A method for preparing rice seedling substrate based on rice and wheat straw, its products and applications

Abstract

This invention discloses a method for preparing a rice seedling substrate based on rice and wheat straw, its products, and applications. This application converts rice and wheat straw into earthworm castings, optimizes the earthworm castings, and prepares a rice seedling substrate more suitable for rice seedling cultivation practices in the middle and lower reaches of the Yangtze River. The water retention capacity of this seedling substrate is significantly superior to that of general seedling substrates. When using the "running water" irrigation method, it can continuously supply water to the seedlings even without timely irrigation, ensuring robust root growth; it can continuously control the pH of the seedling substrate, significantly improving the seedling's root development; and it can increase nutrient retention, ensuring the formation of strong seedlings.

Description

Technical Field

[0001] This invention relates to a method for preparing a rice seedling substrate based on rice and wheat straw, its products and applications, and belongs to the field of rice cultivation. Background Technology

[0002] Mechanized rice transplanting is an integral part of intensive rice production technology and an inevitable trend in modern rice cultivation. Currently, the area under mechanized transplanting nationwide exceeds 40%. Rice seedling raising technology is a key link in mechanized transplanting technology and has a significant impact on mechanized rice production. Robust root growth and well-developed root systems are crucial for successful seedling raising. The seedling substrate provides the site environment for seedling root growth; therefore, providing a good root growth environment based on rice growth habits is an essential condition for a high-quality seedling substrate. Many existing seedling substrate formulas primarily focus on waste utilization, lacking integration with agricultural technology and agronomy.

[0003] In the middle and lower reaches of the Yangtze River, rice and wheat are mainly grown in rotation. Farmers traditionally use a "run-up watering" method for substrate-based seedling cultivation. This involves flooding the substrate, draining the water immediately afterward, and repeating the process once the surface is dry. This maintains a balance between moisture and moisture in the substrate, reducing the risk of seedling rot and promoting strong seedlings. However, excessive water loss in the substrate can easily harm the root development of rice seedlings, hindering the formation of strong seedlings. In practice, farmers often misjudge the timing of this "run-up watering," frequently causing root damage and affecting root development. Furthermore, the formation of strong rice seedlings requires acid control, water retention, and proper maintenance, as well as stable substrate materials to prevent seedling burn during cultivation and ensure the safety of rice seedling cultivation. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a rice seedling substrate based on rice and wheat straw that is suitable for rice planting habits in the middle and lower reaches of the Yangtze River, its preparation method and its application.

[0005] Technical solution: The present invention describes a method for preparing a rice seedling substrate based on rice and wheat straw, which involves soaking the straw in pig or cattle breeding waste liquid to form a wet material, draining the water after soaking, and piling it into long strips on the ground; the conductivity of the breeding waste liquid is 5~20 mS / cm. Place a mixture of earthworms and earthworm castings in equal proportions on both sides of a long stack; replenish the wet material when 60% to 70% of the material in the wet stack has been digested; harvest the earthworm castings every 3 to 4 months; perform static aerobic fermentation on the earthworm castings, and then mix them with an acidifier, a water-retaining agent, and a fertilizer-retaining agent to obtain the rice seedling substrate.

[0006] Furthermore, the straw is soaked in livestock waste liquid for 3 to 7 days.

[0007] Furthermore, the wet material is piled on the ground into long stacks approximately 20cm high and 40cm wide; the mixture of earthworms and earthworm castings is piled into long stacks 5cm high and 10cm wide.

[0008] Furthermore, the acidifier includes peat, ferrous ammonium sulfate, and sulfur.

[0009] Furthermore, the water-retaining agent includes potassium polyacrylate and acrylic resin.

[0010] Furthermore, the fertilizer retainer is attapulgite.

[0011] Furthermore, the static aerobic fermentation treatment includes the following steps: covering the earthworm castings with a molecular membrane, aerating, maintaining the temperature above 50°C for 20 days, and then sieving after fermentation.

[0012] Furthermore, the aeration conditions are 6-8 hours / day, with an intensity of 2.5-4.5 cubic meters / (square meter·hour).

[0013] Furthermore, the composition ratio of the rice seedling substrate is as follows: 500 kg of earthworm castings with a moisture content of 30% after static aerobic fermentation treatment, 70-100 kg of peat with a moisture content of 30%, 0.8-1.2 kg of ferrous ammonium sulfate, 0.8-1.2 kg of sulfur powder, 1.2-1.8 kg of powdered potassium polyacrylate, 1.2-1.8 kg of powdered acrylic resin, 15-30 kg of 200-mesh attapulgite, and 5-8 kg of 600-mesh attapulgite.

[0014] The rice seedling substrate prepared by the preparation method described in this invention.

[0015] The rice seedling raising method of the present invention involves germinating rice seeds indoors until they show white sprouts, then sowing them on a seedbed in a greenhouse. Using the aforementioned rice seedling substrate, the seedlings are raised using a "running water" irrigation method, which involves irrigating the seedbed with a large amount of water. The seedling substrate absorbs water rapidly through osmosis and adsorption until it becomes saturated, and then the irrigation water is immediately drained.

[0016] Furthermore, before sowing, sun-dry the seeds for 1-2 days, then soak them for 2-3 days until the rice seeds show signs of ripening. Fill the seedling trays with seedling substrate to 2 / 3 of their height, place them on the seedbed, and evenly sow the ripening rice seeds, covering them with the seedling substrate until the seeds are no longer visible. Using the above-mentioned rice seedling substrate, seedlings are raised using the "running water" irrigation method.

[0017] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: This application optimizes the method for preparing earthworm castings from rice and wheat straw and improves the earthworm castings, resulting in a rice seedling substrate that is more suitable for rice cultivation habits in the middle and lower reaches of the Yangtze River. When using the "running water" irrigation method for seedling cultivation, it can still continuously supply water to the seedlings even when irrigation is not timely, ensuring robust root growth of rice seedlings; it can continuously control the pH of the seedling substrate, significantly improving the seedling's root-forming ability; and it can increase the nutrient retention capacity, ensuring the formation of strong seedlings. Attached Figure Description

[0018] Figure 1 This is a flowchart of the matrix preparation process.

[0019] Figure 2 Photo of seedlings grown on substrate. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0021] Example 1

[0022] (1) Optimize the applicant's existing patent technology (ZL 200910264525.5), without adding livestock and poultry manure or biological sludge, directly soak the straw in the waste liquid of pig, cattle and other livestock breeding to soften it and increase nitrogen, forming wet material. The operation steps are as follows: Chop the rice and wheat straw into pieces less than 10 cm and put them into the dairy cattle breeding waste liquid pool taken from the experimental farm of Yangzhou University. The water quality parameters of the breeding waste liquid were tested and found to be: chemical oxygen demand (COD) 1.17 g / L, ammonia nitrogen 1.28 g / L, pH 8.24, total dissolved solids (TDS) 9.67 g / L, and conductivity 12.6 mS / cm. After soaking the straw for 3 days, take it out and drain the excess water to form wet material. On the ground, pile the wet material into long stacks about 20 cm high and 40 cm wide, with each stack spaced 25 cm apart, forming a rice and wheat straw wet material pile. Place a 1:2 weight ratio of earthworms and earthworm castings on the ground on both sides of a wet material pile, forming a long stack 5cm high and 10cm wide, ensuring close contact between the mixture and the wet material and the ground. When 60% of the material in the wet material pile has been digested, immediately add more wet material to cover it, covering it with a 5cm layer. Repeat this process of adding material and digestion. Harvest the earthworm castings every 3-4 months. During harvesting, remove the top 0-15cm layer of the mixture containing earthworms. Excavate the remaining earthworm castings directly, replenish with wet material to form a wet material pile, and then move the removed mixture back to both sides of the wet material pile. Repeat the above steps to continue preparing straw-derived earthworm castings.

[0023] (2) The collected earthworm castings from straw are subjected to static aerobic fermentation treatment using a molecular membrane. The collected earthworm castings are directly piled into long stacks with a height of 1.5m, a width of 4.0m, and an unlimited length. The stacks are covered with a molecular membrane (e-PTFE microporous membrane) and aerated for 6-8 hours / day at an aeration intensity of 2.5-4.5 cubic meters / (square meter·hour). The temperature of the stack will rise after 3-5 days. The stack temperature is maintained above 50℃ for 20 days and the moisture content is ≤30%. This process kills pests and residual earthworms in the earthworm castings, while also inactivating weed seeds and insect eggs, thereby reducing the moisture content of the earthworm castings and eliminating pests and weeds.

[0024] (3) The fermented earthworm castings are passed through a drum sieve with a 1cm aperture and used as the main material for seedling cultivation substrate.

[0025] To optimize the acidifier usage parameters, the following four treatments were set up: earthworm castings + peat (F1), earthworm castings + ferrous ammonium sulfate (F2), earthworm castings - sulfur powder (F3), and earthworm castings + peat + ferrous ammonium sulfate + sulfur powder (F4). The amount of earthworm castings (30% moisture content) used was 500 kg. In F1, the amount of peat (30% moisture content) was 150 kg, in F2, the amount of ferrous ammonium sulfate was 2 kg, in F3, the amount of sulfur powder was 2 kg, and in F4, the amounts of peat, ferrous ammonium sulfate, and sulfur powder were 80 kg, 1 kg, and 1 kg, respectively. The control (CK0) used earthworm castings, fermented from rice and wheat straw decomposed by earthworms, without any added additives, as the seedling substrate. The seedling raising method was the "running water" method commonly used in the middle and lower reaches of the Yangtze River. Specifically, the rice seeds were first sun-dried indoors for 2 days, then soaked for 2 days until the seeds showed signs of sprouting. The seedling substrate was then filled to 2 / 3 of the height of the seedling trays and placed on the seedbed. The sprouted rice seeds were then evenly sown in the greenhouse, and the seedling substrate was covered until the seeds were no longer visible. Afterward, the seedlings were watered once daily. When the rice seedlings reached the transplanting standard (20 days old), samples were taken for relevant index measurements. The results are detailed in Table 1. Table 1. Seedling cultivation effects of adding different acidifiers to seedling substrates

[0026] Note: There are significant differences between different letters of a, b, c in the same row at the 0.05 level; the seedling vigor index is (stem width / plant height + root dry weight / above-ground dry weight) × total plant dry weight. The same applies below.

[0027] Table 1 shows that using earthworm castings (CK0) alone as a substrate had the weakest effect, indicating the need for measures to adjust traits. The seedlings treated with F1 (peat), F2 (ferrous ammonium sulfate), and F3 (sulfur powder) showed no significant differences in overall indicators, but were all significantly better than the control CK0, indicating that all three single acidifying agents could effectively improve seedling quality. The F4 treatment (earthworm castings + peat + ferrous ammonium sulfate + sulfur powder) achieved the highest levels in key indicators such as leaf chlorophyll content, stem width, root cohesion, plant height, longest adventitious root, number of adventitious roots per plant, leaf width, leaf length, and dry weight, indicating its significant advantages in promoting root development, enhancing plant vigor, and biomass accumulation. The seedling vigor index of the F4 treatment was also significantly higher than other treatments, indicating that the seedlings cultivated from it had the best overall quality. In summary, F4, through the synergistic effect of multiple components, optimized substrate properties and is the optimal acidifying agent combination.

[0028] Example 2

[0029] To optimize the parameters for using fertilizer retaining agents, three treatments were set up: earthworm castings + 200-mesh attapulgite soil (M1), earthworm castings + 600-mesh attapulgite soil (M2), and earthworm castings + 200-mesh attapulgite soil + 600-mesh attapulgite soil (M3). The amount of earthworm castings (30% moisture content) was 500 kg, the amount of 200-mesh attapulgite soil in M1 was 40 kg, the amount of 600-mesh attapulgite soil in M2 was 10 kg, and the amounts of 200-mesh attapulgite soil and 600-mesh attapulgite soil in M3 were 20 kg and 5 kg, respectively. Earthworm castings were used directly as the seedling substrate as a control (CK0). The preparation, aerobic fermentation, and sieving methods of the earthworm castings, as well as the seedling management methods, were the same as in Example 1. When the rice seedlings reached the transplanting standard (20 days old), samples were taken for relevant index measurements. The results are detailed in Table 2. Table 2. Seedling cultivation effects of adding attapulgite soil with different particle sizes as a seedling substrate.

[0030] Table 2 shows that there were no significant differences in the overall growth indicators of seedlings treated with M1 (200 mesh) and M2 (600 mesh), but both were significantly better than the control CK0. This indicates that attapulgite soil of different single particle sizes can effectively improve the performance of earthworm casting seedling substrate and enhance seedling quality. M3 (200 mesh + 600 mesh attapulgite soil composite) was significantly better than other treatments in all indicators, with root cohesion increasing by 31.5%, root / crown ratio increasing by 56%, and seedling vigor index increasing by 18.7%. This indicates that the synergistic effect of attapulgite soil of different particle sizes can better optimize the substrate pore structure and fertilizer retention performance, promoting the coordinated growth of seedling roots and aboveground parts. Comparing the treatments, the improvement in root-related indicators (cohesion, adventitious root length / number, root dry weight) was significantly higher than that of aboveground parts, especially the M3 treatment, which showed the most significant improvement in root indicators. This indicates that the combination of attapulgite soil particle sizes has a more prominent effect on improving the water retention, fertilizer retention, and aeration of the substrate, and can better meet the needs of seedling root growth. In summary, M3 optimizes the matrix properties through the synergistic effect of multiple particle sizes, making it the best fertilizer retention agent combination.

[0031] Example 3

[0032] To optimize the water-retaining agent usage parameters, three treatments were set up: earthworm castings + potassium polyacrylate (N1), earthworm castings + acrylic resin (N2), and earthworm castings + potassium polyacrylate + acrylic resin (N3). The amount of earthworm castings (30% moisture content) was 500 kg, N1 used 3 kg of potassium polyacrylate, N2 used 3 kg of acrylic resin, and N3 used 1.5 kg each of potassium polyacrylate and acrylic resin. Earthworm castings were used directly as the seedling substrate as a control (CK0). The preparation, aerobic fermentation, and sieving methods of the earthworm castings, as well as the seedling management methods, were the same as in Example 1. However, the frequency of irrigation was different. To enhance the water-retaining agent's resistance to water stress, irrigation was performed once daily for the first 8 days of seedling cultivation, and then once every 3 days thereafter. When the rice seedlings reached the transplanting standard (20 days old), samples were taken for relevant index measurements. The results are detailed in Table 3. Table 3. Seedling raising effects of adding different water-retaining agents to seedling substrates under water stress.

[0033] Table 3 shows that compared with the control CK0, the N1, N2, and N3 treatments with added water-retaining agents significantly improved seedling growth indicators. Chlorophyll content increased by 9.3%–17.6%, root cohesion increased by 91.3%–137.4%, and seedling vigor index increased by 31.2%–51.2%, indicating that the water-retaining agent effectively improved the water-holding capacity of the earthworm casting substrate and mitigated the adverse effects of water stress on seedling growth. There were no significant differences in the various growth indicators between the N1 (potassium polyacrylate) and N2 (acrylic resin) treatments, indicating that the two single water-retaining agents were essentially equivalent in alleviating water stress and promoting seedling growth. The improvement in root-related indicators (cohesion, adventitious root length / number, and root dry weight) was significantly greater in each treatment than in the aboveground parts, especially in N3 (potassium polyacrylate + acrylic resin), where root cohesion increased by 137.4% compared to the control. This indicates that the improvement in substrate water retention by the water-retaining agent is more beneficial to the growth and development of seedling roots, thereby promoting aboveground growth. N3 (potassium polyacrylate + acrylic resin) significantly outperformed other treatments in all indicators. Specifically, the seedling vigor index increased by 74.9% compared to the control (CK0) and by 43.4%–50.5% compared to single water-retaining agent treatments. This indicates that the synergistic effect of the two water-retaining agents more effectively improves the water retention performance of the substrate, promotes the coordinated growth of seedling roots and aboveground parts, and enhances seedling resistance. In summary, N3 optimizes substrate properties through multiple synergistic effects, making it the optimal combination of water-retaining agents.

[0034] Example 4

[0035] (1) Earthworm castings were prepared from rice and wheat straw. The earthworm castings were subjected to molecular membrane static aerobic fermentation and sieved, in the same way as in Example 1.

[0036] (2) 70 kg of untreated peat (30% moisture content), 1.2 kg of ferrous ammonium sulfate, 0.8 kg of sulfur powder, 1.8 kg of powdered potassium polyacrylate, 1.2 kg of powdered acrylic resin, 20 kg of 200 mesh attapulgite, and 8 kg of 600 mesh attapulgite are put into a drum mixer and mixed thoroughly to obtain an auxiliary material mixture.

[0037] (5) Add 500 kg of earthworm castings (30% moisture content) after static aerobic fermentation to a drum mixer containing the auxiliary material mixture, mix thoroughly, measure and package to obtain the seedling substrate product (T1).

[0038] Example 5

[0039] (1) Chop rice and wheat straw into pieces smaller than 10 cm, soak them in a livestock and poultry wastewater pond (same as in Example 1) for 5 days, then remove them and drain excess water to form wet material. Pile the mixture into long stacks about 20 cm high and 40 cm wide on the ground, with each stack spaced 25 cm apart. Place a mixture of earthworms and earthworm castings (weight ratio 1:2) on both sides of the long stacks, ensuring the mixture is in close contact with the stacks, with a height of 3 cm and a width of 10 cm. When 70% of the wet material in the long stacks has been digested, promptly cover the stacks with wet material to a thickness of 3 cm. Repeat this process of adding material to digest the mixture. Harvest earthworm castings every 3-4 months. When harvesting, remove the top 0-15 cm layer of the mixture containing earthworms. Dig out the remaining earthworm castings directly, replenish with wet material to form a wet material pile, and then move the removed mixture back to both sides of the wet material pile. Repeat the above steps to continue preparing earthworm castings.

[0040] (2) The method of treating the collected earthworm castings by molecular membrane static aerobic fermentation and sieving is the same as in Example 1.

[0041] (3) 100 kg of untreated peat (30% moisture content), 0.8 kg of ferrous ammonium sulfate, 1.2 kg of sulfur powder, 1.2 kg of powdered potassium polyacrylate, 1.8 kg of powdered acrylic resin, 30 kg of 200 mesh attapulgite, and 5 kg of 600 mesh attapulgite are put into a drum mixer and mixed thoroughly to obtain an auxiliary material mixture.

[0042] (4) Add 500 kg of earthworm castings (30% moisture content) after static aerobic fermentation to a drum mixer containing the auxiliary material mixture, mix thoroughly, measure and package to obtain seedling substrate (T2).

[0043] Example 6

[0044] (1) Chop rice and wheat straw into pieces smaller than 10 cm, soak them in a livestock and poultry wastewater pond (same as in Example 1) for 7 days, then remove them and drain excess water to form wet material. Pile the mixture into long stacks about 20 cm high and 40 cm wide on the ground, with each stack spaced 25 cm apart. Place a mixture of earthworms and earthworm castings (weight ratio 1:2) on both sides of the long stacks, ensuring the mixture is in close contact with the stacks, with a height of 3 cm and a width of 10 cm. When 65% of the material in the long stacks has been digested, promptly cover the stacks with a mixture of straw and livestock and poultry manure, covering it to a thickness of 4 cm. Repeat this process of adding material for digestion. Harvest earthworm castings every 3-4 months. When harvesting, remove the top 0-15 cm layer of the mixture containing earthworms. Dig out the remaining earthworm castings directly, replenish with wet material to form a wet material pile, and then move the removed mixture back to both sides of the wet material pile. Repeat the above steps to continue preparing earthworm castings.

[0045] (2) The method of treating the collected earthworm castings by molecular membrane static aerobic fermentation and sieving is the same as in Example 1.

[0046] (3) First mixing. Put 85 kg of untreated peat (moisture content 30%), 1.0 kg of ferrous ammonium sulfate, 1.0 kg of sulfur powder, 1.5 kg of powdered potassium polyacrylate, 1.5 kg of powdered acrylic resin, 15 kg of 200 mesh attapulgite, 7 kg of 600 mesh attapulgite and other materials into a drum mixer and mix thoroughly to obtain the auxiliary material mixture.

[0047] (4) Add 500 kg of earthworm castings (30% moisture content) after static aerobic fermentation to a drum mixer containing the auxiliary material mixture, mix thoroughly, measure and package to obtain the seedling substrate product (T3).

[0048] The products of Examples 4, 5, and 6 of this invention were used as seedling substrates, forming the experimental groups (T1, T2, T3); a commercially available general seedling substrate, made from peat, mushroom residue fermentation products, vermiculite, etc., produced by Jiangsu Tianxiang Biotechnology Co., Ltd., was used as control 1 (CK1); and earthworm castings formed from rice and wheat straw digested by earthworms, fermented without any additives, were used directly as the seedling substrate, forming control 2 (CK2). The rice variety was Wuyujing 9108. The seedling raising method was the "running water" method commonly used in the middle and lower reaches of the Yangtze River, the same as in Example 1. When the rice seedlings reached the transplanting standard (20 days old), samples were taken for relevant index measurements. The results are detailed in Table 4. Table 4. Seedling raising effects of different seedling substrate formulations

[0049] Table 4 shows that the seedling growth indicators of CK2 (pure earthworm castings substrate) were significantly better than those of CK1 (commercially available general-purpose substrate), indicating that earthworm castings themselves have good fertilization efficiency and physicochemical properties, making them an excellent raw material for seedling cultivation substrates. Optimizing the formula by adding auxiliary materials can further improve its seedling cultivation effect. Compared with CK1 and CK2, treatments T1, T2, and T3 showed significant improvements in all seedling growth indicators. The seedling vigor index increased by 98.9%–110.5% compared to CK1 and by 86.2%–97.0% compared to CK2, indicating that the self-developed formula can effectively improve the physicochemical properties of the seedling cultivation substrate, promote seedling growth, and improve seedling quality. T3 was significantly better than T1 and T2 in most indicators, with the seedling vigor index increasing by 5.8%–5.9% compared to T1 and T2, indicating that the T3 formula has better water retention, fertilizer retention, and aeration properties, which are more conducive to seedling growth. There was no significant difference in seedling growth indicators between the T1 and T2 formulas, indicating that the substrate performance of these two formulas is comparable. The root-related indicators (cohesion force, adventitious root length / number, and root dry weight) of the T1, T2, and T3 treatments showed significantly greater improvement than those of the aboveground parts. In particular, the root cohesion force of the T3 treatment increased by 100% compared to CK1 and by 67.3% compared to CK2. This indicates that the self-developed formula optimizes the pore structure and fertilizer retention performance of the substrate, better meeting the needs of seedling root growth and thus promoting aboveground growth.

[0050] Example 7 To verify the water stress resistance of the product of this invention, the experimental treatment and seedling management methods were the same as in Example 6, but the interval of "running water" irrigation was changed. During the first 8 days of seedling cultivation, "running water" was applied once a day, and then changed to once every 3 days thereafter. Other management methods remained unchanged. The results are detailed in Table 5. Table 5. Seedling raising effects of different seedling substrate formulations under water stress.

[0051] Table 5 shows that under water stress conditions, the seedling growth indicators of CK2 (pure earthworm castings substrate) were significantly better than those of CK1 (commercially available general-purpose substrate), indicating that earthworm castings themselves have good water-holding capacity and can better provide water for seedlings under water stress conditions. Optimizing the formula by adding auxiliary materials can further enhance its resistance to water stress. The seedling growth indicators of treatments T1, T2, and T3 were all significantly better than those of CK1 and CK2, with the seedling vigor index increasing by 164.6%–188.5% compared to CK1 and by 122.6%–142.8% compared to CK2. This indicates that the self-developed formula can effectively improve the water-holding capacity of the seedling substrate, reduce the adverse effects of water stress on seedling growth, and enhance the seedlings' resistance. Treatment T3 was significantly better than T1 and T2 in most indicators, with the seedling vigor index increasing by 7.6%–9.1% compared to T1 and T2, indicating that the substrate performance of the T3 formula is superior and more conducive to seedling growth under water stress conditions. The root-related indicators (cohesion strength, adventitious root length / number, and root dry weight) of the T1, T2, and T3 treatments showed significantly greater improvement than those of the aboveground parts. In particular, the root cohesion strength of the T3 formula increased by 198.5% compared to CK1 and by 132.3% compared to CK2, indicating that the self-developed formula substrate has good water retention, fertilizer retention, and stable pH properties, which are beneficial to improving the seedlings' resistance to water stress.

Claims

1. A method for preparing a rice seedling raising substrate based on rice and wheat straw, characterized by, The straw is soaked in pig or cattle breeding waste liquid to form wet material, and the wet material is controlled to dry after being fished out, and is stacked into long piles on the ground; the conductivity of the breeding waste liquid is 5-20 mS / cm; The mixture of earthworms and earthworm manure in equal proportion is stacked on both sides of the long piles; when the material of the wet material pile is digested by 60%-70%, the wet material is supplemented in time; the earthworm manure is collected every 3-4 months; the earthworm manure is subjected to static aerobic fermentation treatment, and then is mixed with acid adjusting agent, water retaining agent and fertilizer retaining agent, so that the rice seedling raising substrate is obtained.

2. The production method according to claim 1, characterized by, The straw is soaked in the breeding waste liquid for 3-7 days.

3. The production method according to claim 1, characterized by, The wet material is stacked into long piles with a height of about 20 cm and a width of about 40 cm on the ground; the mixture of earthworms and earthworm manure is stacked into long piles with a height of 5 cm and a width of 10 cm.

4. The preparation method according to claim 1, characterized in that, The acid adjusting agent comprises peat, ferrous ammonium sulfate and sulfur.

5. The preparation method according to claim 1, characterized in that, The water retaining agent comprises potassium polyacrylate and acrylic resin.

6. The method of claim 1, wherein, The static aerobic fermentation treatment comprises the following steps: covering a molecular film on the earthworm manure, aeration, waiting for the temperature to rise to above 50℃ and maintaining for 20 days, and screening after the fermentation is completed.

7. The production method according to claim 6, wherein The fertilizer retaining agent is attapulgite.

8. The method of claim 1, wherein, The proportion of the components of the rice seedling raising substrate is as follows: 500 kg of the earthworm manure subjected to the static aerobic fermentation treatment and having a water content of 30%, 70-100 kg of peat having a water content of 30%, 0.8-1.2 kg of ferrous ammonium sulfate, 0.8-1.2 kg of sulfur powder, 1.2-1.8 kg of powdered potassium polyacrylate, 1.2-1.8 kg of powdered acrylic resin, 15-30 kg of 200-mesh attapulgite, and 5-8 kg of 600-mesh attapulgite.

9. The rice seedling raising substrate prepared by the preparation method of any one of claims 1-6.

10. A method for raising seedlings of rice, characterized by, The rice seeds are germinated in a room, and are sowed on a seedling bed in a greenhouse when the rice seeds are white, and the rice seedling raising substrate of claim 9 is used, and a seedling raising method of watering "running water" is used for seedling raising.

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