A grafting method for Pujiang oranges
By using Pujiang orange rootstock, hydroponics, and fine-tube technology to optimize citrus grafting, the problem of low survival rate in alkaline soils and low-temperature areas was solved, achieving close grafting and rapid nutrient delivery, thus improving the growth adaptability of citrus trees.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 眉山职业技术学院
- Filing Date
- 2023-01-04
- Publication Date
- 2026-07-17
AI Technical Summary
Existing citrus grafting methods have low survival rates in alkaline soils and low-temperature areas, resulting in unstable grafting, insufficient nutrient delivery, and negatively impacting citrus tree growth.
Using Pujiang orange as rootstock, the planting pit was dug below the joint point, the rootstock roots were pruned, and the rootstock was fixed with a film wrapping. Combined with hydroponics and burying with fine soil, root nutrient solution was injected, and thin tubes were inserted to provide air and nutrients, thus optimizing the joint structure.
It improves the survival rate of grafting, ensures a tight connection between the rootstock and scion, facilitates rapid nutrient delivery, enhances root development, and helps the plant adapt to alkaline soils and low-temperature environments.
Smart Images
Figure CN115968661B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of contact bonding, and in particular to a contact bonding method for Pujiang oranges. Background Technology
[0002] Citrus is the world's largest fruit production and an important fruit in China, ranking first globally in both acreage and yield. The selection of superior rootstock varieties is fundamental to high-quality and high-yield citrus production. Rootstocks not only affect the growth vigor, yield, fruit size, and quality of citrus scions, but also their adaptability and resistance. Sichuan and Chongqing are major citrus-producing areas, where a significant portion of the soil is alkaline. Citrus trees planted with trifoliate orange or tangerine as rootstock will exhibit varying degrees of yellowing, premature aging, and even death, hindering the development of the citrus industry in this region. Furthermore, intermittent low temperatures exist in this area, causing varying degrees of frost damage to citrus trees. Therefore, selecting rootstock varieties that maintain high, stable, and high-quality citrus production while also possessing specific traits such as alkalinity resistance and cold tolerance is a crucial objective when choosing citrus rootstocks in the alkaline soils of Sichuan and Chongqing, and in the northern citrus-producing areas of Sichuan.
[0003] Citrus trees have upward-reaching root systems, making them susceptible to drought and frost damage, and their nutrient absorption capacity needs improvement. Approach grafting is an ancient method of grafting between scions and rootstocks. The general procedure involves making a long, oval-shaped incision, 1.5–3.0 cm long and deep enough to reach the xylem, at the corresponding points on both the scion and rootstock branches, and then aligning and binding the incisions. However, traditional approach grafting methods have poor healing ability and low survival rates.
[0004] The closest prior art disclosed in the prior art (publication number: 201810069516.X) is a grafting method to enhance the drought resistance of citrus. Although it can enhance drought and wind resistance, the effect is not ideal in some areas, such as the alkaline soils of Sichuan and Chongqing. Moreover, the survival rate of grafting is low. There are generally two reasons for the low survival rate: first, the connection between the scion and the rootstock is not stable enough after grafting, which makes it difficult to transport nutrients and the roots cannot absorb enough nutrients, thus affecting the normal growth of the scion.
[0005] Therefore, we propose a grafting method for Pujiang oranges to solve the above problems. Summary of the Invention
[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for grafting Pujiang oranges.
[0007] To achieve the above and other related objectives, the present invention provides a method for contacting Pujiang oranges, comprising:
[0008] Select a grafting point at the base of the citrus tree to be grafted, and dig a planting pit 10-20cm below the grafting point and at a distance of 10-20cm from the trunk.
[0009] Select Pujiang sweet oranges with a diameter of 0.4-0.6cm as the approach grafting rootstock. Prune the roots of the approach grafting rootstock, keeping the main root at 10-15cm, and remove thorns and leaves.
[0010] Ensure that the length of the rootstock is sufficient to insert into the grafting interface, and plant the root of the rootstock in the planting pit. Cut off the upper end of the rootstock and make two grafting surfaces that are opposite to each other and form a right-angled trapezoid.
[0011] The connection point between the grafted rootstock and the citrus tree is wrapped with a 2cm film, ensuring that the grafted rootstock does not move during the wrapping process. The film is wrapped layer by layer from top to bottom from the connection point, with a wrapping width of more than 10cm.
[0012] Cover the root system of the grafted rootstock with fine soil, press it down firmly, and irrigate with water-soluble fertilizer containing humic acid diluted 150-300 times with water until the root system is thoroughly watered. Cover with a film or straw to retain moisture.
[0013] After grafting, check the survival rate of the graft every 20 days. Remove any new shoots sprouting from the rootstock. Once the wounds on the rootstock and grafting point have completely healed, remove the binding film.
[0014] In one embodiment, the downward-facing interface includes:
[0015] Cut 1-2cm from bottom to top along the joint point, and set the cut part as the wrapping part, forming an opening between the wrapping part and the fruit tree;
[0016] An inner opening is made from bottom to top along the lower end of the opening. The depth of the inner opening is slightly smaller than that of the opening, and there is a connecting part between the inner opening and the opening, with the thickness of the connecting part being less than 5mm.
[0017] Both the opening and the inner opening are located in the cambium layer of the fruit tree;
[0018] The entire abutment portion is cut off, so that the opening connects with the inner opening to form the abutment interface;
[0019] Cut off 1 / 2 to 3 / 4 of the packaged portion from the bottom;
[0020] The abutment surface is inclined upward from the side wall of the abutment rootstock towards the middle, and the height of the abutment surface is set to be greater than the height of the cut-off wrapping part, so that after the abutment surface is inserted into the abutment interface, the lower end of the abutment surface is exposed outside the abutment interface.
[0021] In one embodiment, the abutment point is located on a smooth trunk, 10-20cm from the ground. An "L"-shaped abutment interface is cut at the abutment point, with a vertical cut length of 1cm-2cm and a horizontal cut length of 0.8-1.2cm. The abutment interface penetrates into the cambium layer but does not penetrate into the xylem.
[0022] In one embodiment, when the diameter of the orange tree to be grafted is less than 2 cm, the number of rootstocks is 1.
[0023] When the diameter of the orange tree to be grafted is between 2cm and 6cm, the number of rootstocks used for grafting is 2.
[0024] When the diameter of the orange tree to be grafted is 6cm or more, the number of rootstocks used for grafting is 3.
[0025] In one embodiment, the root system of the grafted rootstock has 8 or more layers, and each layer of root system has no less than 3 branch roots, and the length of the grafted rootstock is 18-46cm.
[0026] The rootstock for grafting was cultured hydroponically for more than 24 hours before grafting;
[0027] The hydroponic method includes:
[0028] Plant the roots of the grafted rootstock in a hydroponic solution;
[0029] A ring of ion exchange membrane is placed in the hydroponic solution, the diameter of which is slightly larger than the root of the rootstock.
[0030] The concentration of the hydroponic solution inside the ion exchange membrane is set to 1.8-2.0 ms / cm, and the concentration of the hydroponic solution outside the ion exchange membrane is set to 2.9-3.2 ms / cm.
[0031] In one embodiment, the pH range of the hydroponic solution is set to 5.5-6.2, and a rooting agent is added to the hydroponic solution, the concentration of which is 0.2-0.5 mol / L.
[0032] In one embodiment, planting the roots of the grafted rootstock into the soil includes:
[0033] Dig a root pit below the rootstock;
[0034] Furthermore, the depth of the root pit should be slightly greater than the root of the scion;
[0035] After burying the roots in the root pit, cover it with soil;
[0036] Insert a thin tube into the soil;
[0037] And rooting solution is injected through a thin tube;
[0038] The thin tube should be left in place for 3-5 days before being removed.
[0039] In one embodiment, the connection point between the grafting rootstock and the citrus tree is wrapped with a 2cm film, comprising:
[0040] The fruit tree to be grafted is pressed together with the rootstock, and the rootstock is bent.
[0041] In one embodiment, the lower end of the thin tube is tapered and closed at the lower end, while the upper end is open. Multiple vents are provided on the four sides of the thin tube, and the vents are arranged downwards from the outside of the thin tube to the inside of the thin tube.
[0042] In one embodiment, inserting the thin tube into the soil includes:
[0043] The thin tube is inserted vertically or at an angle into the soil;
[0044] The lower end of the tube extends below the root;
[0045] Furthermore, the insertion point of the thin tube into the soil is located above the root edge.
[0046] As described above, the contact method provided by the present invention has the following beneficial effects:
[0047] By using the superior Pujiang fragrant orange variety as the scion, which has excellent alkali resistance and drought resistance and is suitable for alkaline soil, and by cutting a part of the space at the interface, the connection between the rootstock and the scion can be made tight enough when they need to be tied together. This allows for faster nutrient delivery and a tighter connection after grafting, thereby improving the survival rate of grafting.
[0048] Before grafting, hydroponics and adjusting the concentration of the nutrient solution can greatly increase the development of the root system and allow the roots to absorb certain nutrients, thereby reducing the risk of nutrient deficiency. In addition, by inserting a thin tube, air can be provided to the roots more quickly, which further improves the bonding between the roots and the soil after grafting. Nutrient solution or rooting solution can also be injected through the thin tube, which further improves the development of the root system and increases the survival rate of grafting. Attached Figure Description
[0049] Figure 1 The table shows a comparison of stem diameter and vertical height between Ziyang and Pujiang oranges.
[0050] Figure 2 This chart shows a comparison of root growth of Ziyang and Pujiang oranges 180 days after planting.
[0051] Figure 3 This image shows the growth of the rootstock for Pujiang oranges.
[0052] Figure 4 Displayed as Figure 3 A diagram showing the growth of tangerine rootstocks planted in the same location.
[0053] Figure 5 The image shows the above-ground growth of Pujiang orange and tangerine plants after 210 days of water cultivation.
[0054] Figure 6 The diagram shows the structure of the fruit tree to be grafted and the rootstock before grafting.
[0055] Figure 7 The diagram shows the structure of the fruit tree being grafted and the rootstock after grafting.
[0056] Figure 8 The diagram shows a three-dimensional structure of the rootstock.
[0057] Figure 9 This is a schematic diagram of the side structure of the rootstock.
[0058] Figure 10 The diagram shows the connection structure between the scion and the rootstock.
[0059] Figure 11 The diagram shows a cross-sectional structure of a thin tube.
[0060] Figure 12 This diagram shows the positional relationship between the thin tube and the root of the scion. Detailed Implementation
[0061] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.
[0062] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.
[0063] Example 1: As Figures 1 to 12 As shown, the present invention provides a method for grafting Pujiang oranges, comprising:
[0064] Select a grafting point at the base of the citrus tree to be grafted. The grafting point should be on a smooth trunk, 10-20cm above the ground. Make an "L"-shaped grafting joint at the grafting point, with a vertical cut length of 1cm-2cm and a horizontal cut length of 0.8-1.2cm. The grafting joint should penetrate into the cambium layer but not into the xylem. Dig a planting pit 10-20cm below the grafting joint, at a distance from the trunk.
[0065] Select Pujiang sweet oranges with a diameter of 0.4-0.6cm as the grafting rootstock. Prune the root of the grafting rootstock, keeping the main root at 10-15cm. Remove thorns and leaves to facilitate grafting.
[0066] Ensure that the length of the rootstock is sufficient to insert into the graft union, and plant the root of the rootstock in the soil. Cut off the upper end of the rootstock and make two graft union surfaces that are opposite to each other and form a right-angled trapezoid.
[0067] The connection point between the grafted rootstock and the citrus tree is wrapped with a 2cm film, ensuring that the grafted rootstock does not move during the wrapping process. The film is wrapped layer by layer from top to bottom from the connection point, with a wrapping width of more than 10cm.
[0068] Cover the root system of the grafted rootstock with fine soil, press it down firmly, and irrigate with water-soluble fertilizer containing humic acid diluted 150-300 times with water until the root system is thoroughly watered. Cover with a film or straw to retain moisture.
[0069] After grafting, check the survival rate of the graft every 20 days. Remove any new shoots sprouting from the rootstock. Once the wounds on the rootstock and grafting point have completely healed, remove the binding film.
[0070] In one embodiment, the downward-facing interface includes:
[0071] Cut 1-2cm from bottom to top along the joint point, and use the cut part as the wrapping part, forming an opening between the wrapping part and the fruit tree;
[0072] Make an inner opening from bottom to top along the lower end of the opening. The depth of the inner opening is slightly smaller than that of the opening, and there is a joint between the inner opening and the opening. The thickness of the joint is less than 5mm. This way, the thickness of the joint will not be too thick, making it easy to connect the fruit tree to the rootstock, nor too thin, ensuring the stability of the survival after the connection.
[0073] Both the opening and the inner opening are located in the cambium layer of the fruit tree;
[0074] The entire abutment portion is cut off, so that the opening connects with the inner opening to form an abutment joint.
[0075] Cut off 1 / 2 to 3 / 4 of the wrapping from the bottom; this prevents the wrapping from contacting the bark.
[0076] The abutment surface slopes upwards from the side wall of the abutment rootstock toward the middle, and the height of the abutment surface is set to be greater than the height of the cut-off wrapping part, so that after the abutment surface is inserted into the abutment interface, the lower end of the abutment surface is exposed outside the abutment interface.
[0077] Insert the upper end of the scion into the graft union from the joint, and wrap the scion with the wrapping part. This will stably connect the wrapping part and the scion together. The thickness of the graft union makes cutting easier. After the graft union is cut off, there is space between the wrapping part and the rootstock, the size of which is the space between the opening and the inner opening. This design allows the wrapping part and the scion to fit together more stably when wrapping.
[0078] Cutting off the lower end of the wrapping allows for more space at the joint after binding, facilitating the growth of both the scion and rootstock.
[0079] In one embodiment, when the diameter of the citrus tree to be grafted is less than 2 cm, the number of rootstocks used for grafting is 1.
[0080] When the diameter of the citrus tree to be grafted is between 2cm and 6cm, the number of rootstocks used for grafting is 2.
[0081] When the diameter of the citrus tree to be grafted is 6cm or more, the number of rootstocks used for grafting is 3.
[0082] This setup ensures that when there are many branches of fruit trees, different scions can be grafted onto different branches as needed, so that different branches can receive adequate nutrition.
[0083] In addition, the number of grafts should not be too many. This is to save costs and reduce the difficulty of the work, and also to avoid causing significant damage to the rootstock by cutting the bark and cambium during the grafting process.
[0084] 1. Rootstock for grafting; citrus rootstock seedlings for grafting large trees.
[0085] 2. Approach-grafted citrus tree: A large tree that receives an approach-grafting rootstock.
[0086] Timing of docking: Choose a sunny, windless or light-windy day for docking, generally from February to March or from May to July. It is not advisable to dock during the hot, dry or rainy season.
[0087] Rootstock thickness for grafting: 0.4cm-0.6cm is optimal.
[0088] The number of rootstocks to be grafted is determined as follows: if the diameter of the citrus tree to be grafted is less than 2cm, 1 rootstock is grafted; if the diameter is between 2cm and 6cm, 2 rootstocks are grafted; and if the diameter is more than 6cm, 3 rootstocks are grafted.
[0089] 1. Treatment of the rootstock for grafting: Trim the root system of the rootstock, leaving 10-15cm of the taproot, and remove thorns and leaves from the rootstock to facilitate the grafting operation.
[0090] 2. Selection of the grafting site for the citrus tree. Choose a tree with a smooth trunk for easy grafting, and dig a planting pit 20cm-30cm away from the trunk. Make an "L"-shaped grafting cut at a position less than 20cm from the trunk (to ensure that the rootstock connects seamlessly with the trunk of the citrus tree after growth, avoiding gaps that create a shadow and make it susceptible to pests and diseases). The vertical cut should be 1cm-2cm long, and the horizontal cut should be about 1cm long, reaching the cambium layer but not penetrating into the xylem.
[0091] 3. Two treatments for the rootstock used for grafting. Place the rootstock in the prepared planting pit. Determine the height of the rootstock based on the distance between the planting pit and the grafting site. After pruning the rootstock, make a 40°-50° oblique cut on one side and a flat cut about 1.5cm from the opposite side to remove the phloem.
[0092] 4. Unbinding. Insert the prepared rootstock into the incision in the trunk of the citrus tree to be grafted, and bind it with 2 cm of binding film. Pay special attention to two points: first, secure the rootstock so it cannot move during the binding process; second, wrap the binding film from top to bottom at the grafting point (advantages: 1. facilitates securing the incision between the rootstock and the citrus tree; 2. prevents rainwater from entering the graft union through the branches, affecting the grafting survival rate), at least 10 cm thick.
[0093] 5. Backfilling. Backfill with fine soil to cover the roots of the grafted rootstock, tamping it down to ensure close contact between the roots and the soil. Drench the roots with a 150-300 times diluted solution of humic acid water-soluble fertilizer, and cover with a film or straw to retain moisture, which is beneficial for the survival of the grafted rootstock.
[0094] 6. Management. Check the grafting success rate every 20 days after grafting and regraft as needed; remove any new shoots sprouting from the rootstock; remove the binding film when the wound has completely healed.
[0095] In one embodiment, the root system of the grafted rootstock has 8 or more layers, and each layer of root system has no less than 3 branch roots, and the length of the grafted rootstock is 18-46 cm.
[0096] Before approach grafting, the rootstock is cultured hydroponically for more than 24 hours.
[0097] Hydroponic methods include:
[0098] Plant the roots of the grafted rootstock in a hydroponic solution;
[0099] Set up a ring of ion exchange membrane in the hydroponic solution, with the diameter of the ion exchange membrane slightly larger than the root of the rootstock.
[0100] The concentration of the hydroponic solution inside the ion exchange membrane was set to 1.8-2.0 ms / cm, and the concentration of the hydroponic solution outside the ion exchange membrane was set to 2.9-3.2 ms / cm.
[0101] By setting the number and layer size of the rootstock, it is possible to ensure that the scion has a well-developed root system and is of appropriate length, making it suitable for grafting points of different heights.
[0102] In addition, hydroponics can improve the healthy growth of the root system. By setting up an ion exchange membrane, the concentration of ions inside the ion exchange membrane circle can be ensured to be suitable for root growth. As the roots absorb the nutrients, the hydroponic solution outside the circle can enter the circle, thus keeping the concentration of the hydroponic solution inside the circle within a suitable range.
[0103] In one embodiment, the pH range of the hydroponic solution is set to 5.5-6.2, and a rooting agent is added to the hydroponic solution at a concentration of 0.2-0.5 mol / L.
[0104] By setting the pH value of the hydroponic solution, we can ensure that the hydroponic solution is in a more suitable growth environment for the roots, and the use of rooting agents can further promote root growth.
[0105] In one embodiment, planting the roots of the grafted rootstock into the soil includes:
[0106] Dig a root pit below the rootstock;
[0107] Furthermore, the depth of the root pit should be slightly greater than the root of the scion;
[0108] After burying the roots in the root pit, cover it with soil;
[0109] Insert a thin tube into the soil;
[0110] And rooting solution is injected through a thin tube;
[0111] The thin tube should be left in place for 3-5 days before being removed.
[0112] By inserting a thin tube, air can be provided, and nutrient solution can be easily injected. In addition, the thin tube can be pulled out after a period of time to avoid connecting with the roots.
[0113] In one embodiment, the connection point between the grafting rootstock and the citrus tree is wrapped with a 2cm film, comprising:
[0114] The fruit tree to be grafted is pressed together with the rootstock, and the rootstock is bent.
[0115] In one embodiment, the lower end of the thin tube is tapered and closed, while the upper end is open. Multiple vents are provided on the four sides of the thin tube, and the vents are arranged downwards from the outside of the thin tube to the inside of the thin tube.
[0116] This setup ensures that the tubes can be inserted into the soil more easily, preventing soil from being squeezed into the tubes and ensuring that more air is provided to the roots.
[0117] In one embodiment, inserting a thin tube into the soil includes:
[0118] The thin tube is inserted vertically or at an angle into the soil;
[0119] The lower end of the tube extends below the root;
[0120] Furthermore, the insertion point of the thin tube into the soil is located above the root edge.
[0121] By positioning the thin tubes in this way, the scion's roots can be attracted to grow in the designated direction, thus avoiding overlap with the root system of the rootstock and allowing it to absorb nutrients from the soil more fully.
[0122] The insertion point ensures that the root of the tube is not damaged during insertion.
[0123] Example 2: In one example, the joint includes a vertical cut and a horizontal cut. The length of the vertical cut is greater than the length of the horizontal cut. The length of the horizontal cut is 2-3 cm. The length of the horizontal cut is less than 1 / 15 of the circumference of the fruit tree where the joint is located. The ends of the vertical cut and the ends of the horizontal cut are connected so that the joint forms an L-shape. The rootstock is inserted into the joint through the horizontal cut.
[0124] This cutting method is suitable for trees that are not easy to cut, and the combination of horizontal and vertical cuts can still achieve a good effect in inserting scions.
[0125] The grafting method for Pujiang fragrant oranges described in this invention uses high-quality Pujiang fragrant oranges as scions, which have excellent alkali resistance and drought resistance and are suitable for alkaline soils. Moreover, by cutting a portion of the space at the grafting point, the connection between the rootstock and the scion can be made tight enough when they need to be tied together. This allows for faster nutrient delivery and a tighter connection after grafting, thereby improving the survival rate of the graft.
[0126] Before grafting, hydroponics and adjusting the concentration of the nutrient solution can greatly increase the development of the root system and allow the roots to absorb certain nutrients, thereby reducing the risk of nutrient deficiency. In addition, by inserting a thin tube, air can be provided to the roots more quickly, which further improves the bonding between the roots and the soil after grafting. Nutrient solution or rooting solution can also be injected through the thin tube, which further improves the development of the root system and increases the survival rate of grafting.
[0127] Although the invention has been described herein with reference to specific embodiments thereof, freedom of modification, various alterations and substitutions are also within the scope of the foregoing disclosure, and it should be understood that in some cases, certain features of the invention may be adopted without departing from the scope and spirit of the invention and without corresponding use of other features. Therefore, many modifications can be made to adapt a particular environment or material to the essential scope and spirit of the invention. The invention is not intended to be limited to the specific terminology used in the following claims and / or the specific embodiments disclosed as the best mode contemplated for carrying out the invention, but the invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Therefore, the scope of the invention will be defined only by the appended claims.
Claims
1. A grafting method for Pujiang fragrant oranges, characterized in that, include: Select a grafting point at the base of the citrus tree to be grafted. The grafting point should be on a smooth trunk, 10-20cm from the ground. Make an "L"-shaped grafting joint at the grafting point, with a vertical cut length of 1cm-2cm and a horizontal cut length of 0.8-1.2cm. The grafting joint should penetrate into the cambium layer but not into the xylem. Dig a planting pit 10-20cm below the grafting joint, at a distance from the trunk. Select Pujiang sweet oranges with a diameter of 0.4-0.6cm as the approach grafting rootstock. Prune the roots of the approach grafting rootstock, keeping the main root at 10-15cm, and remove thorns and leaves. Ensure that the length of the rootstock is sufficient to be inserted into the graft union, and plant the root of the rootstock in the planting pit. Cut off the upper end of the rootstock and make two smooth, right-angled trapezoidal grafting surfaces that do not touch each other and are opposite to each other. The connection point between the grafted rootstock and the citrus tree is wrapped with a 2cm film, ensuring that the grafted rootstock does not move during the wrapping process. The film is wrapped layer by layer from top to bottom from the connection point, with a wrapping width of more than 10cm. Cover the root system of the grafted rootstock with fine soil, press it down firmly, and irrigate with water-soluble fertilizer containing humic acid diluted 150-300 times with water until the root system is thoroughly watered. Cover with a film or straw to retain moisture. After grafting, check the survival rate of the graft every 20 days. Remove any new shoots that sprout on the rootstock. Once the wounds on the rootstock and grafting point have completely healed, remove the binding film. The downward-facing interface includes: Cut 1-2cm from bottom to top along the joint point, and set the cut part as the wrapping part, forming an opening between the wrapping part and the fruit tree; An inner opening is made from bottom to top along the lower end of the opening. The depth of the inner opening is slightly smaller than that of the opening, and there is a connecting part between the inner opening and the opening, with the thickness of the connecting part being less than 5mm. Both the opening and the inner opening are located in the cambium layer of the fruit tree; The entire abutment portion is cut off, so that the opening connects with the inner opening to form the abutment interface; Cut off 1 / 2 to 3 / 4 of the packaged portion from the bottom; The abutment surface is inclined upward from the side wall of the abutment rootstock towards the middle, and the height of the abutment surface is set to be greater than the height of the cut-off wrapping part, so that after the abutment surface is inserted into the abutment interface, the lower end of the abutment surface is exposed outside the abutment interface. The joint point is located on a smooth trunk, 10-20cm from the ground. An "L"-shaped joint is cut at the joint point, with a vertical cut length of 1cm-2cm and a horizontal cut length of 0.8-1.2cm. The joint extends into the cambium layer but does not extend into the xylem. When the diameter of the citrus tree to be grafted is less than 2cm, the number of rootstocks used for grafting is 1. When the diameter of the citrus tree to be grafted is between 2cm and 6cm, the number of rootstocks used for grafting is 2. When the diameter of the citrus tree to be grafted is 6cm or more, the number of rootstocks used for grafting is 3. The root system of the grafted rootstock has 8 or more layers, and each layer of root system has no less than 3 branch roots. The length of the grafted rootstock is 18-46cm. The rootstock for grafting was cultured hydroponically for more than 24 hours before grafting; The hydroponic method includes: Plant the roots of the grafted rootstock in a hydroponic solution; A ring of ion exchange membrane is placed in the hydroponic solution, the diameter of which is slightly larger than the root of the rootstock. The concentration of the hydroponic solution inside the ion exchange membrane is set to 1.8-2.0 ms / cm, and the concentration of the hydroponic solution outside the ion exchange membrane is set to 2.9-3.2 ms / cm.
2. The contact method according to claim 1, characterized in that: The pH range of the hydroponic solution is set to 5.5-6.2, and a rooting agent is added to the hydroponic solution at a concentration of 0.2-0.5 mol / L.
3. The contact method according to claim 1, characterized in that: The planting of the rootstock into the planting pit includes: Dig a root pit below the rootstock; Furthermore, the depth of the root pit should be slightly greater than the root of the scion; After burying the roots in the root pit, cover it with soil; Insert a thin tube into the soil; And rooting solution is injected through a thin tube; The thin tube should be left in place for 3-5 days before being removed.
4. The contact method according to claim 1, characterized in that: The process of wrapping the joint between the grafting rootstock and the citrus tree using a 2cm film includes: The fruit tree to be grafted is pressed together with the rootstock, and the rootstock is bent.
5. The contacting method according to claim 3, characterized in that: The lower end of the thin tube is tapered and closed, while the upper end is open. Multiple vents are provided on the four sides of the thin tube, and the vents are arranged downwards from the outside of the thin tube to the inside of the thin tube.
6. The contacting method according to claim 5, characterized in that: The insertion of the thin tube into the soil includes: The thin tube is inserted vertically or at an angle into the soil; The lower end of the tube extends below the root; Furthermore, the insertion point of the thin tube into the soil is located above the root edge.