A device and method for safe planting of plants in chromium-contaminated soil

Abstract

This invention discloses a device and method for the safe cultivation and utilization of plants in chromium-contaminated soil. The structure includes an insertion rod, a fixing frame, a main frame, a groove, a protrusion, a locking block, a baffle, and an extended fixing frame. The insertion rod penetrates the main frame and is movable. The fixing frame is placed above the main frame and can be disassembled. The groove and protrusion are assembled on the side surface of the main frame, and the locking block is fixed to the lower surface of the main frame. The baffle and the main frame are an integrated structure. The insertion rod includes a limiting block, a pushing block, a force-bearing rod, and a fixing rod. The limiting block is installed on the upper surface of the main frame, the pushing block and the force-bearing rod are an integrated structure, and the fixing rod is installed at the bottom of the force-bearing rod. After transplanting the *Plectranthus amboinicus*, the surface soil is first compacted, and then the main frame is used to move the plant into the bottom soil layer. Vertical reinforcement is achieved by the outer shell, and lateral support is provided by the extended body. This structure ensures that the soil of the *Plectranthus amboinicus* inside the main frame is tightly compacted and firmly bonded to the bottom soil, enhancing overall stability.

Description

Technical Field

[0001] This invention belongs to the field of planting, and more specifically, it relates to a device and method for the safe planting and utilization of plants in chromium-contaminated soil. Background Technology

[0002] The safe phytoremediation of chromium-contaminated soil refers to the planting of specific plants in chromium-contaminated soil using scientific phytoremediation techniques and agricultural management practices. These plants absorb, fix, or transform chromium in the soil, reducing its toxicity and mobility. By selecting low-accumulation crops or non-food plants, agricultural, ecological, or economic benefits can be achieved simultaneously with soil remediation, while preventing pollutants from entering the food chain.

[0003] With functions such as improving sleep and reducing swelling and itching, Plectranthus amboinicus has been developed into various products, including essential oil, flavored tea, mosquito repellent, anti-swelling and anti-itch composition for infants, and antibacterial handmade soap. In addition, it is widely used in the food and medical industries, which fully demonstrates that Plectranthus amboinicus is a plant with high economic benefits. More importantly, Plectranthus amboinicus has a high propagation rate and strong reproductive capacity through cuttings, and there are no seasonal restrictions. The cuttings are adaptable and grow quickly, fully demonstrating that Plectranthus amboinicus has a rapid reproductive and growth capacity. However, because the soil on the slopes of mines where Plectranthus amboinicus is planted needs further treatment, the treated and mixed surface layer will form a soft and hard layer with the bottom layer, making it easier for Plectranthus amboinicus to slip and fail during planting. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention provides a device and method for the safe cultivation and utilization of plants in chromium-contaminated soil, the purpose and effectiveness of which are achieved through the following specific technical means:

[0005] Its structure includes an insertion rod, a fixing frame, a main frame, a groove, a protrusion, a locking block, a baffle, and an extension fixing frame. The insertion rod passes through the main frame and is movable. The fixing frame is placed above the main frame and can be disassembled. The groove and protrusion are assembled on the side surface of the main frame. The locking block is fixed to the lower surface of the main frame. The baffle and the main frame are an integrated structure. The extension fixing frame and the fixing frame can be used interchangeably.

[0006] The insertion rod includes a limiting block, a pushing block, a force-bearing rod, and a fixing rod. The limiting block is installed on the upper surface of the main frame, the pushing block and the force-bearing rod are an integrated structure, and the fixing rod is installed at the bottom of the force-bearing rod.

[0007] The fixed rod includes a drill bit, a spring, an elastic opening, an extension body, a housing, and a push rod. The spring is installed between the drill bit and the push rod. The elastic opening passes through the housing to connect the inner and outer spaces. The extension body is connected to the bottom of the push rod. The push rod and the force-bearing rod are an integrated structure. The housing and the main frame are an integrated structure. Each group of extension bodies and elastic openings has four in each group, which are evenly distributed in a circle.

[0008] The bottom of the drill bit has a pointed structure, which can better penetrate into the soil. The top of the drill bit has an inclined angle, which can assist the extension body to move out. The elastic opening unfolds into a petal-shaped structure under the thrust of the extension body, and maintains its own elasticity. It returns to its original shape when the extension body returns to its position. When the extension body moves, it will extend in four directions. Each group of grooves and protrusions has two and can be snapped together with new groups.

[0009] As a further improvement of the present invention, the card block assists the main frame to increase the adhesion between the main frame and the soil and is distributed in a V-shape at the four corners. The baffle assists the assembly of the fixing frame and is provided in four. When the main frame is pressed down, the main frame can be made to be more compact with the soil.

[0010] As a further improvement of the present invention, the fixed rods are provided in groups of two, totaling four. When the push block is pressed down, it is fixed by the limiting block. When the limiting block moves to the side, the force rod will return to its original position by the support of the spring. The outer shell is fixed vertically, and its extension body is fixed laterally. There are four limiting blocks in total, and they are provided in groups of two. The force rod can be released by pressing them to both sides.

[0011] As a further improvement of the present invention, the fixing frame includes a fixing plate, a pull rod, a limiting rod, a limiting frame, and a magnetic block. The fixing plate and the limiting rod are an integrated structure. The pull rod passes through the limiting rod and is movable. The limiting frame and the pull rod are an integrated structure. The magnetic block is connected to the limiting frame. The pull rod has an L-shaped structure, and the vertical rod is convenient for external force to push.

[0012] As a further improvement of the present invention, the limiting frame is a semi-circular structure, and two can be combined to form a circle. The combined range of the limiting frame can stabilize the plant. The pull rod can move horizontally along the limiting rod, and the fixing plate is placed on the baffle.

[0013] As a further improvement of the present invention, the extension fixing frame includes a socket ring and a support bar. The support bar is inserted into the socket ring groove and can be installed and removed. The support bar is an elastic support steel bar that provides auxiliary support for the branches and leaves.

[0014] As a further improvement of the present invention, the method for safely planting and utilizing chromium-contaminated soil is as follows:

[0015] 1. Propagation of Plectranthus: Select healthy, disease-free Plectranthus plants as the mother plant. Take tender branches with 4 leaves and 1 terminal bud from the leaf axil as cuttings. Insert the cuttings into a seedling tray filled with nutrient soil. Water thoroughly immediately after planting and move to a greenhouse for cultivation. The cultivation period is 30 days, during which time water thoroughly every 3-4 days.

[0016] II. Treatment of Chromium-Contaminated Soil: Remove and clean up waste, weeds, stones, and other substances detrimental to plant growth from the chromium-contaminated soil on the mine slopes. The contaminated soil also requires conventional tillage treatments such as loosening and ridging. The pre-treated chromium-contaminated soil (chromium content: 3100±100 mg / kg) can be mixed with three types of fillers at a 1:1 volume ratio to prepare different cultivation substrates: Filler 1: Chromium-contaminated soil + yellow soil (chromium content: 2300±100 mg / kg, labeled T1); Filler 2: Chromium-contaminated soil + nutrient soil (chromium content: 2000±10 mg / kg, labeled T2); Filler 3: Chromium-contaminated soil + a mixture of yellow soil and nutrient soil (volume ratio 1:1, chromium content: 1800±10 mg / kg, labeled T3).

[0017] 3. Transplanting of Plectranthus: Select healthy Plectranthus plants that are 5 cm tall and free from pests and diseases. Loosen the substrate around the seedling tray with a small shovel, then remove the plant from the tray, being careful not to damage the roots. After removing the plant, gently shake off the nutrient-rich soil around the roots, and retain one main branch and two lateral branches. Remove the remaining leaf buds and lateral branches. Plant the plant on the slope of the mine, inserting the main frame into the pre-treated soil. Secure the plant in place with the fixing frame, and water it immediately after transplanting.

[0018] IV. Plectranthus amboinicus cultivation and management: Within 10 days of transplanting, water once every 4-5 days at 6:00 AM. Subsequently, water once every 10-15 days to keep the soil moisture content at 30%-40% of field capacity. After the plant has grown and stabilized for a period of time, the fixing frame and main frame can be removed in sequence.

[0019] The nutrient soil is a mixture of peat moss and perlite in a weight ratio of 10:1.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. After transplanting the Plectranthus amboinicus, first compact the surface soil, then move it into the bottom soil through the main frame. The outer shell provides vertical reinforcement, and the outer extension provides lateral support. This structure ensures that the soil of the Plectranthus amboinicus inside the main frame is tightly compacted and firmly combined with the bottom soil, enhancing the overall stability.

[0022] 2. While the main frame stabilizes the soil of the Plectranthus amboinicus, install the fixing frame above the main frame to further support and limit the plant and soil, ensuring that the Plectranthus amboinicus can grow stably. After the root system of the Plectranthus amboinicus has developed and stabilized, the fixing frame and the main frame can be removed in turn to complete the entire planting process.

[0023] 3. The *Plectranthus amboinicus* plants cultivated by this invention exhibit uniform growth, with consistent growth, numerous and robust branches, and thick and dense leaves. This effectively reduces the soil chromium content by 3.20% to 7.44%, with the chromium primarily concentrated in the roots and present in low concentrations in the leaves, ensuring the safety and effectiveness of the leaf products.

[0024] 4. Each Plectranthus plant is planted and protected using an independent main frame to ensure reasonable spacing between plants and adaptability to subtle changes in the soil environment. When the main frame is not in use, it can be connected by interlocking grooves and protrusions for easy carrying and storage. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a device and method for the safe planting and utilization of plants in chromium-contaminated soil according to the present invention.

[0026] Figure 2 This is a bottom view of the main frame structure of the present invention.

[0027] Figure 3 This is a schematic diagram of the cross-sectional structure of the main frame of the present invention.

[0028] Figure 4 This is a schematic diagram of the structure of the fixing rod of the present invention.

[0029] Figure 5 This is a schematic diagram of the structure of the fixing frame of the present invention.

[0030] Figure 6 This is an exploded structural diagram of a device for the safe planting and utilization of plants in chromium-contaminated soil according to the present invention.

[0031] Figure 7 This is a schematic diagram of the structure of an extension fixing frame according to the present invention.

[0032] Figure 8 This is a schematic diagram illustrating the steps of a method for the safe planting and utilization of plants in chromium-contaminated soil according to the present invention.

[0033] Figure 9 This invention analyzes the growth of Plectranthus amboinicus under different cultivation substrates.

[0034] Figure 10 This study analyzes the ability of *Plectranthus amboinicus* to enrich chromium under different treatments according to the present invention.

[0035] In the diagram: Insert rod-1, Fixing bracket-2, Main frame-3, Groove-4, Protrusion-5, Locking block-6, Baffle-7, Extension fixing bracket-8, Limiting block-11, Push block-12, Force rod-13, Fixing rod-14, Drill bit-41, Spring-42, Elastic opening-43, Extension body-44, Outer shell-45, Push rod-46, Fixing plate-21, Pull rod-22, Limiting rod-23, Limiting bracket-24, Magnetic block-25. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings:

[0037] Example 1: As shown in the attached document Figure 1 To be continued Figure 4 As shown:

[0038] This invention provides a device and method for the safe cultivation and utilization of plants in chromium-contaminated soil. Its structure includes an insertion rod 1, a fixing frame 2, a main frame 3, a groove 4, a protrusion 5, a locking block 6, a baffle 7, and an extension fixing frame 8. The insertion rod 1 penetrates the main frame 3 and is movable. The fixing frame 2 is placed above the main frame 3 and can be disassembled. The groove 4 and protrusion 5 are assembled on the side surface of the main frame 3. The locking block 6 is fixed to the lower surface of the main frame 3. The baffle 7 is an integral structure with the main frame 3. The extension fixing frame 8 is replaceable from the fixing frame 2.

[0039] The insertion rod 1 includes a limiting block 11, a push block 12, a force-bearing rod 13, and a fixing rod 14. The limiting block 11 is installed on the upper surface of the main frame 3. The push block 12 and the force-bearing rod 13 are an integrated structure. The fixing rod 14 is installed at the bottom of the force-bearing rod 13.

[0040] The fixing rod 14 includes a drill bit 41, a spring 42, an elastic opening 43, an extension body 44, a housing 45, and a push rod 46. The spring 42 is installed between the drill bit 41 and the push rod 46. The elastic opening 43 passes through the housing 45 to connect the inner and outer spaces. The extension body 44 is connected to the bottom of the push rod 46. The push rod 46 and the force-bearing rod 13 are an integrated structure. The housing 45 and the main frame 3 are an integrated structure. Each group of extension bodies 44 and elastic openings 43 has four in each group, which are evenly distributed in a circle.

[0041] The bottom of the drill bit 41 has a pointed structure, which can better penetrate into the soil. The top of the drill bit 41 has an inclined angle, which can assist the extension body 44 to move out. The elastic opening 43 unfolds into a petal-shaped structure under the thrust of the extension body 44, and continues to maintain its elasticity. When the extension body 44 returns to its original position, it will extend in four directions. Each set of grooves 4 and protrusions 5 has two and can be snapped together with new sets. The grooves 4 and protrusions 5 can be connected and placed when the main frame 3 is not in use.

[0042] The card block 6 assists the main frame 3 in increasing adhesion between it and the soil and is distributed in a V-shape at the four corners. The baffle 7 assists in the assembly of the fixing frame 2 and is provided in four. When the main frame 3 is pressed down, it can make the main frame 3 and the soil more compact. The tip of the drill bit 41 can help the main frame 3 to extend into the soil better.

[0043] The fixed rods 14 are arranged in groups of two, totaling four. When the push block 12 is pressed down, it is fixed by the limiting block 11. When the limiting block 11 moves to the side, the force rod 13 will return to its original position by the support of the spring 42. The outer shell 45 is fixed vertically, and its extension body 44 provides lateral auxiliary fixation. There are four limiting blocks 11 in total, arranged in groups of two. When they are pressed to the sides, the force rod 13 can be released. The extension body 44 is made of elastic steel plate. When it extends out of the elastic opening 43, it is limited by the drill bit 41 and moves laterally.

[0044] The specific usage and function of this embodiment are as follows:

[0045] In this invention, after the soil pretreatment and mixing are completed, the *Plectranthus amboinicus* is transplanted. The *Plectranthus amboinicus* are planted at predetermined intervals. After the surface soil is further compacted, the main frame 3 is inserted into the soil and easily moved by the tip of the drill bit 41 until it contacts the soil surface. The locking block 6 increases the adhesion friction between the main frame 3 and the soil. After the main frame 3 is stable on the soil surface, the force-bearing rod 13 is pushed by external force, causing its push block 12 to move downwards and press and lock against the limiting block 11. The push rod 46 passes through the outer shell 45. The space constraint pushes the extension body 44 downward. The extension body 44 is restricted by the slope of the upper end of the drill bit 41 and extends into the elastic port 43, so that the extension body 44 can be fixed in the lateral position of the outer shell 45. The insertion rod 1 enters the bottom soil for vertical and lateral fixation. When it is necessary to remove, simply push the limiting block 11 to both sides, and its push block 12 will be released. The spring 42 pushes the force rod 13 upward through its own rebound force, and the extension body 44 will return to its original position. Then the main frame 3 can be taken out as a whole.

[0046] Example 2: As shown in the attached document Figure 5 To be continued Figure 7 As shown:

[0047] The fixing frame 2 includes a fixing plate 21, a pull rod 22, a limiting rod 23, a limiting frame 24, and a magnetic block 25. The fixing plate 21 and the limiting rod 23 are integrated. The pull rod 22 passes through the limiting rod 23 and is movable. The limiting frame 24 and the pull rod 22 are integrated. The magnetic block 25 is connected to the limiting frame 24. The pull rod 22 has an L-shaped structure, and the vertical rod is convenient for external force to push. The magnetic blocks 25 attract each other to fix the limiting frame 24.

[0048] The limiting frame 24 has a semi-circular structure, and two can be combined to form a circle. The combined area of ​​the limiting frame 24 can stabilize the plant. The pull rod 22 can move horizontally along the limiting rod 23. The fixing plate 21 is placed on the baffle 7. The limiting frame 24 limits and consolidates the newly transplanted plant.

[0049] The extension fixing frame 8 includes a socket ring 81 and a support bar 82. The support bar 82 is inserted into the groove of the socket ring 81 and can be installed and removed. The support bar 82 is an elastic support steel bar that provides auxiliary support for branches and leaves. The socket ring 81 has six insertion holes, and the rest of the structure is the same as that of the fixing frame 2.

[0050] The specific usage and function of this embodiment are as follows:

[0051] In this invention, when transplanting *Plectranthus amboinicus*, after the main frame 3 is fixed, the *Plectranthus amboinicus* is placed in the middle of the main frame 3, and the surrounding soil is filled and pressed down. The limiting frame 24 is in the open state, and the fixing plate 21 is placed on the baffle 7. The pulling rod 22 is pushed along the limiting rod 23 to merge the limiting frame 24 together, and the magnetic block 25 is used to attract and fix it, so that the *Plectranthus amboinicus* is in the circle of the limiting frame 24, which helps to fix the growth position of the *Plectranthus amboinicus*. After the *Plectranthus amboinicus* grows stably, the limiting frame 24 is unfolded to both sides, and the fixing frame 2 is removed. Then the main frame 3 can be removed. If it is necessary to transplant a *Plectranthus amboinicus* with larger branches and leaves, the fixing frame 2 is replaced with an extension fixing frame 8, and the support bar 82 is inserted into the hole of the insertion ring 81 to provide auxiliary support for the branches and leaves of the *Plectranthus amboinicus*. Its own elasticity will not affect the growth of the branches and leaves.

[0052] Example 3: As shown in the attached document Figure 8 To be continued Figure 10 As shown:

[0053] The method for safely planting and utilizing chromium-contaminated soil using a device for phytosanitary treatment includes the following steps:

[0054] 1. Propagation of Plectranthus: Select healthy, disease-free Plectranthus plants as the mother plant. Take tender branches with 4 leaves and 1 terminal bud from the leaf axil as cuttings. Insert the cuttings into a seedling tray filled with nutrient soil. Water thoroughly immediately after planting and move to a greenhouse for cultivation. The cultivation period is 30 days, during which time water thoroughly every 3-4 days.

[0055] II. Treatment of Chromium-Contaminated Soil: Remove and clean up waste, weeds, stones, and other substances detrimental to plant growth from the chromium-contaminated soil on the mine slopes. The contaminated soil also requires conventional tillage treatments such as loosening and ridging. The pre-treated chromium-contaminated soil (chromium content: 3100±100 mg / kg) can be mixed with three types of fillers at a 1:1 volume ratio to prepare different cultivation substrates: Filler 1: Chromium-contaminated soil + yellow soil (chromium content: 2300±100 mg / kg, labeled T1); Filler 2: Chromium-contaminated soil + nutrient soil (chromium content: 2000±10 mg / kg, labeled T2); Filler 3: Chromium-contaminated soil + a mixture of yellow soil and nutrient soil (volume ratio 1:1, chromium content: 1800±10 mg / kg, labeled T3).

[0056] 3. Transplanting of Plectranthus: Select healthy Plectranthus plants that are 5 cm tall and free from pests and diseases. Loosen the substrate around the seedling tray with a small shovel, then remove the plant from the tray, being careful not to damage the roots. After removing the plant, gently shake off the nutrient soil accumulated at the roots, and retain one main branch and two lateral branches. Remove the remaining leaf buds and lateral branches. Plant the plant on the slope of the mine, insert the main frame 3 into the pre-treated soil, and use the fixing frame 2 to stabilize the plant. Water the plant immediately after transplanting.

[0057] IV. Plectranthus amboinicus cultivation and management: Within 10 days of transplanting, water once every 4-5 days at 6:00 AM. Subsequently, water once every 10-15 days to keep the soil moisture content at 30%-40% of field capacity. After the plant has grown and stabilized for a period of time, the fixing frame 2 can be dismantled first, and then the main frame 3 can be removed.

[0058] The nutrient soil is a mixture of peat moss and perlite in a weight ratio of 10:1. Plectranthus can survive in all three types of chromium-contaminated soil.

[0059] The specific usage and function of this embodiment are as follows:

[0060] In this invention, in order to achieve the safe utilization and management of chromium-contaminated soil, reduce its ecological pollution, and ensure the safe and effective risk control, a safe and effective way of utilizing chromium-contaminated soil is explored. We mix chromium-contaminated soil with filler and then cultivate Plectranthus amboinicus. Through a completely randomized experiment, we tested the effect of different fillers mixed with chromium-contaminated soil on the growth of Plectranthus amboinicus.

[0061] After multiple experiments and statistical analyses, the effects of different fillers mixed with chromium-contaminated soil on the growth of *Plectranthus amboinicus* were investigated. Figure 9 As shown in the figure. The experimental results showed that Plectranthus could survive under all four types of cultivation substrates, but their growth vigor differed. Among them, the cultivation substrate composed of filler material two or three mixed with chromium-contaminated soil had the best cultivation effect on Plectranthus. Under this cultivation substrate, Plectranthus grew uniformly, with many and robust branches, and thick and dense leaves; the daily plant height growth rate reached 0.18 cm and 0.17 cm, respectively; and the cultivation effect was significantly different from that of other cultivation substrates.

[0062] Figure 9The results of multiple comparisons are represented using letter notation. Following the statistical method for notating multiple comparisons of means, lowercase Latin letters a, b, c, d... are used to indicate the significance level. First, the means of each treatment are arranged from largest to smallest, with the largest mean labeled 'a'. Then, this mean is compared with the following means; those with significant differences are labeled 'b', and so on. Means without significant differences are labeled with the same letter. Means sharing the same letter are considered insignificant; otherwise, they are considered significant.

[0063] Based on the analysis of the influence of cultivation substrate, the enrichment capacity of Plectranthus in soil chromium was compared, that is, the chromium content in soil and the chromium content and enrichment capacity in the roots, stems and leaves of Plectranthus under different cultivation substrates were compared.

[0064] The test results are as follows Figure 10 As shown, after planting *Plectranthus amboinicus*, the chromium content in the soil decreased in all cases. In the chromium-contaminated soil with added filler, the chromium content decreased by 3.20%, 6.25%, and 7.44%, respectively. Among the three organs of *Plectranthus amboinicus*, the roots had the highest chromium content, followed by the stems, and the leaves had the lowest. *Plectranthus amboinicus* exhibited varying abilities to accumulate chromium in the soil. The accumulation in the substrate prepared by mixing filler three with chromium-contaminated soil was significantly higher than that in the substrate prepared by filler two.

[0065] Any technical solution that achieves the above-mentioned technical effects by utilizing the technical solutions described in this invention, or by designing similar technical solutions by those skilled in the art under the inspiration of the technical solutions described in this invention, falls within the protection scope of this invention.

Claims

1. A device for the safe planting and utilization of plants in chromium-contaminated soil, comprising an insertion rod (1), a fixing frame (2), a main frame (3), a groove (4), a protrusion (5), a locking block (6), a baffle (7), and an extension fixing frame (8). The insertion rod (1) penetrates the main frame (3) and is movable. The fixing frame (2) is placed above the main frame (3) and can be disassembled. The groove (4) and the protrusion (5) are assembled on the side surface of the main frame (3). The locking block (6) is fixed to the lower surface of the main frame (3). The baffle (7) and the main frame (3) are an integrated structure. The extension fixing frame (8) and the fixing frame (2) are interchangeable. The device is characterized in that: The insertion rod (1) includes a limiting block (11), a push block (12), a force-bearing rod (13), and a fixing rod (14). The limiting block (11) is installed on the upper surface of the main frame (3). The push block (12) and the force-bearing rod (13) are an integrated structure. The fixing rod (14) is installed at the bottom of the force-bearing rod (13). The fixed rod (14) includes a drill bit (41), a spring (42), an elastic opening (43), an extension body (44), a shell (45), and a push rod (46). The spring (42) is installed between the drill bit (41) and the push rod (46). The elastic opening (43) passes through the shell (45) to connect the inner and outer spaces. The extension body (44) is connected to the bottom of the push rod (46). The push rod (46) and the force-bearing rod (13) are an integrated structure. The shell (45) and the main frame (3) are an integrated structure. Each group of the extension body (44) and the elastic opening (43) has four in each circle and are evenly distributed. The bottom of the drill bit (41) is a pointed structure, which can better penetrate into the soil. The top of the drill bit (41) has an inclined angle, which can assist the extension body (44) to move out. The elastic opening (43) unfolds into a petal-shaped structure under the thrust of the extension body (44), and continues to maintain its elasticity. When the extension body (44) returns to its original position, it will extend in four directions.

2. The device for safe planting and utilization of chromium-contaminated soil according to claim 1, characterized in that: The card block (6) assists the main frame (3) in increasing the adhesion between the main frame (3) and the soil and is distributed in a V-shape at the four corners. The baffle (7) assists in the assembly of the fixing frame (2) and is provided in four.

3. The device for safe planting and utilization of chromium-contaminated soil according to claim 1, characterized in that: The fixed rods (14) are arranged in groups of two, and there are four in total. When the push block (12) is pressed down, it is fixed by the limiting block (11). When the limiting block (11) moves to the side, the force rod (13) will return to its original position by the support of the spring (42). The outer shell (45) is fixed vertically, and its extension body (44) is fixed laterally.

4. The device for safe planting and utilization of chromium-contaminated soil according to claim 1, characterized in that: The fixing frame (2) includes a fixing plate (21), a pull rod (22), a limiting rod (23), a limiting frame (24), and a magnetic block (25). The fixing plate (21) and the limiting rod (23) are an integrated structure. The pull rod (22) passes through the limiting rod (23) and is movable. The limiting frame (24) and the pull rod (22) are an integrated structure. The magnetic block (25) is connected to the limiting frame (24).

5. The device for safe planting and utilization of chromium-contaminated soil according to claim 4, characterized in that: The limiting frame (24) has a semi-circular structure, and two can be combined to form a circle. The combined range of the limiting frame (24) can stabilize the plant. The pull rod (22) can move horizontally along the limiting rod (23).

6. The device for safe planting and utilization of chromium-contaminated soil according to claim 1, characterized in that: The extension fixing frame (8) includes a socket ring (81) and a support bar (82). The support bar (82) is inserted into the groove of the socket ring (81) and can be installed and removed.

7. A method for the safe cultivation and utilization of plants in chromium-contaminated soil, characterized in that: The method for safely planting and utilizing chromium-contaminated soil using the device described in any one of claims 1-6 is as follows:

1. Propagation of Plectranthus: Select healthy, disease-free Plectranthus plants as the mother plant. Take tender branches with 4 leaves and 1 terminal bud from the leaf axil as cuttings. Insert the cuttings into a seedling tray filled with nutrient soil. Water thoroughly immediately after planting and move to a greenhouse for cultivation. The cultivation period is 30 days, during which time water thoroughly every 3-4 days. II. Treatment of Chromium-Contaminated Soil: Remove and clean up waste, weeds, stones, and other substances detrimental to plant growth from chromium-contaminated soil on mine slopes. The contaminated soil also requires conventional tillage treatments such as loosening and ridging. The pre-treated chromium-contaminated soil can be mixed with three types of fillers at a 1:1 volume ratio to create different cultivation substrates: Filler 1: Chromium-contaminated soil + Yellow soil; Filler 2: Chromium-contaminated soil + Nutrient soil; Filler 3: Chromium-contaminated soil + Mixture of Yellow soil and Nutrient soil.

3. Transplanting of Plectranthus: Select Plectranthus plants that are 5 cm tall, healthy, and free from pests and diseases. Use a small shovel to loosen the substrate around the seedling tray, and then remove the plant from the seedling tray. Try not to damage the roots. After removing the plant, gently shake off the nutrient soil accumulated at the roots of the plant, and keep 1 main branch and 2 side branches. Remove the remaining leaf buds and side branches. Plant the plant on the slope of the mine. Insert the main frame (3) into the pre-treated soil. Use the fixing frame (2) to stabilize the position of the plant. After transplanting, immediately water the plant to settle the roots. IV. Plectranthus cultivation and management: Within 10 days of transplanting, water once every 4-5 days at 6:00 AM. After that, water once every 10-15 days to keep the soil moisture content at 30%-40% of field capacity. After the plant has grown for a period of time and stabilized, the fixing frame (2) can be dismantled first, and then the main frame (3) can be removed.

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