Afforestation method in alpine region

Abstract

The invention discloses an alpine region afforestation method, and belongs to the technical field of afforestation, the method comprises the steps of soil pretreatment, nursery stock transplantation, stabilizer application, later-stage management and protection and the like, indigenous tree species nursery stocks are selected in spring for transplantation planting, and then a stabilizer A and a stabilizer B are prepared for application; the stabilizer A continuously reacts to release heat so as to increase the temperature of rhizosphere soil, the stabilizer B inhibits the released heat from dissipating outwards for heat preservation, and the rhizosphere soil is heated and preserved through the combined action of the stabilizer A and the stabilizer B, so that safe overwintering of nursery stocks is guaranteed, and the final afforestation survival rate is increased; the method disclosed by the invention has important significance in promoting the restoration of the ecological environment of the alpine region.

Description

Technical Field

[0001] This invention relates to the field of afforestation technology, and in particular to a method for afforestation in high-altitude and cold regions. Background Technology

[0002] High-altitude and cold regions typically refer to areas with high elevations, cold climates, and harsh environmental conditions. These regions are generally characterized by low average annual temperatures, short frost-free periods, long winters, and strong winds. Afforestation in high-altitude and cold regions is of paramount strategic importance for restoring degraded ecosystems, conserving water resources, maintaining soil and water conservation, addressing climate change, and promoting sustainable socio-economic development in these areas.

[0003] In high-altitude and cold regions, the average annual temperature is low, and the diurnal temperature range is large. The soil freezes deeply and for a long period in winter, making seedling roots highly susceptible to frost damage, resulting in difficulties in overwintering, low survival rates, and limited afforestation effectiveness. Currently, the "root zone mulching method" is commonly used for frost protection, which involves covering the soil surface around the seedlings with materials such as straw, fallen leaves, or mulch to block heat loss from the soil and increase the root zone temperature, thereby ensuring the seedlings' safe overwintering. However, these measures have the following problems in practical application: straw and fallen leaves are easily blown away by strong winds, resulting in poor heat retention; while mulch has poor air permeability and is prone to cracking and failure in low-temperature environments. Furthermore, the heat retention efficiency of these conventional materials is limited. Even with such mulching measures, the soil temperature is still difficult to maintain within the tolerance range of the seedling roots, and the seedlings are still susceptible to low-temperature frost damage, making the heat protection effect less than ideal.

[0004] Therefore, it is currently necessary to find a suitable afforestation method for high-altitude and cold regions to solve the problem that conventional heat-insulating materials such as straw and fallen leaves are difficult to maintain soil temperature and seedlings are difficult to overwinter, resulting in low survival rates of afforestation. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a method for afforestation in high-altitude and cold regions, which solves the problem that conventional heat-insulating materials such as straw and fallen leaves are difficult to maintain soil temperature and seedlings are difficult to overwinter, resulting in low survival rates of afforestation.

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

[0007] A method for afforestation in high-altitude and cold regions, the method comprising the following steps:

[0008] (1) Soil pretreatment: After removing weeds, tree roots and stones from the soil in April and May, the soil was disinfected by spraying with 0.5wt% potassium permanganate solution to obtain pretreated soil;

[0009] (2) Transplanting seedlings: Dig planting holes in the pretreated soil, select 2-3 year old native tree seedlings that are free from pests and diseases, grow vigorously and have well-developed root systems, dip the roots in rooting powder and place them vertically in the center of the planting hole while keeping the roots spread out, then backfill the soil and tamp it down in layers, and finally cover it with a layer of loose soil and water it thoroughly.

[0010] (3) Stabilizer application: In November, dig a circular trench around the transplanted seedlings and apply stabilizer in the trench. After applying the stabilizer, cover the soil surface around the roots of the transplanted seedlings with fallen leaves or straw to help keep them warm.

[0011] (4) Post-maintenance: In the later stage, watering, fertilization and other maintenance can be carried out in accordance with conventional methods.

[0012] In spring, native tree species seedlings are selected for transplanting. At this time, the temperature is more suitable, and the seedlings can recover better, thus ensuring a higher initial survival rate of the afforestation seedlings.

[0013] Furthermore, in step (2), planting holes are dug according to the standard of 1.5-3m plant spacing and 2-4m row spacing; the diameter of the planting hole is 40-60cm and the depth is 40-50cm.

[0014] Furthermore, in step (3), the stabilizer consists of stabilizer A and stabilizer B, and the stabilizer includes the following raw materials:

[0015] Stabilizer A: Bentonite, quicklime, sawdust, soybean lecithin, expanded graphite, decanoic acid, lauric acid, sodium alginate, chitosan quaternary ammonium salt, sodium sulfate, calcium chloride;

[0016] Stabilizer B: Diatomaceous earth, vermiculite.

[0017] Furthermore, the particle size of the wood chips is 0.5–1 mm.

[0018] Furthermore, the method for preparing the stabilizer is as follows:

[0019] Stabilizer A:

[0020] S1: Mix bentonite, quicklime and sawdust evenly to obtain a mixture. Add 15-25% water by mass to the mixture and mix evenly. Then granulate to obtain particles with a particle size of 4-6 mm. Dry at 80-100℃ for 6-12 h, then heat to 600-800℃ at a rate of 5-10℃ / min and keep at that temperature for 0.5-2 h. Then cool naturally to room temperature to obtain porous quicklime particles.

[0021] S2: Add soybean lecithin to 20 times its weight of anhydrous ethanol and stir to dissolve to form a suspension. Then add porous quicklime particles, vacuum to -0.08 to -0.09 MPa and maintain for 20 to 30 minutes. Then soak under normal pressure for 1 to 2 hours, filter to remove the filtrate, and dry at 60℃ for 2 to 6 hours to obtain inner layer particles.

[0022] S3: Mix decanoic acid and lauric acid in a mass ratio of 7:3 to obtain a phase change material. Heat the mixture to 40°C and stir to melt it. Then add expanded graphite and stir continuously at a speed of 150-250 r / min for 10-20 min to obtain an embedding agent. Spray the embedding agent onto the surface of the inner layer particles and transfer it to a 4°C environment for overnight refrigeration. Repeat the embedding agent spraying and refrigeration operation twice to obtain secondary coated particles.

[0023] S4: Dissolve sodium alginate in water to prepare a 2wt% sodium alginate solution, add sodium sulfate and chitosan quaternary ammonium salt and stir to dissolve to obtain a sodium alginate mixture, add secondary coated particles to the sodium alginate mixture and soak for 2-3 minutes, then transfer to a 3wt% calcium chloride solution to gel the sodium alginate on the surface, and then wash with water 2-3 times to obtain stabilizer A.

[0024] Stabilizer B: Diatomaceous earth and vermiculite are mixed in a mass ratio of (2-3):1 and dried at 65°C to constant weight to obtain stabilizer B.

[0025] Furthermore, in step S1, the mass ratio of bentonite, quicklime, and sawdust is (10-12):(30-35):(3-5).

[0026] Furthermore, in step S3, the mass ratio of phase change material to expanded graphite is 1:(2-3).

[0027] Furthermore, in step S3, the amount of embedding agent sprayed in a single application is 4 to 5% of the mass of the inner layer particles.

[0028] Furthermore, in step S4, the mass ratio of sodium alginate solution, sodium sulfate, and chitosan quaternary ammonium salt is 1:(0.14-0.15):(0.01-0.02).

[0029] Furthermore, the stable application method in step (3) is as follows:

[0030] Dig inner and outer ring trenches around the transplanted seedling. The inner ring trench should be 30-50cm from the trunk, 8-10cm wide, and 10-20cm deep. The outer ring trench should be 60-80cm from the trunk, 15-25cm wide, and 20-30cm deep. Then, mix stabilizer A with the soil and backfill it into the inner ring trench. Mix stabilizer B with the soil and backfill it into the outer ring trench. The application rate of stabilizer A is 2-3kg / plant, and the application rate of stabilizer B is 2-3kg / plant.

[0031] This invention involves transplanting seedlings for afforestation in spring, which effectively ensures a high initial survival rate. However, seedlings that have grown into winter are still relatively weak and cannot survive the low temperatures of high-altitude regions relying solely on their own resistance. Therefore, this invention prepares a stabilizer that is applied in circular trenches during winter. The stabilizer increases the soil temperature around the seedling roots, ensuring that the seedlings can successfully overwinter in a relatively warm soil environment, thus maximizing the final afforestation survival rate.

[0032] Specifically, the stabilizer consists of stabilizer A and stabilizer B. In November, during winter, inner and outer ring trenches are dug around the seedlings. Stabilizer A is then applied to the inner ring trench. Stabilizer A uses quicklime as its active ingredient. Quicklime reacts with water, releasing a large amount of heat, which can effectively increase the temperature of the rhizosphere soil. However, directly applying quicklime to the soil results in a violent reaction, which not only releases a large amount of heat instantaneously, causing excessive soil temperature rise and damaging the roots, but also has a short duration of action, failing to achieve a sustained heating effect. Therefore, this invention mixes quicklime with bentonite and sawdust, granulates it, and then sintersulates it at high temperature to prepare porous quicklime particles. These particles are then treated with soybean lecithin to obtain the inner layer particles. During this process, soybean lecithin enters the pores of the porous quicklime, sealing them. After being applied to the soil, the soybean lecithin gradually hydrolyzes and is lost, exposing the quicklime, which then reacts with water to continuously release heat. This prolongs the heating time of the stabilizer without causing excessive heat release that could lead to excessively high soil temperatures and damage to the roots.

[0033] To further enhance the effectiveness of stabilizer A, this invention further employs expanded graphite loaded with phase change material, which is then sprayed onto the surface of the inner layer particles to prepare secondary coated particles. On one hand, the phase change material can absorb excess heat released by the quicklime water in the inner layer particles through phase change, and then release it again through phase change when the temperature decreases, thereby improving the heat utilization rate. On the other hand, expanded graphite has good thermal conductivity, which can promptly conduct the heat released by the inner layer particles into the soil, ensuring stable heat transfer.

[0034] However, when expanded graphite-loaded phase change material is used to coat the inner particles and then applied to the soil, the isolation effect of the phase change material layer makes it difficult for external moisture to penetrate the interior and hydrolyze the quicklime in the inner layer, releasing heat and thus limiting the heating activation of stabilizer A. Therefore, this invention further uses sodium alginate to coat the secondary coated particles already coated with phase change material, and adds sodium sulfate to the sodium alginate solution. When applied to the soil in winter, the solubility of sodium sulfate in the outer sodium alginate gel of stabilizer A decreases under low temperature conditions, leading to crystallization and precipitation. This volume expansion generates mechanical stress on the inner phase change material coating layer, causing the coating layer to break down. Free water in the gel then enters and hydrolyzes the quicklime, releasing heat and thus activating the heating and heat-preserving effect of the stabilizer. Simultaneously, the outer gel has good water absorption and retention properties, allowing it to absorb and store a large amount of water. After the heating and heat-preserving effect of stabilizer A is activated, this water is continuously and slowly released into the interior to react with the quicklime, ensuring the continuous release of heat from the stabilizer.

[0035] Furthermore, since the gel formed by sodium alginate and calcium ions is an ionicly cross-linked network structure, it is easily disrupted by competing cross-linking sites from metal ions in the soil, thus shortening the stabilizer's effective time. Therefore, this invention adds chitosan quaternary ammonium salt, allowing it to enter the gel and bind with sodium alginate through electrostatic interactions, thereby better maintaining the stability of the gel network structure.

[0036] Through the combined action of the components in stabilizer A, the system ensures a continuous, stable, and long-lasting increase in rhizosphere soil temperature. Furthermore, the components in stabilizer A are plant-friendly and effectively promote plant growth. To suppress heat loss from stabilizer A, stabilizer B is prepared by mixing and drying low-thermal-conductivity diatomaceous earth and vermiculite. This mixture is applied to the outer ring trench surrounding stabilizer A to inhibit heat loss through conduction into the surrounding soil. This, combined with the addition of leaf litter covering the rhizosphere surface soil, further enhances heat preservation, ensuring a suitable rhizosphere soil temperature to assist seedlings in overwintering and ultimately guaranteeing a higher survival rate for afforestation seedlings.

[0037] Beneficial effects:

[0038] This invention involves transplanting native tree seedlings from high-altitude and cold regions in the spring, then preparing a stabilizer for application in winter and covering the seedlings with fallen leaves or straw. The stabilizer maintains a relatively high temperature in the rhizosphere soil, and the combination of covering the rhizosphere soil surface with fallen leaves or straw further warms and insulates the soil, ensuring that the seedlings can successfully overwinter and thus guaranteeing the final survival rate of the afforestation project. This invention has promising application prospects in the field of afforestation technology in high-altitude and cold regions. Attached Figure Description

[0039] Figure 1 : This is a picture showing the growth status of Pinus tabuliformis after afforestation according to the present invention. Detailed Implementation

[0040] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings:

[0041] Example 1: Preparation of Stabilizer A

[0042] S1: Mix 11kg bentonite, 32kg quicklime and 4kg sawdust with a particle size of 0.6mm evenly to obtain a mixture. Add 20% water by mass to the mixture and mix evenly. Then granulate to obtain particles with a particle size of 5mm. Dry at 90℃ for 10h, then heat to 700℃ at a rate of 6℃ / min and keep at that temperature for 1.5h. Then cool naturally to room temperature to obtain porous quicklime particles.

[0043] S2: Add soybean lecithin to 20 times its weight of anhydrous ethanol and stir to dissolve to form a suspension. Then add porous quicklime particles to completely immerse them in the suspension. Vacuum the solution to -0.08 MPa and maintain it for 25 min. Then soak the solution under normal pressure for 1.5 h, filter to remove the filtrate, and dry at 60℃ for 4 h to obtain the inner layer particles.

[0044] S3: Mix decanoic acid and lauric acid in a mass ratio of 7:3 to obtain a phase change material. Heat the mixture to 40°C and stir to melt it. Then add 2.5 times the mass of expanded graphite of the phase change material and stir continuously at 200 r / min for 15 min to obtain an embedding agent. Spray the embedding agent onto the surface of the inner layer particles and transfer it to a 4°C environment for overnight refrigeration. Repeat the spraying and refrigeration operation of the embedding agent twice. The specific amount of each spray is 4% of the mass of the inner layer particles to obtain secondary coated particles.

[0045] S4: Dissolve sodium alginate in water to prepare a 2wt% sodium alginate solution. Then, add sodium sulfate and chitosan quaternary ammonium salt in a mass ratio of sodium alginate solution: sodium sulfate: chitosan quaternary ammonium salt = 1:0.14:0.01 and stir to dissolve to obtain a sodium alginate mixture. Add the secondary coated particles to the sodium alginate mixture and soak for 3 minutes. Then, remove them and immediately transfer them to a 3wt% calcium chloride solution to gel the sodium alginate on the surface. Then, wash them three times with water to obtain stabilizer A.

[0046] Example 2: Preparation of Stabilizer A

[0047] S1: Mix 10kg bentonite, 30kg quicklime and 3kg sawdust with a particle size of 0.5mm evenly to obtain a mixture. Add 15% water by mass to the mixture and mix evenly. Then granulate to obtain particles with a particle size of 4mm. Dry at 80℃ for 6h, then heat to 600℃ at a rate of 5℃ / min and keep at that temperature for 0.5h. Then cool naturally to room temperature to obtain porous quicklime particles.

[0048] S2: Add soybean lecithin to 20 times its weight of anhydrous ethanol and stir to dissolve to form a suspension. Then add porous quicklime particles to completely immerse them in the suspension. Vacuum the solution to -0.08 MPa and maintain it for 20 min. Then soak the solution under normal pressure for 1 h, filter to remove the filtrate, and dry at 60℃ for 2 h to obtain the inner layer particles.

[0049] S3: Mix decanoic acid and lauric acid in a mass ratio of 7:3 to obtain a phase change material. Heat the mixture to 40°C and stir to melt it. Then add expanded graphite with a mass of 2 times that of the phase change material. Stir continuously at 150 r / min for 20 min to obtain an embedding agent. Spray the embedding agent onto the surface of the inner layer particles and then transfer it to a 4°C environment for overnight refrigeration. Repeat the spraying and refrigeration operation of the embedding agent twice. The specific amount of each spray is 4% of the mass of the inner layer particles to obtain secondary coated particles.

[0050] S4: Dissolve sodium alginate in water to prepare a 2wt% sodium alginate solution. Then, add sodium sulfate and chitosan quaternary ammonium salt in a mass ratio of sodium alginate solution: sodium sulfate: chitosan quaternary ammonium salt = 1:0.14:0.01 and stir to dissolve to obtain a sodium alginate mixture. Add the secondary coated particles to the sodium alginate mixture and soak for 2 minutes. Then, remove them and immediately transfer them to a 3wt% calcium chloride solution to gel the sodium alginate on the surface. Then, wash them twice with water to obtain stabilizer A.

[0051] Example 3: Preparation of Stabilizer A

[0052] S1: Mix 12kg bentonite, 35kg quicklime and 5kg sawdust with a particle size of 1mm evenly to obtain a mixture. Add 25% water by mass to the mixture and mix evenly. Then granulate to obtain particles with a particle size of 6mm. Dry at 100℃ for 12h, then heat to 800℃ at a rate of 10℃ / min and keep at that temperature for 2h. Then cool naturally to room temperature to obtain porous quicklime particles.

[0053] S2: Add soybean lecithin to 20 times its weight of anhydrous ethanol and stir to dissolve to form a suspension. Then add porous quicklime particles to completely immerse them in the suspension. Vacuum the solution to -0.09 MPa and maintain it for 30 min. Then soak the solution under normal pressure for 2 h, filter to remove the filtrate, and dry at 60℃ for 6 h to obtain the inner layer particles.

[0054] S3: Mix decanoic acid and lauric acid in a mass ratio of 7:3 to obtain a phase change material. Heat the mixture to 40°C and stir to melt it. Then add 3 times the mass of expanded graphite of the phase change material and stir continuously at 250 r / min for 10 min to obtain an embedding agent. Spray the embedding agent onto the surface of the inner layer particles and transfer it to a 4°C environment for overnight refrigeration. Repeat the spraying and refrigeration operation of the embedding agent twice. The specific amount of each spraying is 5% of the mass of the inner layer particles to obtain secondary coated particles.

[0055] S4: Dissolve sodium alginate in water to prepare a 2wt% sodium alginate solution. Then, add sodium sulfate and chitosan quaternary ammonium salt in a mass ratio of sodium alginate solution: sodium sulfate: chitosan quaternary ammonium salt = 1:0.15:0.02 and stir to dissolve to obtain a sodium alginate mixture. Add the secondary coated particles to the sodium alginate mixture and soak for 3 minutes. Then, remove them and immediately transfer them to a 3wt% calcium chloride solution to gel the sodium alginate on the surface. Then, wash them three times with water to obtain stabilizer A.

[0056] Example 4: Preparation of Stabilizer B

[0057] Stabilizer B is obtained by mixing diatomaceous earth and vermiculite in a mass ratio of 2.5:1 and drying at 65°C to constant weight.

[0058] Comparative Example 1: Preparation of Stabilizer A

[0059] Compared with Example 1, the only difference is that in the preparation of stabilizer A in Comparative Example 1, wood chips are not added in step S1, so that it is not prepared into porous quicklime granules, but into conventional quicklime granules. The remaining steps are the same as in Example 1, as shown below.

[0060] S1: Mix 11kg bentonite and 32kg quicklime evenly to obtain a mixture. Add 20% of the mass of water to the mixture and mix evenly. Then granulate the mixture to obtain particles with a particle size of 5mm. Dry at 90℃ for 10h, then heat to 700℃ at a rate of 6℃ / min and keep at that temperature for 1.5h. Then cool naturally to room temperature to obtain quicklime particles.

[0061] S2~S4: Same as in Example 1.

[0062] Comparative Example 2: Preparation of Stabilizer A

[0063] Compared with Example 1, the only difference in Comparative Example 2 is that the original step S2 was omitted in the preparation of stabilizer A, i.e., soybean lecithin was not used to treat the porous quicklime particles. All other steps are the same as in Example 1, as detailed below:

[0064] S1: Same as in Example 1;

[0065] S2: Decanoic acid and lauric acid are mixed in a mass ratio of 7:3 to obtain a phase change material. After heating to 40°C and stirring to melt, 2.5 times the mass of expanded graphite of the phase change material is added. The mixture is stirred continuously at 200 r / min for 15 min to obtain an embedding agent. The embedding agent is sprayed onto the surface of porous quicklime particles and then transferred to a 4°C environment for overnight refrigeration. The spraying and refrigeration operations of the embedding agent are repeated twice. The specific amount of each spray is 4% of the mass of the inner layer particles to obtain secondary coated particles.

[0066] S3: Same as step S4 in Example 1.

[0067] Comparative Example 3: Preparation of Stabilizer A

[0068] Compared with Example 1, the only difference is that sodium sulfate was not added in step S4 when preparing stabilizer A in Comparative Example 3, while the other steps were the same as in Example 1.

[0069] Comparative Example 4: Preparation of Stabilizer A

[0070] Compared with Example 1, the only difference is that chitosan quaternary ammonium salt was not added in step S4 when preparing stabilizer A in Comparative Example 4, while the other steps were the same as in Example 1.

[0071] Comparative Example 5: Preparation of Stabilizer A

[0072] Compared with Example 1, the only difference is that in Comparative Example 5, the mass ratio of sodium alginate solution to sodium sulfate in step S4 during the preparation of stabilizer A is 1:0.1. All other steps are the same as in Example 1.

[0073] Example 5: Afforestation methods in high-altitude and cold regions

[0074] (1) Soil pretreatment: After removing weeds, tree roots and stones from the soil in mid-April, the soil was disinfected by spraying with 0.5wt% potassium permanganate solution to obtain pretreated soil;

[0075] (2) Transplanting seedlings: Dig planting holes with a diameter of about 45cm and a depth of about 45cm in the pretreated soil according to the standard of 2m spacing between plants and 3m spacing between rows. Then select two-year-old healthy native tree seedlings that are free from pests and diseases and have well-developed root systems. Dip the roots in ABT rooting powder and place them in the center of the planting hole, keeping the roots spread out. Then backfill the soil and tamp it down in layers. Finally, cover with a layer of loose soil and water thoroughly to settle the roots.

[0076] (3) Stabilizer application: In mid-November, dig inner and outer ring trenches along the transplanted seedlings. The inner ring trench is 40cm away from the trunk, about 9cm wide, and about 10-20cm deep. The outer ring trench is 60cm away from the trunk, about 20cm wide, and about 25cm deep. Then, mix stabilizer A with the soil and backfill it into the inner ring trench. Mix stabilizer B with the soil and backfill it into the outer ring trench. The amount of stabilizer A applied is 2kg / plant, and the amount of stabilizer B applied is 2kg / plant. After the stabilizer application is completed, cover the soil surface around the seedling roots with fallen leaves to help keep warm.

[0077] (4) Post-maintenance: In the later stage, watering, fertilization and other maintenance can be carried out in accordance with conventional methods.

[0078] Experiment 1: Test on the heat preservation effect of stabilizer

[0079] The heating and heat preservation effects of the stabilizers prepared in Example 1 and Comparative Examples 1-5 were experimentally tested. The specific experimental procedures are as follows:

[0080] Take a plastic box with dimensions of 60×60×50cm (length×width×height). Fill the box with soil containing 25% moisture content up to 5cm below the top edge. Then, using the center point as the center, dig an inner ring trench 8cm wide and 15cm deep 20cm away from the center. Mix stabilizer A evenly with the soil and backfill it into the inner ring trench. Dig an outer ring trench 15cm wide and 20cm deep 40cm away from the center. Mix stabilizer B evenly with the soil and backfill it into the outer ring trench. Then place it in an environment of -4℃. After 12 hours, measure the temperature of the soil at a depth of 10cm from the center point. After 20 days, measure the temperature of the soil at a depth of 10cm from the center point again.

[0081] The experiment was divided into 6 groups: experimental group 1 and control groups 1-5. Experimental group 1 was treated with stabilizer A prepared by the method of Example 1 and stabilizer B prepared by the method of Example 4. Control groups 1-5 were treated with stabilizer A prepared by the methods of comparative examples 1-5 and stabilizer B prepared by the method of Example 4, respectively. The amount of stabilizer A and stabilizer B applied in each group was 2 kg. Three replicate experiments were conducted, and the average temperature of each group is shown in Table 1.

[0082] Table 1

[0083]

[0084] Based on the data analysis in Table 1, we can conclude that:

[0085] (1) The soil temperature at the center of Experiment 1 reached 2.6℃ in 12 hours, indicating that the stabilizer A prepared according to the present invention can start its warming effect in time; the soil temperature at the center of Experiment 1 was 1.5℃ after 20 days, indicating that the combined effect of the stabilizers of the present invention can maintain the soil temperature higher than the ambient temperature for a longer period of time, which is beneficial to reduce the damage of low temperature in winter in high-altitude and cold regions to seedlings, so as to ensure the final afforestation survival rate.

[0086] (2) In control group 1, no sawdust was added during the preparation of porous quicklime particles for stabilizer A. As a result, when soybean lecithin was used for subsequent treatment, only a small amount was adsorbed on the surface of the particles. This led to the hydrolysis of the particles after water entered, resulting in a large amount of heat released and a significant increase in soil temperature. In control group 2, no soybean lecithin was used to treat the porous quicklime particles during the preparation of stabilizer A. As a result, excessive water entered the interior and hydrolyzed the quicklime, causing it to release a large amount of heat in the early stage. Consequently, the temperature-increasing and heat-preserving effect of the stabilizer was short-lived, and the difference between the soil temperature and the ambient temperature was very small on the 20th day. In control group 3, no sodium sulfate was added during the preparation of stabilizer A. As a result, the crystallization failed to precipitate in time to damage the phase change material film layer, and the activation of the stabilizer was limited. Only when the water crystallized in the gel under long-term low-temperature conditions damaged the film layer did the stabilizer activate its temperature-increasing effect.

[0087] (3) In control group 4, no chitosan quaternary ammonium salt was added when preparing stabilizer A. The outer gel structure was unstable, which led to limited water supply to stabilizer A. Later, the gel layer degraded and fell off, resulting in low internal water content and thus limited stabilizer effect. In control group 5, the sodium sulfate content was low when preparing stabilizer A. The crystallization performance was limited in the low temperature environment, resulting in low internal water content after 12 hours. The quicklime water decomposed less heat, resulting in poor soil temperature warming effect.

[0088] Experiment 2: Afforestation Experiment in High-Altitude and Cold Regions

[0089] 1. An afforestation experiment was conducted in the sandy land of Jixiong Town, Gongga County. The experiment was divided into 9 groups: experimental group 1, control group 1-7, and blank control group.

[0090] Experimental group 1 used stabilizer A from Example 1, stabilizer B from Example 4, and the afforestation method from Example 5;

[0091] Control groups 1-5 were treated with stabilizer A (comparative examples 1-5), stabilizer B (Example 4), and the afforestation method (Example 5), respectively.

[0092] Control group 6 used stabilizer A prepared in Example 1, and applied stabilizer B without digging an outer ring trench during afforestation. All other steps were carried out according to the method in Example 5.

[0093] Control group 7 used stabilizer B prepared in Example 1. Stabilizer A was applied without digging an inner ring trench during afforestation, and the remaining steps were carried out according to the method in Example 5.

[0094] The blank control group was not treated with stabilizers, and the remaining steps were the same as in Example 5.

[0095] Each group used healthy, disease-free, and well-developed 2-year-old Pinus tabuliformis seedlings with uniform growth. Ten seedlings were planted in each group. Stabilizer A was applied at a rate of 2 kg / seedling, and stabilizer B was applied at a rate of 2 kg / seedling. The application was carried out in mid-November. The survival rate of seedlings in each group was counted in February of the following year. Each group prepared stabilizers according to the methods of Example 1 and Comparative Examples 1-5 and conducted three replicate experiments. The average data are shown in Table 2.

[0096] Table 2

[0097]

[0098] Based on the data analysis in Table 2, we can conclude that:

[0099] (1) The survival rate of seedlings after wintering in experimental group 1 was 93.3%, while the survival rate of seedlings in the blank control group was only 50.0%, which was 43.3% lower than that in experimental group 1. This shows that afforestation according to the method of the present invention can effectively ensure that seedlings can successfully overwinter and improve the survival rate of afforestation in high-altitude and cold regions.

[0100] (2) Due to the lack of raw materials and changes in content, the effect of stabilizer A prepared in control groups 1-5 was reduced, resulting in varying degrees of decrease in survival rate. In control group 6, the survival rate of seedlings decreased significantly when stabilizer B was not applied during afforestation and the warming effect of stabilizer A was not used to assist in heat preservation. In control group 7, stabilizer A was not applied during afforestation, lacking the warming effect of stabilizer A. The effect of heat preservation stabilizer B alone was poor, and the survival rate of seedlings decreased significantly. This indicates that both stabilizer A and stabilizer B are crucial for ensuring the successful overwintering of seedlings and need to work together to achieve better results.

[0101] 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

Claims

1. A method for afforestation in high-altitude and cold regions, characterized in that, The method includes the following steps: (1) Soil pretreatment: After removing weeds, tree roots and stones from the soil in April and May, the soil was disinfected by spraying with 0.5wt% potassium permanganate solution to obtain pretreated soil; (2) Transplanting seedlings: Dig planting holes in the pretreated soil, select 2-3 year old native tree seedlings, dip the roots in rooting powder and place them vertically in the center of the planting hole while keeping the roots spread out. Then backfill the soil and tamp it down in layers. Finally, cover with a layer of loose soil and water thoroughly to settle the roots. (3) Stabilizer application: In November, dig a circular trench around the transplanted seedlings and apply stabilizer in the trench. After applying the stabilizer, cover the soil surface around the roots of the transplanted seedlings with fallen leaves or straw. (4) Post-maintenance: In the later stage, watering and fertilization can be carried out in accordance with conventional methods.

2. The method for afforestation in high-altitude and cold regions according to claim 1, characterized in that, In step (2), planting holes are dug according to the standard of 1.5-3m plant spacing and 2-4m row spacing; the diameter of the planting hole is 40-60cm and the depth is 40-50cm.

3. A method for afforestation in high-altitude and cold regions according to claim 2, characterized in that, In step (3), the stabilizer consists of stabilizer A and stabilizer B, and the stabilizer includes the following raw materials: Stabilizer A: Bentonite, quicklime, sawdust, soybean lecithin, expanded graphite, decanoic acid, lauric acid, sodium alginate, chitosan quaternary ammonium salt, sodium sulfate, calcium chloride; Stabilizer B: Diatomaceous earth, vermiculite.

4. A method for afforestation in high-altitude and cold regions according to claim 3, characterized in that, The particle size of the wood chips is 0.5 to 1 mm.

5. A method for afforestation in high-altitude and cold regions according to claim 4, characterized in that, The stabilizer is prepared as follows: Stabilizer A: S1: Mix bentonite, quicklime and sawdust evenly to obtain a mixture. Add 15-25% water by mass to the mixture and mix evenly. Then granulate to obtain particles with a particle size of 4-6 mm. Dry at 80-100℃ for 6-12 h, then heat to 600-800℃ at a rate of 5-10℃ / min and keep at that temperature for 0.5-2 h. Then cool naturally to room temperature to obtain porous quicklime particles. S2: Add soybean lecithin to 20 times its weight of anhydrous ethanol and stir to dissolve to form a suspension. Then add porous quicklime particles, vacuum to -0.08 to -0.09 MPa and maintain for 20 to 30 minutes. Then soak under normal pressure for 1 to 2 hours, filter to remove the filtrate, and dry at 60℃ for 2 to 6 hours to obtain inner layer particles. S3: Mix decanoic acid and lauric acid in a mass ratio of 7:3 to obtain a phase change material. Heat the mixture to 40°C and stir to melt it. Then add expanded graphite and stir continuously at a speed of 150-250 r / min for 10-20 min to obtain an embedding agent. Spray the embedding agent onto the surface of the inner layer particles and transfer it to a 4°C environment for overnight refrigeration. Repeat the embedding agent spraying and refrigeration operation twice to obtain secondary coated particles. S4: Dissolve sodium alginate in water to prepare a 2wt% sodium alginate solution, add sodium sulfate and chitosan quaternary ammonium salt and stir to dissolve to obtain a sodium alginate mixture, add secondary coated particles to the sodium alginate mixture and soak for 2-3 minutes, then transfer to a 3wt% calcium chloride solution to gel the sodium alginate on the surface, and then wash with water 2-3 times to obtain stabilizer A. Stabilizer B: Diatomaceous earth and vermiculite are mixed in a mass ratio of (2-3):1 and dried at 65°C to constant weight to obtain stabilizer B.

6. A method for afforestation in high-altitude and cold regions according to claim 5, characterized in that, In step S1, the mass ratio of bentonite, quicklime, and sawdust is (10-12):(30-35):(3-5).

7. A method for afforestation in high-altitude and cold regions according to claim 6, characterized in that, In step S3, the mass ratio of phase change material to expanded graphite is 1:(2-3).

8. A method for afforestation in high-altitude and cold regions according to claim 7, characterized in that, In step S3, the amount of embedding agent sprayed in a single application is 4 to 5% of the mass of the inner layer particles.

9. A method for afforestation in high-altitude and cold regions according to claim 8, characterized in that, In step S4, the mass ratio of sodium alginate solution, sodium sulfate, and chitosan quaternary ammonium salt is 1:(0.14-0.15):(0.01-0.02).

10. A method for afforestation in high-altitude and cold regions according to claim 1, characterized in that, The stable application method in step (3) is as follows: Dig inner and outer ring trenches around the transplanted seedling. The inner ring trench should be 30-50cm from the trunk, 8-10cm wide, and 10-20cm deep. The outer ring trench should be 60-80cm from the trunk, 15-25cm wide, and 20-30cm deep. Then, mix stabilizer A with the soil and backfill it into the inner ring trench. Mix stabilizer B with the soil and backfill it into the outer ring trench. The application rate of stabilizer A is 2-3kg / plant, and the application rate of stabilizer B is 2-3kg / plant.

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