to the temperature and humidity environment, reducing localized dampness and mold growth. First, the embryo undergoes physiological after-ripening at a low temperature of 4–6℃, gradually reducing abscisic acid content. Then, a medium-temperature transition at 8–10℃ activates metabolic enzyme activity. Finally, radicle growth is initiated at 12–15℃, systematically breaking seed dormancy from a physiological perspective. This results in increased seed emergence rate and germination uniformity, laying the foundation for subsequent robust seedling cultivation.

[0015] 2. This invention first crushes and screens the trifoliate orange peel branches before composting, removing fine powder and oversized pieces. A controlled mix of particles within a 12-18mm range is then selected for composting. This avoids the uniformity of pore types caused by single particle sizes and differs from the uncontrolled, random mixing of multiple particle sizes in Comparative Example 2. After the pre-controlled mix of materials is added to the pile, the materials are interleaved, resulting in more even water and heat transfer during composting, ensuring optimal decomposition. Furthermore, by pre-adjusting the carbon-to-nitrogen ratio to 28:1 and precisely controlling the core temperature at 55-65℃ for 18 days, high-temperature aerobic microorganisms fully degrade the lignocellulose, converting it into humus and small-molecule nutrients easily absorbed by the roots. Simultaneously, the high temperature completely neutralizes the branches, eliminating phenolic inhibitors and unwanted bacteria. The resulting decomposed branches have both slow-release nutrient and rhizosphere environment-improving effects, significantly promoting seedling growth and increasing the final seedling pass rate to 90.5%.

[0016] 3. This invention employs a step-by-step preparation process: First, the organic raw materials are pre-mixed and then sealed and piled up. The fermentation heat of the materials achieves overall sterilization at a temperature above 55°C, thoroughly inactivating deep-seated pathogens and insect eggs in the substrate without the need for additional disinfectants. Then, lightweight aggregates and calcium magnesium phosphate fertilizer are added sequentially at different speeds to avoid salt damage caused by localized fertilizer agglomeration. Simultaneously, a two-step method is used to precisely adjust the pH: If the target pH is adjusted directly at once, the organic buffer system inside the substrate is prone to pH rebound and drift, making it difficult to maintain a stable suitable range. This invention adjusts the pH in two steps: first, the pH is coarsely adjusted to approach the target range, and then finely corrected to 5.8, which is suitable for trifoliate orange seedlings, after the organic matter inside the substrate has achieved buffer equilibrium. This avoids the problem of pH rebound and drift, and stably constructs a rhizosphere microenvironment that is breathable, water-retaining, nutrient-balanced, and free of harmful organisms. Ultimately, the seedling disease rate is reduced to 3.2%, and the seedling survival rate is increased to 95.3%. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0018] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0019] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0020] like Figure 1 As shown, this invention provides an optimized cultivation method for trifoliate orange seedlings. The invention provides the following embodiments: Example 1

[0021] 1. Seed collection and variable-temperature sand stratification: Collect fully ripe sour orange fruits from the trees, pile them up for 3 days (pile the freshly harvested fruits for 3 days to soften the pulp; the pile height should not exceed 60cm to prevent the internal temperature of the pile from burning the seed embryo), then rub and wash to remove the seeds, and manually remove shriveled, insect-infested, or damaged seeds.

[0022] Rinse qualified seeds with clean water to remove pulp and chaff, then soak them in a 0.4% potassium permanganate solution for 18 minutes at a liquid-to-seed volume ratio of 3:1, stirring twice during the soaking process. After soaking, rinse the seeds three times with clean water and drain off the surface moisture.

[0023] Select clean, medium-coarse river sand with a particle size of 0.35-0.5mm, sieve to remove stones and impurities, spray with 0.3% potassium permanganate solution for disinfection, drain, and adjust the moisture content of the river sand to 60% (standard: it can be formed into a ball when squeezed in the hand, no water drips between the fingers, and it crumbles when released).

[0024] After disinfection, the seeds and wet river sand were mixed at a volume ratio of 1:3.5. The mixture was then layered and laid alternately: a 5cm thick layer of wet river sand was laid at the bottom of the storage box, followed by a 2cm thick layer of seeds. The seeds were laid alternately, and the top layer was covered with 6cm of river sand to retain moisture.

[0025] The entire process of temperature-dependent layering is divided into three stages: First stage: Sand storage boxes were placed in an environment of 4-6℃ for 32 days for stratification; Second stage: The sand storage box was transferred to an environment buffer treatment of 8-10℃ for 4 days; Third stage: The sand storage box was moved into an environment of 12-15℃ for 12 days for stratification.

[0026] During stratification, turn the seeds over every 7 days, remove any moldy or rotten seeds, and add water to adjust the humidity (the standard for humidity adjustment is: the seeds can be clumped together when squeezed in the hand, but no water drips between the fingers, and they crumble when released). When the seed whitening rate reaches about 72%, stratification can be stopped and sowing can be prepared; if the whitening rate is not reached, the stratification time can be appropriately extended.

[0027] 2. Preparation and filling of seedling substrate: (1) Preparation of decomposed trifoliate orange peel branches: Disease-free branches pruned during winter in the trifoliate orange orchard were collected, shredded, and then passed through 18mm and 12mm standard sieves, retaining branch clippings with a particle size of 12-18mm. Urea was added to adjust the carbon-nitrogen ratio to 28:1, and water was added to adjust the moisture content to 60%. Aerobic composting was carried out in strip piles 1.2m high and 1.5m wide. After the core temperature of the pile reached 58℃, the pile temperature was maintained at 55-65℃ by turning the pile. The high-temperature composting was carried out for a total of 18 days, with the pile being turned once every 5 days. After the pile cooled naturally to the ambient temperature, it was passed through a 10mm sieve to obtain fully decomposed trifoliate orange branch clippings.

[0028] (2) Matrix formulation (parts by weight): 33 parts of decomposed trifoliate orange peel branches, 22 parts of peat moss, 25 parts of decomposed edible mushroom residue, 5.5 parts of perlite, 7 parts of vermiculite, and 4.5 parts of calcium magnesium phosphate fertilizer.

[0029] (3) Preparation process: S21: Add the decomposed bitter orange peel branches, peat moss, and decomposed edible mushroom residue to a mixer and premix for 5 minutes (mixing speed set to 30-40 r / min) to obtain the premixed material; S22: Adjust the moisture content of the premixed materials to 50%, stack them in layers to a height of 1.2m, cover with polyethylene film for insulation and let stand for 60 hours, utilizing the heat of material fermentation for sterilization; after sterilization, allow the materials to cool naturally to room temperature, and preliminarily adjust the pH of the materials to 5.6 with sulfur powder (or citric acid); cover with film for insulation and let stand, utilizing the heat storage of the materials and microbial activity to achieve secondary moist heat sterilization, completing the inactivation of pathogens and weed seeds; after the core temperature reaches above 55℃, maintain it for 24-48 hours.” S23: Add perlite and vermiculite, and stir for 8 minutes (stirring speed set to 25-35 r / min) until homogeneous; S24: Add calcium magnesium phosphate fertilizer and stir for 5 minutes (stirring speed set to 20-30 r / min) to mix well; S25: Finally, fine-tune the matrix pH to 5.8 with citric acid or quicklime.

[0030] (4) Addition and filling of functional microbial agents: Select a black polyethylene nutrient pot with a diameter of 12cm and a height of 15cm (with drainage holes at the bottom). Add Bacillus subtilis (effective viable count ≥20 billion / g) to 0.8% of the total substrate mass. After mixing Bacillus subtilis with the substrate, fill the pot to 1cm from the rim and lightly compact it.

[0031] 3. Sowing and seedling cultivation: Seeds of the trifoliate orange (Citrus trifoliata) that have undergone pre-germination treatment and whose radicles have emerged are manually sown in the center of nutrient pots, 2-3 seeds per pot, at a depth of 1.5cm. The surface is covered with 0.5cm of fine vermiculite to retain moisture. The pots are then placed in a greenhouse for cultivation, with the following environmental conditions controlled: daytime temperature 22-28℃, nighttime temperature 15-18℃, and relative humidity 70%-80%. Watering follows the "water when dry" principle (spray water when the surface substrate turns white and dry, watering thoroughly until water seeps out from the bottom of the pot, avoiding waterlogging). After emergence, thinning is carried out, removing weak and diseased seedlings, ultimately retaining one healthy seedling per pot. When the seedlings have developed four complete true leaves and their roots have formed a complete root ball around the pot's substrate, they are ready for field transplanting.

[0032] 4. Nursery preparation and transplanting: Choose a flat, well-drained sandy loam plot with a soil layer thickness of ≥50cm and a pH value of 5.5-7.0. Avoid planting Rutaceae crops in the previous crop. 15 days before transplanting, deep plow the entire field to a depth of 30cm, apply 2000kg of well-rotted farmyard manure and 50kg of superphosphate per acre, harrow the soil to make raised beds, 1.2m wide, with furrows 30cm wide and 20cm deep.

[0033] Transplanting should be done on a cloudy day in early March. Remove the trifoliate orange seedlings along with the intact substrate soil ball and plant them at a spacing of 30cm × 50cm. The planting depth should be level with the top edge of the original substrate soil ball. Water thoroughly immediately after planting.

[0034] 5. Phased water and fertilizer management: During the seedling establishment period (0-30 days after transplanting): Do not apply fertilizer. Water as needed according to the field growth requirements to keep the soil moist. Clear ditches and drain water promptly after rain.

[0035] During the shoot emergence period (30 days after transplanting until the autumn shoots stop growing): Apply 10 kg of urea per mu before the spring shoots sprout; during the summer shoot growth period, apply 15 kg of 15-15-15 compound fertilizer per mu; during the autumn shoot emergence period, apply 12 kg of high-potassium compound fertilizer (such as high-potassium compound fertilizer with a nitrogen-phosphorus pentoxide-potassium oxide mass ratio of 12:8:20) per mu, apply it in shallow trenches and cover it with soil.

[0036] Lignification period (after autumn shoots stop growing until leaf fall): Apply 80 kg of well-rotted cake fertilizer + 10 kg of potassium sulfate per acre, control nitrogen and increase potassium to promote lignification of branches.

[0037] 6. Shaping, pruning, and pest and disease control: When the seedlings reach a height of 80cm, the trunk should be fixed. Select 3-4 strong branches that are evenly distributed in all directions (strong branches that are staggered around the trunk and do not overlap) as main branches, and remove overly dense branches, crossing branches, and weak branches caused by diseases or pests.

[0038] Pest and disease control: During the spring, summer and autumn shoot emergence periods, spray 0.2-0.3% Bordeaux mixture once each to prevent anthracnose and scab; when red spider mites and leaf miners appear in the field, spray 0.5% matrine aqueous solution in combination with a special acaricide and 25% thiamethoxam water-dispersible granules for control. A total of 3-4 pesticide applications are required throughout the year.

[0039] 7. Seedlings leaving the nursery: After one year of cultivation, the seedlings reach the nursery standard when their ground diameter is ≥0.8cm and plant height is ≥80cm. Water thoroughly one day before lifting the seedlings, and retain an intact root ball with a diameter of 20cm. Dip the roots in moisturizing mud and tie the root ball with straw rope.

[0040] Example 2:

[0041] Seed disinfection: Soak seeds in a 0.3% potassium permanganate solution for 15 minutes; The volume ratio of sand to river sand is 1:3, and the particle size of the river sand is 0.25–0.35 mm. Temperature-dependent lamination: 30 days of lamination at 4-6℃, 3 days of buffering at 8-10℃, and 10 days of lamination at 12-15℃; Decomposed trifoliate orange peel and branch clippings: carbon-nitrogen ratio 25:1, moisture content 55%, core temperature maintained at 55℃ for 15 days; Substrate formula (parts by weight): 28 parts of decomposed trifoliate orange peel and branch scraps, 18 parts of peat moss, 20 parts of decomposed edible mushroom residue, 4 parts of perlite, 5 parts of vermiculite, and 3 parts of calcium magnesium phosphate fertilizer. Substrate preparation: The premixed material has a moisture content of 48%, is covered with film and allowed to stand for 48 hours, and the initial pH is adjusted to 5.0, with a final pH of 5.5; Bacillus subtilis addition amount: 0.5% (total substrate mass); Transplant when the seedlings have three true leaves; The remaining operating procedures are completely consistent with those in Example 1.

[0042] Example 3

[0043] Seed disinfection: Soak seeds in a 0.5% potassium permanganate solution for 20 minutes; The volume ratio of sand to river sand is 1:4, and the particle size of the river sand is 0.4–0.5 mm. Temperature-dependent lamination: 35 days of lamination at 4-6℃, 5 days of buffering at 8-10℃, and 15 days of lamination at 12-15℃; Decomposed trifoliate orange peel and branch clippings: carbon-nitrogen ratio 30:1, moisture content 65%, core temperature maintained at 65℃ for 20 days; Substrate formula (parts by weight): 38 parts of decomposed trifoliate orange peel and branch scraps, 26 parts of peat moss, 30 parts of decomposed edible mushroom residue, 7 parts of perlite, 9 parts of vermiculite, and 6 parts of calcium magnesium phosphate fertilizer. Substrate preparation: The premixed material has a moisture content of 52%, is covered with film and allowed to stand for 72 hours, and the initial pH is adjusted to 5.8, with a final pH of 6.5; The amount of Bacillus subtilis added was 1.0% (total mass of substrate). Transplant when the seedlings have 5 true leaves; The remaining operating procedures are completely consistent with those in Example 1.

[0044] Comparative Example 1: After thoroughly mixing the seeds and moist river sand at a volume ratio of 1:3, the mixture is placed in a sand storage box. The sand storage box is placed in a cool indoor environment and continuously stratified at low temperature for 52 days. During the stratification period, the mixture is turned over and watered every 7 days to adjust the humidity. 12 days before sowing, the entire box is transferred to an environment of 12-15℃ for independent germination.

[0045] The other processes and raw materials are the same as in Example 1; Comparative Example 2: Disease-free and pest-free trifoliate orange branches are collected and crushed. The crushed material is directly used for composting. The carbon-nitrogen ratio is not adjusted, and the cumulative maintenance time of the core temperature at 55-65℃ is not controlled. The composting is carried out in open windrows with regular turning. After 45 days of composting, the material is sieved through a 10mm sieve and the material that passes through the sieve is taken to obtain conventionally decomposed trifoliate orange branch chips. The other processes and raw materials are the same as in Example 1; Comparative Example 3: Substrate composition (parts by weight): 45 parts peat moss, 25 parts coconut coir, 15 parts perlite, 10 parts vermiculite, and 5 parts calcium magnesium phosphate fertilizer. Substrate preparation and filling: All raw materials are added to the mixer at once and mixed uniformly at 30r / min for 18min; step-by-step feeding and graded speed control are eliminated; closed-film covering and biological heat sterilization are eliminated, and sunlight exposure sterilization is used instead (material pile thickness 25-30cm, covered and exposed to the open for 35 days); after the sunlight sterilization is completed, sulfur powder or quicklime is used to adjust the final pH of the substrate to 5.8 once according to the initial pH of the material; no artificial addition of Bacillus subtilis is used; other processes and raw materials are the same as in Example 1.

[0046] Comparative Example 4: Based on Comparative Example 3, Bacillus subtilis was added, and all other aspects were the same as in Comparative Example 3; Comparative Example 5: Based on Comparative Example 3, the matrix composition (parts by mass) was: peat moss: perlite = 7:3, and other components were the same as in Comparative Example 3.

[0047] Experimental design: All examples and comparative examples were set up with 3 biological replicates (as shown below), conducted in the same nursery greenhouse and field plot, with consistent environmental conditions (light, temperature, humidity, and basic soil fertility), and arranged in a randomized block design.

[0048] Seed stratification test: 200 seeds per replicate; Greenhouse seedling experiment: 150 seeds were sown per replicate, and 100 seedlings with uniform growth were selected after emergence; Field cultivation experiment: 50 seedlings were planted per replicate.

[0049] Measurement indicators and methods: Seed stratification stage: When stratification ends, the whitening rate is calculated (number of seeds with radicles breaking through the seed coat / total number of seeds × 100%); on the 7th day after sowing, the germination potential is calculated ((number of germinated seeds on the 7th day / total number of seeds) × 100%), reflecting the uniformity of germination.

[0050] Greenhouse seedling stage (4 true leaf stage): Calculate the emergence rate (emergence rate (%) = number of seedlings / total number of seeds sown × 100%) and the seedling survival rate (survival rate (%) = number of seedlings / total number of seedlings 100%); randomly select 20 seedlings to measure seedling height and ground diameter; and calculate the incidence of diseases such as damping-off and anthracnose during the seedling stage.

[0051] Field nursery stage (1 year of cultivation): Statistical analysis of transplant survival rate (transplant survival rate (%) = number of surviving seedlings / total number of transplanted seedlings × 100%) and nursery qualification rate (those with a ground diameter ≥ 0.8cm and a plant height ≥ 80cm are considered qualified; nursery qualification rate (%) = number of qualified seedlings / total number of surveyed seedlings × 100%); Randomly select 20 seedlings to measure plant height, ground diameter, and root fresh weight.

[0052] Germination time coefficient of variation = (standard deviation of germination time ÷ mean germination time) × 100%; Data statistics: One-way ANOVA was performed using SPSS software, and multiple comparisons were performed using Duncan's method. The significance level was P<0.05.

[0053]

[0054] The data in the table are the arithmetic mean of three biological replicates.

[0055] The data in the table are the arithmetic mean of three biological replicates.

[0056] The data in the table are the arithmetic mean of three biological replicates. Comparing Example 1 and Comparative Example 4, it can be seen that the substrate formula and preparation process are completely identical, except that Comparative Example 4 omits the addition of Bacillus subtilis. There were no significant differences in seed emergence and germination indicators, indicating that the inoculant does not participate in the seed dormancy release process. However, after removing the inoculant, the seedling disease rate increased from 3.2% to 7.8%, and the seedling survival rate and root fresh weight both decreased significantly. Bacillus subtilis has the potential to colonize and form a dominant microbial community in the rhizosphere of Citrus aurantium seedlings; it can inhibit some soil-borne pathogens through niche competition and the metabolism of lipopeptides, thus reducing seedling diseases; at the same time, some Bacillus species can produce auxin metabolites, which have the potential to stimulate fibrous root growth, improve the rhizosphere microenvironment, and enhance seedling resistance.

[0057] The beneficial effects of the above technical solution are as follows: 1. A horizontal comparison between Example 1 and Comparative Example 1 shows that Comparative Example 1 did not employ a three-stage gradient heating stratification process, but only a mixed and constant low-temperature stratification mode. Citrus aurantium seeds are typical physiologically dormant seeds, with dormancy caused by a combination of seed coat mechanical barriers and the inhibitory effect of endogenous abscisic acid. While a single constant low temperature can slowly soften the seed coat and degrade dormancy-inhibiting substances to a small extent, it cannot orderly activate the gibberellin synthesis pathway within the embryo. This results in a disordered and inconsistent seed ripening process, ultimately leading to a seed emergence rate of only 61.2%, a germination potential as low as 51.4%, and poor germination uniformity, directly causing a significant decrease in subsequent seedling emergence and seedling survival rates. Example 1 employs a three-stage gradient temperature stratification process: low-temperature after-ripening, medium-temperature buffering, and high-temperature germination. It uses alternating layers of seeds and moist substrate to prevent seed clumping and ensure each seed is evenly exposed to the temperature and humidity environment, reducing localized dampness and mold. First, the embryo undergoes physiological after-ripening at 4–6℃, gradually reducing abscisic acid content. Then, a medium-temperature transition at 8–10℃ activates metabolic enzyme activity. Finally, radicle growth is initiated at 12–15℃, systematically breaking seed dormancy from a physiological perspective. This results in increased seed emergence rate and germination uniformity, laying the foundation for subsequent robust seedling cultivation.

[0058] 2. Comparing Example 1 and Comparative Example 2, it can be seen that Comparative Example 2, which uses open-air natural composting to prepare trifoliate orange peel branch fragments without controlling the carbon-nitrogen ratio and core temperature, resulted in large temperature fluctuations in the compost pile, making it impossible to maintain a sustained high temperature of 55-65℃. The branch fragments were only simply crushed, without screening or control before composting, resulting in a random mixed state of materials without defined ranges. The materials added to the pile contained a large amount of fine powder and oversized pieces. On the one hand, the recalcitrant components such as lignocellulose in the branch fragments could not be fully decomposed, resulting in low humification and an inability to provide a slow-release carbon source for seedlings. On the other hand, the compost pile was not thoroughly harmless, and residual phenolic autotoxic substances and plant pathogens inhibited root growth. Furthermore, the materials remained disordered in size after fermentation, with fine powder easily clogging the ventilation pores and large pieces easily causing substrate leakage, making the overall pore structure uncontrollable. Although the impact on seed germination was relatively small, it continuously restricted seedling growth during the seedling stage, ultimately resulting in a qualified rate of only 82.4% for seedlings.

[0059] In Example 1, the trifoliate orange peel branches were crushed and sieved before composting to remove fine powder and oversized pieces. A controlled mix of particles within a 12-18mm range was then selected for composting. This avoided the uniformity of pore types caused by single particle sizes and differed from the uncontrolled, random mixing of multiple particle sizes in Comparative Example 2. After the pre-controlled mix of materials was added to the pile, the materials were interleaved, resulting in more even water and heat transfer during composting, ensuring optimal decomposition. Furthermore, by pre-adjusting the carbon-to-nitrogen ratio to 28:1 and precisely controlling the core temperature at 55-65℃ for 18 days, the high-temperature aerobic microorganisms fully degraded the lignocellulose, converting it into humus and small-molecule nutrients easily absorbed by the roots. Simultaneously, the high temperature completely neutralized the branches, eliminating phenolic inhibitors and unwanted bacteria. The resulting decomposed branches combined slow nutrient release with rhizosphere environment improvement, significantly promoting seedling growth and increasing the final seedling pass rate to 90.5%.

[0060] 3. Comparing Example 1 and Comparative Example 3, it can be seen that Comparative Example 3 uses a conventional substrate formula of peat moss + coconut coir, eliminating step-by-step feeding and graded speed control, and abandoning closed biological heat sterilization in favor of sunlight sterilization. One-time feeding and mixing can easily lead to uneven distribution of lightweight aggregates and fertilizers, with localized excessive salt content posing a risk of seedling burn; sunlight exposure can only kill pathogens on the surface of the materials, and cannot completely inactivate residual damping-off and anthracnose pathogens inside the substrate, significantly increasing the risk of seedling diseases. Ultimately, the seedling disease rate reached as high as 9.1%, and the seedling survival rate was only 81.2%. This invention employs a step-by-step preparation process: first, organic raw materials are pre-mixed and then sealed and piled up, relying on the heat of material fermentation to achieve overall sterilization at over 55°C, thoroughly inactivating deep-seated pathogens and insect eggs in the substrate without the need for additional disinfectants; then, lightweight aggregates and calcium magnesium phosphate fertilizer are added sequentially at different speeds to avoid salt damage caused by localized fertilizer agglomeration; simultaneously, a two-step method is used to precisely adjust the pH: if the target pH is adjusted directly at once, the organic buffer system inside the substrate is prone to pH rebound and drift, making it difficult to stably maintain the suitable range; this invention adjusts in two steps, first coarsely adjusting the pH to approach the target range, and then finely correcting it to 5.8, which is suitable for trifoliate orange seedlings, after the organic matter inside the substrate has achieved buffer equilibrium, thus avoiding the pH rebound and drift problem and stably constructing a rhizosphere microenvironment that is breathable, water-retaining, nutrient-balanced, and free of harmful organisms. Ultimately, the seedling disease rate is reduced to 3.2%, and the seedling survival rate is increased to 95.3%.

[0061] In a preferred embodiment, during mass production, the formula combination (mainly the raw materials of S21) that has been experimentally verified to be qualified for the current mass production, the bulk density of the actual premixed material corresponding to the qualified substrate (as a reference bulk density of the premixed material of the corresponding formula combination), and the maintenance time after the core temperature rises to above 55°C are obtained. In S21, the bulk density of the premixed material is sampled and detected, and the target moisture content and target bulk thickness of the premixed material in the corresponding formula combination are determined in S22. Determine the current actual density ratio: the bulk density of the premixed material sampled and tested in S21 ÷ the reference bulk density of the premixed material corresponding to the formula combination in S21; Specifically, when the density ratio is greater than 1.12, the material is generally denser with reduced porosity. The target moisture content is 48%-50%, and the target packing thickness is 1.0-1.1m, reducing the risk of anaerobic digestion. The material particles are tightly compressed, reducing porosity and decreasing air permeability. If the moisture content is too high, the pores are occupied by water, resulting in insufficient oxygen supply and making the pile prone to anaerobic fermentation, producing rancid odors and damaging the substrate quality. Therefore, a lower moisture content within this range is selected, while simultaneously reducing the packing thickness and minimizing the pile's own weight for further compaction, while retaining internal air permeability channels to avoid anaerobic rancidity.

[0062] When the density ratio is less than 0.88, the material is generally loose with increased porosity. With a target moisture content of 51%-52% and a target stacking thickness of 1.2-1.3m, a relatively large stacking thickness is chosen to ensure heat storage in the stack and facilitate core heating. Excessive porosity and permeability cause heat to easily dissipate, making it difficult to reach the sterilization temperature above 55℃ in the core. Appropriately increasing the moisture content allows the water to store the heat generated during fermentation; appropriately increasing the stacking thickness improves the heat retention effect of the stack, reduces heat loss, and ensures the core maintains the sterilization temperature.

[0063] When the density ratio is between 0.88 and 1.12, the bulk density of the material is close to that of the reference sample, the porosity and water holding capacity of the material are within the normal fluctuation range, the target moisture content is 48%-52%, and the target bulk thickness is 1.0-1.3m.

[0064] In S22, the moisture content of the premixed material is adjusted to the current target moisture content of S22, the premixed material is stacked in layers to the current target stacking thickness of S22, covered with a membrane and sealed for heat preservation and left to stand for 48-72 hours for disinfection, and the core temperature is periodically monitored during the disinfection process. After disinfection, it is naturally cooled to room temperature and the pH is adjusted to 5-5.8. In S23, combining the bulk density information from S21 and the core temperature detected in S22, the target feed ratio of perlite and vermiculite is determined, and perlite and vermiculite of the corresponding target ratio are added to the material obtained in S22 and mixed.

[0065] Specifically: Determine the time ratio: the current S22 and core temperature rises above 55°C and then maintains the temperature thereafter ÷ the corresponding reference core temperature rises above 55°C and then maintains the temperature thereafter. The density ratio reflects the initial packing porosity of the premixed materials, while the time ratio reflects the degree of maturation and softening of the organic fibers after S22 high-temperature treatment. A higher density ratio indicates a denser initial state of the material, while a higher time ratio indicates more complete high-temperature maturation and a higher degree of degradation and softening of the organic fibers. This increases the risk of subsequent pressure collapse and loss of aeration pores in the finished matrix, requiring an increase in the proportion of perlite to maintain aeration pores due to its rigid particles. Conversely, a lower time ratio indicates insufficient high-temperature maturation and a more intact fiber skeleton, allowing for an increase in the proportion of vermiculite to improve the water and fertilizer retention performance of the matrix.

[0066] When the density ratio is greater than 1.12 or the time ratio is greater than 1.1, the material is initially dense and / or has a high degree of maturation and softening. Use 6-7 parts perlite and 8-9 parts vermiculite. When the density ratio is <0.88 or the time ratio is <0.9, the material is initially loose and / or the degree of maturation and softening is low, use 4-5 parts perlite and 5-7 parts vermiculite. In other cases, perlite 4-7 parts, vermiculite 5-9 parts; In this embodiment, in S22 controlled by the present invention, the moisture content of the premixed material is adjusted to 48%-52%, and the preset stacking thickness is 1.0-1.3m. However, the pore structure and water absorption and retention capacity of the decomposed trifoliate orange peel, peat moss, and decomposed edible fungus residue in the formula are affected by batch differences in raw material source, decomposition degree, and crushing state. Even if the process parameters fall within the above theoretical window, the internal heat transfer imbalance of the stack is still likely to occur under some boundary conditions, resulting in local anaerobic rancidity, or the core temperature may not reach the disinfection threshold.

[0067] Therefore, this scheme introduces the above density as a verification condition, and makes boundary corrections to the parameters based on the basic theoretical window. It is compatible with material fluctuations caused by different raw material states, ensures balanced heat and moisture transfer inside the stack, and avoids process deviations under boundary conditions.

[0068] If the density ratio is greater than 1.2 or less than 0.8, the dynamic parameter adjustment logic will not be executed, and the material will be returned to the pre-processing stage for re-inspection and re-adjustment. If the time ratio is greater than 1.2 or less than 0.8, the dynamic parameter adjustment logic will not be executed, and the material will be returned to the pre-processing stage for re-inspection and re-adjustment.

[0069] The beneficial effects of the above technical solution are as follows: The raw materials for seedling substrates are affected by factors such as the source of agricultural and forestry waste (e.g., husks, branches, mushroom residue), harvesting season, degree of crushing, and pre-composting status. Besides the normal, minor batch fluctuations within acceptable limits, some non-ideal incoming material conditions deviate from the normal range during production. These conditions are not considered normal fluctuations in raw material density and directly alter the bulk density and internal pore structure of the premixed materials. If a fixed moisture content and pile thickness are used for S22 film-covered, closed, moist heat sterilization, the water-air-heat matching relationship within the pile will be disrupted. This can easily lead to insufficient heat storage in the pile, failing to reach the sterilization temperature, or poor local permeability inducing anaerobic rancidity, resulting in deterioration of the batch substrate quality.

[0070] This invention calculates the density ratio based on the reference bulk density corresponding to a qualified formula, without intervening in the normal minor fluctuations of the incoming material. It only addresses non-ideal operating conditions exceeding the normal fluctuation range by dynamically matching the target moisture content and target bulk thickness of the S22 process, and synergistically controlling the pore-water-gas distribution within the stack. For significantly denser materials, the risk of anaerobic rancidity caused by the self-weight compaction of the stack is avoided by reducing the moisture content and decreasing the bulk thickness. For significantly looser materials, the moisture content is appropriately increased and the bulk thickness is increased to reduce heat loss from the stack, ensuring that the core can stably reach above 55°C and maintain the required sterilization time. This achieves sufficient wet heat sterilization while avoiding localized process failures within the stack, improving the process's compatibility with non-ideal incoming material conditions.

[0071] This invention introduces both density ratio to characterize the inherent porosity of the material and time ratio to characterize the degree of softening during high-temperature curing, using these two dimensions to jointly correct the feeding ratio of perlite and vermiculite. For batches that are initially dense or over-cured at high temperatures, and whose fibers are prone to collapse, the proportion of rigid perlite is increased to offset the loss of aeration porosity caused by subsequent substrate compression and collapse. For batches that are loose or have a low degree of curing and intact fiber skeleton, the proportion of vermiculite is increased to enhance water and fertilizer retention capacity. This ensures that the porosity regulating effect of the mineral filler matches the actual porosity state of the material after sterilization, allowing the finished seedling substrate to simultaneously obtain suitable aeration and water retention porosity. The aeration, water, and fertilizer retention performance are synergistically balanced, significantly reducing the performance differences of the finished substrate caused by different raw material batches and improving the consistency of substrate product performance under mass production conditions.

[0072] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An optimized cultivation method for trifoliate orange seedlings, characterized in that: S1: Collect mature trifoliate orange fruits, remove the seeds and rinse and disinfect them. After disinfection, mix them with wet sand for variable temperature sand stratification. When the white sprouting rate of the trifoliate orange seeds reaches more than 65%, prepare for sowing. S2: Prepare the seedling substrate and fill it into the seedling container. Sow the white-tipped trifoliate orange seeds in the seedling substrate, regulate the temperature and humidity of the seedling environment, and cultivate until the trifoliate orange seedlings grow multiple true leaves. S3: Select a suitable nursery site for the cultivation of trifoliate orange seedlings, prepare the soil in the nursery site, apply fertilizer, transplant the trifoliate orange seedlings along with the complete substrate soil ball to the nursery site, and water them after transplanting; S4: Water and fertilizer management should be carried out in three stages: seedling establishment period, shoot emergence period, and lignification period; S5: After the seedlings reach the required height, select the main branches for shaping and carry out pest and disease control. S6: After the seedlings reach the required diameter and height for sale, lift them up, keeping the root ball intact, and dip the roots in moisturizing mud.

2. The cultivation method according to claim 1, characterized in that: Remove the unqualified bitter orange seeds from S1, and then rinse and disinfect the qualified bitter orange seeds. The disinfection is carried out by placing the rinsed bitter orange seeds in a 0.3%-0.5% potassium permanganate solution and soaking for 15-20 minutes. After soaking, the bitter orange seeds are taken out and rinsed with clean water.

3. The cultivation method according to claim 1, characterized in that: The variable-temperature sand stratification process involves mixing sterilized trifoliate orange seeds with moist river sand at a volume ratio of 1:3 to 4. During sand stratification, alternating layers are laid out, with a layer of river sand followed by a layer of trifoliate orange seeds. After stratification, the seeds are first placed in an environment of 4 to 6°C for 30 to 35 days, then buffered in an environment of 8 to 10°C for 3 to 5 days, and finally stratified in an environment of 12 to 15°C for 10 to 15 days. The seeds are turned over and inspected regularly to prevent mold growth.

4. The cultivation method according to claim 1, characterized in that: The preparation process of the seedling substrate includes: mixing the substrate raw materials, disinfecting the substrate raw materials after mixing, cooling to room temperature, and adjusting the pH value of the substrate to 5.5-6.

5.

5. The cultivation method according to claim 4, characterized in that: The preparation process of the seedling substrate includes: by weight, the substrate raw materials include: 28-38 parts of decomposed trifoliate orange peel branches, 18-26 parts of peat moss, 20-30 parts of decomposed edible mushroom residue, 4-7 parts of perlite, 5-9 parts of vermiculite, and 3-6 parts of calcium magnesium phosphate fertilizer.

6. The cultivation method according to claim 5, characterized in that: The preparation process of the decomposed bitter orange peel branches includes: collecting disease-free bitter orange peel branches and crushing them; passing the crushed material through an 18mm sieve and a 12mm sieve in sequence, retaining bitter orange peel branches in the 12-18mm range; adjusting the carbon-nitrogen ratio of the bitter orange peel branches to 25-30:1 and the moisture content to 55-65%; subjecting the adjusted bitter orange peel branches to aerobic composting; maintaining the core temperature at 55-65℃ for a cumulative period of 15-20 days after the core temperature reaches 55-65℃; turning the pile regularly; and sieving the material after it has decomposed to ambient temperature to obtain decomposed bitter orange peel branches.

7. The cultivation method according to claim 4, characterized in that: After adjusting the pH of the substrate to 5.5-6.5, Bacillus subtilis is mixed in when filling the seedling containers with the substrate; Bacillus subtilis is added at 0.5%-1.0% of the total mass of the seedling substrate.

8. The cultivation method according to claim 4, characterized in that: The preparation process of the seedling substrate includes: S21: Premix well-rotted trifoliate orange peel branches, peat moss, and well-rotted edible mushroom residue to obtain a premixed material; S22: Adjust the moisture content of the premixed materials to 48%-52%, stack the premixed materials in layers to the preset stacking thickness, cover with a film to keep warm and stand for 48-72 hours for disinfection, and after disinfection, let it cool naturally to room temperature and complete the pH adjustment to 5-5.

8. S23: Add perlite and vermiculite to the material obtained in S22 and mix them; S24: Add calcium magnesium phosphate fertilizer to the material obtained in S23 and mix. S25: Adjust the pH of the material obtained in S24 to 5.5-6.5.

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