Artificial soil and its manufacturing method

Abstract

To provide artificial soil that can suppress the occurrence of the heat island phenomenon 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 thickness that allows for planting, and a second layer 20 that contacts the first layer 10 and contains charcoal. Additionally, in this artificial soil, the first layer 10 has a second surface 14 that is different from the first surface 12 of the planting target and / or the natural plant growth target, and that is exposed to the outside air and extends in the thickness direction or is inclined from the first surface 12 in the thickness direction. This soil structure enables the active absorption and retention of moisture, such as rainwater, which can recharge the surrounding soil, including the planting layer, and suppress the occurrence of the heat island effect, which utilizes latent heat due to transpiration from planted plants, thereby contributing to the conservation, creation, and restoration of sustainable natural and living environments.

Description

[Technical Field]

[0001] The present invention relates to an artificial soil and a method for producing the same. [Background technology]

[0002] Global warming and the heat island phenomenon are environmental problems that have become increasingly serious in recent years. Global warming is caused by the greenhouse effect caused by rising carbon dioxide concentrations in the atmosphere, which causes the amount of solar heat absorbed on a global scale to exceed the amount of heat emitted from the Earth into space. On the other hand, the heat island phenomenon occurs when the water retention capacity of soil decreases due to the expansion of artificially covered areas caused by urbanization, resulting in the accumulation of waste heat from solar radiation and energy consumption, resulting in higher temperatures. Particularly in urban areas, the aforementioned environmental problems are closely related to the social issues related to the conservation, creation, and revitalization of green spaces.

[0003] From the perspective of preserving, creating, and restoring green spaces, several prior art technologies have been disclosed for realizing soil suitable for planting, even in urban areas. For example, a greening method has been disclosed in which a waterproof sheet is laid on the roof of a building, the waterproof sheet's water-blocking effect prevents weathering and damage from water leakage, soil is placed on the waterproof sheet, and plant species are cultivated, reducing ceiling burns caused by heat from concrete roofs exposed to direct sunlight, thereby minimizing the occurrence of the heat island effect (Patent Document 1).

[0004] The soil also has an upper layer including the ground surface and a lower layer disposed below the upper layer, the upper layer and the lower layer having an overlapping portion, the lower layer including soil constituent materials and a plurality of first compacts containing charcoal and a binder, the first compacts containing 50% to 95% charcoal and 5% to 50% binder by volume, and the first compacts are 30 mm 3 More than 60mm 3 The saturated hydraulic conductivity of the lower layer is greater than that of the upper layer, and the saturated hydraulic conductivity of the lower layer is 1.0×10 -5A planting ground is disclosed in which the velocity is m / s or more, and in the lower layer, the volume ratio of the multiple first compacts to the mixture of soil constituent materials and the multiple first compacts is 10% or more and 90% or less (Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-204554 [Patent Document 2] Japanese Patent Application Publication No. 2024-075101 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention can contribute to the construction of artificial soil that can achieve at least one function selected from the group consisting of infiltration and / or storage to enable rainwater recharge, utilization of latent heat due to evaporation, and soil carbon storage. Furthermore, the present invention can contribute to the suppression of the urban heat island effect, as well as the suppression of heavy rain disasters by water storage through greening and the conservation, creation, and restoration of sustainable natural and living environments as a concrete measure to prevent global warming through carbon storage.

[0007] During natural vegetation succession, the temperature of bare ground tends to be high due to the low amount of latent heat due to evapotranspiration, just as in cities with low green cover. In contrast, forests increase latent heat due to evapotranspiration while decreasing sensible heat, resulting in a thermal environment that is comfortable for humans and promotes active atmospheric circulation of water. Therefore, the inventors believed that introducing heat transport via the atmospheric circulation of water, such as rainwater, into urban environments would be an economically and physically realistic solution to the heat island phenomenon. Additionally, the inventors believed that actively increasing the water retention capacity of soil, regardless of whether the area is urban or not, could contribute to realizing soil and planting environments that are resilient to climate change, such as global warming.

[0008] However, the inventors have determined that it will be difficult to reliably preserve, create, and restore green spaces (particularly in urban areas) unless the water retention capacity of the soil is not simply increased but also the entire area in which the soil is located is recharged with water, typically from rainwater. This is because, unless we increase the water retention capacity of the soil and take measures to prevent it from reaching its limit, we will not be able to solve the social issue of dealing with heavy rain, typically the so-called "guerilla downpours" and "linear rain bands" that have occurred frequently in recent years.

[0009] In order to solve at least some of the above technical problems, the inventors have determined that the above problems cannot be solved even if the previously mentioned conventional technologies are adopted. Specifically, when the technology of Patent Document 1 is adopted, the waterproof sheet's water-blocking effect can contribute to improving water retention by utilizing a charcoal layer or the like. However, when rainfall exceeds the water-retention capacity, the waterproof sheet's water-blocking effect significantly limits the soil's drainage capacity—in other words, its ability to supply water to other soils. Furthermore, when the technology of Patent Document 2 is adopted, the upper layer serves as a "water-retaining layer" suitable for planting, while the lower layer serves as a "drainage layer," preventing the stored rainwater from recharging the surrounding soil. Furthermore, since the upper layer functions as a "water-retaining layer" suitable for planting, drainage is required to prevent or inhibit root rot and ensure the respiration of the root zone of the plants.

[0010] As a result of intensive research based on the above-mentioned considerations and analyses, the inventors have found that the above-mentioned problems can be solved by arranging or establishing the following two types of soil (1) and (2), which are interconnected and play different roles, and by implementing the ingenuity in (3). As a result, the inventors have discovered that it is possible to suppress the occurrence of the heat island effect, and even in urban areas, to counter heavy rain by recharging moisture such as rainwater, and to promote heat transfer by utilizing latent heat, thereby contributing to the conservation, creation, and restoration of a sustainable natural or living environment. (1) The first layer (soil) that is thick enough for planting and serves as the soil for plants to grow naturally. (2) The 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 in which moisture can freely move in and out, and is actively imbued with charcoal to exhibit high water retention capacity, while also being able to supply moisture to the first layer (in other words, capable of permeating / moving into the first layer). (3) The first layer of (1) is formed so as to have a surface (second surface) that is different from the surface (first surface) of the first layer of (1) that is the target for planting and / or the target for natural plant growth, and that is capable of contacting the outside air (in other words, capable of taking in air (particularly oxygen) from the outside air), and that is inclined in the thickness direction of the first layer or from the surface (first surface) toward the thickness direction.

[0011] In addition to the above points, if the charcoal used to improve the water retention and water supply is actively mixed or placed in the second layer (soil), it can contribute to the realization of a decarbonized society through so-called "carbon storage" using the soil.

[0012] The present invention was created based on the above findings and ingenuity.

[0013] One artificial soil of the present invention comprises a first layer containing soil components and having a thickness sufficient for planting and / or for plants to grow naturally, and a second layer in contact with the first layer and containing charcoal. Additionally, in this artificial soil, the first layer has a second surface that is different from the first surface of the planting target and / or the natural growth target of the plants, is in contact with the outside air, and is in the thickness direction or is inclined from the first surface in the thickness direction.

[0014] This artificial soil includes a second layer that is in direct contact with the first layer, contains charcoal, has high water retention, and can supply moisture to the first layer. Additionally, this artificial soil includes a second surface (a second surface) that is different from the first surface of the planting target and / or natural plant growth target in the first layer and is in contact with the outside air (in other words, can take in air from the outside or does not become waterlogged), extending through the thickness of the first layer or sloping inward from the first surface. As a result, the following technical effects (a) to (c) can be achieved: It can suppress the occurrence of the heat island phenomenon, and even in urban areas, it can counter heavy rainfall by recharging moisture, such as rainwater, and promote heat transfer by utilizing latent heat, thereby contributing to the conservation, creation, and restoration of sustainable natural and living environments. (a) Since the second layer, which may have high water retention capacity, is in direct contact with the first layer, the moisture held in the second layer can be supplied to the first layer (in other words, it can penetrate / migrate into the first layer). (b) Trees, grass, flowers and / or mosses (hereinafter collectively referred to as "plants") planted in the first layer can benefit from the moisture supplied (or discharged) from the second layer. (c) The second layer, which may have high water retention capacity, is less affected by the air supplied from the second surface of the first layer, or the entire root zone of the plant can be prevented or suppressed from becoming waterlogged.

[0015] Furthermore, one method for producing artificial soil of the present invention includes a step of placing a second layer containing charcoal so that it is in contact with a first layer containing soil components and having a thickness that allows planting and / or natural growth of plants. Additionally, in this method for producing artificial soil, the first layer has a second surface that is different from the first surface of the planting target and / or natural growth target, is in contact with the outside air, and is in the thickness direction or is inclined from the first surface in the thickness direction.

[0016] According to this method for producing artificial soil, it is possible to form artificial soil having a second layer that is in direct contact with the first layer, contains charcoal, has high water retention, and can supply moisture to the first layer. In a preferred embodiment of the method for producing artificial soil, the artificial soil can be formed by, for example, subsequently placing the second layer in contact with an existing first layer that contains soil components and has a thickness that allows for planting. From the above perspective, it is noteworthy that existing soil can be converted into the artificial soil relatively easily and / or relatively inexpensively.

[0017] In addition, the artificial soil formed by the above-mentioned manufacturing method has a surface (second surface) in the thickness direction of the first layer or inclined from the first surface toward the thickness direction, which is different from the first surface of the planting target and / or the natural plant growth target of the first layer and can be exposed to the outside air (in other words, it can take in air from the outside, or the entire root zone of the plant is less likely to become waterlogged), and as a result, the following technical effects (a) to (c) can be achieved to form artificial soil that can suppress the occurrence of the heat island phenomenon and, even in urban areas, can contribute to the preservation, creation, and restoration of a sustainable natural or living environment by countering heavy rain through the recharge of moisture, such as rainwater, and by promoting heat transfer through the use of latent heat. (a) Since the second layer, which may have high water retention capacity, is in direct contact with the first layer, the moisture held in the second layer can be supplied to the first layer (in other words, it can penetrate / migrate into the first layer). (b) Trees, grass, flowers and / or mosses planted in the first layer can receive moisture supplied (discharged) from the second layer, or the entire root zone of the plants is less likely to become waterlogged. (c) It is possible to enjoy air supplied from the second surface (the second surface of the first layer) which is less affected by the second layer which may have high water retention.

[0018] In each of the above-mentioned inventions, the surface of the "planting target and / or the target where plants grow naturally" is not limited to the first surface in the first layer. For example, another embodiment that can be adopted in each of the above-mentioned inventions is that the surface of the planting target and / or the target where plants grow naturally is a second surface in addition to the first surface.

[0019] Furthermore, in each of the above-mentioned inventions, the first surface of the "subject to be planted and / or the subject to be naturally grown plants" is not limited to a surface that is (or will be) newly planted and / or a surface where (or will be) newly naturally grown plants. For example, the first surface of the "subject to be planted and / or the subject to be naturally grown plants" may include a case where existing planted and / or already naturally growing plants exist on at least a part of the surface.

[0020] Furthermore, the "thickness direction" of the "first layer" in the present application is not necessarily limited to a vertically downward direction. For example, when plants are planted on the wall surface of a building (typically, so-called "wall greening"), one possible embodiment is that a surface approximately parallel to the wall surface (at least a surface other than a surface approximately perpendicular to the wall surface) corresponds to the first surface of the first layer of the present invention. [Effects of the Invention]

[0021] One artificial soil of the present invention can suppress the occurrence of the heat island phenomenon and, even in urban areas, promote the recharge of moisture, such as rainwater, and heat transfer through the use of latent heat, thereby contributing to the preservation, creation, and restoration of a sustainable natural or living environment. Furthermore, one artificial soil of the present invention can also contribute to so-called carbon storage.

[0022] Furthermore, one method for producing artificial soil according to the present invention can form artificial soil that suppresses the occurrence of the heat island phenomenon and that can contribute to the conservation, creation, and restoration of a sustainable natural or living environment, even in urban areas, by countering heavy rain through the recharge of moisture, such as rainwater, and by promoting heat transfer through the use of latent heat. Furthermore, this method for producing artificial soil can relatively easily and / or relatively inexpensively convert existing soil into artificial soil that suppresses the occurrence of the heat island phenomenon and promotes greening, even in urban areas, thereby contributing to the conservation, creation, and restoration of a sustainable natural or living environment. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram showing a schematic configuration of artificial soil 100 in a first embodiment. [Figure 2] 1A to 1C are diagrams showing a part of the manufacturing process of the artificial soil 100 in the first embodiment. [Figure 3] 1A to 1C are diagrams showing a part of the manufacturing process of the artificial soil 100 in the first embodiment. [Figure 4] 1A to 1C are diagrams showing a part of the manufacturing process of the artificial soil 100 in the first embodiment. [Figure 5] 1A and 1B are photographs and a schematic diagram illustrating an outline of a part of a comparative experiment in the first embodiment. [Figure 6] FIG. 10 is a diagram showing a schematic configuration of artificial soil 200 in a second embodiment. [Figure 7] FIG. 10 is a diagram showing a schematic configuration of artificial soil 300 in a third embodiment. [Figure 8] FIG. 10 is a diagram showing a schematic configuration of another artificial soil 400 according to the third embodiment. [Figure 9] FIG. 10 is a diagram showing a schematic configuration of artificial soil 500 in a modified example (1) of the second embodiment. [Figure 10] FIG. 10 is a diagram showing a schematic configuration of artificial soil 600 in a modified example (2) of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this description, common parts are designated by common reference numerals throughout the drawings unless otherwise specified. In addition, in the drawings, elements of the present embodiment are not necessarily drawn to scale. In addition, some reference numerals may be omitted to make each drawing easier to understand.

[0025] First Embodiment [Outline of Artificial Soil 100] Fig. 1 is a diagram showing a schematic configuration of artificial soil 100 in this embodiment. Fig. 2 to Fig. 4 are diagrams showing a part of the manufacturing process of the artificial soil 100 in this embodiment.

[0026] As shown in FIG. 1, the artificial soil 100 of this embodiment comprises a first layer 10 having a thickness that allows planting and / or the growth of plants, a second layer 20 in contact with 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 plants, such as flowers (P in FIG. 1) or trees (T in FIG. 1), to be planted and / or allows plants to grow naturally. The second layer 20 contains charcoal and is disposed in contact with the first layer 10. The third layer 40 is disposed above the second layer 20 and is water-permeable.

[0028] Additionally, 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 different from the first surface 12 of the planting target and / or the target where the plant will grow naturally and that is open to the outside air. Furthermore, the third layer 40 does not cover the entire second surface 14 of the first layer 10. In other words, even when the third layer 40 is disposed, the second surface 14 of the first layer 10 of this embodiment remains open to the outside air.

[0029] Therefore, in the first layer 10 of the artificial soil 100 of this embodiment, a state in which air can be taken in from at least the second surface 14 is maintained, or the entire rhizosphere of the plant is unlikely to become waterlogged. Therefore, plants such as flowers (P in FIG. 1) or trees (T in FIG. 1) planted 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 little or almost unaffected by the second layer 20, which may have high water retention, and the entire rhizosphere of the plant is unlikely to become waterlogged, which reliably prevents root rot of the plant and makes it possible to plant it.

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

[0031] Furthermore, in this embodiment, since the second layer 20 serves as a water-retaining layer, the "charcoal" that may be contained in the second layer 20 is not particularly limited as long as it can retain moisture to an extent that the effects of this embodiment can be achieved. Representative examples of "charcoal" include powdered charcoal, bamboo charcoal, black charcoal, white charcoal, sawdust charcoal, crushed wood charcoal, biochar (derived from pruning branches, thinnings, charcoal derived from gasified wood biomass power generation, waste wood, food waste, livestock waste, rice husks, rice, straw, nut shells, sewage sludge, paper sludge, industrial waste, and / or municipal waste), or a mixture of two or more of the materials listed above. Furthermore, examples of materials other than the aforementioned "charcoal" that may constitute the second layer 20 include soil constituent materials that may be contained in the first layer 10. Therefore, the second layer 20 may be a mixture of the "soil constituent material" and the "charcoal," or may be the "charcoal" alone. In addition to charcoal, it is a preferred embodiment that second layer 20 contains an inorganic substance that does not decompose in soil. Typical examples of inorganic substances include volcanic rocks such as pumice (mineral akadama soil, Kanuma soil, Hyuga soil, etc.), porous pottery, diatomaceous earth, zeolite, and other porous materials.

[0032] Additionally, unlike the first layer 10, the second layer 20 of this embodiment is not intended to be a layer where plants can be planted or where they can grow naturally. This allows for the charcoal content of the constituent materials of the second layer 20 to be actively increased. Therefore, the charcoal content (volume %) of the second layer 20 is greater than 10% and less than or equal to 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 disposed so as to be in direct contact with the first layer 10, the second layer 20 can also function as a moderate moisture source, supplying moisture from the second layer 20 to the first layer 10 through 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 the water-retentive second layer 20, which is disposed so as to contact 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 permeate / move from the second layer 20 to the first layer 10 can be exhibited.

[0034] As a result, if there are plants planted and / or naturally growing in the first layer 10, the plants can receive moisture supplied (discharged) from the second layer 20 via the first layer 10. This allows, for example, a reduction in the number of irrigation times or the amount of irrigation required to maintain the plants in the first layer 10 within a certain period of time, significantly reducing the burden of plant maintenance. This reduction in the burden of plant maintenance can promote greening and significantly contribute to the preservation, creation, and restoration of sustainable natural and living environments. Furthermore, because the burden of plant maintenance can be reduced, utilizing the artificial soil 100 of this embodiment when planting various plants in public places (e.g., parks, green spaces, etc.) is a preferable aspect from the perspective of promoting the effective use of tax revenues.

[0035] As described above, the artificial soil 100, which is disposed in contact with the first layer 10 and has the water-retentive second layer 20, can promote greening even in urban areas and contribute to the preservation, creation, and restoration of sustainable natural and living environments. For example, the presence of multiple large trees in urban areas can contribute to the formation of a local forest-like environment by providing shade and regulating the temperature through transpiration.

[0036] Furthermore, the material constituting the third layer 40 of this embodiment is not particularly limited as long as it exhibits sufficient permeability to allow water supplied by rainwater or irrigation to reach the second layer 20. Representative examples of materials constituting the third layer 40 include one or more materials selected from the group consisting of natural stone (Shirakawa sand, Kansui sand, Shiratamaseki soil, etc.), pumice, volcanic rocks such as scoria (Akadama soil, Kanuma soil, Hyuga soil, etc.), granular or crushed ceramics, bricks, roof tiles, and other baked goods, porous materials such as diatomaceous earth and zeolite, and wood used for covering (e.g., coconut shell chips). A suitable embodiment is one in which the material constituting the third layer 40 can promote evaporation of moisture contained in the second layer 20 and / or the third layer 40, for example, by utilizing capillary action. Furthermore, providing a sandbar-like design on the surface of the third layer 40 is preferable from the viewpoint of creating an appearance that appeals to the human eye.

[0037] It is a preferred embodiment that the third layer 40 has water retention properties in addition to the water permeability described above. Having water retention properties in the third layer 40 is another preferred embodiment, as it allows the third layer 40 to achieve a water retention capacity that exceeds that of the second layer 20, helping to retain moisture for a longer period of time. Furthermore, if the material constituting the third layer 40 has a large surface area and good breathability, more water will evaporate from the soil surface, allowing for more efficient heat transfer using latent heat. From the above perspectives, a suitable example of a material constituting the third layer 40 that has water permeability and water retention properties, as well as high breathability that increases the amount of water evaporation, is porous soil (porous soil), such as Hyuga soil.

[0038] By positioning the third layer 40 so that its surface is lower than the surface of the first layer 10, the rainwater absorption capacity of the artificial soil 100 can be improved by utilizing the water retention properties of the third layer 40 itself and / or the second layer 20 below 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 "guerilla downpours" and "linear rain bands." Furthermore, because the second layer 20 containing charcoal has higher water retention properties than ordinary soil, the amount of heat of vaporization (latent heat) generated when the water retained by the second layer 20 evaporates can be increased, and / or the time required for the heat of vaporization of the second layer 20 can be prolonged. 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 normal soil is a preferred aspect 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 effect.

[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 a thickness that allows planting and / or the growth of plants. It can be appropriately selected depending on the type of plant to be planted. For example, the thickness of the first layer 10 in which only flowers are to be planted may be thinner than the thickness of the first layer 10 in which trees are to be planted. The thickness of the first layer 10 in which only typical flowers are to be planted is approximately 200 mm to approximately 400 mm (more narrowly, approximately 200 mm to approximately 350 mm), and the thickness of the first layer 10 in which trees are to be planted is approximately 500 mm or more (more narrowly, approximately 400 mm or more).

[0040] 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 about 1000 mm or more and about 2000 mm or less. 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 inhibit water permeability, but a typical thickness of the third layer 40 is about 100 mm or more and about 300 mm or less.

[0041] [Manufacturing method of artificial soil 100] 2 to 4 are diagrams showing a part of the manufacturing process of the artificial soil 100 in this embodiment.

[0042] 2 and 3, first, a portion of existing soil 90 containing soil components that can be planted and / or where plants grow naturally is removed to form a space 70 in which a second layer 20, which will be described later, can be placed. Note that although Fig. 2 shows a state in which plants grow naturally in a portion of the existing soil 90, as long as the existing soil 90 is plantable, it is not necessary for plants to already be growing naturally when removing the portion of the soil.

[0043] Then, as shown in Figure 4, a first placement process is carried out in which only the water-retentive charcoal that constitutes the second layer 20 described above, or a material containing the charcoal (for example, a mixture of "soil constituent material" and "charcoal" as described above) is placed in the space 70 formed by removing a portion of the existing soil 90.

[0044] At this time, the material (charcoal only or a material containing charcoal) is introduced in an amount significantly less than the amount of the existing soil 90 removed. In this embodiment, a portion of the existing soil 90 serves as the first layer 10, having a thickness that allows planting and / or the natural growth of plants. Furthermore, the newly formed first layer 10 by the placement of the second layer 20 has a second surface 14 in the thickness direction of the first layer 10 that is different from the first surface 12 of the planting target and / or the first surface 12 of the natural growth target of the plant and that is exposed to the outside air. Furthermore, this second surface 14 can create a condition in which the entire root zone of the plant is less likely to become waterlogged. Furthermore, this first placement step brings the second layer 20 and the first layer 10 into direct contact as described above, thereby forming a boundary 30 for supplying moisture from the second layer 20 to the first layer 10.

[0045] Thereafter, a second arrangement step is performed in which a water-permeable third layer 40 is arranged above the second layer 20. At this time, the third layer 40 is arranged so as not to cover the entire second surface 14 of the first layer 10. As a result, the artificial soil 100 of this embodiment can be produced, as shown in FIG. 1.

[0046] In the artificial soil 100 of this embodiment, as described above, even if the third layer 40 is disposed, the second surface 14 of the first layer 10 of this embodiment remains in a state in which it can come into contact with the outside air, so that the first layer 10 is able to take in air from at least the second surface 14, and the entire rhizosphere is maintained in a state in which it is difficult for water to stagnate. Therefore, as described above, by employing the artificial soil 100 of this embodiment, respiration in the rhizosphere of plants, such as flowers (P in FIG. 1) or trees (T in FIG. 1) planted or growing naturally in the first layer 10, can be ensured, and root rot can be prevented with a high degree of certainty.

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

[0048] The artificial soil 100 shown in Fig. 1 can be produced through the above-described production process. The above example shows one example of a method for producing the artificial soil 100 in which existing soil 90 is used as the first layer 10 of the artificial soil 100 of this embodiment, but the method for producing the artificial soil 100 of this embodiment is not limited to the above example. For example, another embodiment that can be adopted is to remove the existing soil 90 and then newly arrange the first layer 10 for the artificial soil 100 of this embodiment.

[0049] [Various experiments and analysis results on Artificial Soil 100] In order to confirm the technical effects of the above-mentioned artificial soil 100, 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 structures and laminated structures) in the comparative examples (Comparative Examples 1 to 4).

[0050] First, to ensure that the initial conditions of the measurement targets were consistent, the amount of moisture (initial water absorption or initial water content) adequately provided to the soil of Sample 1 and the soil of each Comparative Example at the initial stage was used as a reference. After seven consecutive days without rainfall had passed, the surface temperatures of the soil of Sample 1 and the soil of each Comparative Example (E1) at 2 p.m., the surface temperatures of the soil of Sample 1 and the soil of each Comparative Example (E2) at 3 p.m., and the amount of moisture evaporated from the soil of Sample 1 and the soil of each Comparative Example (E3) were measured. The inventors measured each of the surface temperatures using an infrared sensor (PerfectPrime, Model IR0005). The amount of water added to Sample 1 and the soil of each Comparative Example until they reached the initial sufficient moisture content (additional water supply amount) was used as the amount of moisture evaporated (evaporation amount).

[0051] The specific soil contents of Sample 1 and each of the Comparative Examples (1 to 3) are as follows: The representative example of powdered coal (fine coal) in Sample 1 below is powdered coal (moisture-containing powdered coal) produced from the Aridagawa Biomass Power Plant (a small, highly efficient woody biomass heat and power supply system manufactured by URBAS). (Sample 1) Depth: approx. 380 mm, volume: approx. 35,000,000 mm 3 In the container, the thickness of the upper layer (corresponding to the third layer 40) of "Hyuga soil" is about 100 mm (volume: about 10,000,000 mm 3 ), and the thickness of the powder coal in the lower layer (corresponding to the second layer 20) is 280 mm (volume: about 25,000,000 mm 3 ) (Comparative Example 1) Sample 1 container initially contained only water at approximately 24.5°C. (Comparative Example 2) Only red soil was placed in the container of Sample 1. (Comparative Example 3) Only Hyuga soil was placed in the container of Sample 1. Assuming

[0052] Table 1 below shows the results of various evaluations of the laminated structure (sample 1) of the second layer 20 and the third layer 40 of this embodiment, and the structures (including single-layer structures and laminated structures) of the comparative examples (comparative examples 1 to 3). Fig. 5 also shows a photograph (row x) and a schematic diagram (row y) outlining some of the comparative experiments (comparative example 2 (column a) and sample 1 (column b)) of this embodiment.

[0053] [Table 1]

[0054] As shown in Table 1, it was confirmed that the surface temperatures of Sample 1, in which the third layer 40 was disposed above the second layer 20, at 2:00 PM and at 3:00 PM were both lower than those of Comparative Examples 1 to 3. It was also found that Sample 1 was able to retain more moisture than Comparative Examples 2 and 3.

[0055] Furthermore, the amount of water evaporated from Sample 1 was greater than that of Comparative Example 1, which contained only water. It was 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. Additionally, although not shown in Table 1 above, the inventors measured a stone without water retention and found that the maximum surface temperature of the stone rose to 59.4°C at 3:00 PM. As a result, the difference between the surface temperature of the stone and that of Sample 1 at 3:00 PM was 32.4°C. It is noteworthy that Sample 1, which includes the second layer 20 and the third layer 40, achieved the aforementioned temperature difference for the stone under direct sunlight.

[0056] Based on the measurement results shown in Table 1, it can be said that by using Sample 1 with a charcoal-containing layer in the lower layer, it is possible to utilize water evaporation and, in other words, to keep the soil surface temperature lower for a longer period of time than 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 high water retention capacity of the second layer 20 can be utilized to suppress the occurrence of the heat island phenomenon.

[0057] <Second embodiment> The artificial soil 200 of this embodiment is similar to that of the first embodiment, except that the third layer 40 in the artificial soil 100 of the first embodiment is not provided. Therefore, the description overlapping with the first embodiment may be omitted.

[0058] Fig. 6 is a diagram showing a schematic configuration of the artificial soil 200 according to this embodiment. As shown in Fig. 6, the first layer 10 of the artificial soil 200 according to this embodiment has a second surface 14 in the thickness direction of the first layer 10 that is different from the first surface 12 that is the planting target and / or the first surface 12 that is the natural growth target of the plant and that can come into contact with the outside air.

[0059] In this embodiment, as described above, the third layer 40 is not disposed on the second layer 20. Therefore, for example, if the thickness of the second layer 20 is made the same as that of the second layer 20 of the first embodiment, a larger area of ​​the second surface 14 that is exposed to the outside air can be ensured. Therefore, plants, such as flowers (P in FIG. 1) or trees (T in FIG. 1) planted or growing naturally on the first layer 10, can more reliably enjoy the air supplied from the second surface 14 (the second surface 14 of the first layer 10), which is little or almost unaffected by the second layer 20, which may have high water retention, and therefore root rot of the plants can be more reliably prevented.

[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 that of the second layer 20 of the first embodiment, the absence of the third layer 40 allows the thickness of the second layer 20 to be made thicker, thereby further increasing the water retention capacity of the second layer 20.

[0061] By positioning the second layer 20 so that the surface of the water-retentive second layer 20 is lower than the surface of the first layer 10, the water-retentive properties of the second layer 20 can be utilized to improve the rainwater absorption capacity of the artificial soil 200. As a result, the artificial soil 200 of this embodiment can mitigate the effects of heavy rain, such as so-called "guerilla downpours" and "linear rain bands." Furthermore, since the charcoal-containing second layer 20 has higher water-retentive properties than ordinary soil, the amount of heat of vaporization (latent heat) generated when the water retained by the second layer 20 evaporates can be increased, and / or the time required for the heat of vaporization of the second layer 20 can be extended. As a result, the artificial soil 200 of this embodiment can suppress the occurrence of the heat island phenomenon.

[0062] <Third embodiment> The artificial soil 300 and the artificial soil 400 of this embodiment are similar to those of the first embodiment, except that the second layer 20 in the artificial soil 200 of the second embodiment is disposed at least partially below the first layer 10. Therefore, descriptions that overlap with those of the first and second embodiments may be omitted.

[0063] Fig. 7 is a diagram showing the general configuration of artificial soil 300 in this embodiment. Fig. 8 is a diagram showing the general configuration of another artificial soil 400 in this embodiment. In the artificial soil 400 shown in Fig. 8, the boundary between a first layer 10 and a second layer 20 (described later) is formed by a combination of a straight line in the horizontal direction of the page and a straight line in the vertical direction of the page, in order to make the drawing easier to see. However, one embodiment of the artificial soil 400 that can be adopted is one in which the boundary is formed by only curved lines or by both curved lines and straight lines.

[0064] In the artificial soil 300 shown in FIG. 7, a portion of the second layer 20 is disposed across the entire lower side of the first layer 10. Therefore, in this example, the volume occupied by the water-retentive second layer 20 may be larger than that of the artificial soil 200 of the second embodiment. Therefore, by employing the artificial soil 300, for example, it is possible to improve the rainwater absorption capacity by utilizing the water-retentive properties of the second layer 20 more than the artificial soil 200. As a result, the artificial soil 300 of this embodiment is more able to mitigate the effects of heavy rain, such as so-called "guerilla downpours" and "linear rain bands," than the artificial soil 200.

[0065] Here, the inventors also considered it important to consider that the high charcoal content of the second layer 20 may cause the soil pH value to become alkaline, which may have a negative impact on the growth or development of plants.

[0066] An example that reflects the above-mentioned idea is artificial soil 400 shown in FIG. 8. In the artificial soil 400 shown in FIG. 8, a portion of the second layer 20 is disposed below the first layer 10. In addition, in the artificial soil 400, the boundary between the first layer 10 and the second layer 20 is formed in a stepped manner in a cross-sectional view, so to speak, such that the thickness of the second layer 20 decreases in stages. In other words, in the cross-sectional view shown in FIG. 8, the second layer 20 below the first layer 10 is disposed so that the volume occupied by the second layer 20 containing charcoal decreases with increasing distance from the interface between the first layer 10 and the second layer 20 near the ground surface (or, in other words, the contact or boundary portion between the second surface 14 and the second layer 20).

[0067] As shown in Figure 8, another possible embodiment is to reduce or suppress the above-mentioned impact on the first layer 10 caused by the pH value of the soil changing to alkaline by making the volume occupied by the second layer 20 containing charcoal smaller as the distance from the interface between the first layer 10 and the second layer 20 near the ground surface increases.

[0068] In the example shown in FIG. 8 , the boundary between the first layer 10 and the second layer 20 is formed in a stepped shape in cross section, so that the total area of ​​the boundary between the first layer 10 and the second layer 20 can be larger than the total area of ​​the artificial soil 300 of this embodiment. As a result, the water-retentive second layer 20 can more reliably supply moisture to the first layer 10; in other words, the ability of the second layer 20 to penetrate / transport moisture into the first layer 10 can be more reliably exhibited. Note that in the example shown in FIG. 8 , the boundary between the first layer 10 and the second layer 20 is stepped in cross section, so that the thickness of the second layer 20 decreases in stages. However, the same effect can be achieved even if the boundary is formed in a sloping shape, so that the thickness of the second layer 20 decreases uniformly.

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

[0070] <Modification (1) of the second embodiment> The artificial soil 500 of this modification is similar to that of 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, descriptions that overlap with those of the first and second embodiments may be omitted.

[0071] Fig. 9 is a diagram showing a schematic configuration of the artificial soil 500 in this modified example (1). As shown in Fig. 9, the first layer 10 of the artificial soil 500 in this modified example has a second surface 14a that is inclined from the first surface 12 toward the thickness direction.

[0072] The artificial soil 500 of this modification (1) also has a second surface 14a that is different from the first surface 12 and is exposed to the outside air. As shown in FIG. 9, the second surface 14a is inclined in the thickness direction from the first surface 12, and therefore has a larger surface area that is exposed to the outside air (i.e., that can take in air from the outside air) than the second surface 14 of the first embodiment. As a result, the air supplied from the second surface 14a (the second surface 14a of the first layer 10) can be more reliably received, with little or no influence from the second layer 20, which may have high water retention. Therefore, by employing the artificial soil 500 of this modification, root rot of plants (e.g., flowers (P in FIG. 9) or trees (T in FIG. 9)) planted or growing naturally in the first layer 10 can be more reliably prevented.

[0073] <Modification (2) of the second embodiment> The artificial soil 600 of this modification is similar to that of the first embodiment, except that the first layer 10 in the artificial soil 200 of the second embodiment has a first surface 12a that is substantially flat but has irregularities formed thereon, and a second surface 14b that is substantially flat but includes irregularities formed thereon, different from the first surface 12a. Therefore, descriptions that overlap with those of the first and second embodiments may be omitted.

[0074] Fig. 10 is a diagram showing a schematic configuration of the artificial soil 600 in this modified example (2). As shown in Fig. 10, the first surface 12a of the first layer 10 of the artificial soil 600 in this modified example is substantially flat but not horizontal. Therefore, in one example of this modified example, the existence of the second surface 14b can be confirmed by using a straight line (a dashed line in Fig. 10) connecting a starting point S recognized as the end of the substantially flat surface to another point E on the plane as a reference point, and checking whether a surface continuing from the starting point S, which is different from the first surface 12a, which is substantially flat, is inclined in the thickness direction with respect to the straight line of the first surface 12a (inclined at an angle represented by θ in Fig. 10).

[0075] As described above, the artificial soil 600 of this modification (2) also has, in addition to the first surface 12a, a second surface 14b that is different from the first surface 12a and is inclined in the thickness direction of the first layer 10 and is exposed to the outside air. Furthermore, as shown in FIG. 10 , the second surface 14b is a generally parallel but uneven surface that is inclined in the thickness direction from the first surface 12a. This allows for a larger surface area that is exposed to the outside air (i.e., that can take in air from the outside) than the second surface 14 of the first embodiment. As a result, the air supplied from the second surface 14b (the second surface 14b of the first layer 10) can be more reliably received, with little or no influence from the second layer 20, which may have high water retention. Therefore, by employing the artificial soil 600 of this modification, root rot of plants (e.g., flowers (P in FIG. 9) or trees (T in FIG. 9)) planted or growing naturally in the first layer 10 can be reliably prevented.

[0076] 10 of this modified example shows plants, such as flowers (P'), growing on the surface of the second surface 14b. However, even in this example, the plants do not entirely cover the second surface 14b of this modified example. Therefore, the second surface 14b of this modified example remains accessible to the outside air. Therefore, the plants can enjoy the air supplied from the second surface 14b (the second surface 14b of the first layer 10), which is little or not affected by the second layer 20, which may have high water retention. This effectively prevents root rot of the plants. Even if the second surface 14b were entirely covered by the plants, the effects of this modified example can be achieved as long as air exchange with the outside air can occur by utilizing gaps in the soil's aggregated structure.

[0077] As described above, the artificial soil 600 of the present modified example (2) can promote greening even in urban areas and contribute to the conservation, creation, and restoration of a sustainable natural or living environment. Furthermore, the artificial soil 600 includes a second layer 20 having water-retaining properties and arranged in contact with the first layer 10, so that 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 second layer 20 can exhibit the ability to penetrate / move water from the second layer 20 to the first layer 10. As a result, the artificial soil 600 can suppress the occurrence of the heat island phenomenon and promote greening, thereby realizing the conservation, creation and regeneration of a sustainable natural or living environment.

[0078] In the above-described embodiments, the boundary between the first layer 10 and the second layer 20, the boundary between the first layer 10 and the third layer 400, and the boundary between the second layer 20 and the third layer 40 are clearly defined. However, the above-described embodiments are not limited to the above-described embodiments. boundary The present invention is not limited to examples in which the difference between the first layer 10 and the second layer 20 is clearly defined. For example, it is possible that the material constituting the first layer 10 and the material constituting the second layer 20 are mixed together in reality near the boundary between the first layer 10 and the second layer 20. However, even in such an example, the effects of each embodiment can be achieved as long as the first layer 10 and the second layer 20 are clearly distinguishable in a region away from the boundary. The same applies to the vicinity of the boundary between the first layer 10 and the third layer 400 and the vicinity of the boundary between the second layer 20 and the third layer 40.

[0079] The disclosure of the above-described embodiments is provided for the purpose of explaining the embodiments, and is not intended to limit the present invention. In addition, other modifications within the scope of the present invention, including other combinations of the above-described embodiments, are also included in the scope of the claims. For example, in the second embodiment, modification (1) or (2) of the second embodiment, or the third embodiment, additionally arranging the third layer 40 of the first embodiment is another modification that can be adopted. [Industrial Applicability]

[0080] The artificial soil and the 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 preserving, creating and restoring 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 including a soil component and having a thickness that allows planting and / or plant growth; a second layer in contact with the first layer and containing charcoal; The first layer has a second surface that is exposed to the outside air and is different from a first surface of the planting object and / or the natural plant growth object, and is inclined in the thickness direction or from the first surface toward the thickness direction, and the second layer is in contact with a surface of the first layer along the thickness direction and has a thickness of 1000 mm or more and 2000 mm or less; Artificial soil.

2. a water-permeable third layer disposed above the second layer; the third layer does not cover all of the second surface of the first layer; The artificial soil according to claim 1.

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

4. The method includes a step of placing a second layer containing charcoal so that the second layer is in contact with a first layer containing soil components and having a thickness that allows planting and / or plant growth; The first layer has a second surface that is exposed to the outside air and is different from a first surface of the planting object and / or the natural plant growth object, and is inclined in the thickness direction or from the first surface toward the thickness direction, and the second layer is in contact with a surface of the first layer along the thickness direction and has a thickness of 1000 mm or more and 2000 mm or less; Method for producing artificial soil.

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