Pruning method for maintaining root growth during the start-up period of the second crop of grapes

Abstract

The present application relates to the grape cultivation technical field, especially to the grape two harvests a year second batch fruit starting period maintains the pruning method of root growth, applies to the second batch fruit starting stage in grape two harvests a year cultivation, specifically, after the first batch fruit of grape is harvested, 1-2 root branches with leaves are kept as carbon preservation branches, and the rest fruiting mother branches are treated by progressive leaf retention pruning.The core of the method is that, in the second batch fruit starting stage, the fruiting mother branch leaves are not removed immediately, but part of the branch leaves are kept and gradually transitioned, sudden interruption of carbon flow of the tree body is avoided, and root activity after branch pruning is prevented from sudden decrease.

Description

[Technical Field]

[0001] This invention relates to the field of grape cultivation technology, and in particular to a pruning method for maintaining root growth during the initiation period of the second crop of grapes harvested twice a year. [Background Technology]

[0002] The "two-harvest, two-generation" cultivation model has become an important way to achieve high-efficiency grape cultivation in the southern tropical regions. After the first harvest (summer fruit), the vines typically need to recover their vigor, be pruned, and have new shoots promoted within 25-35 days to ensure the smooth start of the second harvest (winter fruit). However, traditional production generally uses a method of "complete leaf removal and pruning + chemical bud promotion" to quickly promote new shoots. But this method is prone to causing a momentary interruption of carbon source flow, resulting in insufficient substrate for root respiration, rapid decline of fine roots, and even cessation of growth and necrosis, which seriously affects the root-crown coordination and thus restricts the growth of branches and leaves, as well as fruit quality and yield in the second harvest. Most existing technologies only focus on chemical bud promotion or single temperature control, lacking solutions to the core bottleneck problem of "root stagnation caused by post-harvest pruning," lacking systematic protection of root zone vitality and precise, gradual management of pruning methods, and failing to consider an overall management plan that combines real-time root zone monitoring technology with a gradual leaf-preserving and carbon-preserving branch pruning strategy.

[0003] Double-harvest grape cultivation involves artificially controlling the grape growth cycle to achieve two or more harvests within a year. This cultivation model is beneficial for staggered market entry, increasing economic efficiency, and compensating for potential yield reductions due to natural disasters. However, in current double-harvest practices, pruning and bud-promoting treatments are often necessary after the first harvest to initiate a second fruiting period. The conventional approach is usually heavy defoliation followed by immediate bud induction: all leaves on the fruiting branches are removed, and then chemical agents are used to promote the sprouting of winter buds. This "one-time complete defoliation + chemical bud induction" treatment has significant drawbacks: after the sudden loss of photosynthetic leaves, the vine's carbohydrate "source" is interrupted, and the root system quickly enters a state of growth stagnation due to the lack of photosynthetic products. The interruption of carbon flow in the root zone significantly reduces root respiration, hinders the formation of new root hairs, and weakens the ability to absorb water and nutrients, thereby affecting the sprouting and growth of the second flush of shoots. The direct consequence is uneven and delayed bud sprouting in the second crop, with some buds even failing to sprout into branches due to insufficient nutrient supply; even when they do sprout, the new shoots are weak. Due to damaged root vitality, the development of the second crop is restricted, often resulting in small bunches, fewer berries, and decreased quality, ultimately failing to achieve ideal yield and quality. This conventional defoliation pruning method clearly does not fully consider the balance of the grapevine's source-sink relationship, and its adverse impact on root growth is a significant reason for the poor yield of the second crop.

[0004] To address the aforementioned issues, our team attempted to partially retain leaves or postpone pruning after the first harvest to reduce the impact on photosynthesis. However, without systematic monitoring and scientific guidance, relying solely on experience to control leaf retention often yields inconsistent results: retaining too many leaves can hinder new shoot growth, while retaining too few can lead to root depletion. Therefore, an improved pruning method is urgently needed to prevent a sudden drop in root activity after the first harvest, ensuring a smooth start and robust growth of the second harvest. [Summary of the Invention]

[0005] In view of the above, this invention aims to overcome the irrationality of the current post-harvest pruning method in double-harvest grape cultivation, and to solve the problems of interrupted carbon flow in the root zone, cessation of root growth, and poor bud sprouting in the second crop caused by one-time leaf removal. To achieve the above objectives, the technical solution adopted by this invention is:

[0006] A pruning method for maintaining root growth during the initiation of the second fruiting season in grapes that are harvested twice a year includes the following steps: After the first fruiting season, retain 1-2 leafy branches for carbon conservation, and gradually prune the remaining fruiting branches to preserve leaves. This ensures that the plant retains some leaves for photosynthesis during the germination of the second winter buds, preventing carbon flow interruption that could lead to root cessation and thus guaranteeing a successful initiation of the second fruiting season.

[0007] Furthermore, the carbon-preserving branch is a robust branch near the main trunk of the grapevine.

[0008] This invention also proposes a management method for maintaining root growth during the initiation period of the second crop of grapes harvested twice a year. The management method includes the pruning method described above combined with other management methods to maintain the root growth of the plant during the initiation period of the second crop.

[0009] Furthermore, the method includes:

[0010] (1) Root irrigation: After the first harvest of fruit, the root zone of the grapevines is irrigated with root-promoting solution;

[0011] (2) Sprouting: After the first batch of fruit is harvested, apply a sprouting agent to the buds that are to be sprouted.

[0012] (3) Supplemental lighting: After pruning, supplemental lighting measures are implemented on the grapevines to extend the light exposure time of the retained leaves and promote the sprouting and growth of new shoots.

[0013] Furthermore, the root-promoting solution comprises the following components: liquid biostimulant, sucrose, indoleacetic acid, potassium sulfate, urea, chelated Zn / B trace elements, and Trichoderma preparation.

[0014] Furthermore, the germination agent is a cyanamide-based chemical germination agent.

[0015] The present invention has at least the following beneficial effects:

[0016] Currently, in conventional double-harvest grapevines, after the first harvest, all branches that have borne fruit are typically pruned from the base. It is believed that fruit-bearing branches (especially summer fruit) will gradually age after harvest, and if retained, they will continue to consume nutrients. Therefore, existing pruning methods involve directly cutting them off from the base. When using conventional methods to prune after the first harvest, the white roots of the grapevine will turn into yellow roots, thus losing their nutrient transport vitality. The specific technical challenge lies in how to maintain the supply of photosynthetic products to the plant and preserve root vitality by improving pruning methods after the first harvest, thereby ensuring the timely sprouting and vigorous growth of branches for the second harvest.

[0017] Based on this, this application proposes a progressive leaf-preserving and root-promoting pruning method based on root zone monitoring, applied to the second crop initiation stage of double-harvest grape cultivation. Specifically, after the first crop harvest, a balanced transition mechanism of "leaf preservation—root promotion—bud promotion" is established: the retention of some leaves ensures a continuous supply of photosynthetic products, while root zone monitoring and environmental control ensure that the root system is in good physiological condition, thereby enabling the timely and vigorous sprouting of the second crop of winter buds. The entire process achieves a smooth transition of the grapevine from the first to the second crop, avoiding root growth stagnation and physiological imbalance caused by a sudden loss of photosynthetic sources. Compared with the existing method of complete leaf removal pruning after the first crop of double-harvest grapes, the progressive leaf-preserving and root-promoting pruning method of this invention has significant technical progress and beneficial effects. First, this invention, through carbon-preserving branches and gradual pruning, continuously supplies carbon sources, effectively preventing the interruption of carbon flow in the root zone and maintaining the normal growth momentum of the root system. Second, root zone monitoring and scientific regulation allow for more rational timing of leaf removal, resulting in uniform sprouting of the second crop of winter buds and vigorous new shoot growth. Third, through water and fertilizer supplementation and optimized light, the overall physiological state of the plant is better, leading to full development of the second crop of fruit bunches, increased average bunch weight, and improved berry plumpness and quality. Finally, the method of this invention reduces the impact of extreme pruning on the plant, exhibiting higher operability and stability. Therefore, this invention significantly improves the efficiency of producing a second crop of grapes under a two-harvest-a-year model, achieving both increased yield and quality, and has significant practical value and promising prospects for grape cultivation. [Attached Image Description]

[0018] Figure 1 Comparison of grape root morphology under transparent root windows 14 days after treatment with different pruning methods.

Detailed Implementation Methods

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0020] Example 1:

[0021] This embodiment provides a pruning method for maintaining root growth during the initiation period of the second crop of grapes harvested twice a year. The method is to not immediately remove all the leaves of the fruiting mother branches during the initiation stage of the second crop, but to retain some branches and leaves for a gradual transition, so as to avoid a sudden interruption of carbon flow in the tree.

[0022] The specific steps are as follows:

[0023] (1) Establishment of carbon-preserving branches: After the first harvest, select a strong branch near the main trunk of the grapevine as a "carbon-preserving branch" and retain it without pruning. The carbon-preserving branch is a branch with sufficient healthy leaves and the fruit clusters have been removed. The retained carbon-preserving branch continues to perform photosynthesis throughout the winter bud sprouting process of the second harvest, continuously providing carbohydrates to the plant (i.e., the "carbon-preserving" function). When the leaves of the second shoot can support the root system activity, prune the established carbon-preserving branch to the 6th node, keeping the same pruning node as the main fruiting branch, so as to facilitate the synchronization of subsequent management.

[0024] (2) Gradual leaf-preserving pruning: 25 days after the first harvest, a gradual pruning strategy is adopted for the remaining fruiting branches on the main vine side arms of the shaped structure (straight or T-shaped pruning structure) except for the carbon-preserving branches, rather than completely removing the leaves at once.

[0025] a. During the first pruning, cut the fruiting mother branch to 5 nodes, removing only the leaves and petioles at the terminal bud node of the cut, while retaining all functional leaves at the other nodes;

[0026] b. Seven days after the first pruning, perform a second pruning, removing some of the old leaves, including petioles, from the branches that were retained in the previous pruning, while still keeping a certain number of green leaves on the plant. Repeat this leaf removal process in stages to gradually transition the plant to ensure that some leaves are always active. This gradual leaf-preserving pruning ensures that the plant does not experience a "zero-leaf" period during the sprouting and growth of the second batch of winter buds, thus maintaining the normal physiological activities of the root system.

[0027] During the pruning process described above, root zone monitoring guides the timing and extent of leaf removal. This monitoring includes real-time or periodic measurements of soil / rhizosphere CO2 flux, temperature, and moisture content, with a focus on monitoring root zone CO2 flux (soil respiration rate) to assess root activity. The leaf removal pruning plan is dynamically adjusted based on monitoring data. For example, when root zone CO2 flux remains stable (decreases by no more than 20%) or slightly increases, the next step of leaf removal can be carried out until all old leaves are removed. If a significant decrease in CO2 flux is observed (a decrease exceeding 20% ​​and lasting for more than 48 hours, indicating reduced root activity), the pace of leaf removal is slowed down, or measures such as increased water and fertilizer application are taken to restore root vitality. Root zone monitoring enables scientific decision-making during the leaf removal pruning process, ensuring that each step is performed within the tolerance range of the root system.

[0028] Example 2:

[0029] This embodiment provides a pruning method for maintaining root growth during the initiation period of the second crop of grapes harvested twice a year. The method is to not immediately remove all the leaves of the fruiting mother branches during the initiation stage of the second crop, but to retain some branches and leaves for a gradual transition, so as to avoid a sudden interruption of carbon flow in the tree.

[0030] The specific steps are as follows:

[0031] (3) Carbon-preserving branches: After the first harvest, select two strong branches near the main trunk of the grapevine as "carbon-preserving branches" and retain them without pruning. The carbon-preserving branches are branches with sufficient healthy leaves and the fruit clusters have been removed. The two retained carbon-preserving branches will continue to perform photosynthesis throughout the winter bud sprouting process of the second harvest, continuously providing carbohydrates to the plant (i.e., the "carbon-preserving" function). When the leaves of the second shoots can support the root system activity, prune the established carbon-preserving branches to the 6th node, keeping the same pruning node as the main fruiting mother branch, so as to facilitate the synchronization of subsequent management.

[0032] (4) Gradual leaf-preserving pruning: Within 35 days after the first harvest, a gradual pruning strategy is adopted for the remaining fruiting branches on the main vine side arms of the shaped structure (straight or T-shaped pruning structure) except for the carbon-preserving branches, rather than completely removing the leaves at once.

[0033] a. During the first pruning, cut the fruiting mother branch to 6 nodes, removing only the leaves and petioles at the terminal bud node of the cut, while retaining all functional leaves at the other nodes;

[0034] b. After the first pruning, 15 days later, perform a second pruning, removing some of the old leaves, including petioles, from the branches that were retained in the previous pruning, while still keeping a certain number of green leaves on the plant. Repeat this leaf removal process in stages to gradually transition the plant to ensure that some leaves are always active. This gradual leaf-preserving pruning ensures that the plant does not experience a "zero-leaf" period during the sprouting and growth of the second batch of winter buds, thus maintaining the normal physiological activities of the root system.

[0035] During the pruning process described above, root zone monitoring guides the timing and extent of leaf removal. This monitoring includes real-time or periodic measurements of soil / rhizosphere CO2 flux, temperature, and moisture content, with a focus on monitoring root zone CO2 flux (soil respiration rate) to assess root activity. The leaf removal pruning plan is dynamically adjusted based on monitoring data. For example, when root zone CO2 flux remains stable (decreases by no more than 20%) or slightly increases, the next step of leaf removal can be carried out until all old leaves are removed. If a significant decrease in CO2 flux is observed (a decrease exceeding 20% ​​and lasting for more than 48 hours, indicating reduced root activity), the pace of leaf removal is slowed down, or measures such as increased water and fertilizer application are taken to restore root vitality. Root zone monitoring enables scientific decision-making during the leaf removal pruning process, ensuring that each step is performed within the tolerance range of the root system.

[0036] Example 3:

[0037] This embodiment provides a management method based on the pruning method in Embodiment 2. The management method includes the pruning method in Embodiment 1, and also includes the following management method:

[0038] (1) Sprouting treatment: Apply cyanamide chemical sprouting agent to the retained buds. In addition, dip the winter buds at the 6th node on the carbon-protected branches and the terminal buds of the remaining fruiting mother branches with a 20-fold dilution of 50% (w / v) cyanamide aqueous solution. During the operation, take care to avoid contact between the solution and other winter buds and leaves to prevent non-target buds from sprouting prematurely or leaves from being burned.

[0039] (2) Root zone growth promotion and environmental regulation: During the transition period from the harvest of the first crop to the sprouting of the second crop, a series of environmental regulation measures that are conducive to the growth of roots and new shoots are combined to improve the effectiveness of the method of the present invention.

[0040] Specifically, it includes:

[0041] (a) Root irrigation treatment: Immediately after the first harvest, irrigate the root zone of the grapevines. This replenishes soil moisture, preventing excessive water loss due to post-harvest high temperatures and transpiration, and provides nutrients to promote rapid root recovery. Drip irrigation (28 mm water flow) is used, and the following components are dissolved in the irrigation solution:

[0042] ① Liquid biostimulant 80Lhm -2 Its active ingredients are selected from: fucoidan, humic acid, chitosan oligosaccharide and amino acid chelates; ② sucrose 250 mg·L -1 ③ Indoleacetic acid (IAA) 15 μmol·L -1 Or its sustained-release analogues, such as indolebutyric acid (IBA) or naphthaleneacetic acid (NAA); ④ Urea 4 kg hm -2 With 6 kg / hm of potassium sulfate -2 Provides readily available nitrogen and potassium; ⑤ Chelates Zn / B trace elements 0.5 kg hm -2 ⑥ Trichoderma harzianum preparation 10 kg / hm -2 Colony count ≥ 1×10 8 CFU g -1 .

[0043] If the root zone temperature monitoring value is >32℃, add 80mg·L-1 of γ-aminobutyric acid (GABA) to the above drip irrigation solution, and at the same time lay a biodegradable white reflective film between the grape rows to reduce the root zone temperature by 2℃.

[0044] When the CO2 flux in the root zone decreases by more than 20% from the pre-pruning baseline value and persists for more than 48 hours, it is determined that the root zone's metabolic function is weakened. In this case, the following measures should be implemented before the terminal bud shoots enter the flowering period:

[0045] ① Repeatedly apply a root irrigation solution composed of 7000 times diluted brown algae oligosaccharide;

[0046] ② If the root temperature is higher than 32℃, add 50mg·L-1 of γ-aminobutyric acid (GABA) to the above root irrigation solution to enhance the heat resistance and root inhibition ability;

[0047] ③ The minimum interval between each root irrigation is 3 days to avoid excessive moisture or seepage stress in the root zone.

[0048] (b) Light Management (Supplemental Lighting): If the second crop's initiation period falls during a season of reduced sunlight or in a greenhouse cultivation environment, supplemental lighting can be provided to the plants. After the pruning and bud-promoting treatments are completed, the new shoot initiation stage begins. To prolong the photosynthetic sensing and carbon flow output cycle, when the measured illuminance at the top of the canopy is below 50 lux after sunset, the LED light source will be automatically activated for supplemental lighting.

[0049] ① The supplemental lighting should last for 4 consecutive hours per day;

[0050] ②The light intensity is 80 lux;

[0051] ③ The spectral ratio is 5:1, consisting of red light with a wavelength of approximately 650 nm and blue light with a wavelength of approximately 450 nm.

[0052] This treatment is used to supplement the light signal of the terminal buds and carbon-conserving branches under conditions of insufficient natural photoperiod, to prolong the photosynthetic sensing and carbon flow output cycle, to ensure the continuous activity of root metabolism, and to stabilize the root-crown synergistic process.

[0053] (c) Water Management: Throughout the entire process from the first harvest to the start of the second harvest, soil moisture content is monitored using a soil tensiometer or conductivity sensor and continuously maintained within 70% of field capacity (FC), keeping the soil moist but not waterlogged to provide a good respiration environment for the roots. Irrigation is provided promptly when the soil is too dry, and drainage is ensured when it is too wet to avoid the adverse effects of drought stress or waterlogging and oxygen deficiency on root vitality. Appropriate soil moisture helps maintain high root respiration intensity and nutrient absorption efficiency.

[0054] (d) Nutrient supply: Five days after the first harvest, apply 2800 kg / hm² of bio-organic fertilizer to the soil surface along the planting rows. -2 And low-chlorine compound fertilizer (15-15-15) 300kg / hm -2 When applied in conjunction with root irrigation, it promotes rapid replenishment of nutrients to the tree after the first harvest.

[0055] Experimental example:

[0056] Comparative experiment on grape cultivation methods of "two harvests a year":

[0057] Experimental materials and conditions: Several two-year-old rain-sheltered Sunshine Rose grapevines with consistent growth conditions (16-20 fruiting branches per vine) were selected. The experiment was conducted during the first harvest season. The grapevines were divided into multiple groups of 5 vines each to reduce the influence of individual differences.

[0058] First-crop fruit harvesting and processing: When the first crop of Sunshine Rose grapes is fully ripe (July 15), the first crop of grapes in each group is harvested, and the harvesting method and time are the same.

[0059] Thirty days after harvesting, the plants were pruned individually, and the groups were as follows:

[0060] Group 1: The pruning method of Embodiment 2 of this application is adopted, and then management is implemented through Embodiment 3;

[0061] Group 2: On the 30th day after harvest, all fruiting branches were cut down to the 6th node and all leaves below the cut were removed. Then, management was carried out in accordance with the method of Example 3.

[0062] Group 3: The root irrigation solution was only water, and the other methods were the same as Group 1;

[0063] Group 4: Remove the fill light treatment; other methods are the same as Group 1.

[0064] Group 5: The root irrigation solution was only water; other methods were the same as Group 2.

[0065] Group 6: Remove the supplementary lighting process; other methods are the same as Group 2.

[0066] Observation indicators and methods: Under the above group treatments, the following indicators were continuously monitored and compared:

[0067] Root zone CO2 flux: Using a portable soil respiration measurement system, the root zone CO2 flux (unit: μmol·m⁻¹) of each group of plants was measured 1 day before pruning and sprouting, and 3, 7 and 14 days after pruning and sprouting. -2 ·s -1 Three plants were selected from each group for testing, and the average value was taken to reflect the changes in root respiration intensity.

[0068] Root-to-shoot ratio: After the second harvest, three grapevines from the first and second groups were taken respectively, and their underground dry weight and aboveground dry weight were measured. The root-to-shoot ratio was calculated as root dry weight / branch, leaf and fruit dry weight. The effect of the above treatment on the biomass distribution of the plant was compared.

[0069] Net photosynthetic rate: On the morning of the third day after pruning and bud induction, the net photosynthetic rate P of the group with remaining leaves in the method of this invention and the conventional group with very few remaining leaves were measured using a portable photosynthesis meter. n (Unit: μmol·m) -2 ·s -1 After the second flush of new shoots produces new leaves (14 days after pruning and bud induction), the net photosynthetic rate of several groups of new leaves is measured to assess the recovery.

[0070] Second-crop indicators: Record the bud break rate (the percentage of new shoots actually sprouting per vine out of the number of winter buds that can sprout), average weight of a single second-crop, berry size, and soluble solids content (sugar content) of each group of grapes, as well as other yield and quality indicators. At the time of harvest of the second crop (late December), five bunches of grapes from each group were randomly selected for weighing and quality analysis.

[0071] The experimental results are shown in Table 1-4:

[0072] Table 1 Changes in CO2 flux in the root zone before and after pruning

[0073]

[0074] According to the results in Table 1, on the 7th day after the first harvest of grapes, the average CO2 flux in the root zone of the group using the method of this invention was maintained at approximately 4.8 μmol·m⁻¹. -2 ·s -1The decrease in root activity was only 14.3% compared to before pruning, while root activity was significantly impaired in other treatment groups. This indicates that the method of the present invention effectively maintained the respiration activity and metabolic stability of the roots after pruning, while conventional leaf removal pruning caused metabolic obstruction in the root zone due to the instantaneous interruption of carbon source, resulting in a significant decrease in root activity (Group 2). In addition, light and root irrigation treatments also had a certain impact on the maintenance of CO2 flux in the root zone (Groups 3 to 6), indicating that the method of the present invention has a significant protective effect on root activity.

[0075] Table 2 compares the root-to-crown ratio of Group 1 and Group 2.

[0076] Root-to-crown ratio Group 1 0.25 Group 2 0.21

[0077] According to the results in Table 2, the average root-to-shoot ratio of the method group of this invention was 0.25, significantly higher than the 0.21 of the control group with complete leaf removal pruning. This indicates that the "gradual leaf-preserving pruning + carbon-preserving branch establishment" technique in this invention can effectively maintain continuous root growth after pruning, ensure the underground support system required for the supply of nutrients and water to the aboveground parts, and maintain good root-leaf synergy. Conversely, the control group experienced a sudden interruption of carbon source supply after pruning, resulting in a temporary stagnation of root growth and limited root weight gain throughout the entire second fruiting cycle, ultimately leading to a lower root-to-shoot ratio.

[0078] Table 3 Net photosynthetic rate (μmol·m⁻¹) -2 ·s -1 )

[0079] Time Node Group 1 Group 2 Day of pruning 8.04 8.34 3 days after pruning 10.28 0 7 days after pruning 11.05 0 14 days after pruning 13.18 8.47 21 days after pruning 23.41 22.45

[0080] Table 3 compares the net photosynthetic rates of the first and second groups. Because the group using the method of this invention retained some mature leaves during the pruning and bud-promoting stage, the plants still possessed basic photosynthetic carbon supply capacity after topping and bud-promoting. Specifically, the average net photosynthetic rate on the day of pruning was 8.04 μmol·m⁻¹. -2 ·s -1 On day 3, it increased to 10.28 μmol·m -2 ·s -1 On day 7, it reached 11.05 μmol·m -2 ·s -1 This process effectively maintained the carbon source supply in the root zone and promoted the coordinated development of roots and cap. In contrast, the average net photosynthetic rate of the leaves in the conventional defoliation group, measured before defoliation, was 8.34 μmol·m⁻¹. -2 ·s -1 After pruning, the loss of all functional leaves is equivalent to a net photosynthetic rate of 0 μmol·m⁻¹ before the formation of functional leaves on new shoots. -2 ·s -1 This creates a distinct "photosynthetic gap." The average photosynthetic rate only recovers to 8.47 μmol·m⁻¹ after the new leaves unfold on the 14th day. -2·s -1 It is still lower than the 13.18 μmol·m⁻¹ of the same period in this invention group. -2 ·s -1 On day 21, the average net photosynthetic rate of new leaves in the control group reached 22.45 μmol·m⁻¹. -2 ·s -1 The average net photosynthetic rate of new leaves obtained by the method of this invention reached 23.41 μmol·m⁻¹. -2 ·s -1 The present invention group is still slightly superior. Therefore, the method of the present invention can effectively avoid the "photosynthetic window period" and ensure the continuity of root metabolism, which is a key measure to prevent root growth cessation after pruning.

[0081] Table 4. Ear Growth and Quality

[0082]

[0083] According to the results in Table 4, the method of the present invention effectively promoted the sprouting of new shoots and the development of fruit clusters in the second crop. Experimental investigations showed that the bud sprouting rate of the group using the method of the present invention reached 100%, achieving the sprouting of all predetermined buds, with uniform sprouting and an average sprouting time of 7.6 days after pruning; while the sprouting rate of other groups was also 100%, the average sprouting time was longer, and the sprouting was less uniform. Furthermore, the second crop of fruit obtained under the management of the first group of the present invention had better quality, characterized by larger and heavier fruit clusters, and a higher soluble solids (sugar content) content in the fruit compared to other groups.

[0084] In addition to improvements in root zone CO2 flux and fruit indicators, this invention also demonstrates significant advantages in root physiological structure. Figure 1 Comparative images of grape root morphology under transparent root windows 14 days after treatment with different pruning methods. Figure 1 A (above image) shows a plant with dense root system, many white roots, and strong activity, obtained using the "progressive leaf-preserving pruning + carbon-preserving branch" technology of the first group of this invention. Figure 1 Figure B (below) shows the second group of pruning methods. It was found that the conventional complete leaf removal in the second group led to inhibited root regeneration, sparse root fibers, an extremely low proportion of white roots, and root browning in some areas. This phenomenon confirms that the "gradual leaf-preserving and root-promoting pruning method" described in this invention significantly improves root structure and vitality, and is more effective than conventional pruning methods in preventing root stagnation and promoting new root regeneration, ensuring a stable root-to-crown ratio and the continuity of root zone function.

[0085] In summary, the comparative data from the embodiments fully demonstrate the superiority of the progressive leaf-preserving and root-promoting pruning method provided by this invention. By scientifically preserving leaves and controlling the environment during pruning and bud promotion after the first harvest, this method successfully avoids the negative impact on the plant's root system caused by excessive leaf removal in conventional methods, maintaining good root and shoot growth vigor, and ultimately significantly improving the yield and quality of the second grape harvest. This invention is characterized by its simple operation and significant effects, providing strong support for the widespread application of double-harvest grape cultivation.

[0086] The examples described above are merely illustrative of several embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A pruning method for maintaining root growth during the initiation period of the second crop of grapes harvested twice a year, characterized by: The method includes: (1) Establishment of carbon-preserving branches: After the first harvest, select two strong branches near the main trunk of the grapevine as "carbon-preserving branches" and retain them without pruning; the carbon-preserving branches are branches with sufficient healthy leaves and the fruit clusters have been removed; when the leaves of the second shoots can support the root system activity, prune the established carbon-preserving branches to the 6th node, keeping the same pruning node as the main fruiting mother branch; (2) Gradual leaf-preserving pruning: Within 35 days after the first harvest, a gradual pruning strategy is adopted for the remaining fruiting branches on the lateral arms of the main vine of the shaped structure, except for the carbon-preserving branches, as follows: a. During the first pruning, cut the fruiting mother branch to 6 nodes, removing only the leaves and petioles at the terminal bud node of the cut, while retaining all functional leaves at the other nodes; b. After the first pruning, 15 days later, perform a second pruning, removing some of the old leaves, including petioles, from the branches that were retained in the previous pruning, while still keeping a certain number of green leaves on the plant. Repeat this process of removing leaves in stages to gradually transition the plant so that it always has some leaves in operation.

2. A management method for maintaining root growth during the initiation period of the second crop of grapes harvested twice a year, characterized in that, The management method includes using the pruning method described in claim 1 in conjunction with other management methods to maintain the root growth of the plants during the initiation period of the second crop.

3. The management method according to claim 2, characterized in that, The management method includes: (1) Root irrigation: After the first harvest of fruit, the root zone of the grapevines is irrigated with root-promoting solution; (2) Sprouting: After the first batch of fruit is harvested, apply a sprouting agent to the buds that are to be sprouted. (3) Supplemental lighting: After pruning, supplemental lighting measures are implemented on the grapevines to extend the light duration of the retained leaves and promote the sprouting and growth of new shoots.

4. The management method according to claim 3, characterized in that, The root-promoting solution comprises the following components: liquid biostimulant, sucrose, indoleacetic acid, potassium sulfate, urea, chelated Zn / B trace elements, and Trichoderma preparation; the active ingredient of the liquid biostimulant is selected from: fucoidan oligosaccharides, humic acid, chitosan oligosaccharides, and amino acid chelates.

5. The management method according to claim 3, characterized in that, The germination agent is a cyanamide-based chemical germination agent.

Images