Planting soil and method for producing the same

Abstract

This invention provides a planting soil incorporating biochar in a way that allows for the widespread introduction of greening plants, and a method for producing the same. [Solution] A planting soil for cultivating plants, comprising a soil base material made of artificial soil, fertilizer, and biochar, having a pH value in the neutral range, and the biochar content is set according to the plant. The soil base material is artificial lightweight soil, the fertilizer is peat moss, the biochar is at least one of rice husk charcoal and bamboo charcoal, and the plant is a plant for greening.

Description

Technical Field

[0001] The present invention relates to a planting soil suitable for greening of artificial ground and a method for producing the same.

Background Art

[0002] In response to recent climate change, technologies for carbon dioxide absorption and storage are desired. One such technology is carbon storage by mixing biochar with soil. Biochar is obtained by carbonizing organic matter as a raw material under anaerobic or low oxygen conditions at a heat treatment temperature of 350°C or higher. By mixing it with soil, the carbon dioxide fixed by photosynthesis is trapped in the soil, contributing to carbon storage. In the domestic J-Credit system and the like, efforts to mix biochar with soil are credited, so technological development aimed at increasing the introduction destinations and amounts of biochar for the purpose of increasing transaction amounts is desired.

[0003] Biochar also functions as a soil conditioner. Although its properties vary depending on the raw material, rice husk charcoal and bamboo charcoal are alkaline and have a neutralizing effect on acidic soil. Also, the density varies depending on the raw material, and it is desired to select the raw material and adjust the mixing amount according to the purpose of introducing biochar. Furthermore, an effect of improving soil water retention according to the physical properties of the base soil has also been reported (for example, see Non-Patent Document 1).

[0004] As a conventional technology that utilizes the alkaline action of biochar, there is a known method of introducing smoked charcoal or the like for the purpose of weed control to form an alkaline greening base (for example, see Patent Document 1). However, in this method, since it is not for the purpose of neutralization and is for cultivating plant species that can only grow in alkaline soil, the problem is that the options for greening plants are narrowed. Also, as other conventional technologies, a lightweight planting base composed of carbide and cement (for example, see Patent Document 2), and a method of mixing charcoal with vegetable juice and fruit juice from the viewpoint of soil microbial activity to keep the soil in the neutral range and maintain high bacterial activity (for example, see Patent Document 3) have been developed.

[0005] On the other hand, a carbon sequestration agriculture evaluation system is known that evaluates the amount of carbon sequestration in the soil and the amount of greenhouse gas reduction based on the characteristics of soil conditioners containing biochar, information on agricultural land into which soil conditioners containing biochar have been mixed, and information on the varieties and yields of crops produced on that land (see, for example, Patent Document 4). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Ministry of Agriculture, Forestry and Fisheries, Agriculture, Forestry and Fisheries Research Council website, "Development of CO2 Reduction and Absorption Technologies for Food, Agriculture, Forestry and Fisheries," [online], [Accessed October 24, 2024], Internet<URL:http: / / www.affrc.maff.go.jp / docs / gikikin / attach / pdf / gikikin-1.pdf> [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-48802 [Patent Document 2] Japanese Patent Publication No. 2009-329032 [Patent Document 3] Japanese Patent Publication No. 2012-80829 [Patent Document 4] Japanese Patent Publication No. 2022-153012 [Overview of the project] [Problems that the invention aims to solve]

[0008] In artificial ground greening projects, particularly those in urban areas, the introduction of biochar as a soil conditioner for planting bases is anticipated. In greening projects on artificial ground, soil weight reduction is often required due to load limitations imposed by building structures, and lightweight artificial soil is frequently used as the base soil. Because lightweight artificial soil has low nutrient retention, peat moss or compost are often introduced simultaneously to ensure adequate nutrient content. Peat moss has a low specific gravity and is easy to use in terms of load limitations, but its pH is strongly acidic (3-4), requiring a neutralizing agent for plant growth. On the other hand, while compost has a neutral pH, its high specific gravity necessitates avoiding its active introduction into the soil due to load limitations. Therefore, generally, peat moss and compost are often mixed in equal proportions. Thus, for soil used in greening projects on artificial ground, considering load limitations, it is desirable to add a soil conditioner with low specific gravity and neutralizing properties.

[0009] Examples of soil conditioners with low specific gravity and alkaline properties include bamboo charcoal and rice husk charcoal, which are types of biochar. Many of these have an alkaline pH exceeding 9 and also have a low specific gravity.

[0010] Many artificial lightweight soils have low water retention, and from the perspective of plant growth, measures to prevent soil drying are often required. Biochar containing bamboo charcoal and rice husk charcoal often has high water retention, and when mixed with soil, it is expected to prevent poor growth of greening plants even when there is no rainfall after construction and the soil is dry.

[0011] By introducing biochar, which has a low specific gravity and alkaline properties, into a soil mixture of artificial lightweight soil and peat moss, it is possible to achieve both soil lightening and neutralization. In this case, it was desirable to introduce biochar in a way that would allow for the widespread introduction of greening plants.

[0012] The present invention has been made in view of the above, and aims to provide a planting soil incorporating biochar in a manner that allows for the widespread introduction of greening plants, and a method for producing the same. [Means for solving the problem]

[0013] To solve the above-mentioned problems and achieve the objective, the planting soil according to the present invention is a planting soil for cultivating plants that contains a soil base material made of artificial soil, fertilizer components, and biochar, has a pH value in the neutral range, and the biochar content is set according to the plant.

[0014] Furthermore, another planting soil according to the present invention is characterized in that, in the above-described invention, the soil base material is artificial lightweight soil, the fertilizer is peat moss, the biochar is at least one of rice husk charcoal and bamboo charcoal, and the plant is a plant for greening.

[0015] Furthermore, the method for producing planting soil according to the present invention is a method for producing the above-described planting soil, characterized by comprising the steps of: setting the biochar content in accordance with the plant; and mixing the soil base material, the fertilizer, and the biochar at the set content to produce planting soil.

[0016] Furthermore, another method for producing planting soil according to the present invention is a method for producing the above-described planting soil, characterized by comprising the steps of: setting the biochar content in accordance with the plant; and mixing the biochar at the set content with a mixed soil obtained by mixing the soil base material and the fertilizer to produce planting soil. [Effects of the Invention]

[0017] The planting soil according to the present invention contains a soil base material made of artificial soil, fertilizer, and biochar, and is a planting soil for cultivating plants, having a pH value in the neutral range, and the biochar content is set according to the plant, thus providing the effect of introducing biochar in a way that allows for the wide introduction of greening plants.

[0018] Moreover, according to another planting soil of the present invention, the base material for the soil is artificial lightweight soil, the fertilizer component is peat moss, the biochar is at least one of rice husk charcoal and bamboo charcoal, and the plant is a plant for greening. Therefore, in the planting soil for greening on artificial ground, it has the effect of achieving both soil weight reduction and neutralization.

[0019] Moreover, according to the method for manufacturing the planting soil of the present invention, it is a method for manufacturing the above-mentioned planting soil, which includes a step of setting the content rate of the biochar corresponding to the plant, and a step of mixing the base material for the soil, the fertilizer component, and the biochar with the set content rate to manufacture the planting soil. Therefore, it has the effect of being able to manufacture the planting soil into which biochar is introduced in a form that allows for wide introduction of greening plants.

[0020] Moreover, according to another method for manufacturing the planting soil of the present invention, it is a method for manufacturing the above-mentioned planting soil, which includes a step of setting the content rate of the biochar corresponding to the plant, and a step of mixing the biochar with the set content rate into the mixed soil obtained by mixing the base material for the soil and the fertilizer component to manufacture the planting soil. Therefore, it has the effect of being able to manufacture the planting soil into which biochar is introduced in a form that allows for wide introduction of greening plants.

Brief Description of the Drawings

[0021] [Figure 1] Figure 1 is a photographic view showing the state of Zoysia grass 16 days after no irrigation.

Modes for Carrying Out the Invention

[0022] Hereinafter, embodiments of the planting soil and its manufacturing method according to the present invention will be described in detail based on the drawings. Note that the present invention is not limited by this embodiment.

[0023] The planting soil according to an embodiment of the present invention contains a soil base material made of artificial soil, fertilizer components, and biochar, and is a planting soil for cultivating plants, having a pH value in the neutral range. In this embodiment, a greening soil intended for greening on artificial ground is assumed, and the plants are assumed to be plants for greening (for example, grass).

[0024] For the soil base material, artificial lightweight soil, such as that used as the base soil for greening on artificial ground, can be used. Because artificial lightweight soil is relatively light, it is advantageous for reducing the weight of planting soil.

[0025] It is desirable to use a fertilizer that contains a large amount of peat moss as its main component. The fertilizer may consist solely of peat moss, or it may include other fertilizers. Compost may be used as the fertilizer other than peat moss. Using only peat moss as the fertilizer, without using compost which has a high specific gravity, is suitable for reducing the weight of the soil.

[0026] Biochar can be made from materials such as rice husk charcoal or bamboo charcoal. Biochar can consist of only rice husk charcoal, only bamboo charcoal, or a combination of both. Rice husk charcoal and bamboo charcoal are alkaline with a pH of around 10, and they have a significant pH-adjusting effect when using only strongly acidic peat moss (pH 3-4) as fertilizer. For this reason, rice husk charcoal and bamboo charcoal are suitable for neutralizing soil containing peat moss. In addition, many types of rice husk charcoal and bamboo charcoal have a low specific gravity, making them suitable for reducing the weight of the soil. Furthermore, because biochar has high water retention, it is suitable for preventing poor growth even when there is no rainfall after application and the soil is dry.

[0027] The biochar content is set in accordance with the plants used for greening. Specifically, the biochar content that does not cause poor plant growth is considered in advance from the perspective of the plant species of the greening plants and the biochar raw materials and production methods. The correspondence between the plant and the biochar content that does not cause poor plant growth is obtained for each plant species of greening plants and the biochar raw materials and production methods. The biochar content can be set from the biochar content that does not cause poor plant growth, as shown in the correspondence between the plant species of greening plants and the biochar raw materials and production methods. Alternatively, a database of suitable biochar raw materials and mixing amounts (content) for each variety of greening plants can be constructed in advance by utilizing the carbon sequestration agriculture evaluation system described in Patent Document 4 above or by conducting a literature search, and the biochar content corresponding to the greening plants can be selected from this database.

[0028] According to this embodiment, biochar can be introduced in a way that allows for the widespread introduction of greening plants. Because biochar is used, it is possible to neutralize the soil through pH adjustment and lighten the soil when a large amount of peat moss is introduced. In addition, the introduction of biochar can improve nutrient retention. Therefore, in greening soil intended for greening on artificial ground, it is possible to achieve soil lightness while maintaining a high nutrient content, taking into account the load limitations of buildings. In particular, even under conditions where there is no rainfall and the soil remains dry, it is possible to improve water retention and prevent poor plant growth.

[0029] Next, a method for producing planting soil according to this embodiment will be described. First, the biochar content is set according to the type of plant. Next, the soil base material, fertilizer, and biochar at the set content are mixed to produce planting soil. Alternatively, planting soil may be produced by mixing the set content of biochar into a soil mixture of soil base material and fertilizer. This method makes it possible to produce planting soil in which biochar has been incorporated in a way that allows for the widespread introduction of greening plants.

[0030] (Examples) Next, embodiments of the present invention will be described. Figure 1 shows the condition of Zoysia japonica 'Nandina domestica' 16 days after starting no-irrigation cultivation, using it as an example. Figure 1(1) shows Zoysia japonica cultivated in a soil area of ​​artificial lightweight soil and peat moss without biochar, (2) shows Zoysia japonica cultivated in a soil area of ​​artificial lightweight soil and peat moss mixed with bamboo charcoal at a volume ratio of 30%, and (3) shows Zoysia japonica cultivated in a soil area of ​​artificial lightweight soil and peat moss mixed with rice husk charcoal at a volume ratio of 30%. Figures 1(2) and (3) correspond to the examples of the present invention, and Figure 1(1) corresponds to the comparative example. After 16 days of starting no-irrigation cultivation, the Zoysia japonica in Figure 1(1) had turned brown, while the Zoysia japonica in Figures 1(2) and (3) remained green. Therefore, it can be seen that the examples in which biochar such as rice husk charcoal and bamboo charcoal were mixed were more effective in suppressing the degree of deterioration in growth than the comparative example in which biochar was not mixed.

[0031] Table 1 shows the bulk density of artificial lightweight soil, bamboo charcoal, rice husk charcoal, peat moss, and compost from the perspective of soil weight reduction. As shown in Table 1, rice husk charcoal and bamboo charcoal have a bulk density of less than 1 / 3 that of artificial lightweight soil, indicating that soil weight reduction can be achieved by mixing them.

[0032] [Table 1]

[0033] Table 2 shows the water retention rates of artificial lightweight soil, bamboo charcoal, rice husk charcoal, peat moss, and compost, obtained from their wet and dry bulk densities, from the perspective of water retention. The water retention rates were calculated using the following formula (1). As shown in Table 2, the water retention rates of rice husk charcoal and bamboo charcoal are about twice that of artificial lightweight soil, suggesting that mixing artificial lightweight soil with rice husk charcoal or bamboo charcoal can improve soil water retention. Water retention rate (%) = (Bulk density when wet - Bulk density when dry) / Bulk density when wet ... (1)

[0034] [Table 2]

[0035] Table 3 shows the pH of a mixed soil of artificial lightweight soil, peat moss, and compost when 30% of the artificial lightweight soil is replaced with bamboo charcoal or rice husk charcoal by weight. As shown in Table 3, mixing in rice husk charcoal or bamboo charcoal raises the pH to 7 or higher, suggesting a tendency towards a neutral pH.

[0036] [Table 3]

[0037] As described above, the planting soil according to the present invention contains a soil base material made of artificial soil, fertilizer components, and biochar, and is a planting soil for cultivating plants, having a pH value in the neutral range, and the biochar content is set according to the plants, so that biochar can be introduced in a way that allows for the wide introduction of greening plants.

[0038] Furthermore, according to other planting soils of the present invention, the soil base material is artificial lightweight soil, the fertilizer is peat moss, the biochar is at least one of rice husk charcoal and bamboo charcoal, and the plants are plants for greening, so that both soil lightening and neutralization can be achieved in planting soil intended for greening on artificial ground.

[0039] Furthermore, the method for producing planting soil according to the present invention includes the steps of: setting the biochar content in accordance with the plant; and mixing the soil base material, the fertilizer, and the biochar at the set content to produce planting soil. Therefore, it is possible to produce planting soil in which biochar has been introduced in a manner that allows for the widespread introduction of greening plants.

[0040] Furthermore, according to another method for producing planting soil according to the present invention, the method for producing the above-described planting soil includes the steps of setting the biochar content in accordance with the plant, and mixing the biochar at the set content into a mixed soil obtained by mixing the soil base material and the fertilizer, thereby producing planting soil into which biochar has been introduced in a manner that allows for the widespread introduction of greening plants.

[0041] Furthermore, the Sustainable Development Goals (SDGs) are among the 17 international goals adopted at the UN Summit in September 2015. The planting soil and its manufacturing method according to this embodiment can contribute to achieving some of the 17 SDGs, such as Goal 15, "Protect, restore and promote sustainable use of terrestrial ecosystems." [Industrial applicability]

[0042] As described above, the planting soil and its production method according to the present invention are useful for greening artificial ground, and are particularly suitable for introducing biochar in a way that allows for the widespread introduction of greening plants.

Claims

1. A planting soil for cultivating plants, comprising a soil base material consisting of artificial soil, fertilizer components, and biochar, characterized in that it has a pH value in the neutral range, and the biochar content is set according to the plant.

2. The planting soil according to claim 1, characterized in that the soil base material is artificial lightweight soil, the fertilizer is peat moss, the biochar is at least one of rice husk charcoal and bamboo charcoal, and the plant is a plant for greening.

3. A method for producing planting soil according to claim 1 or 2, comprising the steps of: setting the biochar content in accordance with the plant; and mixing the soil base material, the fertilizer, and the biochar at the set content to produce planting soil.

4. A method for producing planting soil according to claim 1 or 2, comprising the steps of: setting the biochar content in correspondence with the plant; and mixing the biochar at the set content with a mixed soil obtained by mixing the soil base material and the fertilizer to produce planting soil.

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