Seedling raising method for controlling height-diameter ratio of cinnamomum camphora for afforestation

Abstract

The invention discloses a seedling raising method for controlling the height-diameter ratio of cinnamomum camphora for afforestation, and belongs to the technical field of cinnamomum camphora seedling raising. Soya bean lecithin is adopted to embed chlormequat chloride to prepare a slow-release conditioner, the slow-release conditioner is sprayed in the fast-growing period of cinnamomum camphora seedlings, the conditioner slowly releases chlormequat chloride to act on the seedlings, the plant height increase of the seedlings is inhibited, and the yield of the seedlings is increased. Meanwhile, a nutrient solution and drought stress are combined for the seedlings, the height of the seedlings is reduced, meanwhile, ground diameter increase is effectively promoted, thick and strong high-quality cinnamomum camphora seedlings are obtained, and the quality of the cultivated cinnamomum camphora seedlings is improved.

Description

Technical Field

[0001] The invention relates to the technical field of camphor tree seedling cultivation, in particular to a camphor tree seedling cultivation method for controlling the height-to-diameter ratio for afforestation. Background Art

[0002] The height-to-diameter ratio of seedlings is the ratio of seedling height to ground diameter, reflecting the balance between seedling height and diameter. This ratio is a good indicator of seedling resistance and afforestation survival rate. Generally, taller and thinner seedlings have weaker resistance and lower afforestation survival rates, while shorter and thicker seedlings have stronger resistance and higher afforestation survival rates. In actual afforestation, an excessively high height-to-diameter ratio can affect afforestation survival rates, while an excessively low height-to-diameter ratio can impede growth. To ensure afforestation efficiency, it is important to select seedlings with an appropriate height-to-diameter ratio.

[0003] Cinnamomum camphora is a large evergreen tree of the genus Cinnamomum in the Lauraceae family. It is also known as camphor, fragrant camphor, oily camphor, camphorwood, and black camphor. It is widely distributed in the area south of the Yangtze River. Camphor wood is of high quality and can be used to extract camphor oil and aromatic oil. It has a beautiful tree shape, dark green branches and leaves, is relatively fast-growing, and has a well-developed crown and root system. It is suitable for establishing timber forests and is one of the important afforestation tree species in my country. In the process of camphor afforestation, the height-to-diameter ratio of the camphor seedlings used is often too large, resulting in low survival rate of the camphor seedlings after afforestation, easy lodging, and crooked trunks. In order to reduce the height-to-diameter ratio of seedlings, pruning and spraying of chemicals are usually used under conventional methods to reduce the height-to-diameter ratio. However, camphor is a weak apical dominant species, and pruning operations have little effect on reducing the height-to-diameter ratio of seedlings. Spraying of chemicals often requires multiple sprayings, which can easily lead to an excessively high or low height-to-diameter ratio due to improper application of the liquid, reducing the quality of the seedlings and causing waste of the liquid.

[0004] Therefore, it is currently necessary to find a method for regulating the height-to-diameter ratio of camphor to adjust the height-to-diameter ratio of camphor for afforestation within an appropriate range and cultivate high-quality camphor seedlings. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for raising seedlings of camphor trees for afforestation by controlling the height-to-diameter ratio, so as to solve the problem that the height-to-diameter ratio of the seedlings obtained by cultivating camphor tree seedlings under conventional methods is not suitable and the seedling quality is poor.

[0006] The present invention solves the above technical problems through the following technical means:

[0007] A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation, the method comprising:

[0008] (1) Cinnamomum camphora was sown in mid-March and maintained according to conventional methods, maintaining the soil moisture content at 65-70%; thinning was performed in May after the seedlings grew to a height of ≥5 cm;

[0009] (2) Cultivate seedlings until early July, spray the conditioner and stop watering. Apply nutrient solution 3-5 days after the conditioner spraying. Restart watering 3-4 days after the nutrient solution application to maintain soil moisture at 50-55%;

[0010] (3) In early August, the conditioner is sprayed, watering is stopped, and nutrient solution is applied according to the method in step (1). Watering is resumed 5-7 days after the nutrient solution is applied to ensure that the soil moisture is 65-70%. Then, nutrient solution is applied again in mid-September. After cultivation until March of the second year, the seedlings with a height-to-diameter ratio of 70-100 can be transplanted for afforestation.

[0011] The method comprises the following steps: sowing and cultivating camphor trees until July, at which time the seedlings enter a rapid growth period and a conditioner embedded with chlormequat is sprayed. The chlormequat can regulate hormones in the seedlings, inhibit the growth of the seedlings' plant height, and promote the good growth of the seedlings' ground diameter in combination with a nutrient solution, thereby cultivating high-quality camphor tree seedlings with a good height-to-diameter ratio suitable for afforestation; while spraying the conditioner, watering is stopped to induce drought stress in the seedlings, thereby promoting the transport of seedling-generated substances to the lower part of the seedlings and further promoting the growth of the seedlings' ground diameter; and then the seedlings enter a hardening period in mid-September, at which time various components in the nutrient solution work together to promote the lignification of the seedlings. Through the combined action of the conditioner, drought stress and the nutrient solution, the height-to-diameter ratio of the seedlings is controlled and the lignification degree is improved, thereby cultivating high-quality camphor tree seedlings.

[0012] Furthermore, the conditioning agent in step (2) comprises the following raw materials:

[0013] Chlormequat chloride, soy lecithin, Tween-80, chloroform, vitamin C, 4-tert-butyl cyclohexanol, diacetyl.

[0014] Furthermore, the preparation method of the conditioning agent is as follows:

[0015] A: Soybean lecithin is dissolved in Tween-80, diluted with water, and then diacetyl is added. The mixture is heated in a reactor at 60-70°C for 2-4 hours. After the reaction is completed, the mixture is cooled to room temperature and allowed to stand overnight. 4-tert-butyl cyclohexanol is then added, and the mixture is heated to 60-70°C for 1-2 hours. After the reaction is completed, the mixture is naturally cooled to room temperature. The mixture is then placed in an environment at 4-8°C for aging for 12-24 hours and then dried to obtain the pretreated soybean lecithin.

[0016] B: Dissolve the pretreated soybean lecithin in chloroform, add chlormequat chloride and mix to homogenize. After homogenization, heat in a water bath at 70-80°C for 20-40 minutes, then cool to 40-50°C, add vitamin C, stir continuously for 5-10 minutes, cool to room temperature, and then dry to obtain a conditioner.

[0017] Under the traditional method, chlormequat chloride is usually prepared into an aqueous solution for spraying. However, after spraying, it is easily lost into the soil and is quickly decomposed by microbial enzymes. Multiple spraying is required, resulting in waste of liquid medicine and reduced effect. Therefore, the present invention uses soybean lecithin, which has a good promoting effect on plant growth, as an embedding material to coat chlormequat chloride to prepare a conditioning agent. After spraying, the soybean lecithin hydrophobically associates with the wax layer on the leaf surface of camphor seedlings, thereby better adhering to the plant surface and inhibiting loss. At the same time, the soybean lecithin slowly releases the chlormequat chloride so that it continuously enters the seedling body in small amounts, inhibiting excessive growth of the seedling height and promoting growth of the ground diameter.

[0018] However, soybean lecithin is easily decomposed by oxygen and light under natural conditions, which affects the sustained stability of chlormequat release. Therefore, the present invention first uses diacetyl to react with soybean lecithin, and diacetyl reacts with chemical bonds in the soybean lecithin to form a conjugated structure, thereby improving the stability of the molecular chain; further, 4-tert-butyl cyclohexanol is added to carry out a heating reaction, and the 4-tert-butyl cyclohexanol is bound to the soybean lecithin molecular chain to change its molecular structure and reduce its reactivity, thereby obtaining a pretreated soybean lecithin with low reactivity and strong stability for encapsulating chlormequat, so that the encapsulated chlormequat can be continuously and slowly released, thereby ensuring its effect.

[0019] Furthermore, in step A, the mass ratio of soybean lecithin, Tween-80, diacetyl and 4-tert-butyl cyclohexanol is (0.5-1): (1-1.5): (0.02-0.05): (0.01-0.02).

[0020] Furthermore, the mass ratio of soybean lecithin, chloroform, chlormequat chloride and vitamin C after pretreatment in step B is (0.5-1): (0.8-1.2): (0.004-0.008): (0.005-0.01).

[0021] Furthermore, in step B, the homogenization speed is 1000-1500 rpm, and the homogenization time is 3-5 min.

[0022] Furthermore, the nutrient solution preparation method is as follows:

[0023] Ammonium sulfate and potassium dihydrogen phosphate are mixed and added into water, stirred and dissolved, and then proline is added and mixed evenly to obtain a nutrient solution.

[0024] Furthermore, the mass ratio of ammonium sulfate, potassium dihydrogen phosphate and proline is (20-30): (15-25): (2-3).

[0025] Furthermore, when spraying the conditioner, the conditioner and water are stirred and mixed in a mass ratio of 1:100 to form a suspension, and then sprayed, with a spraying amount of 10-20g / plant.

[0026] Furthermore, the amount of nutrient solution applied is 15-30 g / plant.

[0027] Beneficial effects:

[0028] The present invention embeds chlormequat chloride in soybean lecithin to prepare a conditioning agent, which is sprayed during the rapid growth period of camphor tree seedlings. The conditioning agent acts in conjunction with drought stress and nutrient solution to ensure the plant height of the seedlings while promoting the effective growth of the seedling ground diameter, thereby improving the quality of the seedlings. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to specific embodiments:

[0030] The invention discloses a method for raising seedlings of camphor trees for controlling the height-to-diameter ratio for afforestation. Before raising the camphor tree seedlings, a conditioning agent is first prepared, as shown below.

[0031] Example 1: Conditioner Preparation

[0032] A: 0.6 kg of soybean lecithin was dissolved in 1.2 kg of Tween-80, diluted with 3.6 kg of water, and then 0.03 kg of diacetyl was added. The mixture was heated at 65°C in a reactor for 3 hours. After the reaction was completed, it was cooled to room temperature and allowed to stand overnight. Then, 0.015 kg of 4-tert-butyl cyclohexanol was added, and the mixture was heated to 65°C for 1-2 hours. After the reaction was completed, it was naturally cooled to room temperature. The mixture was then allowed to stand at 6°C for 16 hours and then dried at 45°C to obtain the pretreated soybean lecithin.

[0033] B: 0.6 kg of pretreated soybean lecithin was dissolved in 1 kg of chloroform, 0.006 kg of chlormequat chloride was added, and the mixture was homogenized at 1200 rpm for 4 minutes. After homogenization, the mixture was heated in a water bath at 75°C for 30 minutes, and then cooled to 45°C. 0.007 kg of vitamin C was added, and the mixture was stirred continuously for 8 minutes. The mixture was cooled to room temperature, and then spray-dried at an inlet air temperature of 120°C and an outlet air temperature of 80°C to obtain a conditioning agent.

[0034] Example 2: Conditioner Preparation II

[0035] A: 0.5 kg of soybean lecithin was dissolved in 1 kg of Tween-80, diluted with 3 kg of water, and then 0.02 kg of diacetyl was added. The mixture was heated at 60°C in a reactor for 2 hours. After the reaction was completed, it was cooled to room temperature and allowed to stand overnight. Then, 0.01 kg of 4-tert-butyl cyclohexanol was added, and the mixture was heated to 60°C for 1.5 hours. After the reaction was completed, it was naturally cooled to room temperature. The mixture was then placed at 4°C for aging for 12 hours and then dried at 45°C to obtain the pretreated soybean lecithin.

[0036] B: 0.5 kg of pretreated soybean lecithin was dissolved in 0.8 kg of chloroform, 0.004 kg of chlormequat chloride was added, and the mixture was homogenized at 1000 rpm for 5 minutes. After homogenization, the mixture was heated in a water bath at 70°C for 40 minutes, and then cooled to 40°C. 0.005 kg of vitamin C was added, and the mixture was stirred continuously for 10 minutes. The mixture was cooled to room temperature, and then spray-dried at an inlet air temperature of 120°C and an outlet air temperature of 80°C to obtain a conditioning agent.

[0037] Example 3: Conditioner Preparation Three

[0038] A: 1 kg of soybean lecithin was dissolved in 1.5 kg of Tween-80, diluted with 4.5 kg of water, and then 0.05 kg of diacetyl was added. The mixture was heated at 70°C in a reactor for 2 hours. After the reaction was completed, it was cooled to room temperature and allowed to stand overnight. Then, 0.02 kg of 4-tert-butyl cyclohexanol was added, and the mixture was heated to 70°C for 1 hour. After the reaction was completed, it was naturally cooled to room temperature. The mixture was then placed at 6°C for aging for 24 hours and then dried at 45°C to obtain the pretreated soybean lecithin.

[0039] B: 1 kg of pretreated soybean lecithin was dissolved in 1.2 kg of chloroform, 0.008 kg of chlormequat chloride was added, and the mixture was homogenized at 1500 rpm for 3 min. After homogenization, the mixture was heated in a water bath at 80°C for 20 min, and then cooled to 50°C. 0.01 kg of vitamin C was added, and the mixture was stirred continuously for 5 min. The mixture was cooled to room temperature, and then spray-dried at an inlet air temperature of 120°C and an outlet air temperature of 80°C to obtain a conditioning agent.

[0040] Comparative Example 1: Conditioner Preparation

[0041] In contrast to Example 1, the only difference is that no diacetyl is added in step A during the preparation of the conditioning agent in Comparative Example 1, as shown below:

[0042] A: 0.6 kg of soybean lecithin was dissolved in 1.2 kg of Tween-80, diluted with 3.6 kg of water, and then 0.015 kg of 4-tert-butyl cyclohexanol was added. The mixture was heated to 65°C for 1-2 hours. After the reaction was completed, it was naturally cooled to room temperature, and then aged at 6°C for 16 hours, and then dried at 45°C to obtain the pretreated soybean lecithin.

[0043] B: Same as Example 1.

[0044] Comparative Example 2: Conditioner Preparation

[0045] In contrast to Example 1, the only difference is that 4-tert-butyl cyclohexanol is not added in step A during the preparation of the conditioning agent in Comparative Example 2, as shown below:

[0046] A: 0.6 kg of soybean lecithin was dissolved in 1.2 kg of Tween-80, diluted with 3.6 kg of water, and then 0.03 kg of diacetyl was added. The mixture was heated at 65°C in a reactor for 3 hours. After the reaction was completed, the mixture was cooled to room temperature and allowed to stand overnight. The mixture was then aged at 6°C for 16 hours and then dried at 45°C to obtain the pretreated soybean lecithin.

[0047] B: Same as Example 1.

[0048] Comparative Example 3: Conditioner Preparation

[0049] In contrast to Example 1, the only difference is that in the preparation of the conditioner in Comparative Example 3, no static aging treatment is performed in Step A, as shown below:

[0050] A: 0.6 kg of soybean lecithin was dissolved in 1.2 kg of Tween-80, diluted with 3.6 kg of water, and then 0.03 kg of diacetyl was added. The mixture was heated at 65°C in a reactor for 3 hours. After the reaction was completed, the mixture was cooled to room temperature and allowed to stand overnight. Then, 0.015 kg of 4-tert-butyl cyclohexanol was added, and the mixture was heated to 65°C for 1-2 hours. After the reaction was completed, the mixture was naturally cooled to room temperature and then dried at 45°C to obtain the pretreated soybean lecithin.

[0051] B: Same as Example 1.

[0052] Comparative Example 4: Conditioner Preparation

[0053] In contrast to Example 1, the only difference is that vitamin C is not added in step B when preparing the conditioner in Comparative Example 4, as shown below:

[0054] A: Same as Example 1;

[0055] B: 0.6 kg of pretreated soybean lecithin was dissolved in 1 kg of chloroform, 0.006 kg of chlormequat chloride was added, and the mixture was homogenized at 1200 rpm for 4 minutes. After homogenization, the mixture was heated in a water bath at 75°C for 30 minutes, cooled to room temperature, and then spray-dried at an inlet air temperature of 120°C and an outlet air temperature of 80°C to obtain a conditioning agent.

[0056] Example 4: Seedling cultivation method for controlling the height-to-diameter ratio of camphor trees

[0057] The conditioning agent used in this example is the conditioning agent prepared in Example 1;

[0058] The nutrient solution used in this example was prepared by mixing 25 g of ammonium sulfate and 20 g of potassium dihydrogen phosphate, adding the mixture to 4.5 kg of water and stirring to dissolve the mixture. 2.5 g of proline was then added and mixed evenly to obtain a nutrient solution.

[0059] (1) Camphor trees were sown in mid-March and watered and fertilized according to conventional methods to maintain soil moisture at 65-70%. In May, when the seedlings grew to a height of ≥5 cm, they were thinned according to conventional methods.

[0060] (2) When the seedlings are cultivated until early July, the conditioner and water are stirred and mixed in a mass ratio of 1:100 to form a suspension, and then sprayed at a rate of 15 g / plant and watering is stopped. Four days after the conditioner spraying, nutrient solution is applied at a rate of 20 g / plant. Three days after the nutrient solution application, watering is resumed to maintain the soil moisture at 50-55%;

[0061] (3) In early August, the conditioner is sprayed, watering is stopped, and nutrient solution is applied according to the method in step (1). Watering is resumed 6 days after the nutrient solution is applied to ensure that the soil moisture is 65-70%. Then, nutrient solution is applied again in the amount of 20g / plant in mid-September. After cultivation until March of the second year, the seedlings with a height-to-diameter ratio of 70-100 can be transplanted for afforestation.

[0062] Comparative Example 5: Seedling cultivation method for controlling the height-to-diameter ratio of camphor trees

[0063] In contrast to Example 4, the difference is that in Comparative Example 5, no conditioner was sprayed during seedling cultivation, as follows:

[0064] (1) Same as Example 4:

[0065] (2) Stop watering the seedlings until early July. Apply nutrient solution at a rate of 20 g / plant 4 days later. Restart watering 3 days after application of nutrient solution to maintain soil moisture at 50-55%;

[0066] (3) At the beginning of August, stop watering and apply nutrient solution according to the method in step (1). Restart watering 6 days after applying the nutrient solution to ensure that the soil moisture is 65-70%. Then, apply nutrient solution again at a rate of 20g / plant in mid-September. After cultivation until March of the second year, the seedlings with a height-to-diameter ratio of 70-100 can be transplanted for afforestation.

[0067] Comparative Example 6: Seedling cultivation method for controlling the height-to-diameter ratio of camphor trees

[0068] In contrast to Example 4, the difference is that the watering operation is not stopped during seedling cultivation in Comparative Example 6, as follows:

[0069] (1) Same as Example 1;

[0070] (2) When the seedlings are cultivated until early July, the conditioner and water are stirred and mixed in a mass ratio of 1:100 to form a suspension, and then sprayed at a rate of 15 g / plant. Four days after the conditioner spraying, nutrient solution is applied at a rate of 20 g / plant, and the soil moisture is maintained at 65-70%;

[0071] (3) In early August, the conditioner is sprayed and the nutrient solution is applied according to the method in step (1), and the soil moisture is maintained at 65-70%. Then, in mid-September, the nutrient solution is applied again at a rate of 20 g / plant. After cultivation until March of the second year, the seedlings with a height-to-diameter ratio of 70-100 can be transplanted for afforestation.

[0072] Comparative Example 7: Seedling cultivation method for controlling the height-to-diameter ratio of camphor

[0073] In contrast to Example 4, the difference is that in Comparative Example 7, no nutrient solution is applied during seedling cultivation, but clean water is applied, as shown below:

[0074] (1) Same as Example 4;

[0075] (2) When the seedlings are cultivated until early July, the conditioner and water are stirred and mixed in a mass ratio of 1:100 to form a suspension, and then sprayed at a rate of 15 g / plant and watering is stopped. Four days after the conditioner spraying, clean water is applied at a rate of 20 g / plant. Three days after the clean water application, watering is resumed to maintain the soil moisture at 50-55%;

[0076] (3) In early August, the conditioner is sprayed, watering is stopped, and clean water is applied according to the method in step (1). After 6 days of applying clean water, watering is resumed to ensure that the soil moisture is 65-70%. Then, clean water is applied once again at a rate of 20 g / plant in mid-September. After cultivation until March of the second year, the seedlings with a height-to-diameter ratio of 70-100 can be transplanted for afforestation.

[0077] Comparative Example 8: Seedling cultivation method for controlling the height-to-diameter ratio of camphor trees

[0078] In contrast to Example 4, the difference is that in Comparative Example 8, the operations of stopping watering and applying nutrient solution are not performed during seedling cultivation, as follows:

[0079] (1) Same as Example 4;

[0080] (2) When the seedlings are cultivated until early July, the conditioner and water are stirred and mixed in a mass ratio of 1:100 to form a suspension, and then sprayed at a rate of 15 g / plant, maintaining the soil moisture at 65-70%;

[0081] (3) In early August, the conditioner is sprayed and the same maintenance operations are performed according to the method in step (2). In March of the second year, the seedlings with a height-to-diameter ratio of 70-100 can be transplanted for afforestation.

[0082] Comparative Example 9: Seedling cultivation method for controlling the height-to-diameter ratio of camphor

[0083] In contrast to Example 4, the difference is that in Comparative Example 9, the seedlings were grown according to the conventional method for dwarfing, as shown below:

[0084] (1) Same as Example 1;

[0085] (2) During the seedling cultivation period until early July, spray 100 mg / L chlormequat solution and maintain the soil moisture at 65-70%;

[0086] (3) In early August, spray the chlormequat solution according to the method in step (2) and carry out the same management and maintenance. In March of the second year, the seedlings with a height-to-diameter ratio of 70-100 can be transplanted for afforestation.

[0087] Experiment 1: Conditioning agent sustained release experiment

[0088] The release rates of the drug (chlormequat) of the conditioners prepared in Example 1 and Comparative Examples 1-4 were measured at a temperature of 28° C. and a light intensity of 2500 lx on the 5th and 10th days, respectively. The data are shown in Table 1:

[0089] Table 1

[0090] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Release rate on the 5th day (%) 43.6 63.5 58.5 49.3 55.4 Release rate on the 10th day (%) 62.7 89.7 86.8 70.4 79.2

[0091] According to the data analysis in Table 1, we can see that:

[0092] (1) The drug release of the conditioning agent prepared in Example 1 was 43.6% and 62.7% on the 5th and 10th days respectively under the conditions of a temperature of 28°C and a light intensity of 2500 lx. Compared with Comparative Examples 1-4, the drug release of the conditioning agent in Example 1 was slower and more stable, indicating that the conditioning agent prepared according to the method of the present invention has relatively stable performance. After embedding chlormequat chloride, the drug can be slowly and continuously released to act on the seedlings to regulate the plant height and ground diameter of the seedlings, and has a good regulatory effect on cultivating high-quality camphor seedlings with a suitable height-to-diameter ratio.

[0093] (2) No diacetyl was added during the preparation of the conditioning agent in Comparative Example 1, and no 4-tert-butyl cyclohexanol was added during the preparation of the conditioning agent in Comparative Example 2. The stability of the soybean lecithin in Comparative Example 1 was poor, and the reactivity of the soybean lecithin in Comparative Example 2 was strong. In Comparative Examples 1 and 2, the degradation of soybean lecithin was accelerated under the influence of environmental factors such as light and oxygen, and the embedding and fixing performance of chlormequat was unstable, resulting in excessive release of the drug. In Comparative Example 4, no vitamin C was added during the preparation of the conditioning agent, and the oxidative degradation rate of the conditioning agent was relatively fast, resulting in a reduced fixing and protective effect on chlormequat, and thus excessive release.

[0094] Experiment 2: Cinnamomum camphora seedling cultivation experiment

[0095] A camphor seedling cultivation experiment was conducted in Nanchuan Daguan Town, Yunlong Town, Liangping. The experiment was divided into 11 groups, including experimental group 1, control groups 1-9, and a blank control group. The conditioning agents and seedling cultivation methods used in each group are as follows:

[0096] Experimental group 1: using the conditioner of Example 1 and the seedling raising method of Example 4;

[0097] Control groups 1-4: using the conditioners of Comparative Examples 1-4 and the seedling raising method of Example 4 respectively;

[0098] Control group 5: no conditioner was used, and the seedling raising method of comparative example 5 was adopted;

[0099] Control groups 6-8: using the conditioning agent prepared in Example 1 and the seedling raising methods of Comparative Examples 6-8 respectively;

[0100] Control group 9: The seedling raising method of comparative example 9 was adopted, that is, conventional chlormequat solution was sprayed

[0101] Blank control group: No conditioner or nutrient solution was sprayed, and watering was stopped. Instead, conventional care and cultivation were performed, as follows:

[0102] Cinnamomum camphora is sown in mid-March, and watering and fertilizing are carried out according to conventional methods to maintain soil moisture at 65-70%; in May, when the seedlings grow to a height of ≥5cm, thinning is carried out according to conventional methods, and seedlings with a height-to-diameter ratio of 70-100 can be transplanted for afforestation in March of the second year.

[0103] 2. Results: Each group cultivated 20 camphor seedlings. In March of the second year, the plant height and ground diameter of each group of seedlings were measured, and the height-to-diameter ratio was calculated based on the plant height and ground diameter. The experiment was repeated three times, and the data obtained are shown in Table 2:

[0104] Table 2

[0105]

[0106] According to the data analysis in Table 2, we can see

[0107] (1) The plant height and ground diameter values ​​of the seedlings in experimental group 1 were both high, with a height-to-diameter ratio of 81.6. This indicates that the treatment of camphor seedlings according to the method of the present invention can better ensure the plant height of the camphor seedlings while effectively increasing the ground diameter. The cultivated camphor seedlings have a moderate height-to-diameter ratio and are high-quality seedlings suitable for afforestation.

[0108] (2) The stability of the conditioner in the control groups 1-4 was poor, resulting in excessive release of chlormequat. The seedlings absorbed a large amount of chlormequat, which in turn affected their growth. Although the height-diameter ratio of the obtained seedlings was more suitable for afforestation, their plant height and ground diameter were reduced to varying degrees compared with those in the experimental group 1, and the quality of the seedlings was lower than that of the seedlings in the experimental group 1.

[0109] (3) The control group 5 was not sprayed with a conditioner during seedling cultivation, the control group 6 was not subjected to drought stress during seedling cultivation, the control group 7 was not applied with a nutrient solution during seedling cultivation, and the control group 8 was not applied with a nutrient solution and was not subjected to drought stress during seedling cultivation. The ground diameters of the seedlings in the control groups 5-8 were all lower than those in the experimental group 1. This indicates that according to the method of the present invention, by combining the conditioner with drought stress and nutrient solution, the ground diameter can be effectively promoted while ensuring that the seedling height increases at a relatively slow rate, thereby better regulating the height-to-diameter ratio of the seedlings, making them more suitable for afforestation.

[0110] (4) Control group 9 was directly sprayed with chlormequat solution. Since the solution was easily lost and ineffective, the amount of effective ingredients absorbed and utilized by the seedlings was small without increasing the number of spraying times. The degree of plant height reduction was low, and the ground diameter growth was not obvious. The resulting seedlings had poor growth conditions compared with experimental group 1. The blank control group was directly cultivated according to conventional methods, and the plant height grew rapidly and the ground diameter grew slowly.

[0111] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that the technical solutions of the present invention may be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, and such modifications or equivalents shall be encompassed by the claims of the present invention. Any techniques, shapes, and structures not described in detail herein are well known.

Claims

1. A method for raising seedlings of camphor trees for afforestation by controlling their height-to-diameter ratio, characterized in that: The method is as follows: (1) Cinnamomum camphora was sown in mid-March and maintained according to conventional methods, during which the soil moisture content was maintained at 65-70%; in May, seedlings were thinned out after the plant height reached ≥5 cm; (2) Cultivate the seedlings until early July, spray the conditioner and stop watering. Apply the nutrient solution 3-5 days after the conditioner spraying. Restart watering 3-4 days after the nutrient solution application to maintain the soil moisture at 50-55%; (3) In early August, the conditioner is sprayed, watering is stopped, and nutrient solution is applied according to the method in step (1). Watering is resumed 5-7 days after the nutrient solution is applied to ensure that the soil moisture is 65-70%. Then, nutrient solution is applied again in mid-September. After cultivation until March of the second year, the seedlings with a height-to-diameter ratio of 70-100 can be transplanted for afforestation.

2. A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation according to claim 1, characterized in that: The conditioning agent in step (2) comprises the following raw materials: Chlormequat, soy lecithin, Tween-80, chloroform, vitamin C, 4-tert-butyl cyclohexanol, diacetyl.

3. A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation according to claim 2, characterized in that: The preparation method of the conditioning agent is as follows: A: Soybean lecithin is dissolved in Tween-80, diluted with water and then added with diacetyl, heated in a reactor at 60-70°C for 2-4 hours, cooled to room temperature and allowed to stand overnight, then added with 4-tert-butyl cyclohexanol, heated to 60-70°C for 1-2 hours, naturally cooled to room temperature after the reaction is completed, then placed in an environment at 4-8°C for aging for 12-24 hours and dried to obtain pretreated soybean lecithin; B: Add the pretreated soybean lecithin into chloroform to dissolve, add chlormequat chloride and mix to homogenize. After homogenization, heat in a water bath at 70-80°C for 20-40 minutes, then cool to 40-50°C, add vitamin C, stir continuously for 5-10 minutes, cool to room temperature, and then dry to obtain a conditioner.

4. A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation according to claim 3, characterized in that: The mass ratio of soybean lecithin, Tween-80, diacetyl and 4-tert-butyl cyclohexanol in step A is (0.5-1): (1-1.5): (0.02-0.05): (0.01-0.02).

5. A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation according to claim 4, characterized in that: After the pretreatment in step B, the mass ratio of soybean lecithin, chloroform, chlormequat chloride and vitamin C is (0.5-1): (0.8-1.2): (0.004-0.008): (0.005-0.01).

6. A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation according to claim 5, characterized in that: In step B, the homogenization speed is 1000-1500 rpm, and the homogenization time is 3-5 min.

7. A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation according to claim 6, characterized in that: The nutrient solution preparation method is as follows: Ammonium sulfate and potassium dihydrogen phosphate are mixed and added into water, and the mixture is stirred to dissolve. Then proline is added and the mixture is mixed evenly to obtain a nutrient solution.

8. A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation according to claim 7, characterized in that: The mass ratio of ammonium sulfate, potassium dihydrogen phosphate and proline is (20-30):(15-25):(2-3).

9. A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation according to claim 8, characterized in that: When spraying the conditioner, the conditioner and water are stirred and mixed in a mass ratio of 1:100 to form a suspension, and then sprayed. The spraying amount is 10-20g / plant.

10. A method for raising seedlings for controlling the height-to-diameter ratio of camphor trees for afforestation according to claim 9, characterized in that: The amount of the nutrient solution applied is 15-30 g / plant.

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