Large-trunk-diameter fruit tree bark grafting method using polystyrene foam for sealing and fixing

Abstract

The invention relates to a large-trunk-diameter fruit tree bark grafting method for sealing and fixing by using polystyrene foam, which comprises the following steps: wrapping a thin plastic film on the cross section of a trunk of a stock to effectively isolate external air and moisture, prevent invasion of germs and reduce water loss; the plastic film can effectively prevent polystyrene foam in later construction from invading a grafting interface, and the problem that interface healing is blocked due to pollution is solved. After the scion is inserted through the marked grafting point, the grafting position of the scion and the stock is fixed through polystyrene foam, a stable protection layer is formed after the polystyrene foam is cured, the joint healing quality is effectively improved, and meanwhile the scion fixing strength is enhanced. The protective layer has good heat preservation and moisture preservation performance, and cambium cell division and healing tissue generation are promoted. After the polystyrene foam is completely cured, the outside is wound and wrapped by a shading film, so that ultraviolet degradation is avoided, and water evaporation is reduced. The whole grafting structure is stable, resistant to wind and rain erosion and suitable for efficient standardized operation of large-scale orchards, and the technical threshold and the labor cost are remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fruit tree grafting, and particularly relates to a grafting method for grafting scion on a fruit tree with a trunk diameter of more than 10 cm. BACKGROUND

[0002] When the variety of a mature orchard is updated, the original stock is usually retained, and a new variety scion is grafted at the cut surface of the stock. The developed root system of the original stock can significantly promote the rapid growth of the new variety scion, so that it can enter the fruiting period in advance. This method effectively shortens the non-income period caused by variety updating, and helps to improve the economic benefits of fruit farmers.

[0003] Currently, when grafting a fruit tree with a thick trunk (diameter greater than 10 cm), the grafting method of grafting scion is usually used. First, cut (saw) the stock at the height where grafting is needed. On one side of the cut surface of the stock, select a smooth position on the bark and vertically cut a knife with a length of about 2-3 cm, cutting through the bark and reaching the wood. The upper part of the scion is retained with 2-3 buds, and the lower part of the scion is obliquely cut with a long cut surface about 3-5 cm long. At the end of the back of the long cut surface, a short oblique surface about 0.5 cm long is cut, so that the lower end of the scion is wedge-shaped, facilitating insertion. Use the tip of the grafting knife to pry the bark at the pre-cut vertical cut of the stock, so that the bark is separated from the wood, forming a "pocket". The long cut surface of the scion is directed inward (toward the wood of the stock), and the tip is aligned with the prying bark pocket. Slowly and smoothly insert the scion between the bark and the wood along the wood of the stock. Loosen the tip, and let the bark of the stock naturally wrap around the scion. Wrap the plastic grafting film with a certain elasticity from the lower part of the joint to the upper part to ensure that the scion and the stock are in close contact and cannot be loosened, and at the same time, the cut surface of the stock and the cut surface of the scion are wrapped tightly to prevent water evaporation, rainwater from entering, and pathogenic bacteria from invading, thereby improving the survival rate of grafting, as shown in Figure 1 .

[0004] However, when the trunk diameter is thick, in order to improve the survival rate of grafting and promote the rapid shaping of the grafted fruit tree, multiple stocks need to be grafted at different positions of the trunk section. This makes the plastic banding difficult to wrap, and it is difficult to ensure uniform stress on the joint, which can cause the scion to deform due to loosening or over-tightening. The existing technology has defects such as complex operation, long time-consuming, high dependence on experience of technical personnel, and certain problems in large-scale application. SUMMARY

[0005] The present application aims to solve the problems of loose scion binding, time-consuming and labor-intensive, and low operation efficiency in the grafting process of thick stock grafting, and provides a grafting method suitable for fruit trees with a trunk diameter of more than 10 cm. The method of the present application significantly improves the survival rate of grafting and the operation efficiency, and is particularly suitable for large-scale orchard transformation of thick stock.

[0006] A method for bark grafting of large-diameter fruit trees using expanding foam for sealing and fixing includes the following steps:

[0007] (1) Rootstock selection and treatment: Select fruit trees with a trunk diameter of more than 10cm as rootstocks, cut the trunks, remove burrs from the cut surfaces in time, and disinfect with fungicide; mark one or more grafting points around the rootstock cut surface according to the number of grafts, and make a vertical cut on the bark at the edge of the rootstock cut surface with the marked point as the center. The length of the cut should be controlled at 2-3 cm and the depth should reach the xylem. Gently pry open the bark along the cut to form an evenly distributed insertion channel; wrap the rootstock cut surface with a thin plastic film, and fix the lower edge to the outside of the trunk with rubber bands or glue to cover the entire cut surface and the cut; make small holes in the plastic film at each cut surface in advance to correspond to the grafting points so that the scion can be inserted.

[0008] (2) Scion preparation and grafting: Select one-year-old branches as scions, retain 2-3 complete buds at the top, make a long cut at the bottom of the scion, and make a short cut at the back end of the long cut to make the bottom of the scion wedge-shaped; insert the prepared scion into the corresponding cut through the small hole of the plastic film along the marked point, so that the long cut of the scion is close to the xylem of the rootstock and the cambium is aligned. After insertion, gently press the top of the scion to ensure that it is stable and does not loosen.

[0009] (3) Scion fixing and sealing: Spray expanding foam around the joint of the rootstock and scion. The plastic film should completely wrap around and adhere to the main trunk downwards; the cut surface of the scion should be covered upwards and extend 1-2 cm beyond the top of the cut surface to form a complete sealing layer, ensuring that no cut of the rootstock or scion is exposed.

[0010] In step (1), the rootstock should be a fruit tree of moderate age, vigorous growth, and free from pests and diseases.

[0011] The period for the trunk cutting treatment in step (1) is the spring when the sap begins to flow but before the buds sprout.

[0012] In step (2), one-year-old branches with full growth and plump buds are selected as scions.

[0013] In step (2), the length of the long sliced ​​surface is 3-5cm, and the length of the short sliced ​​surface is 0.5cm.

[0014] In step (2), the spray should be applied 2-20cm below the lowest point of the main trunk cut of the fruit tree.

[0015] The thin plastic film is a colorless and transparent plastic film.

[0016] The thickness of the thin plastic film is 0.08–0.12 mm.

[0017] In step (3), after the foaming adhesive has fully cured, a light-shielding film is tightly wrapped around the outside as a protective outer covering.

[0018] The method also includes step (4) post-treatment: after the scion sprouts, when the new shoots grow to 20-40cm, support poles are set up in time to prevent wind breakage.

[0019] The bark grafting method of this invention involves wrapping a thin plastic film around the cross-section of the main stem before grafting. This effectively isolates the graft from external air and moisture, preventing pathogen invasion and reducing water loss. The grafting point is marked to determine the grafting position of the scion. After the scion is inserted into the grafting point, expanding foam is used to fix the grafting position between the scion and rootstock. Once the expanding foam has cured, it forms a stable protective layer, effectively improving the quality of interface healing and enhancing the fixation strength of the scion. This protective layer has good heat and moisture retention properties, promoting cambium cell division and callus tissue formation. After the expanding foam has completely cured, a light-shielding film is wrapped around the outside to prevent ultraviolet degradation and reduce moisture evaporation. The entire grafting structure is stable, resistant to wind and rain erosion, and suitable for efficient and standardized operations in large-scale orchards, significantly reducing technical barriers and labor costs.

[0020] The main function of covering the canopy section with plastic film is to prevent expanding foam from seeping into the junction of the rootstock and scion during spraying, causing interface contamination or hindering callus formation. It also effectively isolates external impurities and pathogens, reducing the risk of infection. The plastic film forms a physical barrier, maintaining the stability of the interface microenvironment and preventing expanding foam from directly contacting the cambium and causing cell necrosis. Its smooth surface reduces adhesive adhesion resistance, facilitating natural lysis and detachment later, avoiding secondary damage caused by human intervention. This design reflects a precise balance between plant physiological response and material properties, ensuring a continuous and efficient healing process. While ensuring structural strength, it also reserves sufficient space for tissue regeneration, representing a key aspect of integrating engineering thinking with biological principles. The selection of the plastic film must consider both flexibility and sealing performance; a thickness of 0.08–0.12 mm is ideal. Too thin a film provides insufficient protection, while too thick a film affects adhesion.

[0021] This invention utilizes a pre-perforated plastic film design to achieve precise scion insertion and comprehensive protection of the graft union, effectively preventing the seepage of expanding foam into the graft union, thus avoiding contamination or hindering callus formation, and preventing moisture loss and bacterial infection. The expanding foam sealing technology combines fixation, heat preservation, and moisture retention, promoting rapid cambium healing without the need for subsequent manual removal, significantly reducing maintenance costs. The light-shielding film delays UV degradation, enhancing structural durability. The entire process is simple to operate, highly standardized, and requires minimal personnel skills, making it suitable for widespread application. Furthermore, the materials are inexpensive and environmentally adaptable, maintaining stable performance under various climatic conditions, providing an efficient and reliable modern grafting solution for fruit tree variety renewal. This technology is also compatible with the grafting needs of various fruit tree varieties, possessing broad applicability and promotional value. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the existing method for grafting bark onto large-diameter fruit trees.

[0023] 1 is the scion (with a long cut on one side and a short cut on the other), 2 is the rootstock (with a cut), 3 is the scion inserted into the rootstock cut, and 4 is the grafted seedling wrapped in plastic film.

[0024] Figure 2 This is a schematic diagram of the method described in this application.

[0025] 1 is the scion (with a long cut on one side and a short cut on the other), 2 is the rootstock (with two cuts), 3 is the rootstock trunk cut wrapped with plastic film, 4 is the scion inserted into the rootstock cut through the plastic film, 5 is the area around the junction of the rootstock and scion sprayed with expanding foam, 11 is the plastic film, and 22 is the expanding foam. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the embodiments.

[0027] Example 1

[0028] Rootstock Selection and Treatment: Select fruit trees of moderate age, vigorous growth, and free from pests and diseases as rootstocks. Retain 20-30cm of trunk length above the grafting point and perform trunk pruning in spring when sap begins to flow but before bud break. The cut should be smooth and even, avoiding tearing the bark. Remove any burrs from the cut surface promptly and disinfect with a fungicide to prevent moisture loss and infection. Mark multiple grafting points around the rootstock cut surface according to the number of grafts to be performed. Using the marked points as the center, make vertical cuts along the edge of the rootstock cut surface, with a cut length of 2-3 cm, making two cuts in total, reaching the xylem. Gently pry open the bark along the cuts to create evenly distributed insertion channels. Select a thin plastic sheet with sufficient strength from the rootstock cut surface and secure the edges with rubber bands or glue to cover the entire cut surface. Pre-drill small holes in the plastic sheet at each cut surface corresponding to the grafting point for scion insertion.

[0029] Scion preparation: Select well-developed one-year-old branches with plump buds as scions, retaining 2-3 intact buds at the top. Make a long oblique cut about 3-5 cm long on the lower part of the scion. On the back end of the long cut, make a short oblique cut about 0.5 cm long, so that the lower end of the scion is wedge-shaped. Insert the prepared scion into the corresponding cut through the small holes of the plastic film along the marked points, so that the long cut surface of the scion is in close contact with the xylem of the rootstock and the cambium is aligned. After insertion, gently press the top of the scion to ensure that it is stable and does not loosen.

[0030] Scion Fixation and Sealing: Apply expanding foam (foam adhesive) to the area around the graft union between the rootstock and scion. Spray below the cut surface of the tree (2-20cm), ensuring the plastic film covering the trunk is completely and tightly wrapped with the foam. Spray above the cut surface of the scion (1-2cm), ensuring the gap between the scion and rootstock is completely sealed with foam, effectively isolating them from external air and moisture, preventing pathogen invasion, and reducing water loss. After curing, the foam forms a stable protective layer, effectively improving the quality of graft union healing and enhancing scion fixation strength. This protective layer has good heat and moisture retention properties, promoting cambium cell division and callus tissue formation.

[0031] After the expanding foam has fully cured, it can be wrapped with a light-blocking film to prevent UV degradation and reduce moisture evaporation. The entire grafting structure is stable, resistant to wind and rain erosion, and suitable for efficient and standardized operations in large-scale orchards, significantly reducing technical barriers and labor costs. The light-blocking film is also optional.

[0032] Post-grafting care: After the scion sprouts, support poles should be erected promptly when the new shoots reach 30cm to prevent wind damage. As the new shoots elongate, the stability of the protective layer should be checked regularly to prevent cracking of the adhesive layer due to tree expansion. Once the graft union is fully healed and the new shoots are highly lignified, the outer shading film and inner plastic film should be gradually removed. The foamed adhesive layer will gradually decompose naturally without manual removal, reducing later maintenance costs. The entire process combines physiological principles with engineering thinking, significantly improving the survival rate of grafting onto thick rootstocks and providing a reliable technical approach for the renovation of old orchards and variety renewal.

[0033] Comparative example:

[0034] The operation is basically the same as in Example 1, but before grafting, the main trunk section is not wrapped with a thin plastic film. The scion is directly inserted into the cut position. Instead of spraying expanding foam, a plastic grafting film with a certain degree of elasticity is used to wrap it from the bottom of the interface upwards to ensure that the scion and the rootstock are in close contact and cannot be loosened. At the same time, the cut of the rootstock and the cut surface of the scion are completely wrapped tightly to prevent moisture evaporation, rainwater entry, and pathogen invasion.

[0035] The results are compared in Table 1:

[0036] Table 1. Comparison of the effects of the original bark grafting method for large-diameter fruit trees and this method.

[0037] Grafting survival rate Grafting efficiency (number of scions grafted by one skilled worker in one day) Original method 75％-85％ 200-300 The present method 90％-95％ 500-600

[0038] The bark grafting method of this invention involves wrapping a thin plastic film around the trunk section before grafting. This effectively isolates the graft from external air and moisture, preventing pathogen invasion and reducing water loss. Grafting points are marked to determine the grafting location of the scion. Simultaneously, covering the canopy section with plastic film prevents expanding foam from seeping into the junction of the rootstock and scion during spraying, thus avoiding interface contamination or hindering callus formation. It also effectively isolates external impurities and pathogens, reducing the risk of infection. After the scion is inserted into the grafting point, expanding foam is used to fix the grafting position. Once the foam cures, it forms a stable protective layer, effectively improving the quality of interface healing and enhancing the scion's fixation strength. This protective layer has good heat and moisture retention properties, promoting cambium cell division and callus tissue formation. The entire grafting structure is stable, resistant to wind and rain erosion, and suitable for efficient and standardized operations in large-scale orchards, significantly reducing technical barriers and labor costs.

Claims

1. A method for bark grafting of large-diameter fruit trees using expanding foam for sealing and fixing, comprising the following steps: (1) Rootstock selection and treatment: Select fruit trees with a trunk diameter of more than 10cm as rootstocks, cut the trunks, remove burrs from the cut surfaces in time, and disinfect with fungicide; mark one or more grafting points around the rootstock cut surface according to the number of grafts, and make a vertical cut on the bark at the edge of the rootstock cut surface with the marked point as the center. The length of the cut should be controlled at 2-3 cm and the depth should reach the xylem. Gently pry open the bark along the cut to form an evenly distributed insertion channel; wrap the rootstock cut surface with a thin plastic film, and fix the lower edge to the outside of the trunk with rubber bands or glue to cover the entire cut surface and cut; make small holes in the plastic film at each cut surface in advance to correspond to the grafting point so that the scion can be inserted; (2) Scion preparation and grafting: Select one-year-old branches as scions, retain 2-3 complete buds at the top, make a long cut at the bottom of the scion, and make a short cut at the back end of the long cut to make the bottom of the scion wedge-shaped; insert the prepared scion into the corresponding cut through the small hole of the plastic film along the marked point, so that the long cut of the scion is close to the xylem of the rootstock and the cambium is aligned. After insertion, gently press the top of the scion to ensure that it is stable and does not loosen. (3) Scion fixing and sealing: Spray expanding foam around the joint of the rootstock and scion. The plastic film should completely wrap around and adhere to the main trunk downwards; the cut surface of the scion should be covered upwards and extend 1-2 cm beyond the top of the cut surface to form a complete sealing layer, ensuring that no cut of the rootstock or scion is exposed.

2. According to the method of claim 1, in step (1), the rootstock is selected from fruit trees of moderate age, vigorous growth, and free from pests and diseases.

3. According to the method of claim 1, the period of trunk cutting in step (1) is the spring period when the sap begins to flow but before the buds sprout.

4. According to the method of claim 1, in step (2), the scion is selected from a one-year-old branch with full growth and plump buds.

5. According to the method of claim 1, in step (2), the length of the long sliced ​​surface is 3-5cm and the length of the short sliced ​​surface is 0.5cm.

6. According to the method of claim 1, in step (2), the spraying is applied 2-20cm below the lowest point of the cut on the main trunk of the fruit tree.

7. The method according to claim 1, wherein the thin plastic film is a colorless and transparent plastic film.

8. The method according to claim 1, wherein the thickness of the thin plastic film is 0.08–0.12 mm.

9. According to the method of claim 1, in step (3), after the foamed adhesive has completely cured, a light-shielding film is tightly wrapped around the outside as a protective outer covering.

10. The method according to claim 1, the method further includes step (4) post-treatment: after the scion sprouts, when the new shoot grows to 20-40cm, a support pole is set up in time to prevent wind breakage.

Images