A method for transitional cultivation with vigorous root protection to overcome the obstacle of continuous planting of peach trees

Abstract

This invention provides a method for transitional cultivation with viable root protection to overcome the replanting obstacle of peach trees, aiming to solve the problems of severe replanting obstacles, long renewal cycles, and high costs in the traditional process of renewing old peach orchards. The method is achieved through the following steps: First-year pruning: After harvesting the fruit from the old peach trees, most of the lateral branches on the main branches are removed, leaving only a small number of branches and leaves to maintain the tree's survival. Subsequent watering is only managed according to soil moisture conditions; Planting new seedlings: In the autumn of the first year or the spring of the second year, new peach seedlings are planted between rows or individual trees of the old peach trees; Removing the main trunk of the old tree: In the autumn of the second year, the main trunk of the old peach tree is removed, retaining new root suckers to maintain root survival. The core of this invention lies in the "viable root protection transition" mechanism, which stabilizes the soil microecology by preserving the root system of the old tree, avoiding the concentrated release of autotoxic substances and explosive proliferation of pathogens caused by the sudden removal of old trees, thereby effectively overcoming the replanting obstacle. This method offers the following advantages: significantly improved survival rate of new peach seedlings (up to 92% or more); shortened renewal cycle, achieving a smooth transition in yield; substantial cost reduction; simple operation; and ease of promotion; while also meeting the needs of mechanized operations. This invention is applicable to the renewal of old orchards with stone fruit trees, providing an economical and efficient technical solution to overcome the obstacle of continuous cropping.

Description

Technical Field

[0001] This invention belongs to the field of fruit tree cultivation technology, specifically relating to a cultivation method to overcome the obstacle of continuous cropping (replanting) of peach trees, and in particular a cultivation method to renew old peach orchards or variety renewal by directly planting new peach seedlings between rows without removing the original peach trees, through the means of protecting the living roots. Background Technology

[0002] Peach trees are one of my country's important economic fruit trees, ranking among the world's top in both cultivation area and yield. Peach varieties are rapidly updated, and market demand for new varieties is strong. In actual production, orchard renewal mainly involves two scenarios: First, there is the renewal of trees due to aging: After peach trees have been planted for 8 to 10 years or more, their vigor weakens and their yield and quality decline significantly, requiring overall renewal.

[0003] Secondly, there is variety replacement: Some peach orchards, although the trees are relatively young (5-6 years old) and in good condition, have low economic returns due to the original varieties (e.g., long management cycle, high production costs, low fruit prices). Farmers hope to replace them with new varieties that have higher market value. Variety replacement can be done through top grafting, but this requires advanced grafting techniques, involves complex management processes, high labor costs, and the survival rate and graft compatibility vary depending on the variety combination, making it a high-risk process. Therefore, most farmers choose to directly replace the variety by "removing the old trees and planting new ones."

[0004] Whether it's renewal due to aging trees or renewal due to variety replacement, the traditional approach is "complete orchard removal – deep tilling and soil improvement – ​​fallow rotation – orchard reconstruction." This means first, all peach trees in the orchard are dug up, roots and all, and the soil is deeply tilled, disinfected, or rotated with other crops for 2-3 years before new peach seedlings are replanted. This method has the following prominent problems: 1. Severe problems caused by continuous cropping. During their growth, peach tree roots secrete phenolic acids such as amygdalin and phlorizin into the soil, which are considered autotoxic. Simultaneously, the decomposition of older roots releases toxic compounds like hydrocyanic acid. Furthermore, soils planted with peach trees for extended periods accumulate specific pathogenic microorganisms (such as Fusarium spp., Phytophthora spp., and Meloidogyne spp.), disrupting the soil's microecological balance. Even after deep tilling and disinfection, newly planted peach seedlings commonly exhibit symptoms of continuous cropping problems, including slow growth, poor root development, and even death. The survival rate is typically only 60%–75%, and in severe cases, it can be below 50%. Moreover, the growth of surviving plants is 30%–50% lower than that of newly established orchards, leading to poor orchard establishment results or even failure.

[0005] 2. Long renewal cycle and yield gap. From the removal of old trees to the new trees reaching their peak fruiting period, the entire process usually takes 5 to 6 years or even longer. During this period, fruit farmers have no peach production, and their economic income is completely interrupted.

[0006] 3. High cost. Measures such as old tree excavation, deep soil tilling and disinfection, fallow management or soil replacement all require a large investment of manpower, material resources and financial resources. The cost of renewal per acre is usually more than 3,000 to 5,000 yuan.

[0007] To address the above problems, some improvements have been proposed in the existing technology. For example: CN113179840A discloses a method for renewing old orchards in plain areas. The core of this method is to plant new seedlings between rows without immediately removing the old trees, while subjecting the old trees to "severe pruning" (i.e., retaining the canopy framework while reducing the crown width) to maintain their fruiting capacity. The old trees are then removed after the new trees have grown (approximately 3 years). The core logic of this scheme is "space management"—by pruning the old tree canopy, it frees up light and space for new growth while maintaining the yield of the old trees to achieve "using old trees to support new ones, seamless transition."

[0008] CN201410381941.1 discloses a method for rapid renewal of old peach orchards, which adopts root pruning treatment + rooting powder to promote root growth + organic fertilizer to improve soil, and transplants the treated old trees to other places. It mainly solves the problem of rejuvenation of old trees and rapid recovery of yield, and does not involve the technical means of planting new seedlings between rows.

[0009] While CN113179840A achieves the renewal effect of "no tree uprooting, no interruption," its "severe pruning" of old trees is essentially a conventional technique within the scope of horticultural pruning. The old trees retain their canopy framework and continue to flower and bear fruit. In this approach, the old tree canopy layer (severe pruning will cause the peach tree to sprout a large number of new branches) still has a certain shading effect on the new growth. Furthermore, the technical path of "severe pruning - continuous fruiting - gradual removal" determines that the old trees always play the role of producers, without consciously utilizing the old tree root system to regulate the soil ecological environment to overcome the continuous cropping obstacle.

[0010] Therefore, there is an urgent need to develop a method for replanting old peach orchards that can overcome the problem of continuous planting of peach trees at its root, achieve a stable transition in yield during the renewal period, and is easy to operate and cost-controlled. Summary of the Invention

[0011] Technical problems to be solved The technical problem this invention aims to solve is as follows: In existing peach orchard renewal methods (including old tree aging renewal and variety replacement renewal), there are problems such as the difficulty in overcoming continuous replanting obstacles, the continuous secretion of autotoxic substances by the roots of the original peach trees affecting the growth of new seedlings, the unavoidable competition between the roots of the original peach trees and the new seedlings, the high technical threshold of top grafting and replacement, the high cost and long cycle of uprooting old trees and planting new ones, and the high cost of seedlings resistant to continuous replanting. This invention provides a cultivation method that can fundamentally alleviate the continuous replanting obstacles of peach trees, is simple to operate, and has low cost.

[0012] Technical solution To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for overcoming the continuous cropping obstacle of peach trees through vigorous root protection transitional cultivation includes the following steps: (1) Heavy pruning after the first harvest: After the old peach trees have harvested their fruit, most of the lateral branches on the main branches of the old peach trees are removed, leaving only a small number of branches and leaves to maintain the survival of the tree. After that, watering is only carried out according to the soil moisture, and no other production management operations (such as fertilization, pruning, pest and disease control) are carried out on the old peach trees. (2) Planting new seedlings between rows or between plants: In the autumn of the first year or the spring of the second year, new peach seedlings are planted between rows or between plants of old peach trees; when planting between rows, the new peach seedlings are planted between two rows of old peach trees; when planting between plants, the new peach seedlings are planted between two adjacent old peach trees in the same row, and the space between rows is reserved for mechanized operations. (3) Saw off the old tree trunk in the second year: In the autumn of the second year, saw off the old peach tree trunk. After sawing, retain 2 to 3 new branches that sprout from the root and keep them below 40cm in height to ensure that the root system does not die until the new peach tree grows up.

[0013] Technical mechanism ("living root protection transition" mechanism) This invention differs fundamentally from existing technologies in its technical concept. Its core lies in proposing a "living root protection transition" mechanism, which is explained in detail below: Phase One – Reducing Old Trees to “Living Root Bioregulators” (From the first harvest to the autumn of the second year): Traditional techniques (such as CN113179840A) involve “severe pruning” of old trees to preserve the canopy framework and fruiting capacity, keeping the old trees as productive fruit trees. This invention takes the opposite approach – removing most of the lateral branches on the main branches of the old tree, significantly simplifying the canopy structure, and retaining only a very small number of branches and leaves to maintain the tree's minimum viability. Specifically: for central-trunk old peach trees, the original trunk height is maintained, and most of the large fruiting branch groups on the trunk are removed, retaining only a small number of small fruiting branches evenly distributed on the trunk; for multi-trunk open-center old peach trees, all main branches are retained, with only 2-4 small branch groups retained on each main branch. Photosynthetic products are only sufficient to maintain the energy required for the root system's basic metabolism. At this point, the old tree has lost its fruiting capacity, and its above-ground parts are intentionally downgraded, but the underground parts – the old tree's root system – remain alive. During this stage, only the most basic watering management is carried out (maintaining soil moisture at a depth of 20cm where the soil can be formed into a ball when squeezed but crumbles when released). The height of newly sprouted branches from the roots of old peach trees is controlled to be below 40cm (so as not to affect the growth of newly planted peach seedlings). No more fertilizer is applied, and no pest or disease control is carried out. The purpose is to keep the old trees in a physiological state of "survival only, no fruit production".

[0014] The second stage—planting new seedlings and rhizosphere transition (starting in autumn of the same year or spring of the following year): While the old tree roots are still viable, new peach seedlings are planted in raised beds between rows of old peach trees or between individual trees. The horizontal distance between the planting location and the main trunk of the adjacent old tree should be no less than 1.2 meters. Whether planted between rows or between individual trees, the selected locations have relatively fewer old peach tree roots, resulting in lower accumulation of autotoxic substances. Simultaneously, the presence of the old tree's living root system maintains the basic structure and functional stability of the rhizosphere soil microbial community, avoiding drastic fluctuations in the soil microecology caused by the sudden death of old trees and root rot (such as explosive proliferation of pathogens and concentrated release of autotoxic substances), providing a relatively stable soil biological environment for the colonization and expansion of the new seedling roots. Raised bed cultivation further improves the aeration and drainage conditions for the new seedling roots, and the applied organic fertilizer provides sufficient nutrients for the newly grown roots. It is worth noting that when interplanting is adopted, the space between rows is completely preserved, which facilitates the subsequent mechanized management of the new peach orchard, such as mechanical rotary tillage, mowing, and spraying, thus meeting the dual needs of overcoming continuous cropping obstacles and mechanized orchard management.

[0015] The third stage – Termination of the old tree's above-ground parts (autumn of the second year): After a transition period of about one year, the new peach seedlings have initially survived and established a certain root system. At this time, the main trunk of the old tree is cut off (the cut is 5-20cm above the ground), leaving only some suckers. However, the root system of the old tree still survives (usually for 1-3 years) and will not cause the release of autotoxic substances. At the same time, the roots of the new seedlings have begun to secrete metabolic products autonomously, gradually establishing their own rhizosphere microbial community.

[0016] In summary, the core of this invention lies in actively transforming old peach trees from "fruit producers" to "soil biological regulators." This is achieved through a step-by-step process: removing most lateral branches to eliminate competition, retaining main branches and a small number of leaves to maintain root survival, and sawing the trunk while leaving the roots for a smooth transition. This utilizes the survival of the old tree's root system to maintain the stability of the rhizosphere microecology, providing a stable soil environment for the growth of new seedlings, thereby overcoming the obstacle of continuous peach tree planting. This technical concept is not disclosed or taught in existing technologies.

[0017] Beneficial effects Compared with the prior art, the present invention has the following beneficial effects: 1. Effectively overcomes the obstacle of continuous cropping. Through the "living root protection transition" mechanism, after removing most of the lateral branches on the main branches of the old tree, the competition for light and water and fertilizer between the old tree and the new seedlings is relieved by significantly reducing the amount of branches and leaves. At the same time, the survival of the old tree's root system is maintained to stabilize the rhizosphere microecology. This avoids the problems of soil microecological collapse, concentrated release of autotoxic substances, and explosive proliferation of pathogens caused by the sudden removal of old trees in traditional methods. Experiments show that the survival rate of new peach seedlings using the method of this invention reaches 92%, which is significantly higher than the 65% to 75% of the traditional method of completely removing and replanting the entire orchard. The growth of the new seedlings is not significantly different from that of peach trees in newly established orchards (non-continuous cropping soil), fundamentally solving the obstacle of replanting peach trees after continuous cropping.

[0018] 2. Achieving a smooth transition in yield. In the first year (the year of pruning), the old trees have already completed their fruiting for that year before pruning. Although they will no longer bear fruit after pruning, the new seedlings have already been planted in the autumn of that year or the following spring. There is only a short-term interruption in yield during the entire renewal cycle, which is basically connected with the new trees entering the initial fruiting period (2-3 years after planting). Compared with the traditional method of completely uprooting the entire orchard (which usually results in a 3-5 year period without yield), this significantly reduces the economic losses for fruit growers.

[0019] 3. Significantly reduced renewal costs. This method eliminates the arduous labor of digging up old tree roots (saving approximately 8-12 man-days per acre), and also eliminates the need for deep soil tilling and fallow rotation. Only basic pruning, ridging, and watering management are required. Based on labor costs in Pingdingshan (70 yuan / day for female workers, 100-120 yuan / day for male workers), the renewal cost per acre using this method is approximately 3050 yuan, a reduction of about 32% compared to the traditional method (approximately 4500 yuan).

[0020] 4. Simple to operate and easy to promote. The method and steps are clear and the operation is simple. Ordinary fruit farmers can implement it after simple training, and it has good prospects for promotion and application.

[0021] 5. Mechanization needs are also taken into account. When interplanting is used, the space between rows is completely preserved without any obstacles. After the new peach orchard is established, mechanized operations such as rotary tillage, mowing, and spraying can be carried out normally, which solves the problem of difficulties in mechanized operations caused by the occupation of space between rows in traditional renewal methods. Attached Figure Description

[0022] - Figure 1 The flowchart of the cultivation method of this invention shows the time sequence of pruning in the first year, planting new seedlings in ridges between rows, and sawing the trunk in the second year.

[0023] - Figure 2 A schematic diagram comparing the tree structure of an old peach tree before and after pruning, showing the state of the tree crown being greatly simplified and only the main branches and a small number of branches and leaves are retained after most of the lateral branches on the main branches are removed (taking the central leader shape and the open center shape as examples respectively).

[0024] - Figure 3 : A schematic diagram of the plan layout for planting new seedlings in ridges between rows, showing the spatial relationship of planting new seedlings between two rows of old peach trees, with a horizontal distance of not less than 1.5m from the main trunk of the adjacent old tree.

[0025] - Figure 4 A schematic diagram of the transition mechanism of living root protection shows the dynamic relationship and smooth transition process among the living root system of old trees, the root system of new seedlings, and the soil microbial community.

[0026] - Figure 5 Example 1: A bar chart comparing the survival rate and growth of the method of the present invention with that of the traditional method. Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention. Unless otherwise specified in the embodiments, conventional conditions are followed.

[0028] Example 1: Fruit and Forest Base in Shihuiyao Village, Baofeng County, Pingdingshan City (Zhongtao Jinkui) Experimental location: Shihuiyao Village Forest and Fruit Base, Baofeng County, Pingdingshan City, Henan Province. It belongs to the warm temperate continental monsoon climate zone, with an average annual temperature of 14.5℃, an annual precipitation of about 650mm, and the soil type is brown soil with a pH value of 7.1.

[0029] Basic information about the old peach orchard: The trees are 5 years old, and the variety is winter peach (a late-maturing hairy peach). This variety has a long management cycle, high production costs, serious pest and disease problems, and low market value of the fruit. It urgently needs to be replaced with a new variety with higher economic benefits. The rootstock is hairy peach rootstock, with a plant spacing of 2.5m × 4m, oriented east-west. The trees are vigorous, with a yield of about 800 kg / mu. There are many missing trees, and some trees have gummosis on their main trunks.

[0030] New seedling variety: Zhongtao Jinkui, rootstock is peach rootstock.

[0031] Implementation steps: (a) Mid-October of the first year (after fruit harvest): Severe pruning of old trees After all the fruit has been harvested, the old peach trees are subjected to severe pruning. In this embodiment, the old peach orchard has a multi-branch open-center shape. According to the treatment method of the open-center tree described in claim 3: most of the lateral branches on each main branch are removed using a pruning saw, leaving all the main branches, and each main branch retains only 2 to 4 small branch groups.

[0032] After pruning, the canopy of old trees is greatly simplified. Although the main branches are retained, most of the lateral branches have been removed, resulting in a significant reduction in photosynthetic area. The fruit trees lose their ability to bear fruit and can only maintain a minimum amount of photosynthesis to support the basic metabolism of the root system.

[0033] (ii) Mid-October of the first year to late October of the second year: Watering management only From the time the branches are removed until the trunk is sawn in the autumn of the following year, the old peach trees after the branches are removed are only watered according to the soil moisture, and no further production management operations such as fertilization, pruning, spraying, thinning flowers and fruits are carried out.

[0034] The criteria for judging watering management are as follows: Take a soil sample at a depth of 20cm from the surface. If the soil can be formed into a clump when squeezed in your hand and crumbles when released, the soil moisture is considered suitable. If it cannot be formed into a clump (the soil is too loose), then water it. If it can be formed into a clump and does not crumble when released (the soil is too wet and tends to accumulate water), then do not water it. Each watering should be done until the water penetrates to a depth of 30-40cm. Check the soil moisture every 7-15 days, depending on the weather and soil conditions.

[0035] The purpose of this management method is to keep the old tree roots alive but in a low-activity state, so that the photosynthetic products are only used to maintain the basic metabolism of the roots, prevent the tree from sprouting a large number of new shoots, and avoid wasting water and fertilizer.

[0036] (III) Mid-to-late November of the first year: Make ridges between rows and plant new peach seedlings. In late November (after the new seedlings have shed their leaves and before the soil freezes), ridging and planting are carried out between two rows of old peach trees. Before ridging, 2000 kg of well-rotted sheep manure organic fertilizer is evenly spread per acre. The ridging specifications are the same as those for conventional peach tree planting: the ridge surface is 1.2 m wide, the ridge height is 20-30 cm, and the ridge direction is consistent with the direction of the old tree row.

[0037] New seedlings are planted on raised beds, with planting holes measuring 50cm × 50cm × 40cm (length × width × depth), and the planting location is in the center of the row. The plant spacing is 3m, and the row spacing is the same as the old peach orchard's 4.0m (the new seedling bed is located in the middle of two rows of old trees).

[0038] When planting, place the seedling in the planting hole, ensuring the roots are spread out. The grafting point should be 5-10cm above the ridge surface. Fill with topsoil and tamp it down, then water thoroughly. After planting, cover the planting basin with a 1.0m wide strip of black horticultural ground cover to retain moisture, prevent weeds, and increase soil temperature.

[0039] New peach seedlings should be selected from first-grade seedlings of the Jin Kui variety of peach grafted onto hairy peach (seedling height ≥ 1.2m, base diameter ≥ 1.0cm, number of lateral roots ≥ 5).

[0040] (iv) Late October of the following year: Saw off the main trunk of the old tree. In late October of the following year (around the time when new seedlings stop growing and begin to shed their leaves), use a chainsaw to cut off the main trunk of the old peach tree from the base. The cut should be 10-15 cm above the ground. New shoots growing from the roots after the cut should be retained, with a height controlled at 40 cm. The old tree's root system should remain in the soil without being dug up.

[0041] (v) From the third year onwards: routine management of new seedlings Starting in the spring of the third year, new peach seedlings are managed with fertilizer and water, pruned (using a Y-shape), and treated for diseases and pests (with a focus on aphids, peach fruit moth, and bacterial leaf spot) according to conventional peach orchard cultivation techniques. Some plants begin to bear fruit in the third year, gradually enter the initial fruiting period from the fourth year, and enter the peak fruiting period in the fifth and sixth years.

[0042] Example 2: Fruit and Forest Base (Blood Peach) in Shanshenmiao Village, Dongzhou Township, Lushan County, Pingdingshan City Experimental site: Forestry and fruit base in Shanshenmiao Village, Dongzhou Township, Lushan County, Pingdingshan City, Henan Province. It belongs to the warm temperate continental monsoon climate zone, with an altitude of about 300m, an average annual temperature of 14.2℃, an annual precipitation of about 680mm, and the soil type is brown soil with a pH value of 6.8 and low soil organic matter content.

[0043] Basic information about the old peach orchard: The trees are 6 years old, the variety is a mid-maturing nectarine, the rootstock is hairy peach, the spacing between trees is 3m × 4m, and the rows are oriented north-south. The trees are weak, and the yield is about 700 kg / mu.

[0044] New seedling variety: Blood Peach (a local specialty variety), rootstock is Prunus pubescens.

[0045] Implementation steps: Step 1, late August of the first year (after fruit harvest): Severe pruning of old trees The operation is the same as in Example 1.

[0046] The second step, from late August of the first year to late October of the second year: Watering management only. The operation is the same as in Example 1, and the soil at a depth of 20cm from the ground surface is used as the criterion for watering: "it can be clumped in your hand but crumbles when dropped."

[0047] The third step, in early March of the following year: ridging the rows and planting new peach seedlings. In early to mid-March of the following year, the seedlings were planted among the existing peach trees, with a horizontal distance of 1.5m from the main trunk of two adjacent existing peach trees (directly between the two trees). The spacing between trees was 3m, and the row spacing was 4m. After planting, the seedlings were thoroughly watered, and the tree basins were covered with black horticultural ground cover. The new peach seedlings were first-grade seedlings of the Blood Peach variety grafted onto Prunus cerasifera rootstock.

[0048] Step 4, late October of the following year: Saw off the main trunk of the old tree. The operation is the same as in Example 1.

[0049] Step 5, from the third year onwards: Routine management of new seedlings Same as Example 1.

[0050] Comparative Example 1 (Traditional complete garden uprooting and replanting) In another old peach orchard in the same area and with the same tree age as in Example 1, the traditional method was used for renewal. The specific operation was as follows: In the autumn of the first year, all old peach trees were dug up and removed by the roots, the soil was deeply tilled to a depth of 50cm, the remaining root system was removed, and the orchard was left fallow for one year. In the spring of the third year, new seedlings of the same variety and size of Zhongtao Jin Kui (with the same rootstock of Prunus serrulata) were planted in the conventional way (without raising ridges), and managed according to the conventional peach orchard cultivation techniques.

[0051] Comparative Example 2 (planting in ridged soil with continuous cropping, without root protection) In the same area as Example 1, a plot of soil where the original peach trees had been removed two years prior was selected. The same specifications were used to create raised beds and apply the same amount of organic fertilizer as in Example 1. New seedlings of the same variety and size were then planted and managed according to conventional peach orchard cultivation techniques. The only difference between this comparative example and the method of this invention is that this plot lacked surviving old tree root systems (the original peach trees had been removed two years prior), and the soil lacked the stabilizing effect of living root systems on the rhizosphere microecology. By comparing with Example 1, the independent contribution of the "living root protection transition" mechanism to overcoming replanting obstacles can be identified.

[0052] Effect verification The growth of seedlings in Examples 1, 2, 1 (Comparative Example), and 2 (Comparative Example 2) was monitored and measured. The results are as follows: Table 1 Comparison of growth indicators at the end of the second growing season (October) after seedling transplanting Seedling survival rate (%) **92.3** **91.8** 68.5 78.2 Plant height growth (cm) 122.5 115.8 68.4 82.6 Main trunk diameter growth (mm) 16.5 15.8 9.2 11.5 Crown diameter (cm, East-West × North-South) 145×138 136×128 82×75 98×92 Average length of new shoots (cm) 68.5 62.3 35.2 46.8 Table 2 Comparison of soil biological indicators (measured in September of the second year after planting, 0-40cm soil layer) Soil fungi / bacteria ratio 0.18 0.41 0.32 0.15 Fusarium count (×10³ cfu / g dry soil) 2.3 11.8 7.5 1.8 Soil urease activity (mg / g·24h) 1.82 0.95 1.21 1.95 Soil organic matter content (g / kg) 15.8 11.2 13.5 16.3 Table 3 Comparison of Renewal Costs (Yuan / Mu) Old tree treatment (repairing / tree digging) - manual 300 1200 Soil preparation ( ridging / deep plowing) 400 800 Organic fertilizer input 1000 1000 Retirement period management 0 300 Watering management manual 150 0 New seedlings and artificial planting 1200 1200 **total** **3050** **4500** Results analysis: (1) Survival rate: The survival rates of seedlings in Example 1 and Example 2 reached 92.3% and 91.8%, respectively, which were about 24 percentage points higher than those in Comparative Example 1 (68.5%) and about 14 percentage points higher than those in Comparative Example 2 (78.2%). This indicates that the "root protection transition" mechanism has a significant effect on improving the survival rate of seedlings, and this effect is independent of the conventional soil improvement effects of ridging and organic fertilizer.

[0053] (2) Regarding growth: The plant height growth (122.5cm and 115.8cm) and trunk diameter growth (16.5mm and 15.8mm) of Examples 1 and 2 were not significantly different from the normal growth of peach trees in newly established orchards (without continuous cropping soil) (annual plant height growth of about 100-150cm and annual trunk diameter growth of about 15-20mm). However, the growth of Comparative Examples 1 and 2 was only about 56% and 67% of that of Example 1, respectively. This indicates that the method of the present invention restores the growth of seedlings in continuously cropped soil to the normal level in non-continuous cropping soil, fundamentally overcoming the obstacle of continuous cropping.

[0054] (3) Soil biological indicators: The soil fungal / bacterial ratio (0.18) and Fusarium count (2.3 × 10³ cfu / g) in Example 1 were close to the levels of newly established orchards without continuous cropping (0.15 and 1.8 × 10³ cfu / g), indicating that the survival of the living root system of old trees effectively inhibited the explosive proliferation of harmful fungi in continuously cropped soils and maintained the healthy structure of the soil microbial community. The Fusarium count (11.8 × 10³ cfu / g) in Comparative Example 1 was about 5 times that of Example 1, and the fungal / bacterial ratio (0.41) was also significantly higher, indicating that the sudden removal of old trees led to an imbalance in the soil microecology. The indicators of Comparative Example 2 were improved but still significantly worse than those of Example 1, further confirming the independent contribution of the "living root protection transition" mechanism.

[0055] (4) Cost: The renewal cost per mu of the method of this invention is about RMB3,050, which is only about 68% of the traditional method (RMB4,500). The main savings are in labor costs for digging up old trees (RMB900 / mu) and deep plowing (RMB400 / mu). The input of organic fertilizer is RMB1,000 / mu (2,000 kg), which is the same as the traditional method. Although this invention generates additional labor costs for watering and management (about RMB150 / mu), the total cost is still significantly lower than that of the traditional method.

[0056] (5) Regarding yield transition: In Examples 1 and 2, the old trees in the first year had already completed their fruiting before pruning. Although they no longer bear fruit after pruning, the new seedlings were planted in the autumn of the same year or the spring of the following year, and some fruiting could be achieved in the third year after planting. Compared with Comparative Example 1 (no yield in the first year after digging up the trees, no yield in the second year after leaving the trees fallow, no yield in the third year after planting, and a small amount of fruiting in the fourth to fifth years, i.e., almost no yield for 3 to 4 years), the yield gap period of the method of this invention is significantly shortened.

[0057] Other implementation methods It should be noted that although the above embodiments of the present invention are described for peach trees, the technical principle of the present invention—that is, the living root protection transition mechanism of "overcoming continuous cropping obstacles by stabilizing the rhizosphere microecology by maintaining the living root system of old trees"—is also applicable to other stone fruit trees with obvious continuous cropping obstacles, including but not limited to plum (Prunus salicina), apricot (Prunus armeniaca), cherry (Prunus avium, Prunus pseudocerasus), etc.

[0058] Furthermore, for different climate regions (such as the rainy areas in the south and the arid areas in the northwest), the watering management parameters and planting time windows can be adjusted appropriately according to the specific local conditions. As long as the core technical route of "removing most of the lateral branches to protect the roots - transitioning to root survival - sawing the trunk and leaving the roots" is followed, it should be considered to fall within the protection scope of this invention.

[0059] For those skilled in the art, without departing from the principle of the present invention, several improvements and adaptive adjustments can be made to the technical parameters such as the tree age range, planting row spacing, type and amount of organic fertilizer in the specific embodiments of the present invention, and these improvements and adjustments should also be considered within the scope of protection of the present invention.

Claims

1. A living root protection transition cultivation method for overcoming the obstacle of peach tree heavy cropping, characterized by, Includes the following steps: (1) In the first year, after the old peach trees have harvested their fruit, most of the lateral branches on the main branches of the old peach trees are removed, leaving only a small number of branches and leaves to maintain the survival of the trees. After that, watering management is carried out only according to the soil moisture, and no other production management operations are carried out on the old peach trees. (2) In the autumn of the first year or the spring of the second year, new peach seedlings are planted between rows or individual trees of old peach trees; (3) In the autumn of the second year, the main trunk of the old peach tree was cut off. After the cutting was done, the new shoots that sprouted from the roots were retained to ensure that the root system did not die. The height was controlled to be below 40cm.

2. The cultivation method according to claim 1, characterized by, The row spacing of the old peach trees mentioned in step (1) is more than 3 meters, preferably more than 4 meters.

3. The cultivation method according to claim 1, characterized in that, The phrase "only a few branches and leaves" in step (1) means that if the old peach orchard tree is a trunk-type tree, the original trunk height is kept unchanged, most of the large fruiting branches on the trunk are removed, and only a few small fruiting branches are kept so that they are evenly distributed on the trunk; if the old peach orchard tree is a multi-main-branch open-center tree, all main branches are kept, and only 2 to 4 small branches are kept on each main branch.

4. The cultivation method according to claim 1, characterized in that, The watering management mentioned in step (1) based on soil moisture means maintaining the soil moisture content in the root distribution layer of old peach trees in the following state: at a depth of 20cm from the ground surface, the soil can be formed into a ball when squeezed and will crumble when released to the ground, so as to maintain the survival of the old peach tree roots.

5. The cultivation method according to claim 1, characterized in that, The horizontal distance between the new peach seedling planting location and the main trunk of the adjacent old peach tree in step (2) shall not be less than 1.2m.

6. The cultivation method according to claim 1, characterized in that, When planting in step (2) is inter-row planting, the new peach seedlings are planted between two rows of old peach trees; when planting is inter-planting, the new peach seedlings are planted between two adjacent old peach trees in the same row, and the inter-row space is reserved for mechanized operations.

7. The cultivation method according to claim 1, characterized in that, In step (2), before planting, ridges are made between rows or between trees of old peach trees. The ridge specifications are the same as those for conventional peach tree planting. Before ridge making, apply 1000-2000 kg of well-rotted organic fertilizer per mu, preferably 2000 kg per mu.

8. The cultivation method according to claim 1, characterized in that, The spacing between new peach seedlings in step (2) is 2.5-3m, and the row spacing is 3-5.0m.

9. The cultivation method according to claim 1, characterized in that, In step (3), when sawing off the main trunk of the old peach tree, the cut should be 5-20cm above the ground. After sawing, the newly sprouted shoots at the base should be retained, with the height controlled below 40cm.

10. The cultivation method according to any one of claims 1 to 9, characterized in that, The method is applicable to the renewal of old orchards with stone fruit trees, including at least one of peach, plum, apricot, and cherry.

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