A short-period cultivar of sargent-cypress afforestation seedling cultivation method

Abstract

The application provides a short-period Chinese tallow tree improved-species afforestation seedling cultivation method and belongs to the technical field of improved-species cultivation of forest trees. The application takes the branch with a diameter of 3.0-3.5 cm of a 2-3-year-old Chinese tallow tree improved-species mother tree as a cutting and carries out cutting disinfection, rooting, greenhouse container substrate cutting, precise temperature, humidity and light control in the rooting period, water and fertilizer coupling in the fast-growing period, main stem directional shaping and seedling hardening and transplanting to complete directional cultivation of the Chinese tallow tree improved-species hardwood cutting. The cutting survival rate of the cultivation method is greater than or equal to 95%, the improved-species seedling can be transplanted for afforestation after 1 year of cultivation, the seedling has a straight main stem and a strong growth with low-cost dry shape control without auxiliary branches, no butterfly orchid clamp and no staged pruning, the cultivation method can significantly shorten the seedling cultivation period, improve the afforestation survival rate and be suitable for large-scale afforestation of the Chinese tallow tree improved-species.

Description

Technical Field

[0001] This invention belongs to the field of forest tree breeding technology, and in particular relates to a method for cultivating short-cycle Chinese tallow tree seedlings for afforestation. Background Technology

[0002] Chinese tallow tree ( Triadica sebifera The Chinese tallow tree (Sapium sebiferum) is a unique, multifunctional native economic tree species, possessing diverse values ​​including ornamental value, oil production, ecological protection, and timber use. Its beautiful tree shape and rich seasonal changes make it an excellent landscape tree species for urban and rural landscaping. Its seeds are rich in oil, serving as an important raw material for biomass energy and industrial oils. Furthermore, the Chinese tallow tree exhibits strong resistance to adverse conditions, tolerance to waterlogging and salinity, making it a promising candidate for major forestry projects such as mine ecological restoration, coastal protection forest construction, and energy forest development. With the high-quality development of ecological construction and the forestry industry, the demand for improved varieties of Chinese tallow trees for afforestation continues to grow. The large-scale, standardized propagation of high-quality seedlings has become a key factor restricting the promotion and application of the Chinese tallow tree industry.

[0003] Currently, the propagation of improved varieties of Chinese tallow tree seedlings still relies mainly on traditional seedling cultivation techniques, including cutting propagation, grafting propagation, and open-field seedling production. Each technique has significant technical bottlenecks, making it difficult to meet the seedling supply demands of large-scale afforestation. Specifically, conventional cutting propagation often uses current-year branches as cuttings, which have low nutrient accumulation and weak rooting ability, generally resulting in low rooting rates and unstable survival rates, making it impossible to achieve stable mass production of improved seedlings. While grafting and softwood cutting propagation can effectively preserve the superior traits of the mother plant, the propagation process is cumbersome, production efficiency is low, and the seedling cultivation cycle is as long as 2-3 years, resulting in slow seedling growth and difficulty in quickly responding to the time-sensitive needs of concentrated afforestation projects. Furthermore, grafted seedlings are prone to problems such as poor graft union healing, skewed main stems, and bent branches, resulting in poor trunk quality, directly affecting the uniformity of the forest stand and the later growth potential of the trees after afforestation. In addition, the traditional open-field seedling cultivation model is significantly constrained by natural climate conditions, the growth rhythm of seedlings is uncontrollable, the annual growth is limited, and the cost of manual management is high, making it impossible to achieve factory-style, standardized mass seedling production.

[0004] Existing technologies for regulating the trunk shape of Chinese tallow tree seedlings primarily use seedlings grown from seed, employing physical methods such as pruning during the branching stage, removing auxiliary branches, and mechanical clamping for trunk shape correction. These techniques focus solely on morphological adjustments in the later stages of seedling growth, failing to deeply integrate with asexual propagation technologies and lacking a comprehensive system encompassing root promotion, rapid growth cultivation, and directional trunk shape development. In summary, current Chinese tallow tree seedling cultivation techniques cannot simultaneously achieve a high cutting survival rate, a short seedling cycle, and excellent trunk shape quality. They also struggle to balance the multiple production goals of preserving superior traits, rapid seedling production, and ensuring seedling quality, becoming a key technological bottleneck restricting the large-scale, standardized afforestation application of superior Chinese tallow tree varieties. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a short-cycle method for cultivating superior Chinese tallow tree seedlings for afforestation. This invention's core technological innovations include robust, thick-branch cuttings, controlled-speed seedling cultivation in greenhouse containers, and non-clamping, unsupported main stem directional cultivation. This achieves the goals of producing superior Chinese tallow tree seedlings within one year, ensuring straight and robust main stems, high-efficiency propagation, and low cost, providing technical support for the large-scale, standardized afforestation of superior Chinese tallow tree varieties.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for cultivating high-quality Chinese tallow tree seedlings for afforestation in a short-cycle manner, comprising the following steps: (1) Select branches with a diameter of 3.0-3.5 cm from the mother tree of the superior Chinese tallow tree, cut them to a length of 15-20 cm as cuttings, and disinfect the cuttings to promote root growth; (2) Add substrate soil to the container, insert the disinfected and root-promoting cuttings into the substrate soil, cultivate them in the greenhouse, control the temperature, humidity and shading rate, and manage water and fertilizer after rooting; (3) When the tallow tree seedlings are 10-20 cm tall, select one upright and strong main shoot, remove the basal suckers and competing branches, and remove buds throughout the later period; (4) When the height of the Chinese tallow tree seedlings is ≥1.8 m and the ground diameter is ≥1.5 cm, the seedlings are transplanted to complete the entire seedling cultivation cycle.

[0007] Furthermore, the superior Chinese tallow tree mentioned in step (1) is a healthy, disease-free Chinese tallow tree that is 2-3 years old, preferably 3 years old.

[0008] Furthermore, the diameter of the cuttings in step (1) is preferably 3.0 cm and the length is 15 cm.

[0009] Furthermore, in step (1), the upper and lower ends of the cutting are cut flat, and the terminal bud is 1.5-2.0 cm away from the upper end, with a smooth cut without splitting; At least two plump buds should be retained at the top of the cutting.

[0010] Further, the disinfection and root-promoting treatment in step (1) is as follows: the base 2-3 cm of the cutting is soaked in a compound microbial agent for 12-15 h, preferably 13 h; The compound microbial agent is a mixed solution of 50% carbendazim at 800 times dilution and indolebutyric acid at a concentration of 600 mg / L.

[0011] Furthermore, the greenhouse described in step (2) is equipped with a misting spray, automatic ventilation and shading system; The container is a biodegradable non-woven fabric container bag with a diameter of 15-20 cm and a height of 25-30 cm. It is breathable and retains water, which is beneficial for root growth and afforestation.

[0012] Further, the substrate soil mentioned in step (2) is peat, coconut coir, perlite, washed fermented cow manure, vermiculite and fermented rice husk in a volume ratio of 5:2:1:1:0.5:0.5.

[0013] Beneficial effects: This invention selects peat as one of the substrate soil raw materials, which has strong fertilizer and water retention capacity, can improve substrate porosity, and maintain stable physical and chemical properties; coconut coir has good air permeability, can retain water for a long time, improve substrate structure, and reduce compaction problems; perlite can significantly enhance the drainage and air permeability of the substrate, reduce bulk density, and prevent water accumulation and root rot; water-washed fermented cow manure is rich in organic matter and nutrients, slowly releases fertilizer, and improves the fertility structure of the substrate; vermiculite has the ability to absorb and store water and nutrients, and can also regulate the pH of the cultivation substrate, playing an acid-base buffering role; fermented rice husk can loosen the substrate, improve air permeability, slowly decompose and replenish organic matter, and optimize the substrate microenvironment. The components, when compounded in a volume ratio of 5:2:1:1:0.5:0.5, synergistically enhance each other's effects. This creates an optimal balance between water and fertilizer retention, aeration and drainage, slow nutrient release, and acid-base buffering. It maintains the loose and stable porous structure of the substrate, preventing waterlogging, root rot, and substrate compaction, while continuously and gently supplying organic nutrients and maintaining a stable rhizosphere pH environment. This creates an excellent rhizosphere microenvironment for efficient rooting of Chinese tallow tree cuttings and robust seedling growth.

[0014] Furthermore, in step (2), the cuttings need to be watered 2-3 times before planting to ensure that the substrate soil is fully saturated with water. The cutting depth is 3 / 4 of the total length of the cutting, the cutting time is in early to mid-April, the substrate soil is compacted, and no water is sprayed within 24 hours after the cutting is inserted.

[0015] Furthermore, the method for controlling temperature, humidity, and shading rate in step (2) is as follows: 1-30 days after cutting, the temperature inside the greenhouse is controlled at 28-32℃, the relative humidity is controlled at 85%-95%, and the shading rate is controlled at 70%-80%. After rooting, the relative humidity is reduced to 70%-75%, and the light intensity is increased to 50%-60%. One month after cutting is the critical rooting period. The cuttings of this invention are relatively thick, with thick bark, high lignification, difficult to heal, and slow to root. Therefore, it is necessary to strictly control the temperature, humidity, and shading rate inside the greenhouse to promote robust root system and rapid growth of the above-ground parts.

[0016] Furthermore, the fertilization management described in step (2) is as follows: spray 0.2%-0.3% high nitrogen water-soluble fertilizer every 10-15 days after rooting, and switch to nitrogen, phosphorus and potassium balanced fertilizer after the seedlings reach a height of 50-80 cm, and keep the substrate soil moist but not waterlogged.

[0017] Furthermore, after rooting, spray with 0.2%-0.3% high-nitrogen water-soluble fertilizer every 10-15 days. After the seedlings have rooted, they enter a rapid growth period. When the seedlings reach a height of 50-80 cm, switch to a balanced nitrogen, phosphorus, and potassium fertilizer. Control the moisture content of the substrate soil according to the stages: 65%-70% in June, 70%-75% in July, 65%-70% in August, and 55%-60% in September. Use drip irrigation and rinse with clean water before fertilizing to prevent salt accumulation. Use a fully water-soluble fertilizer with N:P2O5:K2O=10:8:12 and added calcium and magnesium. Apply 500 times every 7 days in June, 800 times every 4 days in July, 600 times every 5 days in August, and stop nitrogen and supplement with phosphorus and potassium in September. Three days after bud removal, control water and spray lightly to inhibit lower bud sprouting and ensure the straight growth of the main stem.

[0018] Further, step (3) is the main trunk orientation and shaping step. The low-cost trunk shaping cultivation technology of selecting the main shoot and removing buds throughout the process is adopted. The first shaping is carried out when the tallow tree seedlings are 10-20 cm tall: select one upright (upright angle ≤ 5°) and strong (upright is the first choice) main shoot as the main trunk for cultivation, remove the basal sprouts, inward branches and competing branches, and remove buds throughout the process in the later stage, without cutting the top, cutting short, or leaving auxiliary branches; carry out 3-4 fixed-point bud removals in mid-to-late June, mid-July and mid-to-early August. Each time, when the buds at the top of the main trunk sprout (length ≤ 5 cm) and are about to branch, select the buds with an upright angle ≤ 5° as the main trunk extension branches, completely remove the paired buds on the same side, and at the same time remove the lateral buds and sprouts that sprout within 1 m of the main trunk, suppress the formation of dichotomous branches throughout the process, and ensure the continuous straight growth of the main trunk.

[0019] Furthermore, the ventilation, light enhancement, and water control measures to harden the seedlings 15-20 days before leaving the nursery, as described in step (4), are as follows: during the lignification and acclimatization period from October to November, the greenhouse is gradually opened, with daytime temperatures of 15-22℃ and nighttime temperatures of 5-10℃, gradually increasing to full light, and the substrate soil moisture content is 50%-55%; during the stress resistance and hardening period from December to February of the following year, the daytime temperature is 5-15℃ and the nighttime temperature is -2~5℃, the substrate moisture content is 45%-50%, and root control is used to promote dense root balls; 15-20 days before leaving the nursery, the seedlings are fully exposed and adapted, with the substrate soil moisture content being 55%-60%, and the root balls and fibrous roots are dense and do not break apart.

[0020] Furthermore, the seedling cultivation period described in step (4) is 12 months (1 year).

[0021] The beneficial effects of this invention compared to the prior art are as follows: In response to the difficulty of rooting Chinese tallow trees, this invention uses robust 3-year-old branches with a diameter of 3 cm as cuttings. The cuttings have sufficient reserves of endogenous nutrients and rooting substances. Combined with the disinfection and root-promoting treatment of the cuttings and a special composite substrate, this invention effectively breaks through the bottleneck of Chinese tallow tree cutting rooting. The survival rate of cuttings is ≥95%, which is far higher than the level of conventional current-year branch cuttings. This invention enables the stable mass propagation of high-quality Chinese tallow tree clonal seedlings.

[0022] This invention adopts a greenhouse container-based controlled-speed seedling cultivation mode. Through precise control of temperature, humidity, and light during the rooting period and coupled management of water and fertilizer during the rapid growth period, it creates an optimal growth environment for seedlings, breaks the limitations of natural climate on growth rhythm, and significantly improves the growth rate of seedlings. They can reach the standard for afforestation in just one year, which shortens the cycle by 1-2 years compared to traditional open-field seedling cultivation and grafting seedling cultivation. It can quickly respond to the concentrated seedling supply needs of large-scale afforestation projects.

[0023] This invention is equipped with a trunk-oriented cultivation technology, which can guide the trunk of seedlings to grow straight, effectively avoiding problems such as trunk bending, slant, and disordered branching. The qualified rate of seedling trunk shape is ≥90%, which solves the technical defects of poor interface healing and irregular trunk shape in traditional grafting seedling cultivation. The seedlings produced are uniform in size, which can significantly improve the uniformity of forest appearance and the later growth potential of trees after afforestation.

[0024] The technical process of this invention is simple to operate, and the container seedling cultivation mode facilitates standardized and factory-style management, which can significantly reduce field labor costs and production risks caused by natural climate. It has high propagation efficiency and low overall cost, making it suitable for large-scale, standardized propagation and promotion of improved varieties of Chinese tallow tree seedlings. Moreover, the container seedlings cultivated by this invention have complete root systems, vigorous growth, short recovery period after planting, and a survival rate of ≥98%. The seedlings exhibit stable growth in the later stages, which can effectively ensure the construction effectiveness of various afforestation projects such as landscaping, ecological restoration, energy forests, and coastal protection forests. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the container cutting propagation layout in Embodiment 1 of the present invention; Figure 2 This is a root feature diagram of the superior Chinese tallow tree cuttings when the entire cultivation cycle of Embodiment 1 of the present invention is completed; Figure 3 This is a diagram showing the growth morphology of the cuttings of the superior variety of Chinese tallow tree during the entire cultivation cycle of Embodiment 1 of the present invention. Figure 4 This is a line graph showing the annual growth of *Sapium sebiferum* cuttings treated with 600 mg / L indolebutyric acid and 600 mg / L naphthaleneacetic acid in this invention. Detailed Implementation

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0030] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0031] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0032] Example 1 A method for cultivating high-quality Chinese tallow tree seedlings for afforestation with a short cycle includes the following steps: (1) Preparation of cuttings: Select 3-year-old, healthy, disease-free Chinese tallow tree 'Seaside Scarlet' branches with a diameter of 3.0 cm, cut to a length of 15 cm as cuttings, make flat cuts at both the top and bottom, retain 2 plump buds, and the terminal bud is 1.5-2 cm away from the top cut.

[0033] (2) Disinfection and root promotion: Soak the base 2-3 cm of the above cuttings in a compound microbial agent for 13 h. The compound microbial agent is a mixed solution of 50% carbendazim at 800 times dilution and indolebutyric acid at a concentration of 600 mg / L.

[0034] (3) Greenhouse container propagation: Cuttings are propagated in an intelligent temperature-controlled greenhouse equipped with shading, misting, and automatic ventilation systems. Biodegradable non-woven fabric containers with a diameter of 15 cm and a height of 25 cm are used. A substrate soil is prepared by mixing peat, coconut coir, perlite, washed fermented cow manure, vermiculite, and fermented rice husks in a volume ratio of 5:2:1:1:0.5:0.5. This mixture is placed in the biodegradable non-woven fabric containers. The substrate soil is saturated with water twice before cuttings are inserted. The disinfected and root-promoting cuttings are then inserted into the substrate soil in early to mid-April, to a depth of 3 / 4 of the total length of the cutting. No water is sprayed within 24 hours after insertion. A schematic diagram of the container propagation layout is shown below. Figure 1 As shown.

[0035] (4) Seedling management: 1-30 days after cutting, the temperature in the greenhouse is controlled at 28-32℃, the relative humidity is controlled at 85%-95%, and the shading rate is controlled at 75%. After rooting, the relative humidity is reduced to 70%-75%, and the light is increased to 50%-60%.

[0036] (5) Water and fertilizer management: Spray 0.3% high nitrogen water-soluble fertilizer every 10 days after rooting. After the seedlings have rooted, they enter a rapid growth period. After the seedlings reach a height of 80 cm, switch to nitrogen, phosphorus and potassium balanced fertilizer. Control the moisture content of the substrate soil according to the stages: 65%-70% in June, 70%-75% in July, 65%-70% in August, and 55%-60% in September. Use drip irrigation and rinse with clean water before fertilization to prevent salt accumulation. Use N:P2O5:K2O=10:8:12 fully water-soluble fertilizer with added calcium and magnesium. Apply 500 times every 7 days in June, 800 times every 4 days in July, 600 times every 5 days in August, and stop nitrogen and supplement phosphorus and potassium in September. Control water and spray lightly 3 days after bud removal to inhibit the sprouting of lower buds and ensure the straight growth of the main stem.

[0037] (6) Main stem orientation and shaping: When the Chinese tallow tree seedlings are 10-20 cm tall, the first shaping is carried out: select one upright (upright angle ≤ 5°) and strong (upright is the first choice) main shoot as the main stem for cultivation, and remove the basal suckers, inward branches and competing branches; carry out 3-4 fixed-point bud removal in mid-to-late June, mid-July and mid-to-early August. Each time, when the buds at the top of the main stem are about to sprout (length ≤ 5cm) and are about to branch, select the buds with an upright angle ≤ 5° as the main stem extension branches, completely remove the paired buds on the same side, and at the same time remove the lateral buds and suckers sprouting within 1m of the main stem, suppress the formation of dichotomous branches throughout the process, and ensure the continuous straight growth of the main stem.

[0038] (7) Seedling hardening and transplanting: From October to November, during the lignification and acclimatization period, the greenhouse is gradually opened, with daytime temperatures of 15-22℃ and nighttime temperatures of 5-10℃, gradually increasing to full light, and the substrate soil moisture content is 50%-55%; from December to February of the following year, during the stress resistance and hardening period, with daytime temperatures of 5-15℃ and nighttime temperatures of -2~5℃, and the substrate moisture content is 45%-50%, controlling root growth and promoting dense root balls; 18 days before transplanting, the seedlings are fully exposed to the open environment, with the substrate soil moisture content at 55%-60%, and the root balls are dense and do not break apart. When the height of the Chinese tallow tree seedlings is 1.8 m, the ground diameter is 1.5 cm, and the main stem is straight, they can be transplanted for afforestation. The survival rate of afforestation is ≥98%. The root characteristics of the cuttings of the superior Chinese tallow tree variety after completing the entire cultivation cycle of 12 months are as follows: Figure 2 As shown, the growth morphology is as follows Figure 3 As shown.

[0039] Example 2 A method for cultivating high-quality Chinese tallow tree seedlings for afforestation with a short cycle includes the following steps: (1) Preparation of cuttings: Select 3-year-old, healthy, disease-free Chinese tallow tree 'Seaside Evening Glow' branches with a diameter of 3.2cm and cut them to a length of 18cm as cuttings. Make flat cuts at both the top and bottom, retaining 2 plump buds, with the terminal bud 1.5-2cm away from the top.

[0040] (2) Disinfection and root promotion: Soak the base 2-3 cm of the above cuttings in a compound microbial agent for 13 h. The compound microbial agent is a mixed solution of 50% carbendazim at 800 times dilution and indolebutyric acid at a concentration of 600 mg / L.

[0041] (3) Greenhouse container cuttings: Cuttings are propagated in an intelligent temperature-controlled greenhouse equipped with shading, misting, and automatic ventilation systems. Biodegradable non-woven fabric container bags with a diameter of 20 cm and a height of 25 cm are selected. Peat, coconut coir, perlite, water-washed fermented cow manure, vermiculite, and fermented rice husks are mixed in a volume ratio of 5:2:1:1:0.5:0.5 to prepare substrate soil. The substrate soil is placed in the biodegradable non-woven fabric container bags. Before cuttings are inserted, the substrate soil is irrigated three times to fully saturate the substrate soil. Then, the cuttings that have been disinfected and root-promoting are inserted into the substrate soil in mid-April. The insertion depth is 3 / 4 of the total length of the cuttings. No water is sprayed within 24 hours after cuttings are inserted.

[0042] (4) Seedling management: 1-30 days after cutting, the temperature in the greenhouse is controlled at 28-30℃, the relative humidity is controlled at 85%-95%, and the shading rate is controlled at 75%. After rooting, the relative humidity is reduced to 70%-75%, and the light is increased to 50%-60%.

[0043] (5) Water and fertilizer management: Spray 0.22% high nitrogen water-soluble fertilizer every 14 days after rooting. After the seedlings have rooted, they enter a rapid growth period. After the seedlings reach a height of 65 cm, switch to nitrogen, phosphorus and potassium balanced fertilizer. Control the moisture content of the substrate soil according to the stages: 65%-70% in June, 70%-75% in July, 65%-70% in August, and 55%-60% in September. Use drip irrigation and rinse with clean water before fertilization to prevent salt accumulation. Use N:P2O5:K2O=10:8:12 fully water-soluble fertilizer with added calcium and magnesium. Apply 500 times every 7 days in June, 800 times every 4 days in July, 600 times every 5 days in August, and stop nitrogen and supplement phosphorus and potassium in September. Control water and spray lightly 3 days after bud removal to inhibit the sprouting of lower buds and ensure the straight growth of the main stem.

[0044] (6) Main stem orientation and shaping: When the Chinese tallow tree seedlings are 15-20 cm tall, the first shaping is carried out: select one upright (upright angle ≤ 5°) and strong (upright is the first choice) main shoot as the main stem for cultivation, and remove the basal suckers, inward branches and competing branches; carry out 3-4 fixed-point bud removal in mid-to-late June, mid-July and mid-to-early August. Each time, when the buds at the top of the main stem are about to sprout (length ≤ 5 cm) and are about to branch, select the buds with an upright angle ≤ 5° as the main stem extension branches, completely remove the paired buds on the same side, and at the same time remove the lateral buds and suckers sprouting within 1m of the main stem, suppress the formation of dichotomous branches throughout the process, and ensure the continuous straight growth of the main stem.

[0045] (7) Hardening off seedlings: During the lignification and acclimatization period from October to November, the greenhouse is gradually opened, with daytime temperature of 15-22℃ and nighttime temperature of 5-10℃, and gradually full light. The substrate soil moisture content is 50%-55%. During the hardening and stress resistance period from December to February of the following year, the daytime temperature is 5-15℃ and the nighttime temperature is -2~5℃. The substrate moisture content is 45%-50%. Root control promotes dense root balls. 16 days before leaving the nursery, the seedlings are fully exposed for adaptation. The substrate soil moisture content is 55%-60%. The root balls and fibrous roots are dense and do not break apart. When the height of the Chinese tallow tree seedlings is 1.7 m, the ground diameter is 1.3 cm, and the main stem is straight, they can be left for afforestation. The survival rate of afforestation is ≥98%.

[0046] Comparative Example 1 A method for cultivating superior Chinese tallow tree seedlings for afforestation differs from Example 1 in that: one-year-old, robust, and disease- and pest-free branches of the superior Chinese tallow tree variety 'Seaside Scarlet' are selected; The remaining preparation methods are the same as in Example 1.

[0047] Comparative Example 2 A method for cultivating superior Sapium sebiferum seedlings for afforestation (grafting propagation) differs from Example 1 in that: the scion is a healthy, disease-free, one-year-old branch of the superior Sapium sebiferum variety 'Seaside Scarlet' with a diameter of 0.8-1.5cm, the rootstock has a diameter of 2-3cm, the grafting is done by cleft grafting, and the management is done by conventional management methods.

[0048] Comparative Example 3 A method for cultivating superior Chinese tallow tree seedlings for afforestation differs from Example 1 in that: 3-year-old, robust, and disease-free branches of the superior Chinese tallow tree variety 'Seaside Scarlet' with a diameter of 4.5cm are selected; The remaining preparation methods are the same as in Example 1.

[0049] Comparative Example 4 A method for cultivating superior Sapium sebiferum seedlings for afforestation differs from Example 1 in that the volume ratio of peat, coconut coir, perlite, water-washed fermented cow manure, vermiculite, and fermented rice husks is 5.2∶2∶1∶1∶0.3∶0.5. The remaining preparation methods are the same as in Example 1.

[0050] The cutting survival rate, seedling cycle, and dryness qualification rate (upright angle ≤ 5°) of the cultivation methods of Examples 1-2 and Comparative Examples 1-4 were statistically analyzed, and the results are shown in Table 1.

[0051] Table 1. Statistics on survival rate, seedling cycle and qualified stem shape of Chinese tallow tree under different seedling raising methods.

[0052] Comparative Example 5 A method for cultivating superior Sapium sebiferum seedlings for afforestation differs from Example 1 in that the concentration of indolebutyric acid is 200 mg / L. The remaining preparation methods are the same as in Example 1.

[0053] Comparative Example 6 A method for cultivating superior Sapium sebiferum seedlings for afforestation, which differs from Example 1 in that the concentration of indolebutyric acid is 400 mg / L; The remaining preparation methods are the same as in Example 1.

[0054] Comparative Example 7 A method for cultivating superior Sapium sebiferum seedlings for afforestation, which differs from Example 1 in that the concentration of indolebutyric acid is 800 mg / L; The remaining preparation methods are the same as in Example 1.

[0055] Comparative Example 8 A method for cultivating superior Sapium sebiferum seedlings for afforestation differs from Example 1 in that: indolebutyric acid at a concentration of 600 mg / L is replaced with naphthaleneacetic acid at a concentration of 200 mg / L; The remaining preparation methods are the same as in Example 1.

[0056] Comparative Example 9 A method for cultivating superior Sapium sebiferum seedlings for afforestation differs from Example 1 in that: 600 mg / L indolebutyric acid is replaced with 400 mg / L naphthaleneacetic acid; The remaining preparation methods are the same as in Example 1.

[0057] Comparative Example 10 A method for cultivating superior Sapium sebiferum seedlings for afforestation differs from Example 1 in that: 600 mg / L indolebutyric acid is replaced with 600 mg / L naphthaleneacetic acid; The remaining preparation methods are the same as in Example 1.

[0058] Comparative Example 11 A method for cultivating superior Sapium sebiferum seedlings for afforestation differs from Example 1 in that: 600 mg / L indolebutyric acid is replaced with 800 mg / L naphthaleneacetic acid; The remaining preparation methods are the same as in Example 1.

[0059] The survival rate of cuttings propagated using the cultivation methods of Example 2 and Comparative Examples 5-11 was statistically analyzed. A control group was set up using water, where indolebutyric acid was replaced with water. Each treatment was replicated four times, with 10 cuttings per replicate, for a total of 360 cuttings. The results are shown in Table 2. Line graphs of annual growth of *Sapium sebiferum* cuttings under treatments of 600 mg / L indolebutyric acid and 600 mg / L naphthaleneacetic acid are shown below. Figure 4 As shown.

[0060] Table 2. Statistical analysis of the survival rate of superior varieties of Sapium sebiferum propagated by cuttings under different hormone types and concentrations.

[0061] As shown in Table 2, the highest survival rate of cuttings of the superior variety of Chinese tallow tree was 97.5% when the hormone type was indolebutyric acid and the concentration was 600 mg / L.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for cultivating high-quality Chinese tallow tree seedlings for afforestation using a short-cycle cultivation process, characterized in that, Includes the following steps: (1) Select branches with a diameter of 3.0-3.5 cm from the mother tree of the superior Chinese tallow tree, cut them to a length of 15-20 cm as cuttings, and disinfect the cuttings to promote root growth; (2) Add substrate soil to the container, insert the disinfected and root-promoting cuttings into the substrate soil, cultivate them in the greenhouse, control the temperature, humidity and shading rate, and manage water and fertilizer after rooting; (3) When the tallow tree seedlings are 10-20 cm tall, select one upright and strong main shoot, remove the basal suckers and competing branches, and remove buds throughout the later period; (4) When the height of the Chinese tallow tree seedlings is ≥1.8 m and the ground diameter is ≥1.5 cm, the seedlings are transplanted to complete the entire seedling cultivation cycle.

2. The method for cultivating short-cycle, high-quality *Sapium sebiferum* seedlings for afforestation according to claim 1, characterized in that, The superior Chinese tallow tree mother trees mentioned in step (1) are healthy, disease-free, and 2-3 year old Chinese tallow tree mother trees; The cuttings are cut flat at both ends, with the terminal bud 1.5-2.0 cm from the top.

3. The method for cultivating short-cycle, high-quality *Sapium sebiferum* seedlings for afforestation according to claim 1, characterized in that, The disinfection and root-promoting treatment in step (1) is as follows: the base 2-3 cm of the cuttings is soaked in a compound microbial agent for 12-15 h; The compound microbial agent is a mixed solution of 50% carbendazim at 800 times dilution and indolebutyric acid at a concentration of 600 mg / L.

4. The method for cultivating short-cycle, high-quality *Sapium sebiferum* seedlings for afforestation according to claim 1, characterized in that, The container mentioned in step (2) is a biodegradable nonwoven bag with a diameter of 15-20 cm and a height of 25-30 cm.

5. The method for cultivating short-cycle, high-quality *Sapium sebiferum* seedlings for afforestation according to claim 1, characterized in that, The substrate soil mentioned in step (2) is peat, coconut coir, perlite, washed fermented cow manure, vermiculite and fermented rice husks in a volume ratio of 5:2:1:1:0.5:0.

5.

6. The method for cultivating short-cycle, high-quality *Sapium sebiferum* seedlings for afforestation according to claim 1, characterized in that, The depth of the cutting in step (2) is 3 / 4 of the total length of the cutting.

7. The method for cultivating short-cycle, high-quality *Sapium sebiferum* seedlings for afforestation according to claim 1, characterized in that, The control methods for temperature, humidity and shading rate in step (2) are as follows: 1-30 days after cutting, the temperature in the greenhouse is controlled at 28-32℃, the relative humidity is controlled at 85%-95%, and the shading rate is controlled at 70%-80%. After rooting, the relative humidity is reduced to 70%-75%, and the light is increased to 50%-60%.

8. The method for cultivating short-cycle, high-quality *Sapium sebiferum* seedlings for afforestation according to claim 1, characterized in that, The water and fertilizer management in step (2) is as follows: spray 0.2%-0.3% high nitrogen water-soluble fertilizer every 10-15 days after rooting. After the seedlings reach a height of 50-80 cm, switch to nitrogen, phosphorus and potassium balanced fertilizer and keep the substrate soil moist but not waterlogged.

9. The method for cultivating short-cycle, high-quality *Sapium sebiferum* seedlings for afforestation according to claim 1, characterized in that, In step (4), the seedlings are hardened off by ventilation, increased light and controlled watering 15-20 days before leaving the nursery.

10. The method for cultivating short-cycle, high-quality *Sapium sebiferum* seedlings for afforestation according to claim 1, characterized in that, The seedling period described in step (4) is 12 months.

Images