A special nutrient solution for forest container seedling raising and a preparation method thereof

Abstract

The application discloses a kind of special nutrient solution for container seedling of forest and preparation method thereof, belong to the technical field of forest seedling.The nutrient solution is based on macroelement, ethylenediaminetetraacetic acid chelated iron and conventional trace element, compound mineral source humic acid, compound amino acid, brown algae extract, paclobutrazol and compound rooting powder, add citric acid and mineral source potassium fulvate to stabilize EC value, prevent and control salt injury, and supplemented with chitosan and betaine to enhance seedling resistance, the pH value of nutrient solution is 5.5-6.5, EC value is 1.2-2.0 mS / cm.The application is prepared by mother liquor pretreatment, step-by-step dissolution, parameter control and membrane filtration process, can be segmented according to forest growth stage Application, can promote root seedling, control overgrowth, reduce salt injury, significantly improve seedling survival rate and seedling quality, suitable for large-scale production of container seedling of forest.

Description

Technical Field

[0001] This invention relates to the field of forest tree seedling nutrient preparation technology, specifically to a special nutrient solution for forest tree container seedling cultivation and its preparation method. Background Technology

[0002] With the rapid advancement of urban greening and landscape construction, the demand for ornamental green seedlings continues to grow, and container seedling cultivation has become the mainstream seedling cultivation method. This method has advantages such as short seedling cultivation cycle, high transplant survival rate, and year-round production. However, the root space of seedlings in containers is limited, the substrate has poor fertilizer retention, and salt is easily accumulated, which can easily lead to problems such as nutrient imbalance, root burn, excessive growth, and weak stress resistance, seriously affecting the uniformity and commercial value of seedlings.

[0003] Currently, most commercially available nutrient solutions for forest seedling cultivation are general-purpose and not optimized for container seedling environments and the growth characteristics of ornamental greening seedlings. They generally suffer from defects such as a single nutrient ratio, an emphasis on macronutrients while lacking synergistic effects of biostimulants and stress-resistance components, and an inability to meet the dynamic nutrient requirements of seedlings, rapid growth stages, and later growth stages. At the same time, some nutrient solutions have complex preparation processes and high costs, making it difficult to meet the needs of large-scale production.

[0004] Existing technologies struggle to simultaneously address seedling growth, plant shape control, ornamental quality, and stress resistance enhancement, failing to effectively resolve pain points in container seedling cultivation such as uneven nutrient supply, poor root development, and substrate salt damage. Therefore, developing a scientifically formulated, adaptable nutrient solution for all growth stages, easily prepared, and combining growth-promoting and stress-resistance-enhancing functions specifically for container seedling cultivation of forest trees has significant practical importance and application value. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, this invention proposes a special nutrient solution for container seedling cultivation of forest trees and its preparation method. This nutrient solution is adapted to the special environment of container seedling cultivation and has the functions of balanced nutrient supply, promoting root growth and seedling development, regulating plant shape, enhancing stress resistance, and stabilizing EC (electrical conductivity) value to prevent salt damage. At the same time, the preparation process is simple and low-cost, and it can meet the seedling cultivation needs of ornamental greening seedlings throughout the entire growth stage.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A nutrient solution specifically for container seedling cultivation of forest trees, the nutrient solution being prepared from the following raw materials in parts by weight:

[0008] Macroelements: Potassium nitrate 8-12 parts, ammonium dihydrogen phosphate 4-6 parts, calcium nitrate 5-8 parts, magnesium sulfate 3-5 parts;

[0009] Trace elements: 0.1-0.3 parts of ferric sodium ethylenediaminetetraacetate, 0.05-0.15 parts of boric acid, 0.03-0.08 parts of manganese sulfate, 0.02-0.06 parts of zinc sulfate, 0.01-0.03 parts of copper sulfate, and 0.005-0.015 parts of ammonium molybdate;

[0010] Biostimulants: 0.5-1.5 parts mineral-derived humic acid, 0.3-0.8 parts compound amino acids, and 0.2-0.5 parts brown algae extract;

[0011] Growth regulators: paclobutrazol 0.01-0.03 parts, rooting powder 0.02-0.05 parts;

[0012] Components for stabilizing EC values ​​against salt damage: 0.1-0.3 parts citric acid, 0.1-0.2 parts potassium humate from mineral sources;

[0013] Stress-resistance enhancing factors: chitosan oligosaccharide 0.05-0.1 parts, betaine 0.05-0.1 parts;

[0014] Add deionized water to a total of 100 parts;

[0015] The nutrient solution has a pH of 5.5-6.5 and an EC value of 1.2-2.0 mS / cm.

[0016] Optionally, the mineral-derived humic acid has a molecular weight of 500-1000 Da, and the free amino acid content in the complex amino acid is ≥90%.

[0017] Optionally, the rooting powder is composed of naphthaleneacetic acid and indolebutyric acid in a mass ratio of 1:1.5-2.5.

[0018] Optionally, in the component for preventing salt damage and stabilizing EC value, the weight ratio of citric acid to mineral-derived potassium humate is 1:0.5-2.

[0019] Optionally, in the stress-resistance enhancing factor, the weight ratio of chitosan oligosaccharide to betaine is 1:1.

[0020] Optionally, the preparation method of the nutrient solution specifically for container seedling cultivation of forest trees is as follows:

[0021] S1. Weigh each component raw material separately, and dissolve the mineral humic acid, compound amino acids, brown algae extract, paclobutrazol, rooting powder, chitosan oligosaccharide and betaine in 5-10 parts of deionized water to prepare the corresponding biostimulant mother liquor and growth regulator mother liquor for later use.

[0022] S2. Add macro-element components to the remaining deionized water, control the temperature at 30-40℃, and stir intermittently at 150-200 rpm for 15-20 minutes until completely dissolved to obtain the base solution;

[0023] S3. Add trace element components to the base liquid obtained in step S2, maintain the temperature at 30-40℃, and continue stirring for 10-15 minutes until the mixture is uniform.

[0024] S4. Add the biostimulant stock solution and growth regulator stock solution prepared in S1 to the mixture in step S3 in sequence, and stir for 10-15 minutes to fully mix the components.

[0025] S5. Adjust the pH of the mixture to 5.5-6.5 using 0.5-1 mol / L dilute hydrochloric acid or sodium hydroxide. Adjust the EC value to 1.2-2.0 mS / cm by adding deionized water (if EC is too high) or macro-elements (if EC is too low) (no need to add when EC is in the range of 1.2-2.0 mS / cm). Stir for 5-10 minutes to stabilize the parameters.

[0026] S6. Filter the liquid adjusted in step S5 through a 0.22μm filter membrane to remove impurities, and then fill it to obtain the finished nutrient solution.

[0027] Optionally, in step S1, the dissolution temperature of the biostimulant mother liquor and the growth regulator mother liquor is 25-30℃, and the stirring speed is 100-150 rpm.

[0028] Optionally, the intermittent stirring method in step S2 is: stirring for 3-5 minutes, pausing for 1-2 minutes, and repeating 3-4 times.

[0029] Optionally, the nutrient solution is applied in stages according to the growth stages of the trees:

[0030] Seedling stage: Dilute the nutrient solution 500-600 times and then water the seedlings, applying it once every 7-10 days;

[0031] During the rapid growth period: Dilute the nutrient solution 300-400 times and water the plants every 5-7 days. At the same time, dilute the nutrient solution 800-1000 times and spray the leaves every 10-15 days.

[0032] Later growth stage: Dilute the nutrient solution 400-500 times and water the plants, applying it once every 10-15 days.

[0033] The beneficial effects of this invention are as follows: the nutrient solution of this invention has a significant effect on promoting root growth and seedling development, effectively increasing the number of fibrous roots and improving the transplant survival rate; it can stabilize the EC value, inhibit salt accumulation, avoid root burn and excessive growth in seedlings, and improve the ornamental quality and uniformity of seedlings; it can achieve dynamic fertilization according to the growth stage of trees, has good compatibility with container seedling substrate, and is not prone to compaction and sedimentation; the components work synergistically to significantly improve the stress resistance of seedlings, reduce the risk of disease and pest occurrence, and improve nutrient utilization, thus having excellent seedling cultivation effect and broad application prospects. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] Example 1: This Example 1 describes a nutrient solution specifically for container seedling cultivation of forest trees. The nutrient solution is prepared from the following raw materials in parts by weight:

[0036] Macronutrients: 10 parts potassium nitrate, 5 parts ammonium dihydrogen phosphate, 6.5 parts calcium nitrate, 4 parts magnesium sulfate;

[0037] Trace elements: 0.2 parts ferric sodium ethylenediaminetetraacetate, 0.1 parts boric acid, 0.05 parts manganese sulfate, 0.04 parts zinc sulfate, 0.02 parts copper sulfate, and 0.01 parts ammonium molybdate;

[0038] Biostimulants: 1.0 part mineral-derived humic acid, 0.5 part compound amino acids, and 0.3 part brown algae extract;

[0039] Growth regulators: 0.02 parts paclobutrazol, 0.03 parts rooting powder (naphthaleneacetic acid: indolebutyric acid = 1:2);

[0040] Components for stabilizing EC values ​​against salt damage: 0.2 parts citric acid, 0.15 parts potassium humate from mineral source;

[0041] Stress-resistance enhancing factors: 0.07 parts chitosan oligosaccharide, 0.07 parts betaine;

[0042] Add deionized water to a total of 100 parts;

[0043] This embodiment describes a method for preparing a special nutrient solution for container seedling cultivation of forest trees. The specific preparation steps are as follows:

[0044] S1. Weigh each component raw material separately, and dissolve the mineral humic acid, compound amino acids, brown algae extract, paclobutrazol, rooting powder, chitosan oligosaccharide and betaine in 8 parts of deionized water to prepare the corresponding biostimulant mother liquor and growth regulator mother liquor for later use.

[0045] S2. Add macro-element components to the remaining deionized water, control the temperature at 35℃, and stir intermittently at 180 rpm for 17 min (stir for 5 min, pause for 1 min, repeat 3 times) until completely dissolved to obtain the base solution;

[0046] S3. Add trace element components to the base liquid obtained in step S2, maintain the temperature at 35°C, and continue stirring for 12 minutes until the mixture is uniform.

[0047] S4. Add the biostimulant stock solution and growth regulator stock solution prepared in S1 to the mixture in step S3 in sequence, and stir for 12 minutes to fully integrate the components.

[0048] S5. The pH of the mixture was adjusted to 6.0 using 0.8 mol / L dilute hydrochloric acid, and the EC value was measured to be 1.6 mS / cm. The parameters were stabilized by stirring for 8 min.

[0049] S6. Filter the liquid adjusted in step S5 through a 0.22μm filter membrane to remove impurities, and then fill it to obtain the finished nutrient solution.

[0050] Example 2: This Example 2 describes a nutrient solution specifically for container seedling cultivation of forest trees. The nutrient solution is prepared from the following raw materials in parts by weight:

[0051] Macronutrients: 8 parts potassium nitrate, 4 parts ammonium dihydrogen phosphate, 5 parts calcium nitrate, 3 parts magnesium sulfate;

[0052] Trace elements: 0.1 parts ferric sodium ethylenediaminetetraacetate, 0.05 parts boric acid, 0.03 parts manganese sulfate, 0.02 parts zinc sulfate, 0.01 parts copper sulfate, and 0.005 parts ammonium molybdate;

[0053] Biostimulants: 0.5 parts mineral-derived humic acid, 0.3 parts compound amino acids, and 0.2 parts brown algae extract;

[0054] Growth regulators: 0.01 parts paclobutrazol, 0.02 parts rooting powder (naphthaleneacetic acid: indolebutyric acid = 1:1.5);

[0055] Components for preventing salt damage and stabilizing EC values: 0.1 parts citric acid, 0.1 parts potassium humate from minerals;

[0056] Stress-resistance enhancing factors: 0.05 parts chitosan oligosaccharide, 0.05 parts betaine;

[0057] Add deionized water to a total of 100 parts;

[0058] The preparation method of the special nutrient solution for container seedling cultivation of forest trees in this embodiment is the same as that in Example 1, except that the pH is adjusted to 5.5 and the EC value is 1.2 mS / cm.

[0059] Example 3: This Example 3 describes a nutrient solution specifically for container seedling cultivation of forest trees. The nutrient solution is prepared from the following raw materials in parts by weight:

[0060] Macronutrients: 12 parts potassium nitrate, 6 parts ammonium dihydrogen phosphate, 8 parts calcium nitrate, and 5 parts magnesium sulfate;

[0061] Trace elements: 0.3 parts ferric sodium ethylenediaminetetraacetate, 0.15 parts boric acid, 0.08 parts manganese sulfate, 0.06 parts zinc sulfate, 0.03 parts copper sulfate, and 0.015 parts ammonium molybdate;

[0062] Biostimulants: 1.5 parts mineral-derived humic acid, 0.8 parts compound amino acids, and 0.5 parts brown algae extract;

[0063] Growth regulators: 0.03 parts paclobutrazol, 0.05 parts rooting powder (naphthaleneacetic acid: indolebutyric acid = 1:2.5);

[0064] Components for stabilizing EC values ​​against salt damage: 0.3 parts citric acid, 0.2 parts mineral-derived potassium humate;

[0065] Stress-resistance enhancing factors: 0.1 parts chitosan oligosaccharide and 0.1 parts betaine;

[0066] Add deionized water to a total of 100 parts;

[0067] The preparation method of the special nutrient solution for container seedling cultivation of forest trees in this embodiment is the same as that in Example 1, except that the pH is adjusted to 6.5 and the EC value is 2.0 mS / cm.

[0068] Comparative Example 1: Commercially available general-purpose seedling nutrient solution for conventional forest trees, diluted according to the instructions, has a pH of 6.0 and an EC value of 1.5 mS / cm.

[0069] Performance testing

[0070] 1. Physicochemical properties test of nutrient solution

[0071] (1) Appearance

[0072] Take 50 mL of each of the nutrient solutions prepared in Examples 1-3 and Comparative Example 1, place them in transparent glass beakers, let them stand at room temperature for 30 min, and directly observe the appearance of each nutrient solution. Record whether it is a uniform and transparent liquid, and whether there are any phenomena such as layering, precipitation, or suspended matter.

[0073] (2) Solubility and dispersibility

[0074] Take 10 mL of each nutrient solution and add it to 90 mL of deionized water. Stir thoroughly and let stand for 10 min to dilute. Observe the dissolution state of the diluted solution and record whether there are insoluble substances, flocculation, precipitation, etc. to evaluate the water solubility and dispersibility of the nutrient solution.

[0075] (3) pH value and pH stability

[0076] The initial pH value of each nutrient solution was measured using a pH meter and recorded as pH0. The remaining nutrient solution was sealed and placed in a room temperature (25℃±2℃) environment. After standing for 15 days, its pH value was measured again and recorded as pH1. The pH change rate was calculated according to the formula "pH change rate = |(pH1-pH0) / pH0|×100%" to compare the pH stability of different nutrient solutions.

[0077] (4) EC and EC stability

[0078] The initial EC value of each nutrient solution was measured using a conductivity meter and recorded as EC0. The nutrient solution was sealed and placed in a room temperature (25℃±2℃) environment. After standing for 15 days, its EC value was measured again and recorded as EC1. The EC change rate was calculated according to the formula "EC change rate = |(EC1-EC0) / EC0|×100%". The focus was on verifying the EC stability of the formula of this invention and comparing its difference with that of conventional nutrient solutions.

[0079] Table 1. Test data on appearance, solubility, and dispersibility of different samples.

[0080] sample Appearance Solubility and dispersibility Example 1 Uniform, transparent liquid, without stratification, sediment, or suspended matter. It dissolves completely after dilution, with no flocculation or precipitation. Example 2 Uniform, transparent liquid, without stratification, sediment, or suspended matter. It dissolves completely after dilution, with no flocculation or precipitation. Example 3 Uniform, transparent liquid, without stratification, sediment, or suspended matter. It dissolves completely after dilution, with no flocculation or precipitation. Comparative Example 1 The system was not homogeneous and showed slight stratification and a small amount of sediment after standing. A small amount of insoluble matter was found after dilution, and slight flocculation occurred.

[0081] Table 2. pH and EC stability test data for different samples

[0082] Test Project unit Example 1 Example 2 Example 3 Comparative Example 1 initial pH value - 6.00 5.50 6.50 6.10 pH value after standing at room temperature for 15 days - 6.10 5.60 6.40 5.30 pH change rate % 1.67 1.82 1.54 13.11 Initial EC value mS / cm 1.60 1.20 2.00 1.50 EC value after standing at room temperature for 15 days mS / cm 1.65 1.23 2.08 1.86 EC change rate % 3.13 2.50 4.00 24.00

[0083] The test results show that the nutrient solutions of Examples 1-3 of this invention are uniform and transparent in appearance, without stratification or sedimentation, and completely dissolve after dilution, demonstrating excellent solubility and dispersibility. In contrast, Comparative Example 1 exhibits problems such as stratification and flocculation. The pH change rate of the examples is only 1.54%-1.82%, and the EC change rate is only 2.50%-4.00%, far lower than the 13.11% and 24.00% of Comparative Example 1, fully demonstrating the core advantages of "preventing salt damage and stabilizing EC values," and providing a stable nutrient environment for seedling growth.

[0084] 2. Seedling cultivation application performance test

[0085] Container seedlings of Photinia fraseri with uniform growth and age were selected as test materials. Uniform seedling containers and the same cultivation substrate were used to ensure consistent initial experimental conditions. Three groups were set up: Example 1, Example 2, Example 3, and Comparative Example 1. Each group was replicated three times, with 100 seedlings per group. Except for the type of nutrient solution used, all groups maintained identical conditions regarding light, temperature, humidity, water and fertilizer management, and cultivation environment, adhering to the principle of single-variable comparison. During the experiment, nutrient solution was applied at the conventional seedling frequency, with each group receiving 100 mL of diluted nutrient solution per seedling (consistent with the amount applied in Comparative Example 1). After three months of conventional cultivation, relevant indicators of the seedlings in each group were measured.

[0086] (1) Growth index measurement: The height of each seedling from the substrate surface to the top growth point was measured with a tape measure, and the ground diameter was measured 5cm above the substrate surface with a vernier caliper. The average value of each group was taken.

[0087] (2) Root index determination: 20 seedlings were randomly selected from each group. After washing the roots, the number of fibrous roots with a diameter ≤2mm was counted by a root scanner. The root activity was determined by the plant root activity test (TTC) method (expressed as the number of milligrams of TTC reduced per gram of root per hour).

[0088] (3) Survival index determination: count the number of surviving seedlings in each group and calculate the survival rate of the seedlings; transplant the surviving seedlings to the same environmental conditions and record the survival status and the time of recovery after transplanting (marked by the sprouting of new leaves and no wilting).

[0089] (4) Salt damage index determination: Observe whether the leaves of each seedling show salt damage symptoms such as scorching and salt spots, and count the proportion of salt damage-affected seedlings to the total number of seedlings in the group, which is the salt damage incidence rate.

[0090] (5) Quality index determination: Record the number of yellow and withered leaves and the number of plants affected by pests and diseases in each group, and calculate the yellow and withered leaf rate and the incidence of pests and diseases respectively; determine the degree of lignification of branches by using a lignification degree measuring instrument, or use the manual bending method to assist in the evaluation (the standard of high lignification is that the branches are not easy to break and have good toughness, and the lignification degree is graded from 1 to 5, with grade 1 being the lowest (branches are easy to break and have poor toughness) and grade 5 being the highest (branches are not easy to break and have good toughness)).

[0091] All test data were taken as the average of three replicates for subsequent inter-group difference comparison analysis.

[0092] Table 3. Data on the test results of seedling growth performance of different samples

[0093] Test metrics unit Example 1 Example 2 Example 3 Comparative Example 1 Plant height cm 42.6 39.8 45.2 35.5 diameter mm 8.3 7.6 9.1 6.5 Number of fibrous roots stalk / plant 186 165 203 142 Root vitality mg / (g·h) 1.82 1.65 1.98 1.23 Container seedling survival rate % 98.7 97.3 99.0 82.5 Transplant survival rate % 96.5 94.8 97.8 78.2 Seedling establishment period d 7 8 6 14 Salt injury incidence % 3.2 2.8 2.5 21.6 Yellowing and withered leaf rate % 2.5 2.1 1.8 15.3 Incidence of diseases and pests % 4.8 4.2 3.5 18.7 Lignification grade 4.0 4.0 5.0 3.0

[0094] Compared with Comparative Example 1, the nutrient solution of Examples 1-3 of the present invention has significant effects: the height and diameter of seedlings have increased significantly, the number of fibrous roots and root vitality have been greatly improved; the survival rate of container seedlings and transplanted seedlings is over 94.8%, the seedling recovery period has been significantly shortened; the incidence of salt damage and pests and diseases has been significantly reduced, the degree of lignification has been significantly improved, and it can effectively promote seedling growth, strengthen stress resistance, and comprehensively improve seedling quality and transplant adaptability.

[0095] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nutrient solution specifically for container seedling cultivation of forest trees, characterized in that, The nutrient solution is prepared from the following raw materials in parts by weight: Macroelements: Potassium nitrate 8-12 parts, ammonium dihydrogen phosphate 4-6 parts, calcium nitrate 5-8 parts, magnesium sulfate 3-5 parts; Trace elements: 0.1-0.3 parts of ferric sodium ethylenediaminetetraacetate, 0.05-0.15 parts of boric acid, 0.03-0.08 parts of manganese sulfate, 0.02-0.06 parts of zinc sulfate, 0.01-0.03 parts of copper sulfate, and 0.005-0.015 parts of ammonium molybdate; Biostimulants: 0.5-1.5 parts mineral-derived humic acid, 0.3-0.8 parts compound amino acids, and 0.2-0.5 parts brown algae extract; Growth regulators: paclobutrazol 0.01-0.03 parts, rooting powder 0.02-0.05 parts; Components for stabilizing EC values ​​against salt damage: 0.1-0.3 parts citric acid, 0.1-0.2 parts potassium humate from mineral sources; Stress-resistance enhancing factors: chitosan oligosaccharide 0.05-0.1 parts, betaine 0.05-0.1 parts; Add deionized water to a total of 100 parts; The nutrient solution has a pH of 5.5-6.5 and an EC value of 1.2-2.0 mS / cm.

2. The nutrient solution for container seedling cultivation of forest trees according to claim 1, characterized in that, The mineral-derived humic acid has a molecular weight of 500-1000 Da, and the free amino acid content in the complex amino acid is ≥90%.

3. The nutrient solution for container seedling cultivation of forest trees according to claim 1, characterized in that, The rooting powder is composed of naphthaleneacetic acid and indolebutyric acid in a mass ratio of 1:1.5-2.

5.

4. The nutrient solution for container seedling cultivation of forest trees according to claim 1, characterized in that, In the component for preventing salt damage and stabilizing EC value, the weight ratio of citric acid to mineral-derived potassium humate is 1:0.5-2.

5. The nutrient solution for container seedling cultivation of forest trees according to claim 1, characterized in that, In the stress-resistance enhancing factor, the weight ratio of chitosan oligosaccharide to betaine is 1:

1.

6. A method for preparing a special nutrient solution for container seedling cultivation of forest trees, used to prepare the special nutrient solution for container seedling cultivation of forest trees as described in any one of claims 1-5, characterized in that, The specific preparation method is as follows: S1. Weigh each component raw material separately, and dissolve the mineral humic acid, compound amino acids, brown algae extract, paclobutrazol, rooting powder, chitosan oligosaccharide and betaine in 5-10 parts of deionized water to prepare the corresponding biostimulant mother liquor and growth regulator mother liquor for later use. S2. Add macro-element components to the remaining deionized water, control the temperature at 30-40℃, and stir intermittently at 150-200 rpm for 15-20 minutes until completely dissolved to obtain the base solution; S3. Add trace element components to the base liquid obtained in step S2, maintain the temperature at 30-40℃, and continue stirring for 10-15 minutes until the mixture is uniform. S4. Add the biostimulant stock solution and growth regulator stock solution prepared in S1 to the mixture in step S3 in sequence, and stir for 10-15 minutes to fully mix the components. S5. Adjust the pH of the mixture to 5.5-6.5 using 0.5-1 mol / L dilute hydrochloric acid or sodium hydroxide, and adjust the EC value to 1.2-2.0 mS / cm by adding deionized water or macro-elements. Stir for 5-10 min to stabilize the parameters. S6. Filter the liquid adjusted in step S5 through a 0.22μm filter membrane to remove impurities, and then fill it to obtain the finished nutrient solution.

7. The method for preparing a special nutrient solution for container seedling cultivation of forest trees according to claim 6, characterized in that, In step S1, the dissolution temperature of the biostimulant mother liquor and the growth regulator mother liquor is 25-30℃, and the stirring speed is 100-150 rpm.

8. The method for preparing a special nutrient solution for container seedling cultivation of forest trees according to claim 6, characterized in that, The intermittent stirring method in step S2 is as follows: stir for 3-5 minutes, pause for 1-2 minutes, and repeat 3-4 times.

9. A nutrient solution for container seedling cultivation of forest trees according to any one of claims 1-5, characterized in that, The nutrient solution is applied in stages according to the growth stages of the trees: Seedling stage: Dilute the nutrient solution 500-600 times and then water the seedlings, applying it once every 7-10 days; During the rapid growth period: Dilute the nutrient solution 300-400 times and water the plants every 5-7 days. At the same time, dilute the nutrient solution 800-1000 times and spray the leaves every 10-15 days. Later growth stage: Dilute the nutrient solution 400-500 times and water the plants, applying it once every 10-15 days.