JP7658585B2 - How to lay a vegetation mat - Google Patents

Description

The present invention relates to a method for laying a vegetation mat used for greening slopes (roads, mountainside slopes, riverbeds, riverbanks, lakeshores, etc.).

Porous carbon materials such as charcoal, which is made by carbonizing plants, and activated carbon have a very large internal surface area, and when mixed into soil, they improve the soil's air permeability, water retention, permeability, and fertility retention, and also have the effect of keeping the soil warm, increasing soil microorganisms, correcting acidic soil, and replenishing minerals, so they are used as soil improvement materials.

The applicant has also developed an anion-adsorbing carbon material that has been given anion adsorption properties, and has put it to practical use as a soil improvement fertilizer (Patent Document 1).

JP 2005-306716 A

However, since the above carbon materials are used by scattering them on the ground surface or burying them in layers in the soil, there is a risk that the charcoal itself or the soil above the charcoal layer may be washed away by strong winds or heavy rain, which could result in the charcoal not being able to fully function.

The present invention has been made with the above-mentioned matters in mind, and its object is to provide a method for laying a vegetation mat which can easily perform its function fully while preventing the loss of carbonized materials made from carbonized plant raw materials.

In order to achieve the above-mentioned object, the method of laying a vegetation mat of the present invention is a method of laying a vegetation mat which comprises a long substrate bag integrated into a sheet-like member , and which arranges multiple substrate bags at intervals from the toe side of the slope , the longitudinal direction of the substrate bags being arranged along the contour lines, and the substrate bags containing vegetation substrate including seeds of greening plants or fertilizer or growth base material or soil improvement material, as well as carbonized plant raw materials, and the substrate bags which are relatively closer to the toe of the slope contain a smaller amount of carbonized material and a larger amount of fertilizer, and the substrate bags which are relatively closer to the toe of the slope contain a larger amount of carbonized material and a smaller amount of fertilizer (claim 1).

In the above-mentioned method for laying a vegetation mat, the carbonized material may be capable of selectively adsorbing monovalent anions (claim 2).

In the above-mentioned method for laying a vegetation mat, the carbonized material may be a calcium-introduced raw material obtained by introducing calcium ions into a plant-based raw material and then carbonizing the calcium-introduced raw material (claim 3).

In the above-mentioned method for laying a vegetation mat, the plant material may be coffee grounds (claim 4).

The present invention provides a method for laying a vegetation mat that can easily prevent the runoff of carbonized materials made from carbonized plant raw materials while allowing the mat to fully exhibit its functions.

In other words, in the method of laying a vegetation mat of the invention according to each claim of the present application, the carbonized material made by carbonizing plant raw materials and the vegetation substrate are contained within a substrate bag, thereby preventing these from being washed away by strong winds, heavy rain, etc., and thereby making it easier for the carbonized material to fully perform its functions.

In addition, plants grow by absorbing carbon dioxide from the air and fixing it inside their bodies, and this carbon dioxide is released back into the air when the plant is burned or rots. However, the method of laying the vegetation mat of the present invention uses carbonized material made by carbonizing plant raw materials, which is less likely to rot and in this form can limit the release of carbon dioxide into the air, thereby contributing to the prevention of global warming by reducing the amount of carbon dioxide, a greenhouse gas, released into the air.

Furthermore, in the method of laying the vegetation mat of the present invention, by storing the carbonized material in a substrate bag together with a vegetation substrate containing other components, it is possible to improve the water and soil environment by activating soil microorganisms such as actinomycetes, increasing fertilizer retention by increasing humus, and promoting soil aggregate formation.

In the method of laying a vegetation mat of the invention according to claim 2, nitrate nitrogen, an environmentally harmful substance, can be adsorbed onto a carbonized material capable of selectively adsorbing monovalent anions, thereby effectively suppressing the pollution of groundwater, rivers, etc., caused by nitrogen leaching from fertilizers (chemical fertilizers, organic fertilizers), etc., contained in a substrate bag.

In the method for laying a vegetation mat according to the invention of claim 3, functional carbon, which is a carbonized product obtained by carbonizing a calcium-introducing raw material, is used, and the nitrate nitrogen adsorbed to this functional carbon is not washed away by rainfall, etc., but can be used as a nutrient by plants. Therefore, the leached nitrogen from the fertilizer adsorbed to the functional carbon becomes a nutrient for plants and is efficiently used for plant growth, making it possible to reduce the amount of fertilizer (or the amount of nitrogen contained in the fertilizer) contained in the substrate bag. In addition, since the functional carbon after nitrate nitrogen is adsorbed by plants can re-adsorb nitrate nitrogen, it is extremely effective in preventing nitrogen pollution and can also be used very efficiently.

Approximately 400,000 tons of coffee beans are imported to Japan annually, and most of the coffee grounds left after extraction are incinerated, so there is a strong demand for effective use of coffee grounds, and the method for laying a vegetation mat of the invention according to claim 4 makes effective use of coffee grounds and contributes to the SDGs. Moreover, to obtain the carbonized material of the invention according to claim 4, it is only necessary to mix calcium chloride with coffee grounds and carbonize them, so the manufacturing method is simple, and coupled with the extremely low cost of raw materials, it is extremely advantageous in terms of economic rationality.

1A and 1B are an explanatory diagram and an exploded perspective view of a vegetation mat (laid on a slope) according to one embodiment of the present invention. 4A is a vertical cross-sectional view of the vegetation mat, and FIG. 4B is a vertical cross-sectional view of a modified example of the vegetation mat.

The following describes an embodiment of the present invention.

Figure 1 (A) shows a vegetation mat 1 laid on a slope N, and this vegetation mat 1 comprises multiple long substrate bags 2 integrated with sheet-like members 3, 4, and 5.

As shown in Figures 1(B) and 2(A), the vegetation mat 1 has an erosion prevention material 3, a retaining sheet (crepe paper in this example) 4, and a net-like member 5, layered in this order from the bottom, and as shown in Figure 2(A), the base material bag 2 and coarse fibers 6 are sandwiched between the erosion prevention material 3 and the retaining sheet 4, which are integrated with a connecting device 7 such as a stapler. Then, as shown in Figure 1(A), the vegetation mat 1 can be laid and fixed to the slope N by appropriately driving in anchor pins 8 and 9.

The substrate bag 2 is a long, thin, cylindrical bag-like body with both ends closed that contains the vegetation substrate and carbonized material.

The vegetation substrate stored in the substrate bag 2 includes the seeds of greening plants (vegetation seeds), fertilizer, or growth base materials (soil, water-retaining materials, admixtures, etc.) or soil improvement materials, such as those that are mainly composed of vermiculite and contain vegetation seeds, or topsoil seed banks, specifically those that are made by appropriately mixing growth aids such as peat moss, bark compost, and water-retaining materials with topsoil that contains vegetation seeds from natural ground or forests near the slope N on which the vegetation mat 1 is laid.

The carbonized material contained in the base bag 2 is a carbonized material obtained by carbonizing a plant-based raw material, and can be, for example, an anion-adsorbing carbon material obtained by contacting and kneading a suitable concentration (e.g., 1 to 20% by weight) of a metal chloride (e.g., calcium chloride) with the plant-based raw material (coffee grounds) by suitable means (e.g., dropping, applying, spraying, atomizing, immersion, etc.) and then carbonizing the material at a suitable temperature (e.g., 400 to 1000°C, preferably 500 to 900°C, most preferably 600 to 800°C) to contain the metal chloride in the carbonized material.

Here, when obtaining the anion-adsorbing carbon material, the contact and kneading of the plant-based raw material with the metal chloride is considered to be carried out in a state where there is an appropriate amount of moisture, and it is preferable to keep at least one of the plant-based raw material and the metal chloride in a wet state (including a solution state), or to put both into water and mix them. Therefore, for example, when wet coffee grounds are used as the plant-based raw material, calcium chloride as the metal chloride that is contacted and kneaded with it may be in a dry state (solid state) or in a wet state (liquid state). Also, when a solution containing calcium ions is brought into contact with the plant-based raw material to obtain a calcium-introducing raw material and this calcium-introducing raw material is carbonized to obtain the anion-adsorbing carbon material, the plant-based raw material may be in a dry state or in a wet state.

The anion-adsorbing carbon material obtained in this manner has anion adsorption properties because anions capable of ion-exchange with the anions to be adsorbed (e.g., chloride ions) are bound, either directly or via a metal, to the functional groups formed on the micropore walls of the carbide. Unlike conventional ion exchange resins, such anion-adsorbing carbon material selectively adsorbs only monovalent anions (nitrate ions, nitrite ions, fluoride ions, bromate ions, chlorate ions, iodate ions, etc.).

When calcium hydroxide is used as the metal chloride to obtain an anion-adsorbing carbon material, it is preferable to contact and knead the plant-derived raw material with the metal chloride, carbonize the mixture, and then perform an acid treatment (e.g., immersion in an HCl solution). However, when calcium chloride is used as the metal chloride, such an acid treatment may be unnecessary.

On the other hand, the bag-like body constituting the substrate bag 2 can be formed using a sheet-like body that is impermeable to the vegetation substrate and carbonized material and has water or moisture permeability. For example, if the substrate bag 2 is to contain seeds of plants for greening, it goes without saying that the bag should have properties that do not inhibit the germination or rooting of the seeds.

The erosion prevention material 3 is a member that comes into contact with the slope N when the vegetation mat 1 is laid on the slope N, so it is preferable that it has excellent adhesion to the slope N and has an erosion prevention effect, and at the same time, it is preferable that it does not inhibit the buds and roots of plants growing in the area where the vegetation mat 1 is laid, and can firmly hold the coarse fibers 6 arranged on the upper side of the erosion prevention material 3. In this example, a cotton sheet is used as the erosion prevention material 3, and the softness of the cotton sheet gives it excellent adhesion to the slope N, and its structure makes it easy to make the mesh appropriately dense to make it excellent in water absorption and heat retention.

The retaining sheet 4 is intended to prevent coarse fibers 6 from leaking through the mesh of the net-like member 5 above the vegetation mat 1 when it is transported, etc., and it is desirable for it to have water permeability, a smaller mesh than the net-like member 5, and tensile strength sufficient not to hinder the germination and root growth of vegetation seeds. In this example, crepe paper made of vegetable fiber (with a basis weight of 13 g/ ^m2 ) is used for the retaining sheet 4.

The net-like member 5 preferably has a strength capable of holding down and holding down other members below the net-like member 5 so that they are not blown away by strong winds or the like when the vegetation mat 1 is laid on the slope N. In this example, a coconut fiber net is used as the net-like member 5, which is made by twisting coconut fibers together to form a net shape with a mesh size of about 5 to 100 mm and a basis weight of 300 to 1000 g/ ^m2 . Each coconut fiber has a diameter of about 0.1 to 0.3 mm and has continuous holes with a diameter of 3 to 15 mm inside, which gives it excellent water retention and prevents the topsoil of the slope N from eroding.

At least one of wood wool, wood chips, shredder dust, plant stems and leaves such as straw, loose bark, and loose cloth fibers is selected as the coarse fibers 6. In particular, when wood wool, wood chips, shredder dust, loose bark, and other tree-derived materials are selected, the porosity of the fibers themselves contributes to heat retention and humidity control, which is beneficial and desirable for plant growth. Among these, wood wool is the most desirable because of the effects obtained from the above-mentioned actions. Wood wool, wood chips, and bark can be obtained inexpensively by using thinned wood and fallen timber. For example, when thinned wood from coniferous trees is processed into wood wool and used as the coarse fibers 6, coniferous trees have a tracheid structure and a large surface area, so that coarse fibers 6 with excellent water retention and heat retention properties can be obtained.

The vegetation mat 1 in this example (each of the three sheet-like members 3, 4, 5) has a generally rectangular shape, for example, 1 m wide by 2 to 5 m long, and is arranged so that its short side (width direction) is aligned with the contour lines of the slope N. Furthermore, each substrate bag 2 is arranged so that its long side extends in the short side (width direction) of the vegetation mat 1, that is, the long side of the substrate bag 2 also follows the contour lines. The long side dimension of the substrate bag 2 is approximately the same as the short side dimension of the vegetation mat 1, and the multiple substrate bags 2 are arranged at appropriate intervals (for example, 10 cm intervals) in the long side direction of the vegetation mat 1.

In the vegetation mat 1 of this example, which is constructed as described above, the carbonized plant raw material and the vegetation substrate are contained in the substrate bag 2, which prevents them from being washed away by strong winds, heavy rain, etc., and also makes it easier for the carbonized material to fully function.

In addition, plants grow by absorbing carbon dioxide from the air and fixing it inside their bodies, and this carbon dioxide is released back into the air when the plant is burned or rotted. However, the vegetation mat 1 in this example uses carbonized plant materials, which are less likely to rot and limit the release of carbon dioxide into the air. This contributes to the prevention of global warming by reducing the amount of carbon dioxide, a greenhouse gas, released into the air.

Furthermore, in the vegetation mat 1 of this example, by storing the carbonized material in the substrate bag 2 together with the vegetation substrate containing other components, it is possible to improve the water and soil environment by activating soil microorganisms such as actinomycetes, increasing fertilizer retention by increasing humus, and promoting soil aggregate formation.

In the vegetation mat 1 of this example, when a carbide (anion-adsorbing carbon material) capable of selectively adsorbing monovalent anions is placed in the substrate bag 2, this carbide can be made to adsorb nitrate nitrogen, which is an environmentally hazardous substance, so that, for example, contamination of groundwater, rivers, etc. due to leaching nitrogen from fertilizers (chemical fertilizers, organic fertilizers) etc. placed in the substrate bag 2 can be effectively suppressed.

In addition, the vegetation mat 1 of this example uses functional charcoal obtained by carbonizing the calcium-introducing raw material, and the nitrate nitrogen adsorbed to this functional charcoal is not washed away by rainfall, etc., but can be used as a nutrient by plants (see <Plant growth function test> described later). Therefore, the leached nitrogen from the fertilizer adsorbed to the functional charcoal becomes a nutrient for plants and is efficiently used for plant growth, making it possible to reduce the amount of fertilizer (or the amount of nitrogen contained in the fertilizer) contained in the substrate bag. In addition, since the functional charcoal can re-adsorb nitrate nitrogen after nitrate nitrogen has been adsorbed by plants (see <Nitrate nitrogen re-adsorption ability test> described later), it is extremely effective in preventing nitrogen pollution and can also be used very efficiently.

Approximately 400,000 tons of coffee beans are imported to Japan annually, and most of the coffee grounds left after extraction are incinerated, so there is a strong demand for effective use of coffee grounds. The vegetation mat 1 of this example makes effective use of coffee grounds, which also contributes to the SDGs. Moreover, to obtain the carbonized material used in the vegetation mat 1 of this example, it is sufficient to mix coffee grounds with calcium chloride and carbonize them, so the manufacturing method is simple, and combined with the extremely low cost of raw materials, it is extremely advantageous in terms of economic rationality.

The vegetation mat 1 in this example can be installed simply by attaching it to the slope N with anchor pins 8 and 9, making installation extremely easy. Since no large-scale plant such as that used for spraying vegetation substrate is required, environmental measures such as plant installation and noise and wastewater are not necessary.

The carbonized material stored in the base material bag 2 of the vegetation mat 1 in this example can be functional carbon (anion-adsorbing carbon material) obtained by carbonizing calcium-introduced raw material in which calcium ions have been introduced into a plant-based raw material, specifically functional carbon (manufactured by Nippon Shokusei Co., Ltd.) obtained by carbonizing wet coffee grounds mixed with calcium chloride. Therefore, the following describes the evaluation tests conducted on this functional carbon. The regular charcoal used in each of the following tests was simply carbonized cypress chips, and the anion exchange resin was "Amberlite IRA400J" (manufactured by Organo Co., Ltd.).

<Nitrate nitrogen adsorption capacity test>
200 mg each of regular charcoal, functional charcoal, and anion exchange resin were immersed in 50 ml of nitrate nitrogen solution (50 mg/L (NO ₃ ^- -N)) for 10 hours (20°C), and the amount of nitrate nitrogen adsorbed was measured, obtaining the results shown in Table 1.

As shown in Table 1, no nitrate nitrogen adsorption was observed with ordinary charcoal, but functional charcoal was found to have the same nitrate nitrogen adsorption capacity as an anion exchange resin.

<Plant growth function test>
1/5000a Wagner pots filled with decomposed granite soil were placed in each of the 1st to 5th areas, with no other additions in the 1st area, 30g of regular charcoal added in the 2nd area, 30g of functional charcoal added in the 3rd area, 30g of charcoal soaked in a 1000ppm nitrate nitrogen solution, washed and dried added in the 4th area, and 30g of functional charcoal soaked in a 1000ppm nitrate nitrogen solution, washed and dried added in the 5th area. Then, 40 tall fescue plants were placed in each pot, and after they were grown for a certain period of time, the dry weights of the roots (underground) and stems (above ground) and the nitrogen content per gram of plant were measured, and the results in Table 2 were obtained.
1st group: Control group (no additive)
Section 2: Charcoal was added Section 3: Functional charcoal was added Section 4: Charcoal soaked in nitrate nitrogen was added Section 5: Functional charcoal soaked in nitrate nitrogen was added

As shown in Table 2, the results in area 3, where functional charcoal was added, were equivalent to those in areas 1, 2, and 4, where no functional charcoal was added. Here, the functional charcoal is made from unfermented coffee grounds, and when using coffee grounds as a substitute for compost, it is recommended that they be fully fermented before use; it is known that if coffee grounds are used without fermentation, the growth inhibitors contained in the coffee grounds will inhibit plant growth. However, it can be seen that the functional charcoal mentioned above, despite using unfermented coffee grounds, does not inhibit plant growth.

As shown in Table 2, the 5th plot, to which functional carbon soaked in nitrate nitrogen was added, showed higher values for both dry matter weight and nitrogen content compared to the other test plots. This shows that the nitrate nitrogen adsorbed by the functional carbon is available to plants as nutrients.

<Nitrate nitrogen re-adsorption ability test>
First, an adsorption test was conducted by immersing 1 g of functional carbon in 150 ml of a 100 mg/L nitrate nitrogen solution and measuring the amount of nitrate nitrogen adsorbed. After that, the nitrate nitrogen adsorbed on the functional carbon was washed and regenerated with a 1 mol/L KCl solution, and the above adsorption test was conducted again. This procedure was repeated 10 times, and the results in Table 3 were obtained.

As shown in Table 3, the amount of nitrate nitrogen adsorbed per gram of functional carbon was approximately 10 mg even after the 10th regeneration, and the adsorption performance was maintained. From this, it can be said that functional carbon has the ability to re-adsorb nitrate nitrogen, and even if nitrate nitrogen that has been adsorbed once is taken by a plant, for example, it will adsorb the nitrate nitrogen if newly supplied.

The present invention is not limited to the above embodiment, and can be modified in various ways without departing from the spirit of the present invention. For example, the following modifications can be mentioned:

In general, when a vegetation mat is laid on a slope N, because the slope N is inclined, rainfall, etc. can cause water to flow down the surface of the slope N, and if the fertilizer components contained in the laid vegetation mat are leached into the flowing water, they will flow to the foot of the slope. As a result, more fertilizer components are distributed to the foot of the slope than to the top of the slope. This, combined with the fact that more water is retained at the foot of the slope than to the top of the slope, actually means that when a vegetation mat is laid on a slope N, the vegetation condition is often best near the foot of the slope, regardless of the type of vegetation mat.

In this regard, the carbonized material contained in the base material bag 2 in the vegetation mat 1 of this example has the function of receiving the fertilizer components flowing down from the toe side and suppressing their movement to the toe side. Therefore, for example, in a vegetation mat 1 in which multiple base material bags 2 are arranged at intervals from the toe side to the toe side, the amount of carbonized material and fertilizer (and water-retentive material) contained in each base material bag 2 may be uniform, but instead, the amount of carbonized material contained in the base material bag 2 located relatively closer to the toe side may be small and the amount of fertilizer (and water-retentive material) may be large, and the amount of carbonized material contained in the base material bag 2 located relatively closer to the toe side may be large and the amount of fertilizer (and water-retentive material) may be small. In this way, the fertilizer components (and moisture) that are leached into the running water and flow down can be efficiently adsorbed by the carbonized substrate bag 2 (and water-retaining material) at the foot of the slope, which reduces the bias in which more fertilizer components (and moisture) are distributed to the foot of the slope than to the top of the slope, and ultimately makes it possible to achieve uniform greening across the entire slope N.

In the vegetation mat 1 shown in FIG. 2(A), the vegetation substrate is held only in the substrate bag 2, i.e., only one layer of the vegetation substrate is provided, but this is not limiting, and two or more layers of the vegetation substrate may be provided. For example, as shown in FIG. 2(B), it is possible to provide a space for storing the vegetation substrate under the vegetation mat 1 shown in FIG. 2(A). In this example, a second mat 10 containing the vegetation substrate is placed under the vegetation mat 1, and the two are integrated with a connector 11 such as a stapler, and the upper surface 10a of the second mat 10 is made of crepe paper, and the lower surface 10b is made of jute felt.

It goes without saying that the above modifications may be combined as appropriate.

REFERENCE SIGNS LIST 1 Vegetation mat 2 Base material bag 3 Erosion prevention material 4 Retaining sheet 5 Net-like member 6 Coarse fiber 7 Connector 8 Anchor pin 9 Anchor pin 10 Second mat 10a Upper surface portion 10b Lower surface portion 11 Connector N Slope

Claims (4)

A method for laying a vegetation mat, which comprises integrating a long base material bag into a sheet-like member and arranging multiple base material bags at intervals from the toe side of the slope , wherein the longitudinal direction of the base material bags is arranged along the contour lines, and the base material bags contain vegetation base material including seeds of greening plants, fertilizer, growth base material, or soil improvement material , as well as carbonized plant raw materials, and the base material bags located relatively closer to the toe of the slope contain a smaller amount of carbonized material and a larger amount of fertilizer, and the base material bags located relatively closer to the toe of the slope contain a larger amount of carbonized material and a smaller amount of fertilizer . The method for laying a vegetation mat according to claim 1, wherein the carbonized material is capable of selectively adsorbing monovalent anions. 3. The method for laying a vegetation mat according to claim 2, wherein the carbonized material is a calcium-introduced raw material obtained by introducing calcium ions into a plant-based raw material and then carbonizing the calcium-introduced raw material. 4. The method for laying a vegetation mat according to claim 3, wherein the plant material is coffee grounds.