Rice seed coating agent and mechanized transplanting and rice oil dual-purpose soft disk seedling raising method

Abstract

This invention discloses a rapeseed seed coating agent and a method for mechanized transplanting using dual-purpose rice-oilseed trays, relating to the field of agricultural seedling technology. The rapeseed seed coating agent comprises the following components: a carbon dioxide trap, a compound fungicide, a plant growth regulator, and a solvent. The mechanized transplanting method for dual-purpose rice-oilseed trays includes seed drying, disinfection, substrate preparation, tray sowing, darkening treatment, and seedling management. This invention optimizes the concentration, ratio, and frequency of seed coating agent components with those of seedling fertilization, achieving robust rapeseed seedling cultivation. It is suitable for rice and rapeseed seedling cultivation in rice-oilseed rotation areas, solving the problem of incompatible transplanting equipment for rice and rapeseed mechanized transplanting. It has advantages such as low seedling cost, simple process, high qualification rate, and suitability for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of agricultural seedling technology, specifically to a rapeseed seed coating agent and a method for mechanized transplanting of seedlings using rice-oilseed dual-purpose trays. Background Technology

[0002] Rice and rapeseed are two major grain and oilseed crops. In areas with multiple cropping systems, rice-rapeseed rotation is a widely used planting pattern. Achieving full mechanization of production for these two crops is of great significance for ensuring food security, reducing labor intensity, and improving agricultural production efficiency. Transplanting is a crucial step in the rice and rapeseed planting process. Compared to direct seeding, transplanting can effectively alleviate crop rotation conflicts, resist seedling adversity, and ensure planting density and population quality, making it an important technical measure for achieving stable and increased yields. However, currently, there is a lack of universal seedling raising methods that can simultaneously adapt to the mechanized transplanting requirements of both rice and rapeseed, which has become a technical bottleneck restricting the development of full mechanization in rice-rapeseed rotation.

[0003] For rice and rapeseed transplanting, existing technologies generally employ separate seedling raising methods. Rice transplanting has gradually become mechanized, with the mainstream method using mat-shaped or pot-shaped mat-shaped seedlings. For rapeseed transplanting, there are currently two main methods: one is bare seedling transplanting, where rapeseed seedlings are raised in the field, pulled up, and then planted manually or using a semi-automatic transplanter. This is the mainstream method for rapeseed transplanting, but it is still labor-intensive, causes severe root damage, and has a long recovery period. The other method uses mat-shaped seedling raising, employing 9-inch rice seedling trays filled with substrate for precision sowing to cultivate well-developed mat-shaped seedlings, which are then planted using a rapeseed transplanter.

[0004] The aforementioned existing technologies have the following problems and shortcomings in practical applications: First, the use of 9-inch rice seedling trays has poor general effectiveness and high equipment costs: 9-inch rice seedling trays are designed for rice root systems, but rapeseed has a taproot system with a large root volume and high nutrient absorption. If the seedling tray is too shallow, it will not be able to grow deeply, easily resulting in uneven seedlings and "leggy" seedlings, high damage during transplanting, low survival rate after transplanting, and poor stress resistance. This forces farmers or cooperatives practicing rice-rapeseed rotation to purchase two completely different sets of seedling raising equipment and transplanting machinery, which not only increases equipment purchase costs but also occupies a large amount of storage space, resulting in low equipment utilization. Second, the seedling raising process is complex and has high requirements for hypocotyl length: Rapeseed tray seedling raising requires the preparation of a special substrate, and the operation of sowing, watering, and fertilization is delicate and the process is relatively complex, which is difficult for ordinary farmers to master, limiting its large-scale promotion and application. Excessively long hypocotyls (resulting in "leggy seedlings") are the most common cause of seedling failure, directly leading to lodging, frost damage, and yield reduction after transplanting. Thirdly, the seedling qualification rate is low, resulting in poor transplanting performance: transplanting naked rapeseed seedlings suffers from severe root damage, slow seedling establishment, and low survival rates; while tray seedling cultivation offers better root protection, improper management can easily lead to leggy and weak seedlings, and the root system is not firmly bound, making them prone to falling apart during transplanting, similarly affecting transplanting quality. Fourthly, it cannot adapt to the needs of large-scale production: existing rapeseed seedling cultivation methods are difficult to achieve standardized, intensive, factory-style seedling production.

[0005] It is evident that existing technologies, whether focused on rice or rapeseed, are incompatible with each other in terms of their core seedling carriers (seedling trays), seedling media, and agronomic management measures. They cannot simultaneously adapt to the transplanting equipment and agronomic requirements of both crops, thus failing to solve the aforementioned problems of high cost, complex processes, low pass rates, and inability to scale up production.

[0006] In conclusion, there is an urgent need for a universal seedling raising method that can meet the requirements of both mechanized rice transplanting and mechanized rapeseed transplanting. Summary of the Invention

[0007] To overcome the shortcomings of the above-mentioned technologies, the purpose of this invention is to provide a rapeseed seed coating agent and a method for raising seedlings in rice-oilseed dual-purpose trays for mechanized transplanting. This solves the problems of high cost, complex process, low qualification rate, and inability to scale up mechanized seedling raising in rice-oilseed rotation in the prior art. The same set of seedling raising equipment and transplanting machinery can be used for raising seedlings of rice and rapeseed, and is suitable for rice-oilseed rotation planting mode.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A rapeseed coating agent suitable for mechanized transplanting is characterized by comprising the following components: a carbon dioxide trap, a compound fungicide, a plant growth regulator, and a solvent.

[0009] As a preferred embodiment, the carbon dioxide trapping agent and the compound fungicide are liquid formulations, while the plant growth regulator is a solid formulation. The volume ratio of the carbon dioxide trapping agent, the compound fungicide, and the solvent is 14-16:0.8-1.2:4-6. The content of the plant growth regulator in the rapeseed seed coating agent is 0.008-0.01 g / mL. The plant growth regulator includes gibberellic acid, indoleacetic acid, brassinolide, uniconazole, and excipients. The effective components of the seed coating agent must be controlled within a suitable range. If the concentration is too high, it can easily cause an excessively thick film on the seed surface, reducing air permeability, inhibiting seed respiration and germination, leading to uneven emergence, radicle burn, and hypocotyl malformation. If the concentration is too low, the hypocotyl of the seedlings will be slender, with obvious internodes and slender petioles, resulting in severe seedling lodging and high seedling loss rates during mechanical transplanting.

[0010] Furthermore, the carbon dioxide capture agent is photocarbon slurry; the compound bactericide is cyprodinil; and the solvent is water.

[0011] Furthermore, in the plant growth regulator, the excipients include light calcium carbonate and corn starch; in the plant growth regulator, the mass percentages of gibberellic acid, indoleacetic acid, brassinolide, uniconazole, light calcium carbonate, and corn starch are 0.1-0.15%, 0.0004-0.0007%, 0.0002-0.0004%, 48-52%, 38-41%, and 8-11%, respectively.

[0012] Furthermore, in the plant growth regulator, the mass percentages of gibberellic acid, indoleacetic acid, brassinolide, uniconazole, light calcium carbonate, and corn starch are 0.135%, 0.00052%, 0.00031%, 50%, 39.89%, and 9.97417%, respectively; and in the rapeseed coating agent, the content of each component is 150 mL of light carbon slurry, 10 mL of cyprodinil, and 2 g of plant growth regulator per 50 mL of water.

[0013] This invention also provides a method for mechanized transplanting of rice and rapeseed seedlings using dual-purpose soft trays, characterized in that the soft trays are standard 420-cell trays; the seedling method is applicable to rice-rapeseed rotation planting patterns, and the same set of seedling equipment and transplanting machinery can be used for both rice and rapeseed seedlings, including the following steps: The seeds are sun-dried and disinfected; the seeds are rapeseed seeds or rice seeds; when the seeds are rapeseed seeds, they are treated with the above-mentioned rapeseed seed coating agent after disinfection; when the seeds are rice seeds, they are coated or soaked for germination after disinfection. Prepare the substrate by adjusting its moisture content to 40-50% using water; the substrate is a universal rice-oilseedling substrate suitable for both rapeseed and rice; the substrate has an EC value of 0.4-0.6 mS / cm, a pH of 5.5-6.5, and a porosity of 65-75%; Substrate is loaded into trays and sown; After sowing, stack the seedling trays and darken them until 45-55% of the seedlings in the trays show yellowing. Then, move them to the seedling nursery. After the sprouts emerge from the soil, place the trays on shelves or seedbeds. Stacking the trays refers to stacking the seedling trays that have already been sown with seeds one on top of the other to create a stable and suitable temperature and humidity environment, which promotes the rapid and uniform germination of the seeds. Seedling yellowing refers to the process during seed germination where the embryo breaks through the soil surface, revealing a yellow or white tender part (usually the embryo). This is a sign of seed germination, indicating that the seed has begun to grow, and is often used as an indicator of the end of germination or the transition to the next stage. Darkening treatment refers to placing the seeds in a completely dark or low-light environment (such as a dark room, covered with black film) after sowing and stacking them in trays, while controlling the appropriate temperature and humidity to promote rapid seed germination. When 45-55% of the seedlings in the trays show yellowing, the trays that have completed darkening germination are moved from the dark room to the normal seedling environment. When the sprouts just break through the surface of the covering substrate (sprouting), the originally stacked trays are separated (stacking trays) and laid flat on multi-layer seedling racks (stripping) or fixed seedbeds (seedbed), thus entering the standard seedling management stage. Seedling management: once the seedlings reach the standard for robust seedlings, harden them off and transplant them.

[0014] As a preferred option, the seed drying process should take 1-2 days.

[0015] As a preferred embodiment, the raw materials of the substrate include the following components by weight: 25-30% light clayey disease-free soil with a particle size of 0-10mm, 50-55% peat moss with a particle size of 0-10mm, 10-20% vermiculite with a particle size of 0-5mm, 3-5% organic fertilizer, and 0.08-0.12% silica-magnesium-calcium bacterial agent; wherein, the effective live bacteria count per gram of silica-magnesium-calcium bacterial agent is ≥200 million; the clay content of the light clayey disease-free soil is 27-30%, and all indicators of the organic fertilizer meet the requirements of the standard "NY / T525-2021 Organic Fertilizer".

[0016] As a preferred embodiment, the floppy disk is a standard seedling tray with 420 holes; the single-hole structure of the floppy disk is a stepped conical pot with a larger upper hole and a smaller lower hole, with 12 holes horizontally and 35 holes vertically, for a total of 420 holes. The vertical spacing between adjacent holes is 18-20mm, and the horizontal spacing is 23-25mm; the height of an independent hole is 25-27mm; the slope of the pot's edge is less than 6 degrees; the lower water-holding protrusion is an inverted flat-truncated hollow cone, and the water-holding pool is located on the top of the elliptical bottom. The bottom of the pot has ten circular adjustable permeable holes with a diameter of 4.5-5.5mm, and the single-hole volume is 3.5-4.5mL, suitable for the root growth of both rice and oilseed crops.

[0017] As a preferred embodiment, when filling the substrate trays, the surface is leveled and then the holes are pressed in to a depth of 5-8 mm, with a surface flatness error of ≤2 mm. During sowing, when the seeds are rapeseed, they are treated with a seed dressing and then air-dried before direct sowing. Sowing is done using a seeder or manually, one seed per hole. When the seeds are rice, they are germinated and sown after the seed buds have emerged. Sowing is done using a seeder or manually, 2-3 seeds per hole. After sowing, the soil or substrate is covered to a height of 3-5 mm to ensure no seeds are exposed. After sowing, the substrate is thoroughly watered until the surface is moist but not waterlogged, and water flows out from the bottom. Pressing in holes refers to digging grooves in the substrate to hold the seeds, pressing them in to a depth of 5-8 mm, where the hole depth is the depth of the groove.

[0018] As a preferred option, the darkening treatment is conducted at a temperature of 25-28℃, a relative humidity of 85-90%, and a darkening time of 24-72 hours, providing a uniform germination environment for both rice and oilseeds. Under dark conditions, seedlings emerge at a consistent time, are robust, and exhibit strong resistance, facilitating subsequent unified transplanting and field management.

[0019] As a preferred embodiment, the seedling management includes: Light management: After the seeds germinate, expose them to strong light as much as possible, with a light intensity of 150-320 PPFD. Otherwise, the seedlings will have elongated internodes, lighter leaf color, thinner leaf thickness, and weak stems, making them prone to excessive growth. Water management: Water when the soil is dry to the touch, keep the substrate moist, and drain water promptly on rainy days; Watering when the soil is dry to the touch refers to a conventional watering management principle, which means watering thoroughly, and then watering again when the surface of the soil is dry but the lower layer is not completely dry. This ensures that the roots get enough water, prevents the soil from being too wet for a long time, which can lead to root rot or disease, and promotes the roots to grow deeper. Fertilization Management: If the seedlings are rice seedlings, begin fertilization at the one-leaf-one-heart stage, spraying 2-3 times in total. If the seedlings are rapeseed seedlings, begin fertilization after the cotyledons have fully expanded, spraying 4-6 times in total. The fertilizers used include a water-soluble fertilizer with an NPK ratio of 20-10-20 and a compound fertilizer with an NPK ratio of 17-17-17. Apply 1-2 times every 3-4 days, using either the water-soluble fertilizer or the compound fertilizer each time, alternating between the two. When using fertilizer, the concentration should be adjusted between 1-2.5 g / L depending on the seedling condition. NPK=20-10-20 means that the mass percentages of N, P (as P2O5), and K (as K2O) in the water-soluble fertilizer are 20%, 10%, and 20%, respectively, with the rest being auxiliary materials. NPK=17-17-17 means that the mass percentages of N, P (as P2O5), and K (as K2O) in the compound fertilizer are 17%, 17%, and 17%, respectively, with the rest being auxiliary materials.

[0020] Excessive growth control: For rapeseed, use phosphatidylcholine slurry during the cotyledon stage and apply it with irrigation water; for rice, use phosphatidylcholine slurry for foliar spraying during the one-leaf-one-heart stage to control internode length and promote root growth; prevent excessive growth during the seedling stage and cultivate short and sturdy seedlings; the dosage of phosphatidylcholine slurry is 10-15 mL per liter of water; irrigation with water refers to dissolving soluble fertilizers or pesticides in water while irrigating and applying them evenly to the seedbed or field with the water flow. This method is labor-saving and efficient, allowing nutrients to reach the vicinity of the root system directly and improving absorption and utilization; the one-leaf-one-heart stage refers to the morphological indicators of seedling growth, which is the stage when the seedling has unfolded its first true leaf and the heart leaf (unfurled young leaf) has just emerged. At this time, the plant is still small and sensitive to the external environment, and it is often used to determine the starting time for pesticide application, fertilization, or transplanting; Pest and disease control: Control damping-off, bacterial wilt, aphids, and cabbage caterpillars; disinfect seedbeds with conventional biological agents or low-toxicity agents. The standard for robust seedlings is as follows: Rapeseed: Seedling age 40-45 days, leaf age 5.0-6.0 leaves; short and sturdy without tall stems, i.e. hypocotyl length ≤1.5cm, hypocotyl thickness ≥1.5mm; white, dense and well-developed root system; the root system wraps around and covers the entire substrate ball, suitable for mechanized operations; Rice: Seedling age 25-28 days, leaf age 5.0-5.5 leaves, seedling height 12-14cm, seedlings are uniform and strong, without diseased leaves, no yellow roots, white roots, and no less than 5 roots per seedling.

[0021] The concentration of fertilizer applied during the seedling stage should be set at 1-2.5 g / L, preferably once every 3 days. If the concentration is higher than 2.5 g / L, osmotic pressure stress is likely to occur, causing seedling burn, root burn, and leaf wilting. If it is lower than 1 g / L, the nutrient supply will be insufficient, resulting in stunted seedlings, small and thin leaves, pale leaf color, and slow growth.

[0022] The instructions for fertilizer use during the seedling stage are as follows: Assuming fertilization is applied twice every 4 days, then each of the two types of fertilizers should be applied once within those 4 days. If the first application is a water-soluble fertilizer with NPK=20-10-20, then the next application should be a compound fertilizer with NPK=17-17-17, and so on, alternating between the two types of fertilizers.

[0023] Fertilizer concentrations can be referenced as follows: For normal, healthy seedlings, a lower concentration is recommended, with a reference range of 1.0-1.5 g / L; If yellowing seedlings appear (yellow leaves, slow growth, and stunted plants), these seedlings urgently need nutrients and require a higher concentration to promote leaf greening and stem and leaf growth, with a recommended concentration of 1.8-2.2 g / L; If seedlings have already shown severe nitrogen or potassium deficiency symptoms, a high-concentration fertilizer solution should be used for "intensive fertilization," with a recommended concentration of 2.2-2.5 g / L.

[0024] As a preferred method, during the hardening-off process, the substrate moisture content is controlled at 25-35%; the hardening-off time is 3-5 days; the seedling requirements are: the root ball completely wraps around the pot, without breaking apart or falling off the tray; rapeseed seedlings are 10-12cm tall, and rice seedlings are 12-14cm tall. Hardening-off refers to the process of gradually adapting seedlings to the open-field environment before transplanting by gradually lowering the temperature, increasing ventilation, reducing moisture, and increasing light exposure. Hardening-off can improve the seedlings' resistance to adverse conditions (cold, drought, wind, etc.), reduce the recovery time after transplanting, and improve the survival rate.

[0025] As a preferred option, the transplanting process can be carried out using both mechanical and manual methods, with the soil attached to the roots.

[0026] As a preferred embodiment, the seedling raising method is used for rice and rapeseed seedling raising in rice-rapeseed rotation areas. When the rice-rapeseed rotation area enters the rice season, rice seedlings are raised using the method and then transplanted to the field. After the rice harvest, when the rapeseed season begins, rapeseed seedlings are raised using the same method and then transplanted to the field, repeating this process for rice-rapeseed rotation. This method allows for the initial raising of rice seedlings for transplanting in rice-rapeseed rotation areas, followed by the raising of rapeseed seedlings after the rice harvest, alternating between the two methods. It eliminates the need to replace seedling trays, seedling raising equipment, and transplanting machinery, offering advantages such as low seedling raising costs, simple procedures, high pass rates, and suitability for large-scale production.

[0027] The rapeseed coating agent of the present invention is composed of photocarbon pulp, cyprodinil, gibberellin, indoleacetic acid, brassinolide, and uniconazole, with each component acting synergistically.

[0028] Photocarbon slurry, as a carbon dioxide capture agent, enhances photosynthesis by capturing carbon dioxide from the air and enriching it around the crop. It can improve the photosynthetic efficiency of seedlings, increase leaf thickness and stem strength, improve the rhizosphere microenvironment, enhance the rapeseed seedlings' resistance to low temperature and waterlogging, inhibit excessive growth under high-density seedling raising conditions, make seedlings short and sturdy with dark green leaves, significantly improve the seedlings' resistance to mechanical damage, and reduce the rate of seedling breakage and damage during mechanized transplanting.

[0029] As a highly effective fungicide combination, cyprodinil can simultaneously prevent and control soil-borne and seed-borne diseases such as damping-off, seedling blight, and root rot in rapeseed seedlings. It effectively reduces the incidence of seed rot, bud rot, and diseased seedlings, ensuring seedling survival rate and healthy seedling roots. It also ensures that the seedling clumps are tightly packed and do not fall apart, meeting the requirements for mechanized seedling harvesting and transplanting.

[0030] Gibberellin can promote rapid seed germination under low temperature stress, shorten the seedling emergence period of stacked trays, improve the turnover rate of rice and oilseed dual-purpose soft trays, ensure uniform seedling growth, and facilitate standardized mechanized transplanting operations. Indoleacetic acid can promote the elongation of the taproot and the development of fibrous roots in rapeseed seedlings, increase the number of roots and the density of root hairs, accelerate the intertwining of seedling roots in the soft substrate, and quickly form a dense root system, significantly improving the integrity of the seedling block and reducing the phenomenon of missed planting and missing plants during mechanical transplanting.

[0031] Brassinolide, as a highly efficient plant growth regulator, can balance the growth regulation effects of gibberellin and indoleacetic acid, optimize the seedling type suitable for mechanical transplanting such as plant height and stem diameter, and at the same time improve the seedling's stress resistance and recovery ability, so that the seedlings survive quickly and recover early after transplanting, laying the foundation for high yield in the later stage.

[0032] Uniconzcole is a highly effective, broad-spectrum triazole plant growth regulator. Its core functions are to control excessive growth, dwarf plants, and prevent lodging. It breaks apical dominance and promotes the development of underground root systems. It effectively enhances the strength of stems and leaves and the density of the root system, adapting to the intensity of machine operation and increasing the resistance of seedlings to breakage, impact, and damage.

[0033] Compared with the prior art, the present invention has the following advantages: This invention provides a rapeseed coating agent and a method for raising seedlings in rice-oilseed dual-purpose trays for mechanized transplanting. It is applicable to rice and rapeseed seedling raising in rice-oilseed rotation areas, solving the problem that rice and rapeseed cannot share transplanting equipment during mechanized transplanting. It has the advantages of low seedling raising cost, simple process, high qualification rate, and is suitable for large-scale production.

[0034] This invention achieves robust rapeseed seedling cultivation by optimizing the concentration, ratio, and frequency of seed coating agent components, seedling fertilizer concentration, and application frequency. By rationally controlling the coating agent and fertilization parameters, and alternating application with specific nitrogen, phosphorus, and potassium ratios, this invention synergistically promotes seed germination, above-ground leaf growth, and underground root development. This results in rapeseed seedlings with short, thick, and straight hypocotyls, moderate plant height, no internodes, large leaves, and robust petioles, exhibiting significant seedling vigor. This makes the seedlings suitable for mechanized rapeseed transplanting, laying the foundation for high and stable rapeseed yields.

[0035] This invention employs a 420-cell stepped pot, serving two purposes in one. It utilizes the same tray, substrate, and germination environment, reducing equipment investment and achieving compatibility between rice and rapeseed. It standardizes the entire process of substrate, sowing, germination, watering and fertilization, and hardening off. Watering and fertilization use the same fertilizer applied at different times, simplifying the process and achieving optimal results. All dimensions, ratios, temperature, humidity, and watering and fertilization are specific quantitative indicators, ensuring uniqueness and uniform seedling standards. It is highly adaptable to machine transplanting, exhibiting significant economic benefits and guaranteeing that both rapeseed and rice seedlings meet quality standards, with a machine transplanting qualification rate ≥95%. The trays can be rolled for transport, simplifying operation, reducing labor and substrate waste, and making it suitable for large-scale, factory-style seedling cultivation. Attached Figure Description

[0036] Figure 1 This is a diagram showing the results of rapeseed seedling cultivation using the mechanized transplanting method for rice and oilseed dual-purpose soft trays as described in Embodiment 3 of the present invention. Figure 2 This is a diagram showing the results of rapeseed seedling cultivation using the seedling raising method in Comparative Example 1; Figure 3 This is a diagram showing the results of rapeseed seedling cultivation using the seedling raising method in Comparative Example 2; Figure 4 This is a diagram showing the results of rapeseed seedling cultivation using the seedling raising method in Comparative Example 3; Figure 5 This is a diagram showing the results of rapeseed seedling cultivation using the seedling raising methods in Comparative Example 4. Figure 6 This is a diagram showing the results of the second seedling cultivation of rapeseed using the method described in Example 3 of this invention. Figure 7 This is a diagram showing the results of the second seedling cultivation of rapeseed using the method described in Example 3 of this invention. Figure 8 This is a diagram illustrating the rapeseed seedling cultivation process using conventional seedling raising methods. Figure 9 This image shows the results of rapeseed seedling cultivation using conventional seedling raising methods. Figure 10 This is a diagram showing the results of the second rice seedling cultivation using the method described in Example 3 of this invention. Figure 11 This is a diagram showing the results of rice seedling cultivation using conventional seedling raising methods. Detailed Implementation

[0037] To better explain the present invention, the main contents of the present invention are further illustrated below with reference to specific embodiments, but the contents of the present invention are not limited to the following embodiments.

[0038] This invention discloses a rapeseed seed coating agent suitable for mechanized transplanting, comprising the following components: a carbon dioxide trap, a compound fungicide, a plant growth regulator, and a solvent; wherein the carbon dioxide trap and the compound fungicide are liquid formulations, and the plant growth regulator is a solid formulation; the volume ratio of the carbon dioxide trap, the compound fungicide, and the solvent is 14-16:0.8-1.2:4-6; the amount of plant growth regulator added to the rapeseed seed coating agent is 0.008-0.01 g / mL. The plant growth regulator includes gibberellic acid, indoleacetic acid, brassinolide, uniconazole, and excipients.

[0039] The present invention provides a method for mechanized transplanting of rice seedlings using dual-purpose rice and oilseed trays, comprising: (I) Structural characteristics of the calculus plate The standard seedling tray, measuring 66.4cm × 29.6cm with 420 holes, is used. The single-cell structure is a stepped conical pot, wider at the top and narrower at the bottom: 12 cells horizontally and 35 cells vertically, totaling 420 cells. The vertical spacing between individual cells is 18-20mm; the horizontal spacing is 23-25mm; the height of each cell is 25-27mm; and the slope of the pot's edge is less than 6 degrees. The lower water-holding platform is an inverted, flat-truncated hollow cone, with the water reservoir located on top of the elliptical base. This platform prevents root entanglement and cross-rooting. Ten adjustable circular permeable holes, 4.5-5.5mm in diameter, are located at the bottom of the pot, providing a single-cell volume of 3.5-4.5mL, suitable for the root growth of both rice and oilseed rape.

[0040] (II) Standard Procedures for General Seedling Raising in Holes 1) Seedling preparation The substrate / nutrient soil uses a general-purpose substrate for rice seedling cultivation: EC value 0.4-0.6 mS / cm, pH 5.5-6.5, porosity 65-75%. It consists of loose, weed-free, low-pest, lightly clayey, disease-free loam (particle size 0-10mm, clay content 27-30%) at a ratio of 25-30 wt%, peat moss (particle size 0-10mm) at a ratio of 50-55 wt%, vermiculite (particle size 0-5mm) at a ratio of 10-20 wt%, organic fertilizer at a ratio of 3-5 wt%, and silica-magnesium-calcium microbial agent (effective viable bacteria count 200 million / g) at a ratio of 0.08-0.12%.

[0041] 1.2) Seedling facilities and equipment: It is advisable to select greenhouses with good heat preservation and light transmission that are easy to operate, and equip them with germination rooms, seedling beds, and environmental control systems such as humidity control, temperature control, and supplemental lighting.

[0042] 1.3) Seed treatment: Sun-dry seeds for 1–2 days, select and disinfect them; after disinfection, treat rapeseed seeds with the above-mentioned rapeseed coating agent to prevent excessive hypocotyl growth, and coat or soak rice seeds to promote germination until they show white.

[0043] 2) Packing and sowing 2.1) Packing: Adjust the substrate moisture content to 40-50%, pack the substrate into trays uniformly, scrape it flat, and press the holes to a depth of 5-8mm. The surface flatness error of the tray should be ≤2mm.

[0044] 2.2) Precision sowing: For rapeseed with 420 holes: after seed dressing, dry in the shade and sow 1 seed per hole; for rice: after germination, sow 2-3 seeds per hole after the seeds have broken through the basal layer, ensuring one seedling / strong seedling per hole. Sowing can be done by seeder or manually.

[0045] 2.3) Covering: Cover with soil / substrate 3-5 mm cm, ensuring the seeds are not exposed.

[0046] 2.4) Watering: The substrate surface should be thoroughly moistened without water accumulation, and water should flow out from the bottom.

[0047] (III) Layering of trays and seedling emergence After sowing, stack the seedlings in trays, with a stack height of 15-20 trays. Maintain a temperature of 25-28℃, a relative humidity of 85-90%, and a darkening time of 24-72 hours. Provide a uniform germination environment for rice and oilseeds. When 45-55% of the seedlings in the trays show yellowing, move the trays to the nursery site and wait for the sprouts to emerge from the soil before placing them on shelves / seedbeds. The germination rate should be ≥90%.

[0048] (iv) Seedling management Light management: After the seeds germinate, expose them to strong light as much as possible, with a light intensity of 150-320 PPFD. Otherwise, the seedlings will have elongated internodes, lighter leaf color, thinner leaf thickness, and weak stems, making them prone to excessive growth.

[0049] Moisture: Keep the substrate moist by watering only when the soil is dry to the touch, and drain water promptly during rainy weather.

[0050] Fertilization: Begin gradual fertilization when rice enters the one-leaf-one-heart stage, spraying 2-3 times. Begin gradual fertilization after rapeseed seedlings have fully expanded their cotyledons, spraying 4-6 times. Fertilizers include water-soluble fertilizer with NPK=20-10-20 and compound fertilizer with NPK=17-17-17. Alternate between the two fertilizers, spraying 1-2 times every 3-4 days. Use one of the water-soluble or compound fertilizers each time, adjusting the fertilizer concentration to 1-2.5 g / L depending on the seedling condition.

[0051] Controlling excessive growth: Apply photocarbon slurry to rapeseed seeds during the cotyledon stage via irrigation; for rice during the one-leaf-one-heart stage, apply photocarbon slurry as a foliar spray to control internode length, promote root growth, prevent excessive seedling growth, and cultivate short and sturdy seedlings. The dosage of photocarbon slurry is 10-15 mL per liter of water.

[0052] Pest and disease control: Control damping-off, bacterial wilt, aphids, and cabbage caterpillars. Disinfect seedbeds with biological agents or low-toxicity agents.

[0053] (v) Standards for robust seedlings Rapeseed: Seedling age 40-45 days, leaf age 5.0-6.0 leaves, short and sturdy without tall stems, with well-formed root system.

[0054] Rice: Seedling age 25-28 days, leaf age 5.0-5.5 leaves, seedling height 12-14cm, seedlings are uniform and strong, without diseased leaves, no yellow roots, white roots, and no less than 5 roots per seedling.

[0055] (vi) Standardize the hardening-off and machine-transplanted seedling standards Water is controlled uniformly, reducing the substrate moisture content to 25-35%; hardening-off time is 3-5 days. Seedling requirements: the root ball should completely wrap around the pot, without breaking apart or detaching from the tray. Rapeseed seedlings are 10-12cm tall, and rice seedlings are 12-14cm tall, both suitable for high-speed rice transplanters. A uniform 420-cell transplanter is used, suitable for both mechanical and manual transplanting, seamlessly connecting rice and rapeseed stubble. Transplanting with soil intact minimizes root damage, promotes rapid greening, and results in a high survival rate.

[0056] The present invention will be further illustrated by specific embodiments below.

[0057] Example 1 A rapeseed coating agent uses carbon dioxide slurry, cyprodinil, and water as a carbon dioxide trap, a compound fungicide, and a solvent, respectively. The dosages of each component are as follows: 150 mL carbon dioxide slurry, 10 mL cyprodinil, 50 mL water, and 2 g plant growth regulator. In the plant growth regulator, the mass percentages of gibberellic acid, indoleacetic acid, brassinolide, and uniconazole are 0.135%, 0.00052%, 0.00031%, and 50%, respectively. The remainder is excipients, and the excipient components and their mass percentages in the plant growth regulator are: 39.89% light calcium carbonate and 9.97417% corn starch.

[0058] The photocarbon raw material was purchased from Shaanxi Photocarbon Ecological Agriculture Co., Ltd., and the photocarbon raw material contained amino acids ≥150g / L, Ca ≥50g / L, N ≥130g / L, K ≥50g / L, Mg ≥10g / L, B ≥5g / L, Zn ≥10g / L, and Fe ≥3g / L.

[0059] Example 2 This embodiment is a rapeseed coating agent, which differs from Example 1 in that the contents of each component are as follows: 160mL of photocarbon pulp, 8mL of cyprodinil, 60mL of water, and 2g of plant growth regulator.

[0060] Example 3 A method for mechanized transplanting of rice seedlings using dual-purpose rice and oilseed trays, comprising the method of this invention, wherein: Seedling tray structure: A standard seedling tray with 420 cells and external dimensions of 66.4cm × 29.6cm is used. The individual cell structure is a stepped conical pot, wider at the top and narrower at the bottom: 12 cells horizontally and 35 cells vertically, totaling 420 cells. The vertical spacing between individual cells is 19mm; the horizontal spacing is 24mm; the height of each cell is 26mm; and the slope of the pot's edge is less than 6 degrees. The lower water-holding protrusion is an inverted, flat-truncated hollow cone, with the water reservoir located on top of the elliptical base. This protrusion prevents root entanglement and cross-rooting. Ten adjustable circular permeable holes, 5mm in diameter, are located at the bottom of the pot, with a single cell volume of 3.5-4.5mL, suitable for the root growth of both rice and oilseed rape. The 420-cell standard seedling tray is a soft tray made of PVC / PET material.

[0061] Rapeseed seeds were treated with the rapeseed seed coating agent described in Example 1; The specific substrate composition is as follows: 30% light clayey disease-free loam (0-10mm, clay content 28%) + 55% peat moss (0-10mm) + 10% vermiculite + 4.9% organic fertilizer + 0.1% silica-magnesium-calcium bacterial agent. The substrate has an EC value of 0.5 mS / cm, a pH of 6, and a porosity of 68%. Water is used to adjust the substrate moisture content to 45%. The effective live bacteria count of the silica-magnesium-calcium bacterial agent is ≥200 million CFU / g. The silica-magnesium-calcium bacterial agent was purchased from Shandong Aifudi Biotechnology Co., Ltd., and contains ≥10.0% organic matter, ≥30.0 ​​U / g agricultural enzymes, ≥10.0% mineral-derived potassium humate, ≥0.5% soil moisture retention agent, ≥30.0‰ magnesium oxide, ≥30.0‰ silicon dioxide, and ≥10.0‰ polyglutamic acid.

[0062] When sowing, plant 1 rapeseed seed per hole and 2-3 rice seeds per hole; Dark germination: Temperature 26℃, humidity 88%, dark 30h; Water and fertilizer control: Rapeseed is fertilized 5 times, starting from the cotyledon unfolding stage, with fertilizer concentrations of 1g / L, 1.25g / L, 1.5g / L, 2g / L, and 2.5g / L respectively, and a fertilization frequency of 3 days / time. The first, third, and fifth fertilizations use water-soluble fertilizer with NPK=20-10-20, and the second and fourth fertilizations use compound fertilizer with NPK=17-17-17. Rice is supplemented with fertilizer 3 times, starting from the one-leaf-one-heart stage, with a fertilization frequency of 3 days / time, and fertilizer concentrations of 1g / L, 1.25g / L, and 1.5g / L respectively. The first and third fertilizations use water-soluble fertilizer with NPK=20-10-20, and the second fertilization uses compound fertilizer with NPK=17-17-17.

[0063] Controlling excessive growth: Apply the light carbon slurry with irrigation water during the cotyledon stage of rapeseed; apply the light carbon slurry as a foliar spray during the one-leaf-one-heart stage of rice, once a year; the dosage of light carbon slurry is 13 mL per liter of water.

[0064] Hardening off seedlings: Harden off seedlings by controlling water for 4 days, keeping the substrate moisture content at 25-35%, and achieving a root ball formation rate of 100%.

[0065] In this embodiment, the rapeseed germination rate is 94% and the seedling establishment rate is 90%; the rice germination rate is 95% and the seedling establishment rate is 92%; the machine transplanting qualification rate is ≥95%, with no broken pots or missed transplanting; compared with traditional crop-seedling cultivation, it saves 17% of labor and 25% of raw material costs.

[0066] This embodiment adopts a mid-season rice-rapeseed rotation model in rice-growing areas of southern China: During the rice season, mid-season rice is sown and raised using the method described in this embodiment from late April to early May, and transplanted in mid-to-late May. After harvesting in mid-to-late September, the rapeseed season begins. Rapeseed is raised using the method described in this embodiment from late September to early October, and transplanted from late October to early November. The following year, after the rapeseed is harvested in early May, rice is replanted.

[0067] Example 4 This embodiment is a method for mechanized transplanting of rice seedlings in soft trays that can be used for both rice and oilseeds. The difference from embodiment 3 is that the specific ratio of the substrate is: 28% light clay disease-free loam (0-10mm, clay content 28%) + 52% peat (0-10mm) + 16.9% vermiculite + 3% organic fertilizer + 0.1% silica-magnesium-calcium bacterial agent.

[0068] Comparative Example 1 This comparative example is a mechanized rice-oilseed dual-purpose soft tray seedling raising method for transplanting. The difference from Example 3 is that the specific components and contents of the rapeseed seed coating agent used for seed dressing are as follows: 10 mL of cyprodinil, 50 mL of water, and 2 g of plant growth regulator.

[0069] Comparative Example 2 This comparative example is a method for mechanized transplanting of rice-oilseed dual-purpose seedling trays. The difference from Example 3 is that the specific components and contents of the rapeseed seed coating agent used for seed dressing are as follows: 100mL of carbon monoxide pulp, 10mL of cyprodinil, 50mL of water, and 2g of plant growth regulator. In the plant growth regulator, the mass percentages of gibberellic acid, indoleacetic acid, and brassinolide are 0.135%, 0.00052%, and 0.00031%, respectively; the mass percentage of light calcium carbonate is 79.89%; and the mass percentage of corn starch is 19.97417%.

[0070] Comparative Example 3 This comparative example is a mechanized rice-oilseed dual-purpose soft tray seedling raising method for transplanting. The difference from Example 3 is that the specific components and contents of the rapeseed seed coating agent used for seed dressing are as follows: 150mL of carbon monoxide pulp, 10mL of cyprodinil, 50mL of water, and 1g of plant growth regulator. Among the plant growth regulator, the mass percentages of gibberellic acid, indoleacetic acid, and brassinolide are 0.135%, 0.00052%, and 0.00031%, respectively; the mass percentage of light calcium carbonate is 79.89%; and the mass percentage of corn starch is 19.97417%.

[0071] Comparative Example 4 This comparative example is a mechanized rice-oilseed dual-purpose soft tray seedling raising method for transplanting. The difference from Example 3 is that the rapeseed seeds are not treated with rapeseed seed coating agent.

[0072] The seedling cultivation of rapeseed in Examples 3 and Comparative Examples 1-4 was statistically analyzed to assess its seedling vigor. The statistical results are shown in Table 1 and Table 2. Figure 1-5 .

[0073] Table 1: Comparison of the effects of different coating agents on rapeseed seedling morphological indicators in Example 3 and Comparative Examples 1-4 Note: Different lowercase letters after the data in the same column in the table indicate significant differences (P < 0.05).

[0074] From Table 1 and Figure 1-5 It was found that different treatments had extremely significant effects on hypocotyl length, petiole length, and leaf length of rapeseed, but no significant effect on leaf width (P>0.05). The hypocotyl length was as follows: Comparative Example 4 (2.17 cm) > Comparative Example 2 / Comparative Example 3 (1.91 cm) > Comparative Example 1 (1.44 cm) > Example 3 (0.9 cm); the petiole length was as follows: Comparative Example 3 (2.31 cm) / Comparative Example 4 (2.17 cm) > Comparative Example 2 (1.74 cm) > Comparative Example 1 (1.47 cm) > Example 3 (1.16 cm); the leaf length was as follows: Comparative Example 3 (1.98 cm) > Comparative Example 4 (1.91 cm) > Comparative Example 1 / Comparative Example 2 / Example 3; there was no significant difference in leaf width among the treatments.

[0075] In summary, the growth-controlling effects of Comparative Examples 1 and 3 with added clopidogrel were significantly better than those of Comparative Examples 2-4 without clopidogrel. Among them, the effect of adding carbonized pulp to Example 3 was better than that of Comparative Example 1, with the shortest hypocotyl, petiole, and leaf length, zero internodes, and the widest leaves. It had the best growth-controlling effect, with compact and sturdy plant type and the best seedling growth.

[0076] The seedling raising method of Example 3 was used for a second seedling raising, and the results were compared with those of conventional seedling raising. The results of rapeseed seedling raising are shown in Table 2 and... Figure 6-9 As shown in Table 3, the results of rice seedling cultivation are presented in Table 3 and... Figure 10-11 As shown. The conventional seedling treatment for rapeseed involves direct sowing in 420-cell trays filled with a mixture of peat moss, perlite, and vermiculite (3:1:1, v / v), with a substrate moisture content of 70% and a sowing depth of 0.5 cm. After sowing, cover with a thin film and place in a germination chamber at 30℃ for 30 hours to germinate. Remove the seedlings when they emerge from the soil. Spray with a diluted nutrient solution (0.2% compound fertilizer solution NPK=17-17-17) 7-10 days after emergence. 3-5 days before transplanting, spray with 0.3-0.5% potassium dihydrogen phosphate. At the two-leaf-one-heart stage, spray with 15-20 mg / L of clopidogrel to control excessive growth. Hardening off the seedlings begins 5-7 days before transplanting. The two-leaf-one-heart stage refers to the period when the seedling has grown two fully expanded true leaves and the third heart leaf has emerged. At this time, the seedling root system further develops, and the seedling's resistance to adverse conditions increases. For conventional rice seedling raising, sow seeds directly into 420-cell trays filled with a mixture of peat moss and loam (7:3, v / v) when the seedling emergence rate reaches over 90%. Maintain a substrate moisture content of 70% and a sowing depth of 0.5 cm. After sowing, cover with a thin film and place in a germination chamber at 30℃ for 72 hours to germinate. Remove seedlings when 45-55% of the seedlings show yellowing. The temperature inside the greenhouse should not exceed 32℃ before emergence. Do not fertilize seedlings within the first 20 days. If seedlings turn yellow after 20 days, spray with a high-nitrogen water-soluble fertilizer 1-2 times. From emergence to the one-leaf stage, spray with 15% paclobutrazol to prevent excessive growth. For hardening-off treatment, refer to the guidelines for rapeseed.

[0077] Table 2: Comparison of morphological indicators between conventional seedling raising and rapeseed seedling raising in Example 3 Note: Different lowercase letters after the data in the same column in the table indicate significant differences (P < 0.05).

[0078] From Table 2 and Figure 6-9 It can be seen that, in the seedling raising results of the second seedling raising using the seedling raising method of Example 3 and the conventional seedling raising, there were significant differences in hypocotyl diameter, SPAD value, leaf area, aboveground dry weight, underground dry weight, and seedling vigor index of rapeseed seedlings due to different seedling raising methods. Among them, the second seedling raising in Example 3 had the largest hypocotyl diameter, SPAD value, underground dry weight, and seedling vigor index, which increased by 51.79%, 15.06%, 32.32%, and 273.81% respectively compared with the conventional treatment; while the hypocotyl length, leaf area, and aboveground dry weight decreased by 78.37%, 16.69%, and 17.95% respectively compared with the conventional treatment.

[0079] Table 3: Comparison of morphological indicators of rice seedlings raised in conventional seedling raising and in Example 3 From Table 3 and Figure 10-11 The results of the second seedling raising using the seedling raising method of Example 3 and conventional seedling raising showed that the treatment in Example 3 significantly promoted the growth and development of rice seedlings, significantly improved root vigor, photosynthetic capacity, and overall biomass accumulation. Compared with conventional treatment, the rice seedlings under the Example 3 (second seedling raising) treatment showed significantly increased stem diameter, leaf area, chlorophyll content (SPAD value), and both aboveground and belowground dry weight, and a significantly improved seedling vigor index. These results indicate that the present invention can effectively improve seedling quality, enhance the growth, stress resistance, and biomass production capacity of rice seedlings, and has significant application value in the field of rice seedling raising technology.

[0080] Therefore, it can be seen that using the method of the present invention for seedling cultivation not only ensures that the seedling morphology indicators are better than those of existing conventional technologies, but also realizes the sharing of rice and oil, ensuring the emergence rate, seedling establishment rate and machine transplanting qualification rate of rapeseed and rice, reducing equipment investment, simplifying operation, reducing labor and substrate waste, and is suitable for large-scale industrialized seedling cultivation.

[0081] Comparative Example 5 This comparative example is a method for mechanized transplanting of rice seedlings in a rice-oil dual-purpose tray. The difference from Example 3 is that only water-soluble fertilizer is used in the fertilization management during the seedling stage, and the N-P2O5-K2O ratio in the water-soluble fertilizer is 20-10-20.

[0082] Comparative Example 6 This comparative example is a method for mechanized transplanting of rice seedlings in a rice-oil dual-purpose tray. The difference from Example 3 is that only water-soluble fertilizer is used in the fertilization management during the seedling stage, and the N-P2O5-K2O ratio in the water-soluble fertilizer is 12-2-14.

[0083] Comparative Example 7 This comparative example is a method for mechanized transplanting of rice seedlings in a rice-oil dual-purpose tray. The difference from Example 3 is that only water-soluble fertilizer is used in the fertilization management during the seedling stage, and the fertilizer formula is N-P2O5-K2O=25-7-8.

[0084] Comparative Example 8 This comparative example is a method for mechanized transplanting of rice seedlings in a rice-oil dual-purpose tray. The difference from Example 3 is that only compound fertilizer is used in the fertilization management during the seedling stage, and the fertilizer formula is N-P2O5-K2O=17-17-17.

[0085] Comparative Example 9 This comparative example is a method for mechanized transplanting of rice seedlings using dual-purpose rice and oilseed trays. The difference between this example and Example 3 is that the water-soluble fertilizer used in the seedling management is formulated with N-P2O5-K2O=20-10-20 and N-P2O5-K2O=12-2-14, which are diluted with water and used alternately.

[0086] The seedling raising method of Example 3 was used for the third seedling raising, and the seedling raising conditions of Comparative Examples 5-9 were statistically analyzed. Six seedling growth indicators were measured: plant height, hypocotyl length, number of leaves, leaf length, leaf width, and petiole length. The results are shown in Table 4. Table 4 shows that there were highly significant differences among treatments in plant height, hypocotyl length, leaf length, leaf width, and petiole length (P<0.01), while there was no significant difference in the number of leaves (P>0.05). Multiple comparisons showed that Example 3 (third seedling raising) performed best in plant height, leaf length, leaf width, and petiole length; Comparative Example 8 showed outstanding performance in hypocotyl length and petiole length; Comparative Example 6 had lower values ​​for all indicators and poor uniformity.

[0087] Table 4: Comparison of the effects of different fertilization ratios on rapeseed seedling growth indicators in Comparative Examples 5-9 and Example 3 Note: Different lowercase letters after the data in the same column in the table indicate significant differences (P < 0.05).

[0088] The membership function values ​​and overall evaluation results for each treatment are shown in Table 5. As can be seen from the table, the average membership function values ​​for different fertilization treatments ranged from 0.04 to 0.88. The treatment in Example 3 (third seedling raising) had the highest average membership function value (0.88), exhibiting a significant advantage in plant height, large leaf length and width, robust petioles, and the strongest overall growth during the seedling stage. The treatment in Comparative Example 8 was second highest (0.67), showing outstanding hypocotyl length and petiole length. The membership function values ​​for Comparative Examples 5, 7, and 9 were moderate. The treatment in Comparative Example 6 had the lowest average membership function value (0.04), indicating weak seedling growth, poor uniformity of traits, and the worst overall performance.

[0089] Table 5: Membership function values ​​and comprehensive evaluation results of different fertilization treatments in Comparative Examples 5-9 and Example 3 In summary, the fertilization method in Example 3 showed the best effect compared to other treatments, significantly promoting seedling growth and resulting in the strongest seedlings, making it the optimal fertilization ratio. Given the presence of certain uncontrollable factors in each seedling raising process, the results obtained from repeating the seedling raising under the conditions of Example 3 three times showed some differences, but these differences were minimal and considered normal in this field, hence this explanation.

[0090] The rapeseed coating agent of this invention is scientifically formulated with photocarbon raw material, cyproconazole, gibberellin, indoleacetic acid, brassinolide, and uniconazole. It achieves synergistic effects in breaking seed dormancy, sterilization and disease prevention, plant type regulation, root promotion and seedling strengthening, and waterlogging resistance. A single treatment can complete the core management of the seedling stage, greatly reducing the cost of pesticides and manual management during the seedling stage.

[0091] The rice-oilseed dual-purpose soft tray seedling raising method of this invention is suitable for mechanized operations. The seedlings raised exhibit uniformity in external morphology such as plant height, stem diameter, number of leaves, internodes, and petioles, as well as stem hardness and lodging resistance. The root system is tightly bound and does not clump together, demonstrating strong resistance to mechanical damage. The rate of broken seedlings, damaged seedlings, missed plantings, and missing seedlings is low during mechanized transplanting. Seedlings recover quickly after transplanting, develop roots early, and have a high survival rate, reducing the need for replanting in the early stages. This effectively solves the problem of the versatility of rice-oilseed dual-purpose soft tray seedling raising with mechanized transplanting.

[0092] The seedlings cultivated by the method of this invention exhibit outstanding stress resistance. Under adverse seedling conditions such as high humidity, low temperature, and high density, the photocarbon pulp in the formula enhances seed vigor and seedling photosynthetic rate, optimizes the rhizosphere microecological environment, and the cyprodinil provides pre-germination sterilization, significantly enhancing the seedlings' comprehensive stress resistance, including resistance to low temperature, waterlogging, and high-density stress.

[0093] This invention significantly reduces costs and increases efficiency, improves the utilization rate of dual-purpose rice and oilseed greenhouses and seedling trays, optimizes seedling plant type for mechanized standardized operations, and effectively reduces labor, equipment, and material costs in large-scale rice-oilseed rotation production, with broad prospects for widespread application. Other parts not described in detail belong to existing technology.

Claims

1. A seed coating agent for rapeseed suitable for mechanized transplanting, characterized in that, It includes the following components: carbon dioxide trap, compound fungicide, plant growth regulator and solvent.

2. The rapeseed coating agent according to claim 1, characterized in that, The carbon dioxide trapping agent and the compound fungicide are liquid formulations, and the plant growth regulator is a solid formulation; the volume ratio of the carbon dioxide trapping agent, the compound fungicide, and the solvent is 14-16:0.8-1.2:4-6; the content of the plant growth regulator in the rapeseed seed coating agent is 0.008-0.01 g / mL; the plant growth regulator includes gibberellic acid, indoleacetic acid, brassinolide, uniconazole, and excipients.

3. The rapeseed coating agent according to claim 2, characterized in that, The carbon dioxide trapping agent is photocarbon slurry; the compound fungicide is cyfluthrin; the content of each component in the rapeseed coating agent is 150 mL of photocarbon slurry, 10 mL of cyfluthrin, and 2 g of plant growth regulator per 50 mL of water; in the plant growth regulator, the mass percentages of gibberellic acid, indoleacetic acid, brassinolide, and uniconazole are 0.135%, 0.00052%, 0.00031%, and 50%, respectively.

4. A method for mechanized transplanting of rice seedlings using dual-purpose rice and oilseed trays, characterized in that, The seedling cultivation method includes the following steps: The seeds are sun-dried and disinfected; the seeds are rapeseed seeds or rice seeds; when the seeds are rapeseed seeds, after disinfection, they are treated with a rapeseed coating agent according to any one of claims 1-3; when the seeds are rice seeds, after disinfection, they are coated or soaked for germination. Prepare a substrate and adjust its moisture content to 40-50%; the substrate is a general-purpose substrate for rice and oilseed cultivation; the substrate has an EC value of 0.4-0.6 mS / cm, a pH of 5.5-6.5, and a porosity of 65-75%; Substrate is loaded into trays and sown; After sowing, stack the seedlings in trays and darken them. Then, promote germination again until 45-55% of the seedlings in the trays show yellowing. Then, move them to the nursery site and wait for the sprouts to emerge from the soil before placing them on trays or seedbeds. Seedling management: once the seedlings reach the standard for robust seedlings, harden them off and transplant them.

5. The method for mechanized transplanting of rice seedlings using dual-purpose rice and oilseed trays according to claim 4, characterized in that, The raw materials of the substrate include the following components by weight: 25-30% light clayey disease-free loam with a particle size of 0-10mm, 50-55% peat moss with a particle size of 0-10mm, 10-20% vermiculite with a particle size of 0-5mm, 3-5% organic fertilizer, and 0.08-0.12% silica-magnesium-calcium bacterial agent; wherein, the effective live bacteria count per gram of silica-magnesium-calcium bacterial agent is ≥200 million.

6. The method for mechanized transplanting of rice seedlings using dual-purpose rice and oilseed trays according to claim 4, characterized in that, During the darkening process, the temperature is 25-28℃, the relative humidity is 85-90%, and the darkening time is 24-72h.

7. The method for mechanized transplanting of rice seedlings using dual-purpose rice and oilseed trays according to claim 4, characterized in that, The seedling management includes light management, water management, fertilization management, and excessive growth control management; In the aforementioned lighting management, the light intensity is 150-320 PPFD; The moisture management adopts the principle of controlling moisture levels when the soil is dry; In the fertilization management: if the seedlings are rice seedlings, fertilization should begin at the one-leaf-one-heart stage; if the seedlings are rapeseed seedlings, fertilization should begin after the cotyledons of the rapeseed seedlings have fully expanded. In the above-mentioned growth control management: if the seedlings are rapeseed seedlings, use photocarbon slurry for irrigation during the cotyledon stage of rapeseed; if the seedlings are rice seedlings, use photocarbon slurry for foliar spraying during the one-leaf-one-heart stage of rice.

8. The method for mechanized transplanting of rice seedlings using dual-purpose rice and oilseed trays according to claim 7, characterized in that, In the fertilization management, the fertilizers used for supplemental fertilization of rapeseed seedlings include water-soluble fertilizer with a formula of NPK=20-10-20 and compound fertilizer with a formula of NPK=17-17-17. One of the water-soluble fertilizer and compound fertilizer is used each time it is sprayed, and the two fertilizers are used alternately. The fertilizer concentration is adjusted between 1-2.5 g / L depending on the seedling condition. In the growth control management, the amount of light carbon slurry used is 10-15 mL of light carbon slurry per liter of water.

9. The method for mechanized transplanting of rice seedlings using dual-purpose rice and oilseed trays according to claim 4, characterized in that, The standard for robust seedlings is as follows: Rapeseed: Seedling age 40-45 days, leaf age 5.0-6.0 leaves; Rice: Seedling age 25-28 days, leaf age 5.0-5.5 leaves, seedling height 12-14cm, no diseased leaves, no yellow roots, and no less than 5 roots per seedling; During the hardening-off process, the substrate moisture content should be controlled at 25-35%; the hardening-off time should be 3-5 days; the seedling requirements are: the root ball should completely wrap around the pot, without breaking apart or falling off the pot; the rapeseed seedlings should be 10-12cm tall, and the rice seedlings should be 12-14cm tall.

10. The method for mechanized transplanting of rice-oilseed dual-purpose seedling trays according to any one of claims 4-9, characterized in that, The seedling raising method is used for rice and rapeseed seedling raising in rice-rapeseed rotation areas. When the rice-rapeseed rotation area enters the rice season, the seedling raising method is used to raise rice seedlings, which are then transplanted to the field. When the rice is harvested and the rapeseed season begins, the seedling raising method is used to raise rapeseed seedlings, which are then transplanted to the field. This process of rice-rapeseed rotation is repeated.

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