Artificial soil and method for producing the same

Abstract

This invention provides artificial soil that can suppress the urban heat island effect and promote greening even in urban areas, thereby contributing to the conservation, creation, and regeneration of a sustainable natural environment. [Solution] One artificial soil 100 of the present invention comprises a first layer 10 containing soil components and having a planting-able thickness, and a second layer 20 in contact with the first layer 10 and containing charcoal. In addition, in this artificial soil, the first layer 10 has a second surface 14 that is in contact with the outside air, is in the thickness direction or sloped toward the thickness direction from the first surface 12, and is different from the first surface 12 on which the planting target and / or the natural habitat of the plants. This soil structure allows for the active uptake and retention of moisture, such as rainwater, and can contribute to the conservation, creation and regeneration of a sustainable natural or living environment by replenishing moisture to the surrounding soil including the planting layer and suppressing the occurrence of the heat island phenomenon by utilizing latent heat from transpiration from planted plants.

Description

Technical Field

[0001] The present invention relates to artificial soil and a method for manufacturing the same.

Background Art

[0002] In recent years, environmental problems such as global warming and the heat island phenomenon have become serious. Global warming is caused by the greenhouse effect due to the increase in the concentration of carbon dioxide in the atmosphere, resulting in the amount of solar heat absorbed on a global scale exceeding the amount of heat released from the earth to the universe. On the other hand, the heat island phenomenon is a phenomenon in which waste heat derived from solar radiation and energy consumption is stored and heated due to the decrease in the water retention capacity of soil due to the expansion of artificial covering areas due to urbanization. Especially in urban areas, the above-mentioned environmental problems are closely related to the above problems through social issues related to the conservation, creation, and regeneration of green spaces.

[0003] From the viewpoints of the conservation, creation, and regeneration of green spaces, a plurality of conventional technologies have been disclosed for realizing soil suitable for planting even in urban areas. For example, a waterproof sheet is laid on the rooftop or roof of a building, and the waterproofing action of the waterproof sheet suppresses damage such as weathering and water leakage of the building. Soil is arranged on the waterproof sheet to grow grass and tree seeds, and the heat from a concrete roof or the like receiving direct sunlight is reduced to relieve ceiling burning, so that the occurrence of the heat island phenomenon can be suppressed as much as possible. A greening method has been disclosed (Patent Document 1).

[0004] Also, it has an upper layer including the ground surface and a lower layer disposed below the upper layer, and the upper layer and the lower layer have an overlapping portion. The lower layer includes a plurality of first formed bodies containing soil constituent materials, carbon, and a binder. The first formed body contains carbon at 50% or more and 95% or less and a binder at 5% or more and 50% or less as a volume ratio. The first formed body has a size of 30 mm 3 or more and 60 mm 3 or less. The saturated permeability coefficient of the lower layer is larger than that of the upper layer, and the saturated permeability coefficient of the lower layer is 1.0×10 -5A planting ground is disclosed in which the density is m / s or greater, and in the lower layer, the multiple first molded bodies make up 10% to 90% of the volume of the mixture of soil constituent materials and multiple first molded bodies (Patent Document 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2005-204554 [Patent Document 2] Japanese Patent Publication No. 2024-075101 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention can contribute to the construction of artificial soil that can realize at least one selected from the group of functions that enable, for example, infiltration and / or storage to allow rainwater recharge, utilization of latent heat through vaporization, and storage of soil carbon. Furthermore, the present invention can contribute to the suppression of the urban heat island phenomenon, the suppression of heavy rain disasters through water storage by greening, and concrete measures to prevent global warming through carbon sequestration, thereby greatly contributing to the conservation, creation, and regeneration of a sustainable natural and living environment.

[0007] In natural vegetation succession, bare ground tends to be hotter because, like cities with low green coverage, it generates less latent heat through evapotranspiration. On the other hand, forests increase latent heat through evapotranspiration while decreasing sensible heat, resulting in a comfortable temperature environment for humans, for example, and also stimulating atmospheric water circulation. Therefore, the inventors considered that introducing heat transport via atmospheric water circulation, such as rainwater, into urban environments is a realistic solution to the urban heat island effect, both economically and physically. In addition, the inventors considered that actively increasing the water retention capacity of soil, regardless of whether it is an urban area or not, can contribute to the realization of soils and planting environments that are resilient to climate change, such as global warming.

[0008] However, the inventors determined that it would be difficult to reliably achieve the preservation, creation, and regeneration of green spaces (especially in urban areas) without not only increasing the water retention capacity of the soil, but also replenishing the entire area in which the soil is located with moisture, such as rainwater. This is because unless measures are taken to increase the water retention capacity of the soil and prevent it from reaching its limit, it will not lead to a solution to the social problem of dealing with heavy rains, such as the so-called "guerrilla downpours" and "linear rainbands" that have become frequent in recent years.

[0009] From the perspective of solving at least some of the above technical problems, the inventors have determined that even if the conventional technologies described above are adopted, the above problems cannot be solved. Specifically, if the technology of Patent Document 1 is adopted, the water-blocking effect of the waterproof sheet can contribute to improving water retention by utilizing a charcoal layer, etc., but for example, when the amount of rain that flows in exceeds its water retention capacity, the water-blocking effect of the waterproof sheet will instead greatly limit the drainage capacity of the soil, in other words, the water supply capacity to soil other than that soil. Furthermore, if the technology of Patent Document 2 is adopted, the upper layer is a "water retention layer" that can be planted, and the lower layer is a "drainage layer", so the stored rainwater cannot be replenished to the surrounding soil. In addition, since the upper layer functions as a "water retention layer" that can be planted, a drainage function is required to prevent or suppress root rot of plants and to ensure respiration of the root zone of the plants.

[0010] Based on the above considerations and analyses, the inventors have diligently conducted research and have found that the above-mentioned problems can be solved by arranging or providing the following two interrelated soils (1) and (2), each playing a different role, and by implementing the ingenuity of (3). As a result, the inventors have learned that it is possible to suppress the occurrence of the heat island phenomenon and, even in urban areas, contribute to the preservation, creation, and regeneration of a sustainable natural and living environment by promoting measures against heavy rainfall through the replenishment of water represented by rainwater and heat transfer through the utilization of latent heat. (1) The first layer (soil) which is thick enough for planting and is primarily used for planting or serves as soil in which plants grow naturally. (2) A second layer (soil) that is in direct contact with the first layer in (1) above and is responsible for both "water retention" and "water supply". More specifically, the second layer (soil) is in direct contact with the first layer, maintaining a state where moisture can freely move, while actively incorporating charcoal to exhibit high water retention capacity, and also capable of supplying moisture to the first layer (in other words, capable of permeating / moving moisture to the first layer). (3) The first layer of (1) is formed such that it has a surface (second surface) that is in the thickness direction of the first layer or inclined toward the thickness direction from the surface (first surface), which is different from the surface (first surface) of the first layer of (1) that is the target of planting and / or the target of the natural growth of plants, and which is in contact with the outside air (in other words, it is capable of taking in air (especially oxygen) from the outside air).

[0011] Furthermore, in addition to the above-mentioned points, by actively mixing or incorporating the charcoal used to improve water retention and water supply into the second layer (soil), it is possible to contribute to the realization of a decarbonized society through so-called "carbon sequestration" using soil.

[0012] This invention was created based on the above-mentioned knowledge and ingenuity.

[0013] One artificial soil of the present invention comprises a first layer containing soil components and having a thickness on which plants can be planted and / or on which plants can grow naturally, and a second layer in contact with the first layer and containing charcoal. In addition, in this artificial soil, the aforementioned first layer has a second surface that is different from the first surface on which plants are to be planted and / or on which plants can grow naturally, and is in contact with the outside air, in the thickness direction or inclined toward the thickness direction from the first surface.

[0014] This artificial soil has a second layer that is in direct contact with the first layer described above, contains charcoal, has high water retention properties, and can supply moisture to the first layer. In addition, this artificial soil has a second surface (second surface) that is in the thickness direction of the first layer, or inclined toward the thickness direction from the first surface, which is different from the first surface of the first layer that is the target of planting and / or the target of natural plant growth, and is in contact with the outside air (in other words, it can take in air from the outside air or does not become a waterlogged condition). As a result, through the technical effects shown in (a) to (c) below, it is possible to suppress the occurrence of the heat island phenomenon and, even in urban areas, promote measures against heavy rainfall through the replenishment of moisture represented by rainwater and heat transfer through the utilization of latent heat, thereby contributing to the conservation, creation, and regeneration of a sustainable natural and living environment. (a) Because the second layer, which may have high water retention capacity, is in direct contact with the first layer, moisture held in the second layer can be supplied to the first layer (in other words, it can penetrate / move into the first layer). (b) Trees, grasses, flowers and / or mosses planted in the first layer (hereinafter collectively referred to as "plants") may benefit from the moisture supplied (discharged) from the second layer. (c) The plant can enjoy air supplied from the second surface of the first layer, which has less influence from the second layer that may have high water retention, or it can prevent or suppress the entire root zone of the plant from becoming waterlogged.

[0015] Furthermore, one method for producing artificial soil according to the present invention includes a placement step of placing a second layer containing charcoal in contact with a first layer containing soil components and having a thickness suitable for planting and / or on which plants can grow naturally. In addition, in this method for producing artificial soil, the aforementioned first layer has a second surface that is in contact with the outside air, is in the thickness direction or inclined toward the thickness direction from the first surface, and is different from the first surface on which plants are to be planted and / or on which plants can grow naturally.

[0016] According to this method for manufacturing artificial soil, it is possible to form artificial soil that includes a second layer containing charcoal, which is in direct contact with the first layer described above, and which has high water retention properties and can supply moisture to the first layer. In a preferred embodiment of this invention for manufacturing artificial soil, for example, the artificial soil can be formed by performing a placement step in which the second layer described above is subsequently placed in contact with an existing first layer containing soil components and having a planting-able thickness. From the above viewpoint, it is noteworthy that existing soil can be transformed into artificial soil relatively easily and / or relatively inexpensively.

[0017] In addition, the artificial soil formed by the above-described manufacturing method has a surface (second surface) that is different from the first surface of the first layer that is the target of planting and / or the target of natural plant growth, which is in contact with the outside air (in other words, it can take in air from the outside air, or the entire root zone of the plant is less likely to be subject to waterlogging conditions), which is in the thickness direction of the first layer, or is inclined toward the thickness direction from the first surface. As a result, through the technical effects shown in (a) to (c) below, it is possible to form an artificial soil that can suppress the occurrence of the heat island phenomenon and, even in urban areas, promote measures against heavy rainfall through the replenishment of water represented by rainwater and promote heat transfer through the utilization of latent heat, thereby contributing to the conservation, creation, and regeneration of a sustainable natural or living environment. (a) Because the second layer, which may have high water retention capacity, is in direct contact with the first layer, moisture held in the second layer can be supplied to the first layer (in other words, it can penetrate / move into the first layer). (b) Trees, grasses, flowers and / or mosses planted in the first layer can benefit from the moisture supplied (discharged) from the second layer, or the entire root zone of the plants is less likely to be waterlogged. (c) It can enjoy air supplied from the second surface (the second surface in the first layer) which is less affected by the second layer which may have high water retention.

[0018] In each of the above inventions, the surface for planting and / or for natural growth of plants is not limited to the first surface in the first layer. For example, in another aspect that can be adopted in each of the above inventions, the surface for planting and / or for natural growth of plants can be the second surface in addition to the first surface.

[0019] Also, in each of the above inventions, the first surface for planting and / or for natural growth of plants is not limited to the surface to be newly planted (or planned to be) and / or the surface where plants will newly grow naturally (or planned to). For example, the first surface for planting and / or for natural growth of plants can include the case where existing planted and / or already naturally grown plants exist in at least a part of the surface.

[0020] Also, the "thickness direction" of the "first layer" in the present application is not necessarily limited to vertically downward. For example, when planting is carried out on the wall surface of a building (typically, so-called "wall greening"), a surface substantially parallel to the wall surface (at least a surface different from the surface substantially perpendicular to the wall surface) can also correspond to the first surface in the first layer of the invention of the present application, which is an aspect that can be adopted.

Advantages of the Invention

[0021] According to one artificial soil of the present invention, it can suppress the occurrence of the heat island phenomenon, and even in an urban area, it can contribute to the conservation, creation and regeneration of a sustainable natural or living environment by promoting the retention of moisture represented by rainwater and heat transfer by latent heat utilization. Also, according to one artificial soil of the present invention, it can also contribute to so-called carbon storage.

[0022] Furthermore, according to one method for producing artificial soil of the present invention, it is possible to create artificial soil that can suppress the occurrence of the heat island phenomenon and contribute to the preservation, creation, and regeneration of a sustainable natural or living environment by promoting measures against heavy rainfall through the replenishment of water represented by rainwater and heat transfer through the utilization of latent heat, even in urban areas. Moreover, according to this method for producing artificial soil, for example, existing soil can be transformed relatively easily and / or relatively inexpensively into artificial soil that can suppress the occurrence of the heat island phenomenon and contribute to the preservation, creation, and regeneration of a sustainable natural or living environment by promoting greening even in urban areas. [Brief explanation of the drawing]

[0023] [Figure 1] This figure shows the general configuration of the artificial soil 100 in the first embodiment. [Figure 2] This figure shows part of the manufacturing process of artificial soil 100 in the first embodiment. [Figure 3] This figure shows part of the manufacturing process of artificial soil 100 in the first embodiment. [Figure 4] This figure shows part of the manufacturing process of artificial soil 100 in the first embodiment. [Figure 5] These are photographs and a schematic diagram illustrating a portion of the comparative experiment in the first embodiment. [Figure 6] This figure shows the general configuration of the artificial soil 200 in the second embodiment. [Figure 7] This figure shows the general configuration of the artificial soil 300 in the third embodiment. [Figure 8] This figure shows the schematic configuration of another artificial soil 400 in the third embodiment. [Figure 9] This figure shows the general configuration of the artificial soil 500 in a modified example (1) of the second embodiment. [Figure 10] This figure shows the general configuration of the artificial soil 600 in a modified example (2) of the second embodiment. [Modes for carrying out the invention]

[0024] Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this description, unless otherwise specified, common parts are denoted by common reference numerals throughout the drawings. Furthermore, the elements of this embodiment are not necessarily shown in their dimensions in the drawings. Also, some reference numerals may be omitted to improve the clarity of the drawings.

[0025] <First Embodiment> [Overview of Artificial Soil 100] Figure 1 shows the general configuration of the artificial soil 100 in this embodiment. Figures 2 to 4 show a part of the manufacturing process of the artificial soil 100 in this embodiment.

[0026] As shown in Figure 1, the artificial soil 100 of this embodiment comprises a first layer 10 having a thickness suitable for planting and / or a thickness suitable for plants to grow naturally, a second layer 20 adjacent to the first layer 10, and a third layer 40 provided above the second layer 20.

[0027] More specifically, in this embodiment, the first layer 10 contains soil components and has a thickness that allows for the planting of plants such as flowers (P in Figure 1) or trees (T in Figure 1), and / or allows plants to grow naturally. The second layer 20 contains charcoal and is arranged in contact with the first layer 10. The third layer 40 is arranged above the second layer 20 and is permeable to water.

[0028] In addition, in the artificial soil 100, the first layer 10 has a second surface 14 in the thickness direction of the first layer 10 that is in contact with the outside air, and is different from the first surface 12 on which the planting target and / or the natural growth target of the plant. Furthermore, the third layer 40 does not cover the entire second surface 14 of the first layer 10. In other words, even if the third layer 40 is placed, the second surface 14 of the first layer 10 in this embodiment remains in a state where it can be in contact with the outside air.

[0029] Therefore, in the first layer 10 of the artificial soil 100 of this embodiment, a state is maintained in which air can be taken in from at least the second surface 14, or the entire root zone of the plant is less likely to become waterlogged. As a result, plants such as wildflowers (P in Figure 1) or trees (T in Figure 1) planted in or growing naturally in the first layer 10 can enjoy the air supplied from the second surface 14 (the second surface 14 in the first layer 10), which is less or almost unaffected by the second layer 20, which has high water retention. This makes it less likely for the entire root zone of the plant to become waterlogged, thus preventing root rot in the plant with a high degree of certainty and making planting possible.

[0030] Here, the "soil components" that the first layer 10 in this embodiment may contain are not particularly limited as long as they are materials on which flowers or trees can grow. Typical examples of soil components include crushed stone, crushed rock, clinker ash, sand, compost, coal ash, minerals, wood chips, rice hulls, bark, peat, coconut shells, coconut husks, fertilizer (which may contain carbonized material), natural soil, or a mixture of two or more of the materials listed above.

[0031] Furthermore, in this embodiment, since the second layer 20 plays the role of a water-retaining layer, the "charcoal" that the second layer 20 may contain is not particularly limited as long as it can retain moisture to the extent that the effects of this embodiment can be achieved. Typical examples of "charcoal" include powdered charcoal, bamboo charcoal, black charcoal, white charcoal, sawdust charcoal, crushed wood charcoal, biochar (made from pruned branches, thinned wood, charcoal derived from gasification wood biomass power generation, waste wood, food residue, livestock excrement, rice husks, rice, straw, nut shells, sewage sludge, paper sludge, industrial waste, and / or general waste), or a mixture of two or more of the materials listed above. In addition, examples of materials other than the aforementioned "charcoal" that can constitute the second layer 20 are soil components that the first layer 10 may contain. Therefore, the second layer 20 may be a mixture of the "soil components" and the "charcoal," or it may be "charcoal" alone. Furthermore, it is a preferred embodiment that the second layer 20 contains inorganic materials that do not decompose in the soil, in addition to "charcoal". Typical examples of "inorganic materials" include volcanic rocks such as pumice (mineral akadama soil, kanuma soil, Hyuga soil, etc.), porous pottery, diatomaceous earth, zeolite, and other porous materials.

[0032] In addition, unlike the first layer 10, the second layer 20 of this embodiment is not intended to be a layer on which plants can be planted or grow naturally. Therefore, it is possible to actively increase the proportion of charcoal in the constituent materials of the second layer 20. Accordingly, the proportion of charcoal (volume %) that the second layer 20 can contain is between 10% and 100%. As a result, the second layer 20 can function as a water-retaining layer. Furthermore, as described above, since the second layer 20 is arranged in direct contact with the first layer 10, the second layer 20 can also function as a suitable water source, supplying moisture from the second layer 20 to the first layer 10 via the boundary 30 between the second layer 20 and the first layer 10. Examples of constituent materials other than charcoal in the second layer 20 are the same as the "soil constituent materials" that the first layer 10 can contain.

[0033] As described above, the artificial soil 100 of this embodiment includes a water-retentive second layer 20 arranged in contact with the first layer 10 as described above. By configuring the second layer 20 to be in direct contact with the first layer 10, the water-retentive second layer 20 can supply water to the first layer 10 while maintaining a state in which water can freely move between the second layer 20 and the first layer 10. In other words, the ability of water to penetrate / move from the second layer 20 to the first layer 10 can be exercised.

[0034] As a result, if there are plants planted and / or naturally growing in the first layer 10, these plants can enjoy the water supplied (discharged) from the second layer 20 through the first layer 10. This makes it possible to reduce, for example, the number of times or the amount of water required to maintain the plants in the first layer 10 within a certain period, thereby significantly reducing the burden of plant maintenance. This reduction in the burden of plant maintenance can greatly contribute to promoting greening and the conservation, creation, and regeneration of sustainable natural and living environments. Furthermore, because the burden of plant maintenance can be reduced, the use of the artificial soil 100 of this embodiment when planting various plants in public places (e.g., parks, green spaces, etc.) is a suitable embodiment from the standpoint of promoting the effective use of tax money.

[0035] As described above, the artificial soil 100, which is arranged in contact with the first layer 10 and has a second layer 20 with water retention properties, can promote greening even in urban areas and contribute to the conservation, creation, and regeneration of a sustainable natural or living environment. Furthermore, for example, the growth of multiple large trees in an urban area can contribute to the formation of a localized environment similar to a forest, such as the creation of shade by these trees and temperature regulation through transpiration.

[0036] Furthermore, the material constituting the third layer 40 in this embodiment is not particularly limited, as long as it is a material that can exhibit permeability that allows water supplied by rainwater or irrigation to reach the second layer 20. Typical examples of materials constituting the third layer 40 are one or more materials selected from the group including natural stone (Shirakawa sand, Kanmizuishi sand, Shiratama soil, etc.), pumice, volcanic rocks such as scoria (Akadama soil, Kanuma soil, Hyuga soil, etc.), granular or crushed ceramics such as pottery, bricks, and tiles, porous materials such as diatomaceous earth and zeolite, and wood used for covering (coconut shell chips, etc.). One preferred embodiment is to use the material constituting the third layer 40 to promote the evaporation of moisture that may be contained in the second layer 20 and / or the third layer 40 by utilizing capillary action. In addition, providing a sandbar-like design on the surface of the third layer 40 is also preferable from the viewpoint of forming an appearance that appeals to human vision.

[0037] Furthermore, it is a preferred embodiment for the third layer 40 to have water retention properties in addition to the water permeability described above. Another preferred embodiment is for the third layer 40 to have even greater water retention properties, as this helps to achieve a water retention capacity exceeding that of the second layer 20, and thus helps to retain moisture for a longer period of time. In addition, if the surface area of ​​the material constituting the third layer 40 is large and has good permeability, more water will evaporate from the soil surface, so heat transfer using latent heat can be realized more efficiently. From the above viewpoints, an example of a material constituting a preferred third layer 40 that has water permeability and water retention properties, as well as high permeability that increases the amount of water evaporation, is porous soil, such as Hyuga soil.

[0038] Furthermore, by positioning the third layer 40 such that its surface is lower than the surface of the first layer 10, for example, the rainwater absorption capacity of the artificial soil 100 can be improved by utilizing the water retention capacity of the third layer 40 itself and / or the second layer 20 located beneath the third layer 40. As a result, the artificial soil 100 of this embodiment can mitigate the effects of heavy rain, such as so-called "guerrilla downpours" and "linear rainbands." Moreover, because the second layer 20 containing charcoal has higher water retention capacity than ordinary soil, it is possible to increase the amount of heat from the heat of vaporization (latent heat) when the water retained by the second layer 20 evaporates, and / or to extend the time over which the heat of vaporization is removed from the second layer 20. As a result, the artificial soil 100 of this embodiment can suppress the occurrence of the heat island phenomenon. Furthermore, the fact that the third layer 40 has higher water retention than ordinary soil is a preferred embodiment because, in addition to the second layer 20, the third layer 40 can more reliably contribute to mitigating the effects of heavy rain and / or suppressing the occurrence of the heat island phenomenon.

[0039] Here, the thickness of the first layer 10 in the artificial soil 100 of this embodiment is not particularly limited as long as it is thick enough for planting and / or for plants to grow naturally. It can be appropriately selected depending on the type of plant to be planted. For example, the thickness of the first layer 10 intended for planting only herbaceous plants may be thinner than the thickness of the first layer 10 intended for planting trees. A typical thickness of the first layer 10 intended for planting only herbaceous plants is about 200 mm to about 400 mm (more narrowly, about 200 mm to about 350 mm), and the thickness of the first layer 10 intended for planting trees is about 500 mm or more (more narrowly, about 400 mm or more).

[0040] Furthermore, the thickness of the second layer 20 in the artificial soil 100 of this embodiment is not limited as long as it can function as a water-retaining layer, but a typical thickness of the second layer 20 is approximately 1000 mm to approximately 2000 mm. In addition, the thickness of the third layer 40 in the artificial soil 100 of this embodiment is not limited as long as it does not impede water permeability, but a typical thickness of the third layer 40 is approximately 100 mm to approximately 300 mm.

[0041] [Method for producing artificial soil 100] Figures 2 to 4 show a part of the manufacturing process of the artificial soil 100 in this embodiment.

[0042] As shown in Figures 2 and 3, first, a portion of the existing soil 90, which includes soil components that are suitable for planting and / or where plants naturally grow, is removed to create a space 70 that allows for the placement of the second layer 20, which will be described later. In Figure 2, a state in which plants naturally grow in a portion of the existing soil 90 is shown, but if the existing soil 90 is suitable for planting, it is not necessary for plants to already be naturally growing when removing a portion of the soil.

[0043] Subsequently, as shown in Figure 4, a first arrangement step is performed in which only water-retentive charcoal, or a material containing said charcoal (for example, a mixture of "soil components" and "charcoal" as described above), which constitutes the second layer 20, is placed in the space 70 formed by removing a portion of the existing soil 90.

[0044] At this time, by introducing a sufficiently small amount of the material (charcoal only, or a material containing charcoal) compared to the amount of existing soil 90 removed, in this embodiment, a portion of the existing soil 90 takes on the role of a first layer 10 having a thickness suitable for planting and / or allowing plants to grow naturally. Furthermore, the first layer 10 newly formed by the arrangement of the second layer 20 has a second surface 14 in the thickness direction of the first layer 10 that is in contact with the outside air, and is different from the first surface 12 for planting and / or the first surface 12 for plants to grow naturally. In addition, this second surface 14 can create a state in which the entire root zone of the plant is less likely to become waterlogged. And, as described above, this first arrangement step brings the second layer 20 and the first layer 10 into direct contact, thus forming a boundary 30 for supplying moisture from the second layer 20 to the first layer 10.

[0045] Subsequently, a second placement step is performed in which a permeable third layer 40 is placed above the second layer 20. At this time, the third layer 40 is placed so as not to cover the entire second surface 14 of the first layer 10. As a result, the artificial soil 100 in this embodiment can be manufactured as shown in Figure 1.

[0046] In the artificial soil 100 of this embodiment, as described above, even if the third layer 40 is placed, the second surface 14 of the first layer 10 of this embodiment remains in a state where it can come into contact with the outside air. As a result, the first layer 10 is able to take in air from at least the second surface 14, and the entire root zone is less likely to become waterlogged. Therefore, as described above, by adopting the artificial soil 100 of this embodiment, respiration of the root zone of plants such as herbaceous plants (P in Figure 1) or trees (T in Figure 1) planted or growing naturally in the first layer 10 is ensured, and root rot can be prevented with high certainty.

[0047] Therefore, if the manufacturing method of the artificial soil 100 of this embodiment is adopted, the existing soil 90 will be utilized as the first layer 10 of the artificial soil 100 of this embodiment. As a result, it is noteworthy that the artificial soil 100 of this embodiment can be created relatively easily and / or relatively inexpensively using the existing soil 90 as the starting soil.

[0048] By following the manufacturing process described above, the artificial soil 100 shown in Figure 1 can be produced. The above example illustrates one method of manufacturing the artificial soil 100 in which existing soil 90 is used as the first layer 10 of the artificial soil 100 of this embodiment. However, the method of manufacturing the artificial soil 100 of this embodiment is not limited to the above example. For example, another possible method is to remove the existing soil 90 and then create a new first layer 10 for the artificial soil 100 of this embodiment.

[0049] [Results of various experiments and analyses on artificial soil 100] To confirm the technical effects of the artificial soil 100 described above, the inventors conducted the following experiments (E1), (E2), and (E3) using the laminated structure of the second layer 20 and the third layer 40 of this embodiment (Sample 1), and the structures (including single-layer and laminated structures) in comparative examples (Comparative Examples 1 to 4).

[0050] First, in order to match the initial conditions of the subjects of measurement, the amount of water (initial water absorption or initial water amount) that was initially supplied to the soil of Sample 1 and each comparative example was used as a baseline. Then, after 7 days had passed without continuous rainfall from that day, the (E1) surface temperature at 2 PM, (E2) surface temperature at 3 PM, and the amount of water evaporated from the soil of Sample 1 and each comparative example (E3) were measured. The inventors measured the aforementioned surface temperatures using an infrared sensor (PerfectPrime, model IR0005). In addition, the amount of water added to Sample 1 and each comparative example until the initial sufficient moisture level was achieved (additional water supply) was defined as the amount of water evaporated (evaporation).

[0051] The specific soil composition of Sample 1 and each comparative example (1-3) is as follows. Note that the representative example of powdered coal (fine pulverized coal) in Sample 1 below is powdered coal (moist pulverized coal) produced from the Aritagawa Biomass Power Plant (a small-scale, high-efficiency woody biomass heat and power supply system manufactured by URBAS). (Sample 1) Depth is approximately 380 mm and volume is approximately 35,000,000 mm³ 3 In this container, the thickness of the upper layer (corresponding to the third layer 40), which is "Hyuga soil," is approximately 100 mm (volume: approximately 10,000,000 mm). 3 ) and the thickness of the lower layer (corresponding to the second layer 20), which is pulverized coal, is 280 mm (volume: approximately 25,000,000 mm) 3 ) (Comparative Example 1) Sample 1 container initially filled only with water at approximately 24.5°C. (Comparative Example 2) Sample 1 container with only red clay added. (Comparative Example 3) Sample 1 container with only Hyuga soil added. This is what

[0052] Table 1 below shows the results of various evaluations of the laminated structure of the second layer 20 and the third layer 40 of this embodiment (Sample 1), and the structures (including single-layer and laminated structures) of comparative examples (Comparative Examples 1 to 3). Figure 5 shows photographs (row x) and schematic diagrams (row y) illustrating the outline of some of the comparative experiments in this embodiment (Comparative Example 2 (column a) and Sample 1 (column b)).

[0053] [Table 1]

[0054] As shown in Table 1, the surface temperature of sample 1, in which the third layer 40 was placed above the second layer 20, at 2 PM and at 3 PM was confirmed to be lower than the surface temperatures of Comparative Examples 1 to 3. Furthermore, it was found that sample 1 could hold more moisture than Comparative Examples 2 and 3.

[0055] Furthermore, the amount of water evaporated from Sample 1 was greater than that evaporated from Comparative Example 1, which contained only water. It was also confirmed that the initial water absorption of Comparative Example 2 was an order of magnitude smaller than that of Sample 1 and Comparative Example 3. In addition, although not shown in Table 1 above, when the inventors measured a stone that does not retain water, it was found that the maximum surface temperature of the stone rose to 59.4 degrees Celsius at 3 PM. As a result, the difference between the surface temperature of the stone and the surface temperature of Sample 1 at 3 PM was 32.4 degrees Celsius. It is noteworthy that Sample 1, equipped with the second layer 20 and the third layer 40, achieved the aforementioned temperature difference relative to the stone under direct sunlight.

[0056] Based on the measurement results shown in Table 1, it can be said that by adopting Sample 1, which has a layer containing charcoal in the lower layer, the surface temperature of the soil can be kept lower for a longer period of time by utilizing the evaporation of water, compared to soil consisting only of Hyuga soil (Comparative Example 3), which has a certain degree of water retention capacity. Therefore, with the artificial soil 100 of this embodiment, which has the same configuration as Sample 1, the occurrence of the heat island phenomenon can be suppressed by taking advantage of the high water retention capacity of the second layer 20.

[0057] <Second Embodiment> The artificial soil 200 of this embodiment is the same as that of the first embodiment, except that the third layer 40 of the artificial soil 100 of the first embodiment is not present. Therefore, explanations that overlap with the first embodiment can be omitted.

[0058] Figure 6 is a diagram showing the schematic configuration of the artificial soil 200 in this embodiment. As shown in Figure 6, the first layer 10 of the artificial soil 200 in this embodiment has a second surface 14 in the thickness direction of the first layer 10 that is in contact with the outside air, which is different from the first surface 12 for planting and / or the first surface 12 for the natural growth of plants.

[0059] In this embodiment, as described above, since the third layer 40 is not placed on the second layer 20, for example, if the thickness of the second layer 20 is made the same as the second layer 20 in the first embodiment, a wider surface area of ​​the second surface 14 that can be exposed to the outside air can be secured. As a result, plants such as wildflowers (P in Figure 1) or trees (T in Figure 1) planted or growing naturally in the first layer 10 can more reliably enjoy the air supplied from the second surface 14 (the second surface 14 in the first layer 10) which is less or almost unaffected by the second layer 20, which has high water retention properties, and thus root rot of these plants can be prevented with greater certainty.

[0060] On the other hand, if the contact area between the second surface 14 of the first layer 10 and the outside air is made the same as the contact area of ​​the second layer 20 in the first embodiment, the thickness of the second layer 20 can be increased because there is no third layer 40, thus further enhancing the water retention capacity of the second layer 20.

[0061] Furthermore, by positioning the water-retentive second layer 20 such that its surface is lower than the surface of the first layer 10, for example, the water absorption capacity of the artificial soil 200 can be improved by utilizing the water-retentive properties of the second layer 20. As a result, the artificial soil 200 of this embodiment can mitigate the effects of heavy rain, such as so-called "guerrilla downpours" and "linear rainbands." Moreover, because the charcoal-containing second layer 20 has higher water retention than ordinary soil, it is possible to increase the amount of heat from the heat of vaporization (latent heat) when the water retained by the second layer 20 evaporates, and / or to extend the time over which the heat of vaporization is removed from the second layer 20. As a result, the artificial soil 200 of this embodiment can suppress the occurrence of the heat island phenomenon.

[0062] <Third Embodiment> In the artificial soil 300 and artificial soil 400 of this embodiment, the second layer 20 in the artificial soil 200 of the second embodiment is the same as in the first embodiment, except that it is located in at least a portion of the lower layer side of the first layer 10. Therefore, descriptions that overlap with the first and second embodiments can be omitted.

[0063] Figure 7 shows the general configuration of the artificial soil 300 in this embodiment. Figure 8 shows the general configuration of another artificial soil 400 in this embodiment. In the artificial soil 400 shown in Figure 8, the boundary between the first layer 10 and the second layer 20, which will be described later, is formed by a combination of straight lines in the horizontal direction of the paper and straight lines in the vertical direction of the paper, in order to make the drawing easier to see. However, it is also possible to adopt an embodiment of the artificial soil 400 in which the boundary is formed by a curve only, or by including both a curve and a straight line.

[0064] In the artificial soil 300 shown in Figure 7, a portion of the second layer 20 is arranged over the entire lower layer of the first layer 10. Therefore, in this example, the volume occupied by the water-retentive second layer 20 can be larger compared to the artificial soil 200 of the second embodiment. Consequently, by adopting the artificial soil 300, for example, improved rainwater absorption capacity can be achieved by utilizing the water-retentive capacity of the second layer 20 more effectively than with the artificial soil 200. As a result, the artificial soil 300 of this embodiment can mitigate the effects of heavy rain, such as so-called "guerrilla downpours" and "linear rainbands," more effectively than the artificial soil 200.

[0065] Here, the inventors considered it important to consider that the presence of a large amount of charcoal in the second layer 20 could cause the soil's pH to become alkaline, which could have a negative impact on plant growth or development.

[0066] An example that reflects the above idea is the artificial soil 400 shown in Figure 8. In the artificial soil 400 shown in Figure 8, a portion of the second layer 20 is located on the lower side of the first layer 10. Furthermore, in the artificial soil 400, the boundary between the first layer 10 and the second layer 20 is formed in a step-like manner, so to speak, in a cross-sectional view, where the thickness of the second layer 20 decreases in stages. In other words, in a cross-sectional view as shown in Figure 8, the second layer 20 on the lower side of the first layer 10 is positioned such that the volume occupied by the second layer 20 containing charcoal decreases as the distance from the interface between the first layer 10 and the second layer 20 near the surface (or, to put it another way, the contact point or boundary between the second surface 14 and the second layer 20) increases.

[0067] As shown in Figure 8, another possible approach is to reduce or suppress the aforementioned effects on the first layer 10 due to a change in the soil's pH value to alkalinity by decreasing the volume occupied by the second layer 20 containing charcoal as the distance from the interface between the first layer 10 and the second layer 20 near the surface increases.

[0068] Furthermore, in the example shown in Figure 8, the boundary between the first layer 10 and the second layer 20 is formed in a step-like manner in cross-sectional view. Therefore, the total area constituting the boundary between the first layer 10 and the second layer 20 can be larger than the total area of ​​the artificial soil 300 in this embodiment. As a result, the water-retentive second layer 20 can supply moisture to the first layer 10 with greater certainty; in other words, the ability of moisture to penetrate / move from the second layer 20 to the first layer 10 can be exerted with greater certainty. Note that in the example shown in Figure 8, the boundary between the first layer 10 and the second layer 20 is shown in a step-like manner in cross-sectional view, where the thickness of the second layer 20 decreases in stages. However, the same effect can be achieved even if the thickness of the second layer 20 decreases uniformly instead of being step-like.

[0069] Furthermore, as shown in Figure 7, even if the thickness or volume of the second layer 20 located below the first layer 10 is uniform, another possible configuration of the artificial soil 300 or artificial soil 400 of this embodiment is to make the charcoal content (or density) of the second layer 20 located below the first layer 10 lower than the charcoal content (or density) of the second layer 20 in other areas.

[0070] <Modification of the second embodiment (1)> The artificial soil 500 in this modified example is the same as in the first embodiment, except that the first layer 10 in the artificial soil 200 of the second embodiment has a second surface 14a that is inclined from the first surface 12 toward the thickness direction of the first layer 10. Therefore, explanations that overlap with the first and second embodiments can be omitted.

[0071] Figure 9 shows the general structure of the artificial soil 500 in this modified example (1). As shown in Figure 9, the first layer 10 of the artificial soil 500 in this modified example has a second surface 14a that slopes toward the thickness direction from the first surface 12.

[0072] In this modified example (1), the artificial soil 500 also has a second surface 14a that is different from the first surface 12 and is in contact with the outside air. Furthermore, as shown in Figure 9, since the second surface 14a is a surface that is inclined toward the thickness direction from the first surface 12, the surface area that is in contact with the outside air (in other words, the surface area that can take in air from the outside) is larger than the second surface 14 of the first embodiment. As a result, it is possible to enjoy air supplied from the second surface 14a (the second surface 14a of the first layer 10), which has little or no influence from the second layer 20, which can have high water retention, with greater certainty. For this reason, by adopting the artificial soil 500 of this modified example, root rot of plants planted or growing naturally in the first layer 10 (for example, flowers (P in Figure 9) or trees (T in Figure 9)) can be prevented with greater certainty.

[0073] <Modification of the second embodiment (2)> The artificial soil 600 in this modified example is the same as in the first embodiment, except that the first layer 10 of the artificial soil 200 in the second embodiment has a first surface 12a which is substantially flat but has irregularities, and a second surface 14b which is different from the first surface 12a and includes a substantially flat but irregular surface. Therefore, explanations that overlap with the first and second embodiments can be omitted.

[0074] Figure 10 shows the general structure of the artificial soil 600 in this modified example (2). As shown in Figure 10, the first surface 12a of the first layer 10 of the artificial soil 600 in this modified example is substantially planar, but not horizontal. Therefore, in this example of the modified example, the existence of the second surface 14b can be confirmed by using a straight line (the dashed line in Figure 10) that connects a starting point S, which is considered to be the edge of the substantially planar surface, to another point E on that surface, as a reference, and determining whether a surface different from the first surface 12a, which is substantially planar, is inclined in the thickness direction with respect to the straight line on the first surface 12a (inclined at an angle represented by θ in Figure 10).

[0075] As described above, the artificial soil 600 of this modified example (2) also has a second surface 14b that is different from the first surface 12a, is inclined in the thickness direction of the first layer 10 and is in contact with the outside air, in addition to the first surface 12a. Furthermore, as shown in Figure 10, the second surface 14b is a surface that is substantially parallel to the first surface 12a but has irregularities, so the surface area that is in contact with the outside air (in other words, air that can be taken in from the outside air) can be larger than the second surface 14 of the first embodiment. As a result, it is possible to enjoy air supplied from the second surface 14b (the second surface 14b of the first layer 10), which is less or almost unaffected by the second layer 20, which has a higher water retention capacity, with greater certainty. For this reason, by adopting the artificial soil 600 of this modified example, root rot of plants planted or growing naturally in the first layer 10 (for example, flowers (P in Figure 9) or trees (T in Figure 9)) can be prevented with greater certainty.

[0076] In Figure 10 of this modified example, plants, represented by flowers (P'), are shown growing from the surface of the second surface 14b. However, even in this example, the plants do not completely cover the second surface 14b of this modified example. Therefore, since the second surface 14b of this modified example remains in a state where it can still be exposed to the outside air, the plants can enjoy the air supplied from the second surface 14b (the second surface 14b in the first layer 10), where the influence of the second layer 20, which has high water retention, is small or almost nonexistent. Thus, root rot of the plants can be prevented with high certainty. Even if the entire second surface 14b were covered by the plants, the effects of this modified example can still be achieved as long as air exchange with the outside air can occur by utilizing the gaps in the soil's aggregate structure, etc.

[0077] As described above, the artificial soil 600 of this modified example (2) can promote greening even in urban areas and contribute to the conservation, creation, and regeneration of a sustainable natural or living environment. Furthermore, since the artificial soil 600 includes a water-retentive second layer 20 positioned in contact with the first layer 10, the second layer 20 can supply water to the first layer 10 while maintaining a state in which water can freely move between the second layer 20 and the first layer 10. In other words, the ability for water to permeate / move from the second layer 20 to the first layer 10 can be exercised. As a result, artificial soil 600 can suppress the occurrence of the heat island phenomenon and promote greening, thereby achieving the preservation, creation, and regeneration of a sustainable natural and living environment.

[0078] In the embodiments described above, the interface between the first layer 10 and the second layer 20, the interface between the first layer 10 and the third layer 400, and the interface between the second layer 20 and the third layer 40 are described as being clearly formed. However, the embodiments described above are not limited to examples where the interfaces are clearly formed as described above. For example, it is realistically possible that the materials constituting the first layer 10 and the materials constituting the second layer 20 become mixed near the interface between the first layer 10 and the second layer 20. However, even in such cases, the effects of each embodiment can be achieved as long as the first layer 10 and the second layer 20 can be clearly distinguished in areas away from that vicinity. The same applies to the areas near the interface between the first layer 10 and the third layer 400, and the areas near the interface between the second layer 20 and the third layer 40.

[0079] The disclosures of the embodiments described above are provided for the purpose of explaining those embodiments and are not intended to limit the present invention. In addition, other modifications that fall within the scope of the present invention, including other combinations of the embodiments described above, are also included in the claims. For example, one other modification that may be adopted is the additional arrangement of the third layer 40 of the first embodiment in the second embodiment, modification (1) or (2) of the second embodiment, or the third embodiment. [Industrial applicability]

[0080] The artificial soil and method for producing the artificial soil of the present invention can be widely used to suppress the occurrence of the heat island phenomenon and promote greening, thereby contributing to the conservation, creation, and regeneration of a sustainable natural or living environment. [Explanation of Symbols]

[0081] 10 1st layer 12,12a 1st page 14,14a,14b 2nd side 20 2nd layer 30, 30a, 30b, 30c, 30d Boundary between the first and second layers 40 3rd layer 70 space 90 Existing soil 100,200,300,400,500,600 Artificial soil

Claims

1. A first layer containing soil components and having a thickness that allows for planting and / or the natural growth of plants, The first layer is in contact with a second layer containing charcoal, The first layer has a second surface that is different from the first surface of the planting target and / or the natural habitat of the plant, is in contact with the outside air, and is inclined in the thickness direction or toward the thickness direction from the first surface. Artificial soil.

2. Above the aforementioned second layer, there is a third layer that is permeable to water, The third layer does not cover the entire second surface of the first layer. The artificial soil according to claim 1.

3. The second layer is arranged on at least a portion of the lower side of the first layer. The artificial soil according to claim 1.

4. The process includes a placement step of placing a second layer containing charcoal in contact with a first layer containing soil components and having a thickness that allows for planting and / or the natural growth of plants, The first layer has a second surface that is different from the first surface of the planting target and / or the natural habitat of the plant, is in contact with the outside air, and is inclined in the thickness direction or toward the thickness direction from the first surface. A method for producing artificial soil.

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