A molded rice seedling tray with seedling strengthening agent and acid adjustment and its preparation method

Abstract

This invention provides a molded rice seedling tray with a seedling-strengthening agent and acid-adjusting properties, and its preparation method, belonging to the field of rice seedling technology. A method for preparing a molded rice seedling tray with a seedling-strengthening agent and acid-adjusting properties includes the following steps: (1) mixing agricultural and forestry waste with sulfur powder and fermenting to obtain acid-adjusting fermented material; (2) mixing a seedling-strengthening agent, zeolite powder, and acidic river silt to obtain a functional masterbatch; (3) mixing the acid-adjusting fermented material, the functional masterbatch, ammonium sulfate, and sodium carboxymethyl cellulose to obtain a pressed material; (4) pressing the pressed material into shape to obtain a molded rice seedling tray with a seedling-strengthening agent and acid-adjusting properties. This invention successfully solves the four core problems in soilless rice seedling cultivation: difficulty in acid adjustment, difficulty in fertilizer transport, high cost, and difficulty in industrialization, achieving a win-win situation for both ecological and economic benefits, and possessing extremely high industrial application value and promotion prospects.

Description

Technical Field

[0001] This invention relates to the field of rice seedling raising technology, and in particular to a molded rice seedling raising tray with a seedling strengthening agent and acid adjustment, and its preparation method. Background Technology

[0002] Rice seedling cultivation is mainly divided into traditional paddy field broadcasting and dry-seedling sparse planting techniques. Currently, the mainstream dry-seedling sparse planting techniques have two main branches: Firstly, there's the method of soil sampling for seedling cultivation. This method suffers from several drawbacks: difficulty in obtaining soil, damage to black soil resources, cumbersome procedures (crushing, sifting, mixing with fertilizer, and adjusting acidity), high labor intensity, and high labor costs. Furthermore, the on-site mixing of acidifiers and seedling strengtheners is difficult to achieve even distribution, resulting in inconsistent seedling quality. Simultaneously, the soil substrate has poor fertilizer and acid retention capacity, typically requiring secondary acidification and fertilization at the one-leaf and two-leaf stages, increasing management difficulty and costs. Additionally, soil-based seedling cultivation requires the use of plastic trays, which are prone to crumbling, and the seedling recovery period after transplanting is long (usually 5-7 days).

[0003] Secondly, there is the soilless seedling raising method that uses fermented straw substrate instead of soil. While existing soilless straw seedling trays solve the problems of soil collection and tray distribution, their production processes (such as water-based slurry preparation) prevent the effective carrying and preservation of seedling-strengthening agents and acid-regulating substances during production. Farmers still need to mix fertilizer and adjust acidity on-site before seedling raising, which does not fundamentally simplify the process. Furthermore, existing technologies have not effectively addressed technical bottlenecks such as the excessively high carbon-nitrogen ratio of straw substrates, poor water and fertilizer retention, high costs, and the lack of a long-term acid-regulating mechanism, thus limiting their large-scale promotion.

[0004] Therefore, developing a rice seedling tray that can achieve uniform acidification and fertilizer loading during the factory prefabrication stage, and is low in cost and has excellent performance, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a molded rice seedling tray with a seedling strengthening agent and acid adjustment, and its preparation method, to solve the problems of difficulty in obtaining soil, difficulty in adjusting acidity, difficulty in carrying fertilizer, high cost and poor seedling quality in rice seedling cultivation.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a molded rice seedling tray with a seedling-strengthening agent and acid-adjusting properties, comprising the following steps: (1) Mix agricultural and forestry waste with sulfur powder at a mass ratio of 90~110:1~1.5 and ferment to obtain acidified fermented material; (2) Mix seedling strengthening agent, zeolite powder and acidic river silt to obtain functional masterbatch; (3) The acid-adjusting fermentation material, the functional masterbatch, ammonium sulfate and sodium carboxymethyl cellulose are mixed to obtain the pressed material; (4) Press the material into shape to obtain a molded rice seedling tray with seedling strengthening agent and acid adjustment.

[0007] Preferably, in step (1), the agricultural and forestry waste includes the following raw materials in parts by volume: 45-65 parts straw, 25-45 parts wood ear fungus residue, 5-9 parts river silt, and 6-10 parts rice husk ash residue.

[0008] Preferably, the moisture content of the agricultural and forestry waste is adjusted to 35-45%; the moisture content of the agricultural and forestry waste is adjusted to 50-60% after being mixed with sulfur powder; the fermentation temperature is 25-35℃, the fermentation time is 25-35 days, and the material is turned over every 3-5 days during the fermentation process; after the fermentation is completed, the material is simmered for 5-9 days and then dried at 70-90℃ until the moisture content is below 15%.

[0009] Preferably, in step (2), the mass ratio of the seedling strengthening agent, zeolite powder and acidic river silt when mixed is 20~25:50~100:600~700; the pH of the acidic river silt is 5.5~6.5 and the water content is ≤15%.

[0010] Preferably, in step (3), the volume ratio of the acid-adjusting fermentation material to the functional masterbatch is 1700~1800:700~800. 1~1.5 kg of ammonium sulfate is added to each cubic meter of the mixture of acid-adjusting fermentation material and functional masterbatch, and the amount of sodium carboxymethyl cellulose added is 0.015~0.025% of the total mass of the acid-adjusting fermentation material and functional masterbatch. During mixing, sodium carboxymethyl cellulose is prepared into an aqueous solution with a concentration of 0.8~1.2%, and added to the mixture of acid-adjusting fermentation material, functional masterbatch, and ammonium sulfate by spraying.

[0011] Preferably, in step (4), the pressing material is laid in the seedling tray mold during the pressing process and held under the pressure of a 300-400 ton hydraulic press for 5-10 seconds; the thickness of the laid material is 2-4 cm.

[0012] Preferably, step (4) further includes storing the prepared rice seedling trays with seedling strengthening agent and acidity adjustment by filling them with nitrogen; the method of nitrogen filling and storage is as follows: after stacking the prepared rice seedling trays with seedling strengthening agent and acidity adjustment, they are put into nylon + PE composite film packaging bags, vacuumed and filled with nitrogen, and then heat-sealed.

[0013] Preferably, in step (2) when preparing the functional masterbatch, the seedling strengthening agent, zeolite powder and acidic river silt are mixed in equal increments.

[0014] Preferably, in the industrial production of the molded rice seedling trays containing seedling strengthening agents and acid-adjusted materials, the raw materials are mixed using the single-tray quota weight method. The single-tray quota weight method refers to pre-determining the dry weight of each raw material required for a single rice seedling tray, and then calculating and adding each raw material according to the method of "rated dry weight of a single tray × total number of trays in the batch".

[0015] This invention provides a molded rice seedling tray containing a seedling strengthening agent and adjusted acidity, prepared according to the preparation method described above.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. Achieved factory-scale pre-acidification and long-term acidification: For the first time, the sulfur powder fermentation acidification process was successfully applied to the industrial production of rice seedling trays. By completing a fermentation cycle of more than 30 days in the factory, the substrate of the seedling trays is made acidic by itself. During the seedling period (30-35 days), the acidity is slowly released through the continuous action of sulfur bacteria, maintaining the pH value in the suitable range of 5.5-6.5, thus avoiding secondary acidification operations during the seedling period.

[0017] 2. Achieved precise, factory-scale fertilizer delivery: Utilizing the strong adsorption properties of zeolite powder and the "equal incremental" process, the industry challenge of evenly mixing seedling strengtheners in large quantities of agricultural and forestry waste was solved. Simultaneously, through scientifically proportioned ammonium sulfate, the problem of microbial nitrogen depletion during the fermentation process of high carbon-to-nitrogen ratio substrates was precisely compensated, ensuring that seedlings do not suffer from nutrient deficiency at the 2-3 leaf stage, eliminating the need for secondary topdressing.

[0018] 3. Achieving low-cost, high-value utilization of waste: In addition to conventional straw, waste materials such as mushroom residue, river silt, and rice husk ash are used as core raw materials. Through particle size control, desalination and washing, volume proportioning, and fermentation, waste is transformed into valuable resources. The addition of trace amounts of sodium carboxymethyl cellulose binder solves the problem of difficult molding of high-proportion inert materials, keeping the cost per tray below 0.8 yuan, giving it strong market competitiveness.

[0019] 4. Significantly improves seedling quality and grain yield: Field comparative trials in multiple regions have proven that rice seedlings raised using the seedling trays of this invention have whiter, thicker, and more lateral roots and root hairs, resulting in a more secure seedling tray that does not fall apart during transport; the seedlings recover quickly after transplanting (within 48 hours) and tiller earlier. Compared to traditional soil-based seedling raising, the average yield per mu (unit of land area) increases by 8-12%.

[0020] 5. Protect the ecological environment: It completely replaces the soil used for seedling raising, fundamentally protecting black soil resources and preventing soil erosion; at the same time, it absorbs a large amount of agricultural and forestry waste, which is in line with the green, low-carbon and circular development strategy.

[0021] 6. This invention establishes a complete technical bridge from "laboratory volume ratio" to "industrialized weight quota". It not only discloses the core volume ratio of acid-adjusting fermentation material to functional masterbatch of 7:3, but also key process parameters such as 2.5kg dry weight per tray and 22.5g / tray of seedling strengthening agent. This allows those skilled in the art to directly build a factory and start production without creative labor, significantly lowering the threshold for technological industrialization. Detailed Implementation

[0022] This invention provides a method for preparing a molded rice seedling tray with a seedling-strengthening agent and acid-adjusting properties, comprising the following steps: (1) Mix agricultural and forestry waste with sulfur powder at a mass ratio of 90~110:1~1.5 and ferment to obtain acidified fermented material; (2) Mix seedling strengthening agent, zeolite powder and acidic river silt to obtain functional masterbatch; (3) The acid-adjusting fermentation material, the functional masterbatch, ammonium sulfate and sodium carboxymethyl cellulose are mixed to obtain the pressed material; (4) Press the material into shape to obtain a molded rice seedling tray with seedling strengthening agent and acid adjustment.

[0023] In this invention, in step (1), the agricultural and forestry waste includes the following raw materials in parts by volume: 45-65 parts straw, 25-45 parts wood ear fungus residue, 5-9 parts river silt, and 6-10 parts rice husk ash; preferably, it includes the following raw materials in parts by volume: 50-60 parts straw, 30-40 parts wood ear fungus residue, 6-8 parts river silt, and 7-9 parts rice husk ash; more preferably, it includes the following raw materials in parts by volume: 55 parts straw, 35 parts wood ear fungus residue, 7 parts river silt, and 8 parts rice husk ash.

[0024] In this invention, the length of the straw is 5-10 mm, preferably 7-9 mm, and more preferably 8 mm. If the straw is too long, it is easy to entangle and cause uneven spreading. If it is too short (<1 mm), it will become powdery, resulting in a heavy and sticky substrate with poor air permeability.

[0025] In this invention, the particle size of the fungus residue is 2-3 mm, preferably 2.5 mm; the river silt is dried or sun-dried and then crushed to 1-3 mm, preferably 2 mm.

[0026] In this invention, the particle size of the rice husk ash residue is 2-4 mm, preferably 3 mm. The rice husk ash residue is also soaked and washed 2-3 times with clean water until the water is clear, then drained for later use. This step effectively removes soluble salts and most alkaline substances from the surface of the ash residue, rapidly reducing the EC value and pH value, thus lessening the burden on subsequent acidification.

[0027] In this invention, the moisture content of the agricultural and forestry waste is adjusted to 35-45%, preferably 40%; after mixing the agricultural and forestry waste with sulfur powder, the moisture content is adjusted to 50-60%, preferably 55%; the fermentation temperature is 25-35℃, preferably 28-32℃, more preferably 30℃, and the fermentation time is 25-35 days, preferably 28-32 days, more preferably 30 days; during the fermentation process, the material is turned over every 3-5 days, preferably every 4 days; after the fermentation is completed, the material is steamed for 5-9 days and then dried at 70-90℃ until the moisture content is below 15%, preferably steamed for 7 days.

[0028] In this invention, in step (2), the mass ratio of the seedling strengthening agent, zeolite powder and acidic river silt when mixed is 20~25:50~100:600~700, preferably 21~24:60~90:620~680, and more preferably 22.5:75:652.5; the pH of the acidic river silt is 5.5~6.5, preferably 6.0, and the water content is ≤15%.

[0029] In this invention, the particle size of the zeolite powder is 140-270 mesh, preferably 170-230 mesh, and more preferably 200 mesh, to ensure its strong adsorption and ion exchange capacity.

[0030] In this invention, in step (3), the mass ratio of the acid-adjusting fermentation material, the functional masterbatch, ammonium sulfate, and sodium carboxymethyl cellulose is 1700~1800:700~800:4.5~6:0.4~0.6, preferably 1720~1780:720~780:5~5.5:0.45~0.55, and more preferably 1750:750:5.31:0.5; during mixing, sodium carboxymethyl cellulose is prepared into an aqueous solution with a concentration of 0.8~1.2%, preferably a 1% aqueous solution, and added to the mixture of the acid-adjusting fermentation material, the functional masterbatch, and ammonium sulfate by spraying.

[0031] In this invention, the sodium carboxymethyl cellulose is a food-grade, non-toxic type with a viscosity of 7000-8000.

[0032] In this invention, in step (4), the pressing material is laid in the seedling tray mold during the pressing process, and the pressure is maintained for 5 to 10 seconds under the pressure of a 300-400 ton hydraulic press, preferably for 8 seconds under the pressure of a 350 ton hydraulic press; the thickness of the laid material is 2 to 4 cm, preferably 3 cm.

[0033] In this invention, step (4) further includes storing the prepared rice seedling trays with seedling strengthening agent and acidity adjustment in nitrogen-filled packaging; the method of nitrogen-filled packaging storage is as follows: after stacking the prepared rice seedling trays with seedling strengthening agent and acidity adjustment, they are put into nylon + PE composite film packaging bags, vacuumed and filled with nitrogen gas, and then heat-sealed.

[0034] In this invention, when preparing the functional masterbatch in step (2), the seedling strengthening agent, zeolite powder and acidic river silt are mixed according to the equal incremental method.

[0035] In this invention, when industrially preparing the molded rice seedling trays containing seedling strengthening agents and acid-adjusting agents, the raw materials are mixed using the single-tray quota weight method. After determining the rated weight of a single rice seedling tray, the batch feeding instructions are set according to the method of single-tray rated weight × total number of trays in the batch.

[0036] This invention provides a molded rice seedling tray containing a seedling strengthening agent and adjusted acidity, prepared according to the preparation method described above.

[0037] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention. The seedling strengthening agent used in the following embodiments is the Humiao brand seedling strengthening agent produced and sold in Heilongjiang Province.

[0038] Example 1

[0039] 1. Raw material pretreatment and particle size control

[0040] To balance the shapeability, air permeability, water retention, and root growth space of the seedling tray, the optimal particle size of the material was determined through numerous orthogonal experiments: Straw: Crush to a length of 5-10mm; Wood ear fungus residue: Crush to 2-3mm; River silt: After drying, crush to 1-3mm; Rice husk ash: Crush to 2-4mm, soak and wash 3 times with clean water before use until the water is clear, drain and set aside. Zeolite powder: 200 mesh; Sodium carboxymethyl cellulose: Food-grade, non-toxic, with a viscosity of 7000~8000.

[0041] 2. Preparation of acidified fermentation materials

[0042] By volume, take 5.5 parts of the pretreated straw, 3.5 parts of the mushroom residue, 0.7 parts of the river silt, and 0.8 parts of the rice husk ash to obtain agricultural and forestry waste materials. At this time, the moisture content of the agricultural and forestry waste materials is controlled at about 40%, and then put them into a horizontal mixer.

[0043] Start the mixer and, while mixing, evenly sprinkle sulfur powder, which accounts for 1.2% of the dry weight of the agricultural and forestry waste material. At the same time, spray water to increase the moisture content of the mixed material to 55%.

[0044] Transfer the mixture to a fermentation tank with ventilation ducts, continuously introduce air, and control the material temperature between 25 and 35°C. Turn the compost pile every 4 days using a turner, and regularly test the pH and EC values. The fermentation cycle is 30 days, followed by a 7-day static settling period to allow any incompletely converted material to continue reacting. Fermentation is complete when the pH value is 5.5–6.5 and the EC value is 1.0–3.5 mS / cm.

[0045] After fermentation, the material is dried at 80°C in a low-temperature stainless steel mesh belt dryer to control the final moisture content to ≤15%, thus obtaining "acid-adjusting fermentation material" with long-lasting acid-adjusting function for later use.

[0046] 3. Preparation of functional masterbatch

[0047] Preparation of acidic river sludge powder: The river sludge powder is sprayed and soaked with a 20% sulfuric acid solution, and the pH value of the material is monitored in real time until it stabilizes between 5.5 and 6.5. Excess acid solution is drained and the moisture content is controlled to ≤15% for later use.

[0048] The composition and weight of the functional masterbatch are calculated as follows: 22.5 parts seedling strengthener, 75 parts zeolite powder, and 652.5 parts acidic river silt; the 22.5 parts seedling strengthener and 75 parts zeolite powder have the same volume.

[0049] The calculated amount of seedling-strengthening agent powder is mixed with an equal volume of zeolite powder (200 mesh) in a small three-dimensional mixer at a speed of 8 rpm for 5 minutes. Then, an equal volume of acidic river silt powder is added and mixed again at 8 rpm for 5 minutes. Following the principle of "equal incremental addition," twice the volume of the existing mixture is added, and mixing continues at 8 rpm for 5 minutes. This process is repeated until all the acidic silt powder is added, with a total mixing time of no less than 20 minutes. The final mixture is the "functional masterbatch."

[0050] 4. Preparation and molding of pressed materials

[0051] Preparation of sodium carboxymethyl cellulose solution: According to the weight ratio of water to sodium carboxymethyl cellulose dry powder = 99:1, slowly sprinkle the dry powder into the water under high-speed stirring. Stir until completely dissolved and free of particles, then let stand for 4 hours to allow the colloid to fully swell before use.

[0052] Total mixing: The acid-adjusting fermentation material and functional masterbatch prepared above are put into a large mixer at a volume ratio of 7:3 (the mass ratio of the two is also 7:3; in this embodiment, the bulk density of the two materials is basically the same, so the volume ratio and mass ratio are exactly the same. In actual production, the volume ratio should be used as the feeding control standard). At the same time, ammonium sulfate crystal powder is added at a ratio of 1.25 kg per cubic meter of mixture, and dry-mixed at 8 rpm for 5 minutes.

[0053] Adding adhesive: While stirring, spray 2 kg of 1% sodium carboxymethyl cellulose solution (i.e., containing 20 g of sodium carboxymethyl cellulose dry powder, corresponding to an addition amount of 0.02%) per 100 kg of dry material; stir at 8 rpm for 5 minutes to make the material uniformly moistened, and obtain the pressed material. At this time, the moisture content of the material is controlled between 18 and 20%.

[0054] Pressing: The pressed material is evenly spread into the seedling tray mold by an automatic material spreading vehicle, with a material thickness of 3cm; the 350-ton hydraulic press is started, pressure is applied and held for 8 seconds, and the mold is removed to obtain a formed rice seedling tray with seedling strengthening agent and acid adjustment.

[0055] 5. Nitrogen-filled packaging and storage

[0056] The freshly demolded seedling trays are removed by a robotic arm and stacked in flat plastic trays, 20 trays per stack. The stacks are then pushed into the automatic packaging line and placed into custom-made nylon + PE composite film bags (8-10 microns thick, 650×300×20mm). The equipment first cuts and seals the bags, leaving an air extraction port; then a vacuum pump removes most of the air from the bags; next, high-purity nitrogen generated by a nitrogen generator is introduced, just enough to cover the surface of the seedling trays; finally, the air extraction port is heat-sealed.

[0057] Nitrogen-packed products are stacked in the warehouse at a height not exceeding 6 meters. The warehouse must be well-ventilated, dry, protected from light, and rodent-proof.

[0058] Example 2

[0059] To verify the actual effect of the product prepared in Example 1, a multi-point, multi-group comparative test was conducted in the Heilongjiang Reclamation Area in 2025.

[0060] Experimental sites: Team 12 of Xinhua Farm, Team 8 of Junchuan Farm, and Branch Farm 2 of 852 Farm.

[0061] Experimental period: April to May 2025 (seedling stage).

[0062] Experimental Design: Each farm trial consisted of three treatment groups: Group A (product of Example 1; containing 22.5g of seedling strengthener per tray), Group B (traditional soil seedling raising; soil collected on-site, mixed with fertilizer, and acidified), and Group C (soilless organic straw rice seedling trays produced by Mudanjiang Ruihe Agricultural Technology Co., Ltd. in Heilongjiang Province; requiring on-site acidification and fertilization). Uniform varieties and water and fertilizer management were implemented.

[0063] The product of this invention (2 people, operation time 4-5 hours): arranging seedling trays—watering thoroughly to saturation—sterilizing the seedling trays—sowing—covering with fine soil—sterilizing the top layer of soil—covering with a breathable and heat-insulating film and a heat-insulating and moisture-retaining plastic film; the fungicide used is hymexazol (applied according to the instructions), the same below; Traditional field soil seedling raising: On-site fertilization and acidity adjustment of the carrier. Operation procedure: (6 people, operation time 6:00 am to 6:00 pm), take field soil, transport, crush, sieve soil — field acidity adjustment + seedling strengthening agent (Humiao brand rice seedling strengthening agent, 28g / tray) + fungicide — mix — water — sow — cover with fine soil — sterilize the top soil — cover with breathable and heat-insulating film and heat-insulating and moisture-retaining plastic film — acidity adjustment and fertilization again at the one-leaf and one-heart stage and the two-leaf and one-heart stage; Soilless organic straw rice seedling trays (commercially available straw trays): (6 people, operation time 6:00 AM to 6:00 PM), cover with plastic base tray—place trays—water thoroughly until saturated—adjust acidity—mix fertilizer (Humiao brand rice seedling strengthening agent, 28g / tray)—sterilize—water—sow—cover with fine soil—sterilize top soil—cover with breathable and heat-insulating film and heat-insulating and moisture-retaining plastic film—adjust acidity and supplement fertilizer twice at the one-leaf and one-heart stage and the two-leaf and one-heart stage.

[0064] Seedling quality survey method: The seedling quality survey was conducted one day before transplanting (seedling age 30-32 days). Three sampling points were selected for each replicate, with each sampling point having an area of ​​100 cm². 2 After cleaning, 20 representative seedlings were selected according to the following criteria: (1) Seedlings with height >13cm, 11~13cm, 9~11cm, 7~9cm and <7cm were sampled in proportion; (2) 60 seedlings were selected for each treatment, and the seedling height, leaf age, stem base width, longest root length and number of roots were measured; (3) 100 seedlings were selected to determine the above-ground dry weight of 100 seedlings (blanched at 105℃ for 30min, dried at 80℃ to constant weight).

[0065] The experimental results are shown in Tables 1 to 4.

[0066] Table 1 Comparison of seedling quality indicators (average values ​​from three locations)

[0067] Table 2 Detailed data on dry weight per 100 plants at each test site

[0068] Significance test: The t-test showed that the differences between group A and group B, and between group A and group C were highly significant (P<0.01).

[0069] Table 3. Acidity Adjustment and Fertilizer Supplementation

[0070] Note: When adjusting the acidity of groups B and C, use commercially available solid acid adjusters and adjust the acidity according to the instructions. When supplementing fertilizer for groups B and C, use the same type of seedling strengthening agent as the base fertilizer (Humiao brand rice seedling strengthening agent), and use 1 / 3 of the 28-gram base fertilizer amount, which is 9.33 grams.

[0071] Table 4 Yield Results

[0072] in conclusion: 1. Seedling Quality: The seedlings produced by this invention are significantly superior to those from traditional soil-based seedling cultivation and commercially available soilless straw seedling trays in key indicators such as plant height, leaf age, stem base width, root length, root number, and dry weight per 100 plants. The dry weight per 100 plants is 53.3% higher than that from traditional soil-based seedling cultivation, indicating greater accumulation of dry matter and stronger seedlings. Group A seedlings have white roots, numerous fibrous roots, strong root-binding ability, do not crumble when lifted, have wide stem bases, and a significantly higher dry weight per 100 plants than Groups B and C.

[0073] 2. pH Adjustment and Fertilization: This invention eliminates the need for secondary pH adjustment and fertilization throughout the entire seedling stage, maintaining a stable pH value within the suitable range of 4.8-5.3. In contrast, traditional soil-based seedling cultivation and commercially available soilless straw seedling trays require 1-2 on-site pH adjustments and 1 fertilization, otherwise, obvious yellowing leaves and damping-off symptoms will appear.

[0074] 3. Seedling establishment and yield: The seedlings of this invention recover to green within 48 hours after transplanting, which is 3-4 days earlier than traditional soil seedling raising (5-6 days). The average yield of this invention is 1479 catties per mu, which is 10.0% higher than traditional soil seedling raising and 6.9% higher than commercially available soilless straw seedling trays, showing a significant yield increase.

[0075] 4. Operating procedure: This invention only requires placing the tray, watering, sowing, and covering with soil, saving 60% of labor and shortening the operation time by more than 50% compared with traditional soil seedling cultivation; compared with commercially available soilless straw seedling trays, it eliminates the on-site acidification and fertilizer mixing process.

[0076] Example 3

[0077] This embodiment provides a single-tray quota weight method material calculation and feeding instruction system suitable for large-scale industrial production. This method uses the "absolute dry weight of all materials required for each seedling tray" as a benchmark to reverse-calculate the batch feeding quantity, achieving precise and traceable standardized production.

[0078] 1. Standard quota for single-pan material (dry weight basis)

[0079] After extensive pressing tests and seedling verification, the total dry weight of the pressed material in a single seedling tray (mold inner cavity volume 4.246L) was determined to be 2.5kg, and the quotas for each component are shown in Table 5.

[0080] Table 5 Single-pane material quota standard

[0081] Validation data: -Total weight of functional masterbatch = 22.5 + 75 + 652.5 = 750g / tray; -Seedling strengthening agent concentration = 22.5 / 750 = 3.0%; - Total dry weight of a single tray = 1750 + 750 + 5.31 + 0.5 = 2505.81 g ≈ 2.506 kg; - The cost of the seedling strengthening agent is 22.5g × 7 yuan / kg = 0.1575 yuan / tray, which is comparable to traditional seedling raising and has better results; - Cost of ammonium sulfate = 5.31g × 3 yuan = 0.0159 yuan / plate.

[0082] 2. Batch production material feeding instruction sheet (taking 10,000 trays as an example of a batch)

[0083] (1) Production line material requisition instruction A - acidification and fermentation line

[0084] Table 6 Production Line Material Requisition Instruction A

[0085] (2) Production line material requisition instruction B - sludge powder pretreatment line

[0086] Table 7 Production Line Material Requisition Instructions B

[0087] (3) Production line material requisition instruction C - Functional masterbatch preparation line

[0088] Table 8 Production Line Material Requisition Instructions C

[0089] Total output of functional masterbatch: 225 + 750 + 6525 = 7500 kg; Single tray allocation: 7500 kg ÷ 10,000 trays = 0.75 kg / tray.

[0090] (4) Production line material requisition instruction D - Ammonium sulfate & sodium carboxymethyl cellulose

[0091] Table 9 Production Line Material Requisition Instructions D

[0092] 3. Final Mixed Instructions (Equal Incremental Method - Industrial Version)

[0093] Step 1: Premix (start with smaller ingredients)

[0094] - Add the functional masterbatch (7500 kg) prepared by instruction C and the ammonium sulfate (53.1 kg) received by instruction D into a premixer and mix for 4 minutes at 7 revolutions per minute.

[0095] - Transfer the 1% sodium carboxymethyl cellulose solution (500 kg) prepared according to instruction D to the spray storage tank for later use.

[0096] Step 2: Increment the total volume by equal amounts

[0097] - First mixing: Take 1750 kg of the acidified fermentation material from instruction A, and add it to a twin-shaft paddle mixer at a volume ratio of approximately 1:1 with 753.125 kg of the premixed functional masterbatch + ammonium sulfate mixture. Mix for 2 minutes at 7 revolutions per minute.

[0098] - Second mixing: Add an equal volume of 1750 kg of acid-adjusting fermentation material, mix for 2 minutes at 7-8 revolutions per minute.

[0099] - Step-by-step scaling: Add the remaining acid-adjusting fermentation material in increments of "2 times, 4 times, 8 times" until all 17,500 kg of acid-adjusting fermentation material has been added.

[0100] - Adding adhesive: In the last 3 minutes of mixing, evenly spray 500 kg of 1% sodium carboxymethyl cellulose solution through a high-pressure atomizing nozzle.

[0101] -Total mixing: 10 minutes, until the material is moist and uniform, "it can be clumped together when squeezed, but crumbles when touched".

[0102] Step 3: Suppression

[0103] - The compressed material after total mixing is conveyed to the automatic feeding machine.

[0104] - Feed the seedlings evenly into the seedling tray mold at a feeding precision of 2.5kg±50g per tray.

[0105] -350 tons of pressure, hold pressure for 8 seconds, demold and form.

[0106] 4. Product Cost and Economic Benefit Analysis

[0107] Based on an annual production scale of 10 million trays, the results are shown in Table 10. Compared with traditional soil seedling cultivation, farmers save about 50 yuan per mu in labor costs for soil collection, sifting, fertilizer mixing, acidification, and secondary topdressing, while increasing yield by 8-12% and income by 150-200 yuan per mu, resulting in significant comprehensive socio-economic benefits.

[0108] Table 10 Product Composition and Economic Benefit Analysis

[0109] Advantages of this embodiment: (1) The “single-plate quota weight method” was established for the first time, and the laboratory volume ratio (7:3) was successfully transformed into a weight feeding instruction that the production line can execute, filling the measurement gap from formulation to industrialization.

[0110] (2) The precise quantitative amount of seedling strengthening agent is 22.5g / tray. After field verification in three locations in Heilongjiang in 2025, the seedling uniformity rate is ≥98%, there is no seedling burn or excessive growth, the root system is white and dense, the root force is strong, and the seedlings turn green again 48 hours after transplanting, which is significantly better than the soil seedling raising and fertilization program.

[0111] (3) Achieve full-process quality traceability: Each batch of material requisition, feeding, and loss is accurately recorded, significantly improving the consistency of finished products.

[0112] (4) Significantly reduce the operational threshold: Production line workers do not need to understand volume ratio and bulk density conversion, and can directly collect materials by "kilogram".

[0113] (5) It is fully compatible with the 7:3 volume ratio technical feature and is the best implementation of the core inventive point, rather than a substitute.

[0114] As can be seen from the above embodiments, the present invention provides a molded rice seedling tray with seedling strengthening agent and acid adjustment and its preparation method, which successfully solves the four core problems of "difficulty in acid adjustment, difficulty in fertilizer carrying, high cost, and difficulty in industrialization" in soilless rice seedling cultivation, and achieves a win-win situation of ecological and economic benefits, with extremely high industrial application value and promotion prospects.

[0115] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a molded rice seedling tray containing a seedling-strengthening agent and adjusted acidity, characterized in that, Includes the following steps: (1) Mix agricultural and forestry waste with sulfur powder at a mass ratio of 90~110:1~1.5 and ferment to obtain acidified fermented material; (2) Mix seedling strengthening agent, zeolite powder and acidic river silt to obtain functional masterbatch; (3) The acid-adjusting fermentation material, the functional masterbatch, ammonium sulfate and sodium carboxymethyl cellulose are mixed to obtain the pressed material; (4) Press the material into shape to obtain a molded rice seedling tray with seedling strengthening agent and acid adjustment.

2. The preparation method according to claim 1, characterized in that, In step (1), the agricultural and forestry waste includes the following raw materials in parts by volume: 45-65 parts straw, 25-45 parts wood ear fungus residue, 5-9 parts river silt, and 6-10 parts rice husk ash residue.

3. The preparation method according to claim 2, characterized in that, The moisture content of the agricultural and forestry waste is adjusted to 35-45%; the moisture content of the agricultural and forestry waste is adjusted to 50-60% after being mixed with sulfur powder; the fermentation temperature is 25-35℃ and the time is 25-35 days, and the material is turned over every 3-5 days during the fermentation process; after the fermentation is completed, the material is steamed for 5-9 days and then dried at 70-90℃ until the moisture content is below 15%.

4. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of the seedling strengthening agent, zeolite powder and acidic river silt when mixed is 20~25:50~100:600~700; the pH value of the acidic river silt is 5.5~6.5 and the water content is ≤15%.

5. The preparation method according to claim 1, characterized in that, In step (3), the volume ratio of the acid-adjusting fermentation material to the functional masterbatch is 1700~1800:700~800. 1~1.5 kg of ammonium sulfate is added to each cubic meter of the mixture of acid-adjusting fermentation material and functional masterbatch. The amount of sodium carboxymethyl cellulose added is 0.015~0.025% of the total mass of the acid-adjusting fermentation material and functional masterbatch. During mixing, sodium carboxymethyl cellulose is prepared into an aqueous solution with a concentration of 0.8~1.2%, and added to the mixture of acid-adjusting fermentation material, functional masterbatch, and ammonium sulfate by spraying.

6. The preparation method according to claim 1, characterized in that, In step (4), the pressing material is laid in the seedling tray mold during the pressing process and held under the pressure of a 300-400 ton hydraulic press for 5-10 seconds; the thickness of the material is 2-4 cm.

7. The preparation method according to claim 1, characterized in that, Step (4) also includes storing the prepared rice seedling trays with seedling strengthening agent and acidity adjustment by filling them with nitrogen; the method of nitrogen filling and storage is as follows: after stacking the prepared rice seedling trays with seedling strengthening agent and acidity adjustment, they are put into nylon + PE composite film packaging bags, vacuumed and filled with nitrogen, and then heat-sealed.

8. The preparation method according to any one of claims 1 to 6, characterized in that, In step (2), when preparing the functional masterbatch, the seedling strengthening agent, zeolite powder and acidic river silt are mixed according to the equal incremental method.

9. The preparation method according to claim 8, characterized in that, When industrially preparing the molded rice seedling trays containing seedling strengthening agents and acid-adjusted materials, the raw materials are mixed using the single-tray quota weight method. The single-tray quota weight method refers to pre-determining the dry weight of each raw material required for a single rice seedling tray, and then calculating and adding each raw material according to the method of "rated dry weight of a single tray × total number of trays in the batch".

10. A molded rice seedling tray containing a seedling strengthening agent and adjusted acidity, prepared according to the preparation method of any one of claims 1 to 9.

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