A method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation.

Abstract

This invention provides a method for controlling Spartina alterniflora and promoting natural mangrove restoration based on rolling mulching and in-situ mud slurry, belonging to the field of ecological control technology. The method involves mechanically rolling Spartina alterniflora to flatten most of it and press it into the tidal flat soil. Then, a biodegradable mulch film is laid on top, and mud slurry is extracted and applied to form a mud slurry cover layer. A mangrove seed interception and planting device is then installed on the mud slurry cover layer to prevent mangrove seeds from growing naturally, thereby reducing the cost of Spartina alterniflora control and improving the efficiency of Spartina alterniflora control.

Description

Technical Field

[0001] This invention relates to the field of ecological control technology, specifically to a method for controlling Spartina alterniflora and promoting the natural restoration of mangroves based on rolling mulching and in-situ mud siltation. Background Technology

[0002] Spartina alterniflora, native to North America, was introduced to China in the 1980s for riparian protection. With its extensive root system, salt tolerance, and strong environmental adaptability, Spartina alterniflora has proliferated rapidly, becoming a highly invasive plant. It encroaches on coastal wetlands, displaces native species, reduces biodiversity, alters geomorphology and hydrology, blocks waterways, impacts aquaculture, and disrupts ecological balance and economic value.

[0003] With its extensive root system, salt and flood tolerance, and extremely high reproductive capacity (a single plant can produce millions of seeds annually, and its rhizome segments can regenerate), Spartina alterniflora rapidly clones and spreads in the intertidal zone, crowding out native species (such as reeds, mangroves, and sea sedge) and forming a single dominant community. As of 2023, the area of ​​Spartina alterniflora in China was approximately 1 million mu (about 68,000 hectares), covering 11 coastal provinces including Jiangsu, Zhejiang, Shanghai, Fujian, Shandong, and Guangxi. Fujian has the widest distribution of Spartina alterniflora, ranking first in the country, with a contiguous area of ​​15,000 mu in Xiapu County. Zhejiang has a distribution area of ​​approximately 270,000-300,000 mu, ranking second in the country (after Fujian), concentrated in Ningbo, Wenzhou, Taizhou, and other places.

[0004] The spread of Spartina alterniflora has led to a decline in biodiversity, crowding out food sources for migratory birds, loss of habitats for cranes, geese, and ducks, destruction of benthic animal habitats, and impact on fish resources. Spartina alterniflora promotes siltation, altering the geomorphology and hydrology, blocking waterways, affecting tidal cycles, and reducing the carbon sequestration capacity of wetlands. It has also encroached on laver and shellfish farming areas in tidal flats, resulting in reduced aquaculture production and increasing the cost of dredging ports and waterways. The coastal economy has suffered significant losses due to the spread of Spartina alterniflora.

[0005] With the efforts and guidance of five departments including the National Forestry and Grassland Administration, physical therapies such as "cutting and tilling" and "enclosure and flooding" have been adopted to suppress and eliminate most of Spartina alterniflora. Mangroves have been planted to restore the ecology, and significant results have been achieved in the prevention and control of Spartina alterniflora. The spread of Spartina alterniflora has been effectively curbed, and the expansion of Spartina alterniflora has shifted from "rapid spread" to the stage of "existing stock elimination and recurrence prevention and control". However, there is still a risk of local recurrence.

[0006] The core challenges in controlling Spartina alterniflora lie in the triple combination of its strong invasiveness, environmental constraints, and technological limitations. Biologically, a single plant produces millions of seeds annually, and its underground rhizomes, reaching depths of up to 50 cm (with regeneration possible even with fragments ≥5 cm), along with its salt tolerance (0-35‰) and flood tolerance (surviving 8 hours of daily flooding), result in a recurrence rate exceeding 60% after physical removal, requiring continuous mowing and tilling for 3-5 years. Technically, the short tidal window in tidal flats (≤4 hours daily) and the tendency for machinery to become stuck in silt necessitate high-cost labor (3000-6000 yuan per mu), while chemical weeding is limited by the slow degradation in polluted waters and saline-alkali soils. Ecological alternatives such as mangroves require over 3 years of maintenance before they can compete for establishment. Ecological restoration presents significant challenges: clearing exposes tidal flats, exacerbating soil erosion, while the survival rate of replanted reeds and other soil-stabilizing species is affected by salinity and tidal fluctuations. Furthermore, the trans-regional spread of seeds via tides necessitates a coordinated prevention and control mechanism across regions to coordinate responsibilities and funding, further increasing the complexity of control efforts. To eradicate the problem, it is necessary to overcome three major technical bottlenecks: complete root removal, low-cost sprout suppression, and cross-niche restoration.

[0007] Chinese invention patent application No. 202311804442.7, entitled "A Rapid Method for Controlling Spartina alterniflora," describes a method for rapidly controlling Spartina alterniflora through processes such as mowing, root digging, stem rot removal, dike construction, sand filling, and dike relocation. This method targets the physiological characteristics of the roots and stems, employing physical and biological methods to remove and inhibit the growth of Spartina alterniflora, achieving a one-time eradication of the herb. However, this method involves numerous steps, including mowing, root digging, dike construction, and sand filling, resulting in a large workload and complex implementation.

[0008] Chinese invention patent application No. 202210241773.3, entitled "A herbicide composition and its application," employs a combination of chemical agents to effectively control Spartina alterniflora and other herbicides, featuring a broadened weed control spectrum, reduced application amount, and synergistic effects. However, this method utilizes chemical agents, and the environmental and ecological hazards are still unclear, posing significant potential risks.

[0009] Chinese invention patent application No. 202510222414.7, entitled "A method and system for integrated control of Spartina alterniflora by photovoltaic shading and dike flooding", discloses a method and system for integrated control of Spartina alterniflora by photovoltaic shading and dike flooding. It achieves the suppression and control of Spartina alterniflora through methods such as mowing, dike construction, flooding, and photovoltaic shading. However, this method has disadvantages such as incomplete shading, difficulty in operation after photovoltaic installation, and damage to the original environment by dike construction.

[0010] Chinese invention patent application No. 202411712240.4, entitled "A Method for Effectively Removing Spartina alterniflora," discloses a purely physical method for inhibiting and killing Spartina alterniflora. This method involves deep excavation and layered upside-down burial of the Spartina alterniflora, burying the above-ground parts and shallow surface plants entirely upside down in the soil at least 140cm below the ground surface, thus deeply isolating them from light and air. This method is extremely costly to operate on soft tidal flats, and the fluidity of the soil makes both deep excavation and deep upside-down burial quite difficult.

[0011] Chinese invention patent application No. 202411708113.7, entitled "A Method for Controlling Spartina alterniflora by Covering with Composite Slurry," discloses a method that involves cutting Spartina alterniflora, laying a first composite slurry, allowing it to solidify, and then laying a second composite slurry, which naturally forms a plant replacement layer. However, the composite slurry used in this method is relatively soft and easily affected by tides, making it difficult to solidify and potentially failing to achieve the desired effect.

[0012] Chinese invention patent application No. 202111246195.4, entitled "Method and Application for the Management of Spartina alterniflora," discloses a method of covering Spartina alterniflora with a silver-black two-tone film for 25-50 days before flowering, followed by harvesting. Spartina alterniflora grows in tidal flats, and the covering is done during the greening season, no later than before flowering. During the growing season, the height of the Spartina alterniflora is cut to below 20cm. While the application discloses using wooden stakes to roll the film down to below 20cm before covering, the stems of Spartina alterniflora in the growing season are quite hard, and the film will bounce back after rolling, making it impossible to maintain a lodging state below 20cm. Therefore, this application still requires cutting the Spartina alterniflora to below 20cm during the growing season. However, for low-tide mudflats with soft substrate, mowing machinery may have difficulty entering or operating. Specifically, the cutting blades of the mowing machinery need to maintain a certain clearance from the ground, resulting in a high center of gravity. This high center of gravity makes the machinery prone to tilting on soft low-tide mudflats, further increasing local pressure and causing it to sink. Once the tires sink, the cutting blades will get stuck in the mud and cannot work properly. In addition, mowing operations not only require the machinery to move in the work area but also require power cutting, making the machinery more complex and the work efficiency relatively low. Furthermore, this method requires covering before the flowering period (25-50 days); missing the optimal period significantly reduces the effectiveness. Moreover, in mudflat areas affected by tidal erosion, fixing the film is difficult, requiring complex fixing measures such as wooden stakes and ground nails. The film and ground nails also need to be recycled later, resulting in high labor intensity. Furthermore, if the film is damaged, it is difficult to completely recycle, potentially causing plastic pollution. In addition, it requires covering Spartina alterniflora with a silver-black film for 25-50 days. The film covering not only inhibits Spartina alterniflora, but may also affect the photosynthesis of other organisms on the mudflats, and the mudflats become too low, which is not conducive to mangrove planting. It is not suitable for complex habitats such as mangrove forests.

[0013] In summary, existing physical remediation methods (such as CN202311804442.7, CN202411712240.4, CN202111246195.4) generally suffer from large engineering workloads, severe damage to the original topography of tidal flats, and high costs. Chemical or composite methods (such as CN202210241773.3, CN202510222414.7, CN 202111246195.4) have drawbacks such as potential environmental pollution risks or high operational complexity. More importantly, none of the above methods effectively achieve rapid and low-cost self-repair of the remediated ecosystem, often requiring significant additional human and material resources for vegetation replanting and maintenance. Summary of the Invention

[0014] The present invention aims to solve at least one of the problems mentioned in the background art above, and to provide a low-cost, high-efficiency method for the control of Spartina alterniflora and the natural restoration of mangroves based on rolling mulching and in-situ mud siltation.

[0015] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0016] A method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on roller mulching and in-situ mud siltation includes the following steps:

[0017] S1, Roll the Spartina alterniflora in the area to be treated to break it down and press it into the soil to prevent it from bouncing up;

[0018] S2, biodegradable mulch film is used to cover the rolled Spartina alterniflora;

[0019] S3. In the area to be treated, a high-pressure water gun is used to impact the surface silt of the tidal flat around the biodegradable mulch film, causing it to liquefy and form a mud slurry with a high water content. Then, a mud pump is used to directly suck up the liquefied mud slurry and evenly cover it on the laid biodegradable mulch film to form a mud slurry covering layer.

[0020] S4. A mangrove seed interception and planting device is set in the mud cover layer to intercept, retain and block mangrove plant seeds floating with the tide during low tide, so that the mangrove plant seeds stay in place and take root and plant naturally.

[0021] Further, in step S4, the mud cover layer is divided into several squares by the mangrove seed interception and planting device, which includes a fixing frame fixed on the mud cover layer and an interception net installed on the fixing frame.

[0022] Furthermore, the grid is a square grid with a length of 50 m and a width of 50 m; the fixing frame includes a fixing pile fixed to the mudflat and two frames respectively fixed to opposite sides of the fixing pile, and both frames are equipped with interception nets.

[0023] Furthermore, one end of the fixed pile is driven into the mud cover layer for fixation, and the fixed pile protrudes 30-40cm from the mud cover layer; the frame includes several fixed plates arranged at intervals along the vertical direction, and the fixed plates are fixed to the fixed pile; the interception net is fixed to several of the fixed plates, the bottom side of the interception net extends to the mud cover layer, and the height of the interception net is 20cm higher than the mud cover layer.

[0024] Furthermore, it also includes the following steps: S5, planting of sedge: dividing the mud covering layer into planting units of 10×10 meters to 15×15 meters, and planting sedges that can quickly survive and grow around the perimeter of the planting unit at a plant spacing of 60 cm.

[0025] Furthermore, it also includes the following steps: S6, planting native mangroves: artificially planting mangrove seedlings within the planting unit of the mangrove.

[0026] Further, in step S1, a tracked grass presser is used to roll Spartina alterniflora. The tracked grass presser includes a frame, a track, a rolling mechanism, and a height adjustment component. The track is installed at the bottom of the frame, and the rolling mechanism is located at the end of the frame. The rolling mechanism includes a support rod, a mounting frame, and a roller. The opposite ends of the support rod are respectively hinged to the frame and the mounting frame. The roller is rotatably connected to the mounting frame. The height adjustment component is installed on the frame and connected to the mounting frame to adjust the relative height between the roller and the track.

[0027] Furthermore, the height adjustment assembly includes a first hydraulic cylinder and a second hydraulic cylinder. The first hydraulic cylinder is located above the support rod, and the cylinder body and piston rod of the first hydraulic cylinder are respectively hinged to the frame and the mounting plate. In one height adjustment assembly, the cylinder body of the second hydraulic cylinder is fixed to the frame, and the corresponding piston rod is hinged to the mounting plate. In another height adjustment assembly, the cylinder body and piston rod of the second hydraulic cylinder are respectively hinged to the frame and the mounting plate.

[0028] Furthermore, the roller includes a cylinder rotatably mounted on the mounting plate and a plurality of rolling protrusions evenly spaced along the circumference of the cylinder, wherein the cross-sectional area of ​​each rolling protrusion gradually decreases in the direction away from the cylinder.

[0029] Furthermore, when the tracked grass press is in operation, the lowest point of the roller is 15-20 cm lower than the bottom of the track.

[0030] By adopting the above technical solution, the present invention has the following beneficial effects:

[0031] (1) This invention uses rolling instead of the traditional "cutting + digging of roots and stems", simplifying the complex clearing operation into a one-time mechanical rolling, avoiding a large amount of manual digging and soil transportation work; at the same time, compared with the cutting operation, the rolling mechanism of the tracked grass press used in this method is close to the ground, with a lower center of gravity, and the weight distribution of the equipment is uniform and stable, making it less prone to sinking in soft tidal flats. Moreover, the tracked grass press can complete the rolling of Spartina alterniflora while moving continuously, resulting in high work efficiency. In addition, the use of in-situ mud slurry for covering saves the cost of purchasing soil and long-distance transportation. According to comprehensive estimates, the mechanical and labor costs of this method can be reduced by about 30%-40% compared with the traditional "tillage method" or "burying method", and the construction efficiency can be increased by more than 50%.

[0032] (2) By first fixing the Spartina alterniflora plants and burying some of the seeds through "rolling and pressing into the mud", then covering them with biodegradable mulch to achieve physical oxygen isolation, and finally applying a 0.8-meter-thick mud slurry covering layer for deep pressing to achieve light isolation, these three barriers work together to effectively kill the above-ground parts and underground rhizomes and block the spread of seeds. This can reduce the recurrence rate of Spartina alterniflora from more than 60% in existing methods to less than 5%, basically achieving one-time eradication. At the same time, the tracked grass presser used in this method uses rollers with several rolling protrusions to roll and press Spartina alterniflora. The cross-sectional area of ​​the rolling protrusions gradually decreases in the direction away from the cylinder. At the same time, the height adjustment component is used to adjust the relative height between the roller and the track to ensure that sufficient impact pressure, bending moment and shear stress are applied to Spartina alterniflora during the roller action, ensuring that Spartina alterniflora is pressed and folded into the soil and does not bounce back, and completely burying the Spartina alterniflora seeds to prevent the seeds from being scattered in the mudflats or seawater.

[0033] (3) This invention not only addresses the remediation but also simultaneously achieves ecological reconstruction. In-situ mud mulching directly raises the beach surface to an ideal elevation suitable for mangrove growth (approximately above the average tide level), solving the problem that the beach surface is too low after traditional remediation, which is not conducive to mangrove planting. The combination of artificial planting and the "mangrove seed blocking device" ensures the initial vegetation coverage rate on the one hand, and greatly promotes the natural regeneration of native tree species on the other hand, enabling the ecosystem to quickly move towards a self-sustaining stable state. It is expected that a mangrove community with high biodiversity can be formed within 3-5 years.

[0034] (4) The present invention uses physical methods throughout the process, eliminating the risk of pollution to the aquatic environment by chemical herbicides. The mulch material used is a biodegradable mulch film, which can be completely biodegraded within a set period (24-36 months). The final products are carbon dioxide and water, with no microplastic residue, thus avoiding the "white pollution" problem caused by traditional plastic mulch films.

[0035] (5) The innovative in-situ mud extraction and covering method of this invention has less disturbance to the original tidal flat topography and benthic biological community compared with large-scale excavation and filling. The resulting raised tidal flat is natural and gentle, which is not only conducive to the growth of mangroves, but also has a stronger effect of promoting siltation and stabilizing the tidal flat. It can further enhance the carbon sequestration capacity of the tidal flat and the ecological function of resisting wind and wave erosion.

[0036] Therefore, this invention completely prevents the Spartina alterniflora stems and leaves from regrowing after being exposed on the mudflats by in-situ covering with mulch and slurry. Simultaneously, the barrier device promotes the establishment and growth of native mangrove seeds, enabling the transplantation of native mangroves, ecological restoration, and solving the problem of the difficulty in the natural recovery of native mangroves. Furthermore, the method of this invention eliminates the need for mowing, digging and root treatment, and tilling, allowing for on-site operation and reducing costs. It also avoids the use of chemical agents, reducing construction work, minimizing the impact of chemical substances on the environment, and reducing environmental disturbance. Attached Figure Description

[0037] Figure 1 The flowchart illustrates a preferred embodiment of the present invention for the treatment of Spartina alterniflora and the natural restoration of mangroves based on rolling mulching and in-situ mud siltation.

[0038] Figure 2 This is a schematic diagram of the tracked grass presser used in the preferred embodiment of the present invention, which is a method for controlling Spartina alterniflora and promoting the natural restoration of mangroves based on rolling mulching and in-situ mud siltation.

[0039] Figure 3 for Figure 2 The diagram shows the structure of the rollers in a tracked grass press.

[0040] Figure 4 This is a top view of one of the grid structures formed in the preferred embodiment of the present invention, which is a method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation.

[0041] Figure 5 for Figure 4 Enlarged view of the structure at point A.

[0042] Figure 6 for Figure 5 The main view.

[0043] Figure 7 This is a schematic diagram of the tidal flat cross-section formed after treatment using the preferred embodiment of the present invention, which involves the treatment of Spartina alterniflora based on rolling mulching and in-situ mud siltation, and the natural restoration of mangroves.

[0044] Explanation of main component symbols

[0045] 100. Frame; 200. Track; 1. Roller; 11. Cylinder; 12. Rolling ridge; 2. Support rod; 3, 4. First hydraulic cylinder; 5, 6. Second hydraulic cylinder; 7. Mounting frame; 300. Mangrove seed interception and planting device; 310. Fixing frame; 311. Fixing stake; 312. Frame body; 313. Fixing plate; 320. Interception net. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] Please also see Figure 1 and Figure 7 A preferred embodiment of the present invention provides a method for controlling Spartina alterniflora and promoting the natural restoration of mangroves based on rolling mulching and in-situ mud siltation, comprising the following steps:

[0050] S1, Roll the Spartina alterniflora in the area to be treated, pressing it down and folding it into the soil to prevent it from bouncing up.

[0051] Please see also Figures 2 to 3 In this embodiment, in step S1, a tracked grass press is used to roll Spartina alterniflora. A 6-ton tidal flat bulldozer can be modified by changing the bucket of the tidal flat bulldozer to a roller and making slight modifications to it into a tracked grass press.

[0052] Specifically, the tracked grass compactor includes a frame 100, tracks 200, a rolling mechanism, and a height adjustment assembly. The tracks 200 are mounted at the bottom of the frame 100, each track being 0.6m wide and 2m long. They are driven by a walking drive mechanism to enable the tracked grass compactor to move. The frame 100, tracks 200, and walking drive mechanism are existing technologies and will not be described in detail here. The rolling mechanism is located at the end of the frame 100. In this embodiment, the tracked grass compactor includes two rolling mechanisms, which are respectively located at opposite ends of the frame 100. Each rolling mechanism includes a support rod 2, a mounting frame 7, a roller 1, and a rotary drive. The opposite ends of the support rod 2 are hinged to the frame 100 and the mounting frame 7, respectively. The roller 1 is rotatably connected to the mounting frame 7. The rotary drive is mounted on the mounting frame 7 and connected to the roller 1 to drive the roller 1 to rotate, thereby pressing and bending the Spartina alterniflora and pressing at least a portion of the Spartina alterniflora into the soil. A height adjustment component is mounted on the frame 100 and connected to the mounting frame 7 to adjust the relative height between the roller 1 and the track 200, thereby controlling the shearing force and pressure of the roller 1 on the Spartina alterniflora.

[0053] In this embodiment, the frame 100 is generally rectangular, and two rolling mechanisms are respectively located at the front and rear ends of the frame 100 in the length direction. Each rolling mechanism includes two support rods 2 and two mounting brackets 7, with the two support rods 2 respectively located on opposite sides of the frame 100 in the width direction. The two mounting brackets 7 are respectively hinged to the ends of the two support rods 2 away from the frame 100. The roller 1 includes a cylinder 11 rotatably mounted on a mounting plate 7 and a plurality of rolling protrusions 12 evenly spaced along the circumference of the cylinder 11. In this embodiment, the opposite ends of the cylinder 11 are rotatably connected to the two mounting plates 7. The number of rolling protrusions 12 is six, and the six rolling protrusions 12 are evenly spaced along the circumference of the cylinder 11. Each rolling protrusion 12 extends axially along the cylinder 11, and the cross-sectional area of ​​each rolling protrusion 12 gradually decreases in the direction away from the cylinder 11. The rotary drive can be a geared motor or similar device mounted on the mounting plate 7, which is connected to the cylinder 11 to drive the roller 1 to rotate, thereby crushing and breaking the Spartina alterniflora and pressing it into the mudflats. Simultaneously, the rotational speed of the roller 1 can be adjusted via the rotary drive to apply different impact stresses to the Spartina alterniflora.

[0054] The tracked grass press includes two height adjustment components, each connected to a rolling mechanism. In this embodiment, the height adjustment components include first hydraulic cylinders 3 and 6 and second hydraulic cylinders 4 and 5. The first hydraulic cylinders 3 and 6 are located above their respective support rods 2, and their cylinder bodies and piston rods are hinged to the frame 100 and mounting plate 7, respectively. In this embodiment, the cylinder body of the second hydraulic cylinder 4 of one height adjustment component is fixed to the frame 100, and its corresponding piston rod is hinged to the mounting plate 7. The hinge point between the piston rod of the second hydraulic cylinder 4 and the mounting plate 7 is located between the hinge point of the support rod 2 and the mounting plate 7, and the hinge point of the first hydraulic cylinder 3 and the mounting plate 7. The cylinder body and piston rod of the second hydraulic cylinder 5 of the other height adjustment component are hinged to the frame 100 and the mounting plate 7, respectively. In this embodiment, the second hydraulic cylinder 5 of the other height adjustment component is located above its corresponding first hydraulic cylinder 6. The structures of the first hydraulic cylinders 3 and 6 and the second hydraulic cylinders 4 and 5 are existing technologies and will not be described in detail here for brevity.

[0055] When the tracked grass press is in operation, the relative height between the roller 1 and the track 200 can be adjusted by the telescopic movement of the first hydraulic cylinder 3, 6 and the second hydraulic cylinder 4, 5, combined with the hinged connection between the mounting plate 7 and the support rod 2 and the support rod 2 and the frame 100. Preferably, when the tracked grass press is in operation, the lowest point of the roller 1 is 15-20cm lower than the bottom of the track 200, which makes it easier for the roller 1 to crush and fold the Spartina alterniflora and press it into the muddy tidal flat. The pressure exerted by roller 1 on Spartina alterniflora originates from the weight of the tracked grass press itself and the pressure applied to roller 1 by the first hydraulic cylinders 3, 6 and the second hydraulic cylinders 4, 5. Specifically, by coordinating the first hydraulic cylinders 3, 6 and the second hydraulic cylinders 4, 5, the relative position of roller 1 and the bottom of the track 200 is adjusted, thereby adjusting the depth and pressure of the rolling protrusions 12 of roller 1 into the soil. This ensures that Spartina alterniflora can be bent and partially pressed into the soil, fixing it in place and making it difficult to move. This ensures that subsequent mulching and mud covering are complete, and that Spartina alterniflora is pressed into the mud and no longer bounces up. Furthermore, bending and pressing Spartina alterniflora into the soil completely buries the seeds, preventing them from scattering in the mudflats or seawater. This means that the Spartina alterniflora control method of this embodiment is not affected by the growth period of Spartina alterniflora and can be carried out at any stage of its growth. Experiments have shown that when the tracked grass press of this embodiment is working, the impact pressure exerted on Spartina alterniflora by the rolling ridge 12 as it rotates with the cylinder 11 can reach 3.0-7.5 MPa, the bending moment can reach 9,000-24,000 N∙m, and the shear stress can reach 19-382 MPa. This can damage Spartina alterniflora at various growth stages and effectively crush and break it, as shown in Table 1 (the static pressure in Table 1 is the pressure calculated when an object directly applies pressure to Spartina alterniflora).

[0056] Table 1

[0057]

[0058] Unlike ordinary weeds, Spartina alterniflora has extremely tough stem fibers, a smooth outer skin containing silica, making it very resilient. When using a smooth roller, the pressure primarily comes from above, causing the stems to flatten and lie close to the ground along the direction of pressure, but they are not easily broken. Furthermore, after being rolled by the smooth roller, some more elastic stems may spring back like springs after the pressure is released, failing to completely lie flat. In addition, Spartina alterniflora typically grows in intertidal mudflats where the surface is very slippery and soft mud. When operating in muddy environments, smooth rollers easily become stuck to the mud, causing them to slip and spin aimlessly, failing to effectively transmit rolling pressure. Moreover, the smooth roller primarily acts on the above-ground parts of the Spartina alterniflora, with limited damage to the underground rhizomes. Therefore, using cylindrical structures such as cylinders to directly roll Spartina alterniflora results in relatively low pressure, failing to effectively damage the plant, and limiting the rolling effect.

[0059] In this embodiment, as the rolling ridge 12 moves along the cylinder 11, it concentrates immense pressure along several ridges, creating extremely high local pressure. This easily cuts or crushes the epidermis and internode tissue of the grass stem. Simultaneously, as the rolling ridge 12 presses into the grass stem, it exerts a forward pushing and backward scraping motion, applying a lateral tensile force to the stem. Since plant fibers generally have strong compressive strength but relatively weak tensile and shear strength, the tensile and shearing effects generated by the rolling ridge 12 can more effectively tear the grass stem from the inside. Furthermore, while breaking the stem, the rolling ridge 12's ridges press the broken stem down and into the mud. Because the stem is torn in multiple places and loses its structural support, it prevents it from bouncing back up, thus effectively compressing and breaking the Spartina alterniflora. Furthermore, the rolling ridges 12 can cut through the surface mud, reaching the slightly harder soil below or gripping the grass roots, providing greater driving force and acting as an anti-slip agent. When the rolling ridges 12 are pressed into the ground, they not only break the above-ground stems, but the impact is also transmitted through the soil to the underground rhizomes, causing mechanical damage to the rhizomes or loosening their connection to the root system. Once the rhizomes are broken or damaged, the nutrients stored inside will be lost, and they will be easily invaded by microorganisms, leading to decay, thus inhibiting the regeneration of Spartina alterniflora in the following year.

[0060] S2 uses biodegradable mulch film to cover the rolled Spartina alterniflora.

[0061] In this embodiment, the biodegradable mulch film used is a polylactic acid composite film reinforced with kenaf fiber, which has high tensile strength and integrity. Its purpose is to restrict the exchange and transmission of air and sunlight, causing the roots of *Spartina alterniflora* to be submerged in water and soil, ultimately leading to its death due to lack of oxygen and light. The film material consists of kenaf fiber and polylactic acid fiber, with a basis weight ≥100g / m². The longitudinal tensile strength of the mulch film is ≥5kN / m, and the transverse tensile strength is ≥3kN / m. The composition of polylactic acid fiber and kenaf fiber in the biodegradable mulch film is 77 / 23 (mass ratio). The kenaf is treated with NaOH solution, and a silane agent is added to the mixture to enhance the bonding force between the kenaf and polylactic acid. The biodegradable mulch film is in rolls with a width of 3-4 meters, cut according to the growth area of ​​*Spartina alterniflora*.

[0062] The biodegradable mulch film of this embodiment can maintain its structural integrity in the tidal flat environment for 18 months. Damaged mulch film was found after 20 months. The long-term integrity of the mulch film can ensure the decay of Spartina alterniflora roots and seeds, inhibit the regeneration of Spartina alterniflora, and the mulch film is completely degraded within 36-52 months. It is environmentally friendly and will not cause plastic pollution to the tidal flat.

[0063] In this embodiment, artificial mulching is used to supplement Spartina alterniflora growing in native mangroves to prevent insufficient weed control and recurrence of Spartina alterniflora.

[0064] In this embodiment, the biodegradable mulch film is black, which can more effectively restrict sunlight transmission and accelerate the death of Spartina alterniflora. It is understood that in other embodiments, the biodegradable mulch film may also be of other colors.

[0065] S3. In the area to be treated, a high-pressure water gun is used to impact the surface silt of the tidal flat around the biodegradable mulch film, causing it to liquefy and form a mud slurry with a high water content. Then, a mud pump is used to directly suck up the liquefied mud slurry and evenly cover it on the already laid biodegradable mulch film to form a mud slurry covering layer.

[0066] Specifically, the mud source is preferentially selected from bare mudflats within the treatment area where no Spartina alterniflora grows. Furthermore, the mud cover layer is 0.8 ± 0.2 m thick to meet the subsequent planting needs of mangrove plants.

[0067] S4, a mangrove seed interception and planting device 300 is set in the mud cover layer to intercept, retain and block mangrove plant seeds such as tung flower, white mangrove, and mangrove seed floating with the tide during low tide, so that the mangrove plant seeds (tung flower, white mangrove, and mangrove seed) stay in place and naturally take root and plant.

[0068] Please see also Figures 4 to 6In this embodiment, the mud cover layer is divided into several square grids by a mangrove seed interception and planting device 300. Each square grid is approximately 50 m long and 50 m wide. The mangrove seed interception and planting device 300 includes a fixing frame 310 fixed to the mudflat formed by the mud cover layer and an interception net 320 installed on the fixing frame 310. The fixing frame 310 is fixed to several fixing stakes 311 on the mudflat and two frame bodies 312 respectively fixed to opposite sides of the fixing stakes 311. The fixing stakes 311 are spaced apart circumferentially along the corresponding squares, with one end of each stake driven into the mudflat for fixation, and the stake protruding 30-40 cm from the mudflat. In this embodiment, the fixing stakes 311 are made of bamboo tubes. Each frame body 312 includes several fixing plates 313 spaced apart vertically, and the fixing plates 313 are fixed to the fixing stakes 311. In this embodiment, the fixing plate 313 is made of bamboo strips and can be tied to the fixing stake 311 with steel wire rope or the like. Both frames 312 are equipped with intercepting nets 320. Specifically, the intercepting nets 320 can be tied and fixed to several fixing plates 311 with nylon rope or the like. The bottom side of the intercepting nets 320 extends to the surface of the mudflats and is buried in the mudflat soil. The height of the intercepting nets 320 is approximately 20 cm above the mudflat surface. In this embodiment, the intercepting nets 320 are made of kenaf netting. Using a net made of kenaf fiber, the mesh size of the intercepting nets 320 is 5 cm × 5 cm, which can effectively block the seeds of *Avicennia marina* floating with the tide, causing them to be planted in situ within the squares formed by the intercepting nets 320. It can be understood that when it is necessary to block the seeds of other mangrove plants, such as *Avicennia marina* and *Avicennia marina*, the mesh size of the intercepting nets 320 can be set to other sizes.

[0069] S5, Caulis Indulgence Planting: Divide the mud covering layer into planting units of 10×10 meters to 15×15 meters, and plant fast-growing Caulis Indulgence along the perimeter of the planting unit at a spacing of 60 cm.

[0070] To promote siltation and mangrove seed retention, the area covered by the mud slurry was divided into square planting units ranging from 10×10 meters to 15×15 meters. Rapidly germinating and growing *Cynanchum paniculatum* (a type of mangrove shrub) was planted around the perimeter of each unit, with a spacing of 60 cm between plants. One month after planting, the *Cynanchum paniculatum* rooted and tillered, achieving a survival rate of over 90%. The planting of *Cynanchum paniculatum* serves two purposes: accelerating siltation and preserving mangrove seeds for germination and transplanting.

[0071] S6, Planting native mangroves: Artificially planting mangrove seedlings within the planting unit.

[0072] To ensure rapid ecological restoration of the mudflats, mangrove seedlings are artificially planted within planting units. Kandelia candel (Epipremnum aureum) grows relatively quickly, while Acer palmatum (Red Seaweed) grows more slowly. Combining these two mangrove varieties can increase biodiversity. During planting, Kandelia candel can be planted in one planting unit to form a community, while Acer palmatum can be planted in adjacent units to form another community. To avoid replanting and considering survival rates, the spacing between Kandelia candel and Acer palmatum plants is 30-40 cm.

[0073] After rolling, covering with film, covering with slurry, and intercepting seeds for transplanting, a seedling is formed. Figure 7 The tidal flat section shown can bury Spartina alterniflora deep, completely inhibiting its growth, and allowing native mangroves to re-establish and grow on the bare tidal flat.

[0074] This invention applies a method for controlling Spartina alterniflora and promoting natural mangrove restoration based on rolling mulching and in-situ mud siltation to the tidal flats of Qixing Island, Dangjiang Town, Hepu County, from March 2024 to March 2025. The specific steps are as follows:

[0075] S1, Roll the Spartina alterniflora in the area to be treated, pressing the Spartina alterniflora into the soil and at least part of it to prevent it from bouncing up.

[0076] S2 uses biodegradable mulch film to cover the rolled Spartina alterniflora.

[0077] S3. In the area to be treated, a high-pressure water gun is used to impact the surface silt of the tidal flat around the biodegradable mulch film, causing it to liquefy and form a mud slurry with a high water content. Then, a mud pump is used to directly suck up the liquefied mud slurry and evenly cover it on the laid biodegradable mulch film to form a mud slurry cover layer with a thickness of 0.8 m.

[0078] S4. A mangrove seed interception and planting device is installed in the mud cover layer to intercept, retain, and block the seeds of *Avicennia marina*, *Avicennia gracilis*, and *Kandelia candel* that float with the tide during low tide, allowing the seeds to remain in place and naturally take root and plant.

[0079] S5, Caulis Indulgence Planting: Divide the mud covering layer into planting units of 10×10 meters to 15×15 meters, and plant fast-growing Caulis Indulgence along the perimeter of the planting unit at a spacing of 60 cm.

[0080] S6, Planting native mangroves: Mangrove seedlings are artificially planted within the planting units. 50 cm tall Kandelia candel seedlings are artificially planted in the mud-covered planting units, with a spacing of 30-40 cm between plants. 30 cm tall Paulownia tomentosa seedlings are planted in adjacent planting units, with a spacing of 30-40 cm between plants.

[0081] One year later, two Spartina alterniflora seedlings that had recurred on the experimental mudflats were transplanted as drifting, exotic plants. 26 seedlings were intercepted and transplanted at a height of 10 cm. 2 .

[0082] Experiments show that the method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation in this embodiment not only effectively prevents the growth of Spartina alterniflora, but also promotes the establishment and growth of native mangrove seedlings, achieving good ecological results in prevention and restoration.

[0083] This invention was also tested on the tidal flats of Qixing Island, Dangjiang Town, Hepu County, Guangxi. The control effects of the Spartina alterniflora control and mangrove natural restoration method based on rolling mulching and in-situ mud siltation in this embodiment were compared with the control methods of Spartina alterniflora control by simply tilling and mulching, the control methods of Spartina alterniflora control using the combination of "mulching + iris", the control methods of Spartina alterniflora control using the combination of "mulching + barrier", and the control methods of Spartina alterniflora control using the combination of "mulching + planting". The effects of Spartina alterniflora control and replacement of native mangrove seedlings after one year are shown in Table 2.

[0084]

[0085] As shown in Table 2, the commonly used deep digging and tilling method for controlling Spartina alterniflora has a high recurrence rate; as long as the stems and leaves of Spartina alterniflora are exposed on the mudflats, recurrence is highly probable. However, by using a mulch film followed by covering the composite film with mud and then applying different treatments, Spartina alterniflora stems and leaves were essentially not exposed, preventing recurrence. Recurrence was mainly due to the transplantation of foreign seeds or plants, while situ-grown Spartina alterniflora showed virtually no recurrence. Experiments demonstrate that this invention not only effectively controls the growth of Spartina alterniflora but also promotes the transplantation and growth of native mangrove seedlings, achieving good ecological results in both control and restoration.

[0086] Therefore, compared with the prior art, the method for controlling Spartina alterniflora and restoring mangroves provided by the present invention has the following significant synergistic and beneficial effects:

[0087] (1) This invention uses rolling instead of the traditional "cutting + digging of roots and stems", simplifying the complex clearing operation into a one-time mechanical rolling, avoiding a large amount of manual digging and soil transportation work; at the same time, compared with the cutting operation, the rolling mechanism of the tracked grass press used in this method is close to the ground, with a lower center of gravity, and the weight distribution of the equipment is uniform and stable, making it less prone to sinking in soft tidal flats. Moreover, the tracked grass press can complete the rolling of Spartina alterniflora while moving continuously, resulting in high work efficiency. In addition, the use of in-situ mud slurry for covering saves the cost of purchasing soil and long-distance transportation. According to comprehensive estimates, the mechanical and labor costs of this method can be reduced by about 30%-40% compared with the traditional "tillage method" or "burying method", and the construction efficiency can be increased by more than 50%.

[0088] (2) The present invention first fixes the Spartina alterniflora plants and buries some of the seeds by "rolling and pressing into the mud", then covers them with biodegradable mulch to achieve physical oxygen and light isolation, and finally applies a 0.8-meter-thick mud layer for deep suppression. The combined effect of these three barriers can effectively kill the above-ground parts and underground rhizomes and block the spread of seeds. This can reduce the recurrence rate of Spartina alterniflora from more than 60% in the existing methods to less than 5%, and basically achieve one-time eradication. Meanwhile, the tracked grass press used in this method employs a roller 1 with several rolling protrusions 12 to roll over Spartina alterniflora. The cross-sectional area of ​​the rolling protrusions 12 gradually decreases in the direction away from the roller body. At the same time, the relative height between the roller 1 and the track 200 is adjusted with the height adjustment component to ensure that the roller 1 applies sufficient impact pressure, bending moment and shear stress to the Spartina alterniflora during the operation, ensuring that the Spartina alterniflora is crushed and pressed into the soil, no longer bounces up, and completely buries the Spartina alterniflora seeds, preventing the seeds from being scattered in the mudflats or seawater. At the same time, since the cross-sectional area of ​​the rolling protrusions 12 gradually decreases in the direction away from the roller body, the space between the rolling protrusions 12 gradually increases outward, which is more conducive to the silt entering between the two rolling protrusions 12 being discharged again with the rolling, preventing the roller 1 from being completely covered by silt and failing. In addition, the two rolling mechanisms at both ends of the frame 100 enable the tracked grass presser to roll Spartina alterniflora twice during its forward movement, further improving the rolling effect on Spartina alterniflora.

[0089] (3) This invention not only addresses the issue of landslides but also simultaneously restores the ecosystem. In-situ mud mulching directly raises the beach surface to an ideal elevation suitable for mangrove growth (approximately above the average tide level), solving the problem of the beach surface being too low after traditional landslides, which is not conducive to mangrove planting. It also allows the treatment of Spartina alterniflora to proceed simultaneously with mangrove planting, increasing the speed of mangrove restoration. The combination of artificial planting and the "mangrove seed barrier device" ensures the initial vegetation coverage rate on the one hand, and greatly promotes the natural regeneration of native tree species on the other hand, enabling the ecosystem to quickly move towards a self-sustaining stable state. It is expected that a mangrove community with high biodiversity can be formed within 3-5 years.

[0090] (4) The present invention uses physical methods throughout the process, eliminating the risk of pollution to the aquatic environment by chemical herbicides. The film material used is a composite film material of cotton, linen and polylactic acid ester, which can be completely biodegraded within a set period (24-36 months). The final products are carbon dioxide and water, with no microplastic residue, thus avoiding the "white pollution" problem caused by traditional plastic film.

[0091] (5) The innovative in-situ mud extraction and covering method of this invention has less disturbance to the original tidal flat topography and benthic biological community compared with large-scale excavation and filling. The resulting raised tidal flat is natural and gentle, which is not only conducive to the growth of mangroves, but also has a stronger effect of promoting siltation and stabilizing the tidal flat. It can further enhance the carbon sequestration capacity of the tidal flat and the ecological function of resisting wind and wave erosion.

[0092] Therefore, this invention completely prevents the Spartina alterniflora stems and leaves from being exposed and regrowing on the mudflats by deeply burying it under a film and slurry in situ. Simultaneously, the mangrove seed blocking device 300 promotes the establishment and growth of native mangrove seeds, enabling the transplantation of native mangroves, ecological restoration, and solving the problem of the difficulty in the natural recovery of native mangroves. Furthermore, the method of this invention eliminates the need for mowing, digging and root treatment, and tilling, allowing for on-site operation and reducing costs. It also avoids the use of chemical agents, reducing construction work, minimizing the impact of chemical substances on the environment, and reducing environmental disturbance.

[0093] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit of the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation, characterized in that, Includes the following steps: S1, Roll the Spartina alterniflora in the area to be treated to break it down and press it into the soil to prevent it from bouncing up; S2, biodegradable mulch film is used to cover the rolled Spartina alterniflora; S3. In the area to be treated, a high-pressure water gun is used to impact the surface silt of the tidal flat around the biodegradable mulch film, causing it to liquefy and form a mud slurry with a high water content. Then, a mud pump is used to directly suck up the liquefied mud slurry and evenly cover it on the laid biodegradable mulch film to form a mud slurry covering layer. S4. A mangrove seed interception and planting device is set in the mud cover layer to intercept, retain and block mangrove plant seeds floating with the tide during low tide, so that the mangrove plant seeds stay in place and take root and plant naturally.

2. The method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation as described in claim 1, characterized in that, In step S4, the mud cover layer is divided into several squares by the mangrove seed interception and planting device, which includes a fixing frame fixed on the mud cover layer and an interception net installed on the fixing frame.

3. The method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation as described in claim 2, characterized in that, The grid is a square grid with a length of 50 m and a width of 50 m; the fixing frame includes a fixing post fixed to the mudflat and two frames respectively fixed to opposite sides of the fixing post, and both frames are equipped with interception nets.

4. The method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation as described in claim 3, characterized in that, One end of the fixed pile is driven into the mud cover layer for fixation, and the fixed pile protrudes 30-40cm from the mud cover layer; the frame includes several fixed plates arranged at intervals along the vertical direction, and the fixed plates are fixed to the fixed pile; the interception net is fixed to several of the fixed plates, the bottom side of the interception net extends to the mud cover layer, and the height of the interception net is 20cm higher than the mud cover layer.

5. The method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation as described in claim 3, characterized in that, It also includes the following steps: S5, Caulis Chinnaratus Planting: Divide the mud covering layer into planting units of 10×10 meters to 15×15 meters, and plant fast-growing Caulis Chinnaratus around the perimeter of the planting unit at a spacing of 60 cm between plants.

6. The method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation as described in claim 5, characterized in that, It also includes the following steps: S6, Planting native mangroves: Artificially planting mangrove seedlings within the planting units of *Cynanchum paniculatum*.

7. The method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation as described in claim 1, characterized in that, In step S1, a tracked grass press is used to roll Spartina alterniflora. The tracked grass press includes a frame, a track, a rolling mechanism, and a height adjustment component. The track is installed at the bottom of the frame, and the rolling mechanism is located at the end of the frame. The rolling mechanism includes a support rod, a mounting frame, and a roller. The two ends of the support rod are respectively hinged to the frame and the mounting frame. The roller is rotatably connected to the mounting frame. The height adjustment component is installed on the frame and connected to the mounting frame to adjust the relative height between the roller and the track.

8. The method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation as described in claim 7, characterized in that, The height adjustment assembly includes a first hydraulic cylinder and a second hydraulic cylinder. The first hydraulic cylinder is located above the support rod, and its cylinder body and piston rod are respectively hinged to the frame and the mounting plate. In one height adjustment assembly, the cylinder body of the second hydraulic cylinder is fixed to the frame, and the corresponding piston rod is hinged to the mounting plate. In another height adjustment assembly, the cylinder body and piston rod of the second hydraulic cylinder are respectively hinged to the frame and the mounting plate.

9. The method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation as described in claim 7, characterized in that, The roller includes a cylinder rotatably mounted on the mounting plate and a plurality of rolling protrusions evenly spaced along the circumference of the cylinder, wherein the cross-sectional area of ​​each rolling protrusion gradually decreases in the direction away from the cylinder.

10. The method for controlling Spartina alterniflora and promoting natural restoration of mangroves based on rolling mulching and in-situ mud siltation as described in claim 7, characterized in that, When the tracked grass press is in operation, the lowest point of the roller is 15-20 cm lower than the bottom of the track.

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