A water-holding device suitable for phytoremediation on the peak cluster ridges in karst areas

Abstract

The present invention discloses a water-holding device applicable to phytoremediation of peak cluster ridges in karst areas, comprising a fixing device and a water-holding layer. The fixing devices are arranged at both ends of the water-holding layer, and connection holes are provided on the fixing devices. By fixing it to the area to be repaired with hemp ropes or springs, water is supplemented and plants are transplanted by division, thereby providing water for plant growth. Using layered water-holding matrix materials with different water-holding effects, the water-holding effect is better. The present invention can be flexibly configured and used under the complex terrain conditions of peak cluster ridges, achieving an efficient water-holding effect, improving the efficiency of vegetation restoration in karst areas, reducing the repair cost, and improving the current situation of soil and water loss in peak cluster ridges of karst areas.

Description

Technical Field

[0001] The present invention relates to the technology of difficult vegetation restoration, and particularly to a water-holding device for plant restoration applicable to the peak cluster ridges in karst areas. Background Art

[0002] The peak cluster landform is formed by the combined action of karstification and weathering and denudation, and is characterized by large slopes, shallow soil layers, low water and nutrient contents, etc., which are not conducive to the growth and retention of vegetation. This directly leads to its fragile ecological environment, weak surface vegetation cover, thin or soil-free soil layers, and is prone to serious soil erosion and land desertification. Especially for the peak cluster ridges, the environmental conditions are more severe. The rocky desertification phenomenon leads to land degradation and even forms a harsh ecological environment with exposed rock surfaces. The restoration of vegetation on the peak cluster ridges in karst areas has become an urgent problem to be solved currently.

[0003] It is not easy to carry out plant restoration on the peak cluster ridges in karst areas. The main reason is that its unique geological structure and topography lead to exposed bedrock or shallow soil layers, weak land water storage capacity. Usually, it gets waterlogged when it rains, and soon after the rain, a large amount of surface water turns underground and drought occurs quickly, forming a harsh climate condition of alternating drought and waterlogging. At the same time, the soil is thin and infertile, and it is difficult for water to moisten the roots of plants, so it is very difficult for plants to survive and grow, which greatly affects the vegetation restoration.

[0004] In fact, in the karst ecosystem, vegetation, soil and water are three key factors. Only when the soil and water are effectively managed can the vegetation recover quickly and stably and enter a virtuous cycle. Existing research has found that the soil formation rate in karst areas is extremely slow. The acid-insoluble content of pure carbonate rock is low, only about 4% on average, and the weathering residues are very few. On average, it takes about 8,000 years to form a 1-cm-thick soil layer. At the same time, due to the complex terrain of karst landforms, with the characteristics of high permeability and rapid hydrological cycle, the plant growth conditions are further deteriorated, and problems such as water shortage and unstable water sources have become the difficulties in the vegetation restoration of the peak cluster ridges in karst areas. Therefore, how to effectively manage the soil and maintain the non-loss of water has become the key point in the vegetation restoration of the peak cluster ridges in karst areas.

[0005] Some existing phytoremediation technologies, such as nutrient soil method, plastic film covering for tree planting, etc. Although these methods can solve the problems of water and nutrients in the process of plant growth to a certain extent, there are still some defects. For example, the growth cycle of tree species is long, the remediation effect is slow, the soil erosion rate is greater than the remediation rate, and the land still shows further degradation, and it is impossible to fundamentally retain soil moisture and nutrients. And the existing water conservation and water supply technologies, such as potted plants, water lawns and other technologies, cannot meet the needs of ridge vegetation restoration. Sprinkler irrigation is easy to cause soil erosion and water flow scouring, and is not conducive to long-term maintenance. The Chinese patent application of CN103651051A mentions a water-saving micro-irrigation system. The micro-irrigation engineering has a relatively high technical content, the equipment is relatively complex, the engineering investment is relatively high, and its micro-irrigation only wets the surface soil. At the same time, the requirements for water quality are relatively strict, generally filtering is required, and sedimentation and chemical treatment are also required when necessary, and the operating cost is relatively high. In the karst area, the terrain of the peak cluster ridges is undulating and there are many peaks, so it is difficult to popularize and apply the micro-irrigation technology in the karst area.

[0006] Searching for the existing technologies, the Chinese utility model patent of CN213127425U discloses a vegetation substrate structure for slope restoration, including a water-holding guest soil layer laid on the bottom surface of the slope. An ecological planting layer is arranged above the water-holding guest soil layer. The ecological planting layer is made of a planting material made of a mixture of crushed straws, organic fertilizers, soil, etc. added with plant seeds and then stirred and pressed. A water-conducting layer is laid between the ecological planting layer and the water-holding guest soil layer with a geotextile blanket. A water-retaining layer is arranged above the ecological planting layer. The water-retaining layer is composed of two layers of straw blankets and a gravel material layer sandwiched between the two layers of straw blankets. The outside of the vegetation substrate is penetrated by net pins and fixed with a tendon belt net. A space for stacking the vegetation substrate is formed above the tendon belt net. Both sides are fixed to the anchor cables arranged vertically along the slope, using high-strength steel cables, and the upper ends of the anchor cables are fixed to the anchor piles at the top of the slope. However, there are still the following defects: 1. The water absorption capacity and water-holding capacity of the water-holding guest soil layer are weak, and a relatively high thickness is required to maintain a certain water-holding capacity; 2. The water-conducting layer is made of a geotextile blanket. If it is too thick, it will affect the water-conducting effect and the growth of vegetation roots. If it is too thin, the water-conducting effect is not good; 3. The water-retaining layer is composed of straw blankets and gravel materials. The straw blankets are prone to mildew and rot in a humid environment, produce bacteria, and affect the growth of vegetation; 4. The selected fixing device is an anchoring system composed of anchor cables, pile stakes and tendon belt nets, with a high construction cost, reduced slope stability, easy to cause secondary disasters, and low adaptability to complex terrain.

[0007] The existing vegetation restoration technologies cannot fundamentally solve the problem of difficult water retention in the vegetation restoration of peak cluster ridges in the karst area. And the existing water management technologies have poor effects or cannot be implemented for the high-altitude and steep terrain of peak cluster ridges in the karst area. Therefore, there is an urgent need for a vegetation restoration water retention device suitable for peak cluster ridges in the karst area to flexibly and efficiently manage soil moisture to achieve the effect of vegetation restoration. Summary of the Invention

[0008] In view of the existing problems, the present invention aims to provide a water-holding device suitable for phytoremediation on the peak clusters and ridges in karst areas, so as to solve the problem of difficult water holding in the existing vegetation restoration technology for peak clusters and ridges in karst areas, provide a new technical approach for vegetation restoration while reducing the cost of vegetation restoration, and thus effectively improve the vegetation restoration efficiency of peak clusters in karst areas.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A water-holding device suitable for phytoremediation on the peak clusters and ridges in karst areas described in the present invention includes a fixing device and a water-holding layer. The fixing device is arranged at both ends of the water-holding layer, and connecting holes are arranged on the fixing device; the water-holding layer is a multi-layer water-holding layer, and each layer of the multi-layer water-holding layer is separated from each other and then integrated according to the layers.

[0011] Each layer of the multi-layer water-holding layer is separated by an inner planting bag, and the multi-layer water-holding layer is combined into one body by an outer planting bag.

[0012] Round holes are provided on the inner planting bag and the outer planting bag of the topmost water-holding layer of the multi-layer water-holding layer.

[0013] The multi-layer is 5 layers, which are the first layer, the second layer, the third layer, the fourth layer and the fifth layer in sequence from bottom to top. Each layer is filled with a substrate layer of different materials, and the materials of the substrate layer are filled from top to bottom according to a volume ratio of 1:2:2:2:3; the substrate materials of the fifth layer and the first layer are organic substrate materials, and the substrate materials of the other layers are inorganic substrate materials.

[0014] The organic substrate materials include sphagnum moss, coconut coir fiber, pine bark, snake wood chips, Chinese fir wood chips, and rice husk charcoal; the inorganic substrate materials include floating pumice, charcoal powder, perlite, vermiculite, volcanic rock, and pumice stone.

[0015] The filling of the first layer includes but is not limited to dry sphagnum moss and coconut coir fiber; the filling of the second layer includes but is not limited to floating pumice, pumice stone, rice husk charcoal, and charcoal powder; the filling of the third layer includes but is not limited to volcanic rock and vermiculite; the filling of the fourth layer includes but is not limited to vermiculite, perlite, and snake wood chips; the filling of the fifth layer includes but is not limited to pine bark, Chinese fir wood chips, snake wood chips, and coconut coir fiber.

[0016] The first layer is filled with dry sphagnum moss, the second layer is filled with floating pumice, the third layer is filled with volcanic rock, the fourth layer is filled with vermiculite, and the fifth layer is filled with pine bark.

[0017] The using method of the water-holding device suitable for phytoremediation on the peak clusters and ridges in karst areas includes the following steps:

[0018] (1) Preparation of the first water-holding layer: Lay the organic substrate flat in the inner vegetation bag and record the volume of the filled organic substrate.

[0019] (2) Preparation of the second water-holding layer: Put the inorganic substrate material into the inner vegetation bag, and the volume of the filled inorganic substrate material is 2 / 3 of that of the first water-holding layer.

[0020] (3) Preparation of the third water-holding layer: Put the inorganic substrate material into the inner vegetation bag, and the volume of the filled inorganic substrate material is 2 / 3 of that of the first water-holding layer.

[0021] (4) Preparation of the fourth water-holding layer: Put the inorganic substrate material into the inner vegetation bag, and the volume of the filled inorganic substrate material is 2 / 3 of that of the first water-holding layer.

[0022] (5) Preparation of the fifth water-holding layer: Put the inorganic substrate material into the inner vegetation bag, and the volume of the filled inorganic substrate material is 1 / 3 of that of the first water-holding layer.

[0023] (6) Place the five prepared water-holding layers into the outer vegetation bag in sequence from bottom to top. Set round holes on the outer surface of the inner vegetation bag of the fifth prepared water-holding layer, and set round holes on the upper surface of the outer vegetation bag along the round holes opened on the inner vegetation bag of the fifth water-holding layer; Set fixing devices on the remaining parts at both ends of the outer vegetation bag.

[0024] (7) Set the water-holding device according to the following situations: On the gentle ridge with low and flat terrain, fix the prepared water-holding device by leaning it directly against the rock or clamping it with a rock crack; On the sharp and steep low-terrain ridge, use springs to hook and lock one or more of the water-holding devices around the bare rock in sequence to form an embracing and fixing effect on the bare rock; On the sharp and steep high-terrain ridge, suspend the water-holding device on the surface of the bare rock with a hemp rope, apply marble glue on the side facing the bare rock, and fix the other end of the hemp rope.

[0025] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0026] 1. The first layer of this device uses matrix materials such as coconut coir fiber and dry sphagnum. The water-holding capacity of coconut coir fiber is 8-9 times its own weight, and the water-holding capacity of dry sphagnum is 10-22 times its own weight. The evaporation amount is 1 / 5 of its own weight, and the water-holding time can be up to half a month. Dry sphagnum can absorb both the rainwater filtered downward from the upper layer of the device and the rainwater falling near the surface of the device. Compared with the existing backfilled water-holding guest soil layer, it has stronger water absorption, better water-holding effect, smaller volume, more water absorption channels, and can manage water resources in the restoration area to a greater extent, alleviating the current situation of weak soil water storage capacity in the peak cluster ridge.

[0027] 2. The second, third, and fourth layers of this device adopt inorganic substrates such as pumice, light stone, vermiculite, and rice husk charcoal, with a water absorption rate of 60%-80%, being loose and porous, and rich in minerals. Among them, pumice, light stone, vermiculite, etc. keep the device moist, conduct water and air, and are beneficial for the roots to grow downward. Rice husk charcoal filters impurities, purifies rainwater, and promotes the effectiveness of phosphorus, potassium, and calcium. Compared with the existing water-conducting layers made of geotextiles, etc., it has stronger air permeability, better water-conducting and filtering effects, and at the same time meets the growth space, water quality requirements, and nutrient requirements of plant roots;

[0028] 3. The fifth layer of this device uses organic substrates such as pine bark, Chinese fir sawdust, and snakewood sawdust as coverings. They have a large specific surface area, a small bulk density, and are rich in nitrogen, phosphorus, and potassium. The surface layer intercepts precipitation, infiltrates water, supplements the nutrients required for plant growth, covers the surface layer to reduce the water loss rate of the device, and keeps warm and moisturizes. Compared with the existing straw blanket water-retaining layer, it has a better effect of preventing water loss, provides more nutrients required by plants, is not easy to rot and mildew, improves the growth conditions of plants planted in the device, and improves the current situation of difficult vegetation growth on peak cluster ridges;

[0029] 4. The fixing device of this device is installed according to local conditions based on the terrain of the peak cluster ridge. It directly relies on stones or stone seams on the gentle and flat ridges, uses springs for fixation on the sharp and steep low-lying ridges, and is suspended with hemp ropes and fixed with marble glue on the sharp and steep high-lying ridges. It effectively fits the terrain characteristics of large undulations in slope and numerous peaks in the karst peak cluster ridge area. Compared with the existing anchoring system, it has a lower construction cost, is easier to manufacture, and is more convenient to install. It has stronger versatility and is more easily promoted and applied in the complex terrain of the peak cluster ridge;

[0030] 5. The volume ratio of the five water-holding layers of this device from bottom to top is 3:2:2:2:1. The fifth layer with a volume ratio of 1 can hold water for several days to a week. The infiltrated water is held by the fourth, third, and second layers with a ratio of 2 for 1-7 days. The filtered water is held by the first layer with a volume ratio of 3 for up to half a month. The total volume ratio of the upper four layers is greater than that of the first layer. Each layer holds water, prevents water loss, makes full use of each layer of materials, and ensures more uniform water holding in the device; Compared with the existing device with a single-layer water-holding configuration water-retaining layer, each layer of the matrix material selected for this device has the ability to hold water, has a higher water utilization efficiency of the device, and the water-holding effect is more significant, stable, and controllable. The volume ratio of the five water-holding layers is 3:2:2:2:1, which is not only considered for the water-holding effect, but also for the needs of plant growth, especially the growth of roots. In addition, the thinner upper layer also takes into account the problem of air permeability.

[0031] Other features and advantages of the present invention will be described in the subsequent specification, and some will become obvious from the specification, or will be understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of a water-holding device for phytoremediation applicable to peak cluster ridges in karst areas according to the present invention.

[0033] Figure 2 This is a top view schematic diagram of a water-holding device for phytoremediation applicable to peak cluster ridges in karst areas according to the present invention.

[0034] Figure 3 This is a front view schematic diagram of a water-holding device for phytoremediation applicable to peak cluster ridges in karst areas according to the present invention.

[0035] Figure 4 This is a schematic diagram of the degradation process of the original vegetation on peak cluster ridges with different terrains in karst areas.

[0036] Figure 5 This is a schematic diagram of the vegetation restoration effect of a water-holding device for phytoremediation applicable to peak cluster ridges in karst areas applied to peak cluster ridges with different terrains in karst areas. Specific implementation manners

[0037] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. The accompanying drawings form a part of this application and, together with the embodiments, illustrate the present invention. However, those skilled in the art should understand that the following embodiments are not the only limitations on the technical solution of the present invention. Any equivalent transformation or modification made under the spirit of the technical solution of the present invention should be regarded as falling within the protection scope of the present invention.

[0038] Embodiment 1:

[0039] As Figure 1 shown, the water-holding device for phytoremediation applicable to sharp and steep low-terrain peak cluster ridges in karst areas according to the present invention includes a fixing device and a water-holding layer. The fixing device is arranged at both ends of the water-holding layer, and connection holes are provided on the fixing device.

[0040] As Figure 3 shown, the water-holding layer is a multi-layer water-holding layer, specifically with 5 layers. Each water-holding layer uses an inner planting bag filled with matrix materials, and an outer planting bag is used to assemble each water-holding layer together. From the bottom to the top, they are the first layer, the second layer, the third layer, the fourth layer, and the fifth layer. Different materials of matrix layers are filled between each layer, and the materials of the matrix layers are filled from top to bottom in a volume ratio of 1:2:2:2:3; the matrix materials of the fifth layer and the first layer are organic matrix materials, and the matrix materials of other layers are inorganic matrix materials. The organic matrix materials include sphagnum moss, coconut coir fiber, pine bark, snake wood chips, Chinese fir wood chips, and rice husk charcoal; the inorganic matrix materials include pumice, charcoal powder, perlite, vermiculite, volcanic stone, and pumice stone. Among them, the first layer is filled with dry sphagnum moss, the second layer is filled with pumice, the third layer is filled with volcanic stone, the fourth layer is filled with vermiculite, and the fifth layer is filled with pine bark.

[0041] Use a small knife to cut 2 rows of 3 round holes each on the outer surface of the vegetation bag inside the fifth water-holding layer. After filling the prepared water-holding layer into the outer vegetation bag, wind the bag tightly with a thin string for five rounds and tie a double single knot. On the upper surface of the outer vegetation bag, cut 2 rows of 3 round holes R at the positions of the round holes opened on the vegetation bag inside the fifth water-holding layer, specifically as Figure 2 shown.

[0042] Sphagnum moss can absorb 10 - 22 times its own weight of water, with a pH value of 5 - 6, and the water-holding time can be up to half a month. Pumice has a water absorption of 80%, and the water-holding time is 1 - 3 days. Volcanic rock has a water absorption of 60%, and the water-holding time is 1 - 3 days. Vermiculite can absorb 500 - 650 liters of water per cubic meter, with a pH value of 7 - 9, and the water-holding time is 3 - 7 days. Pine bark has a pH value of 7, and pine bark can absorb 4 - 5 times its own weight of water, with a water-holding time of 3 - 5 days. Coconut coir fiber can hold 8 - 9 times its weight of water, with a pH value of 5.5 - 6.2, and the water-holding time is 2 - 7 days. Perlite has a particle size specification of 2 - 6 mm, a water absorption of 80%, and the water-holding time ranges from several days to several weeks. Lapis light has a water absorption of 80%, and the water-holding time is 1 day or several days. Charcoal powder has a particle size specification of 2 - 6 mm, and the water-holding time is 1 - 3 days. Chinese fir sawdust has a water absorption of 80%, and the water-holding time is 3 - 7 days. Snakewood sawdust has a water absorption of 50%, and the water-holding time is 3 - 7 days. Rice husk charcoal has a water absorption of 50%, a pH value of 7.5, and the water-holding time is 2 - 3 days.

[0043] In this embodiment, the first layer is filled with dry sphagnum moss, the second layer is filled with pumice, the third layer is filled with volcanic rock, the fourth layer is filled with vermiculite, and the fifth layer is filled with pine bark. After testing, the following effects are obtained: After sufficient initial precipitation on the peak cluster ridges in the karst area, the pine bark in the fifth layer can absorb 4 - 5 times its own weight of water, with a water-holding time of 3 - 5 days. After the rain further infiltrates, the continuous wetting times in the fourth layer, the third layer, and the second layer are 3 - 7 days, 1 - 3 days, and 1 - 3 days respectively. The rain further infiltrates to the first layer of dry sphagnum moss, and at the same time, the part of the dry sphagnum moss close to the ground absorbs the surface rainwater near the device, and its water absorption is 10 - 22 times its own weight, with a water-holding time of about 15 days. In the environment of the peak cluster ridges in the karst area, the entire water-holding device can maintain a wetting effect for nearly 30 days at most.

[0044] During use, according to the terrain type, different fixing methods are used to fix the water-holding device of the present invention. On the low, flat and gentle ridges, fix the prepared water-holding device by directly leaning it against a stone or clamping it with a stone crack; on the sharp and steep low-lying ridges, use a spring to hook and lock one or more of the water-holding devices around the bare rock in sequence to form an embracing and fixing effect on the bare rock; on the sharp and steep high-lying ridges, suspend the water-holding device on the surface of the bare rock with a hemp rope, apply marble glue on the side facing the bare rock, and fix the other end of the hemp rope.

[0045] Example 2

[0046] This example is an example of the method for using the water-holding device of the present invention, and the specific steps are as follows:

[0047] (1) Prepare the first water-holding layer: Lay the organic substrate flat in the inner planting bag and record the volume of the filled organic substrate; Lay 500 g of dry sphagnum moss flat in the inner planting bag with a specification of 15×40 cm, so that its volume specification is 15×40×3 cm, and wind the opening with a thin string for five circles and tighten it and tie a double single knot;

[0048] (2) Prepare the second water-holding layer: Put the inorganic matrix material into the inner planting bag, and the volume of the filled inorganic matrix material is 2 / 3 of that of the first water-holding layer: Lay 740 g of charcoal powder with a particle size of 2-6 mm flat in the inner planting bag with a specification of 15×40 cm, so that its volume specification is 15×40×2 cm, and wind the opening with a thin string for five circles and tighten it and tie a double single knot;

[0049] (3) Prepare the third water-holding layer: Put the inorganic matrix material into the inner planting bag, and the volume of the filled inorganic matrix material is 2 / 3 of that of the first water-holding layer: Lay 240 g of vermiculite with a particle size of 1-2 mm flat in the inner planting bag with a specification of 15×40 cm, so that its volume specification is 15×40×2 cm, and wind the opening with a thin string for five circles and tighten it and tie a double single knot;

[0050] (4) Prepare the fourth water-holding layer: Put the inorganic matrix material into the inner planting bag, and the volume of the filled inorganic matrix material is 2 / 3 of that of the first water-holding layer: Lay 100 g of perlite with a particle size of 2-6 mm flat in the inner planting bag with a specification of 15×40 cm, so that its volume specification is 15×40×2 cm, and wind the opening with a thin string for five circles and tighten it and tie a double single knot;

[0051] (5) Prepare the fifth water-holding layer: Put the inorganic matrix material into the inner planting bag, and the volume of the filled inorganic matrix material is 1 / 3 of that of the first water-holding layer: Lay 600 g of snake wood chips with a particle size of 5-10 cm flat in the inner planting bag with a specification of 15×40 cm, so that its volume specification is 15×40×1 cm, and wind the opening with a thin string for five circles and tighten it and tie a double single knot;

[0052] (6) Place the prepared five-layer water-holding layer into the exophytic bag in the order from bottom to top. Set round holes on the outer surface of the exophytic bag within the fifth-layer water-holding layer. Set round holes on the upper surface of the exophytic bag along the round holes opened in the exophytic bag within the fifth-layer water-holding layer. Set fixing devices at the remaining parts at both ends of the exophytic bag: Place the prepared five-layer water-holding layer into the exophytic bag W with the specification of 15×80 cm in the order from bottom to top. Use a knife to open 2 rows of 3 round holes with a diameter of 4 cm on the outer surface of the exophytic bag within the fifth-layer water-holding layer. After loading the prepared water-holding layer, wind the exophytic bag with a thin string for five circles and tighten it to tie a double single knot. Open 2 rows of 3 round holes R with a diameter of 5 cm on the upper surface of the exophytic bag along the round holes opened in the exophytic bag within the fifth-layer water-holding layer. Clamp both ends of the exophytic bag with two long strip wooden boards G1 and G2 of the same size. Each non-woven fabric at both ends of the exophytic bag extends out 2 cm. Use a pneumatic nail gun to nail nails on the upper and lower parts of the clamping plate for fixation, and use a hand drill to drill three evenly arranged round holes on the clamping plate. Hook and lock the round holes on the clamping plate with a spring S hook.

[0053] After the water-holding device is prepared, first place the water-holding device in the area that needs to be repaired, then transplant corresponding plants by dividing them into individual plants, and then carry out cultivation and management.

[0054] Device fixation: Repeat the above steps to make three such plant restoration water-holding devices respectively (Device 1, Device 2, Device 3). The selected terrain category is a sharp and steep low-lying ridge bare rock. The hook-locking method is selected: Hook the G2 clamping plate of Device 1 with a spring S1, and hook the other end of the spring S1 to the G1 clamping plate of Device 2. Hook the G2 clamping plate of Device 2 with a spring S2, and hook the other end of the spring S2 to the G1 clamping plate of Device 3. Hook the G2 clamping plate of Device 3 with a spring S3, and hook the other end of the spring S3 to the G1 clamping plate of Device 1 to form a closed-loop water-holding device, and set the closed-loop water-holding device on the base of the bare rock for fixation.

[0055] Dividing and transplanting: After the device is fixed, divide and transplant 3-5 seedlings of Cymbidium kanran at each of the six hole positions R of Device 1, and the planting depth is 3 cm; divide and transplant 3-5 seedlings of Cymbidium tortisepalum at each of the six hole positions R of Device 2, and the planting depth is 3 cm; divide and transplant 3-5 seedlings of Cymbidium tortisepalum var. longibracteatum at each of the six hole positions R of Device 3, and the planting depth is 3 cm.

[0056] Cultivation and management: Within the first month after ramet transplantation, water once every week. The degree of watering is to slightly moisten the L1 layer of the layered water-holding layer. After one month, no additional watering is required.

[0057] Applying the present invention to the low-lying terrain of the peak cluster ridges in the karst area of southwestern Guangxi, the effect after 12 months of restoration is as Figure 5 shown. It can be seen that after restoration using the present invention, due to the function of the water-holding device, the plants grow well, adapt to the peak cluster ridge area of the karst area, and the restoration effect is remarkable.

Claims

1. A water-holding device applicable to phytoremediation on the peak clusters and ridges in karst areas, characterized in that, It includes a fixing device and a water-holding layer. The fixing device is arranged at both ends of the water-holding layer, and connection holes are provided on the fixing device; springs are connected to the connection holes of the fixing device; The water-holding layer is a multi-layer water-holding layer. The layers of the multi-layer water-holding layer are separated from each other and then integrated according to the layers; The layers of the multi-layer water-holding layer are separated from each other by inner planting bags, and the multi-layer water-holding layer is combined into one by outer planting bags; Round holes are provided on the inner planting bags and outer planting bags of the topmost water-holding layer of the multi-layer water-holding layer; The multi-layer is 5 layers, which are the first layer, the second layer, the third layer, the fourth layer and the fifth layer in sequence from bottom to top. The layers are filled with matrix layers of different materials, and the materials of the matrix layer are filled from top to bottom according to the volume ratio of 1:2:2:2:3; the matrix materials of the fifth layer and the first layer are organic matrix materials, and the matrix materials of the other layers are inorganic matrix materials; The first layer is filled with dry sphagnum moss, the second layer is filled with pumice, the third layer is filled with volcanic stones, the fourth layer is filled with vermiculite, and the fifth layer is filled with pine bark; Set the water-holding device according to the following situations: on the low, flat and gentle ridge, directly fix the water-holding device by leaning on the stones or clamping it with stone seams; on the sharp and steep low-lying ridge, make one or more water-holding devices hook and lock around the bare rock in sequence through springs to form an embracing and fixing effect on the bare rock; on the sharp and steep high-lying ridge, suspend the water-holding device on the surface of the bare rock with hemp ropes, apply marble glue on the side facing the bare rock, and fix the other end of the hemp rope.

2. A method for using the water-holding device applicable to phytoremediation on the peak clusters and ridges in karst areas according to claim 1, characterized in that, It includes the following steps: (1) Prepare the first-layer water-holding layer: lay dry sphagnum moss flat in the inner planting bag and record the volume of the filled dry sphagnum moss; (2) Prepare the second-layer water-holding layer: put pumice into the inner planting bag, and the volume of the filled pumice is 2 / 3 of that of the first-layer water-holding layer; (3) Prepare the third-layer water-holding layer: put volcanic stones into the inner planting bag, and the volume of the filled volcanic stones is 2 / 3 of that of the first-layer water-holding layer; (4) Prepare the fourth-layer water-holding layer: put vermiculite into the inner planting bag, and the volume of the filled vermiculite is 2 / 3 of that of the first-layer water-holding layer; (5) Prepare the fifth-layer water-holding layer: put pine bark into the inner planting bag, and the volume of the filled pine bark is 1 / 3 of that of the first-layer water-holding layer; (6) Put the prepared five-layer water-holding layer into the outer planting bag in sequence from bottom to top. Set round holes on the outer surface of the inner planting bag of the fifth-layer water-holding layer prepared, and set round holes on the upper surface of the outer planting bag along the round holes opened on the inner planting bag of the fifth-layer water-holding layer; set fixing devices at the remaining parts at both ends of the outer planting bag; (7) Set the water-holding device according to the following situations: on the low, flat and gentle ridge, directly fix the water-holding device by leaning on the stones or clamping it with stone seams; on the sharp and steep low-lying ridge, make one or more water-holding devices hook and lock around the bare rock in sequence through springs to form an embracing and fixing effect on the bare rock; on the sharp and steep high-lying ridge, suspend the water-holding device on the surface of the bare rock with hemp ropes, apply marble glue on the side facing the bare rock, and fix the other end of the hemp rope.

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