Green soil and method for producing green soil

Abstract

To provide green soil capable of achieving hardness suitable for use as modified soil while allowing superior plant growth, and to provide a method capable of producing the green soil.SOLUTION: Green soil according to the present invention comprises a soil modifier including dihydrate gypsum, alumina cement, and a water-absorbing agent, as well as soil, and has an electric conductivity of 500 μS / cm or more and 1000 μS / cm or less, a pH of 5.0 or more and 8.6 or less, and a cone index of less than 1000 kN / m2.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In recent years, from the perspective of reducing the environmental load and limiting the capacity of final disposal sites, it has become desirable to reuse soil generated at construction and civil engineering sites, etc., without disposing of it in landfills. However, depending on the properties of the generated soil, it may not be possible to reuse it in its original state.

[0003] In such cases, it has been considered to mix soil with soil conditioners containing alkaline materials such as cement and lime, hydraulic gypsum, etc. to form improved soil, and then use the improved soil for various purposes. Patent Document 1, for example, discloses an example of such improved soil, which is a solidified muddy substance obtained by adding an improvement material consisting of hydraulic gypsum such as hemihydrate gypsum, a coagulant, porous inorganic particles, and a pH adjuster to a muddy substance such as mud, and solidifying and neutralizing the muddy substance. This solidified muddy substance is used, for example, as a backfill material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-001397 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, the use of modified soil for agriculture, horticulture, forest regeneration, etc. has attracted attention, and soil modified to be suitable for plant growth (hereinafter referred to as green soil) has been studied.

[0006] However, conventional modified soil has an alkaline pH, which limits the types of plants that can grow in it. Furthermore, even if the modified soil has a neutral pH, a large amount of soil modifier must be added to the soil for modification. This can lead to an excess of ions in the soil, which can affect plant growth, such as causing physiological disorders. Therefore, conventional modified soil cannot be said to be fully suitable for plant growth.

[0007] The present invention has been made in consideration of these circumstances, and aims to provide green soil that exhibits hardness suitable for use as modified soil and is excellent for plant growth, as well as a method for producing such green soil. [Means for solving the problem]

[0008] The green soil according to the present invention comprises soil and a soil conditioner containing gypsum dihydrate, alumina cement, and a water absorbent, and has an electrical conductivity of 500 μS / cm to 1000 μS / cm, a pH of 5.0 to 8.6, and a cone index of 1000 kN / m. 2 is less than.

[0009] Due to this constitution, the green soil of the present invention has electrical conductivity, pH, and corn index that are suitable for plant growth, so it exhibits hardness that can be used as improved soil while being excellent for plant growth.

[0010] The green soil according to the present invention has a concentration of 10 kg / m 3 More than 20kg / m 3 The following are preferably included:

[0011] The green soil according to the present invention, having such a constitution, has the electrical conductivity, pH, and corn index at values ​​more suitable for plant growth, and is therefore more favorable for plant growth.

[0012] In the green soil according to the present invention, the electrical conductivity is preferably 600 μS / cm or more and 800 μS / cm or less.

[0013] The green soil according to the present invention, having such a constitution, is excellent in plant growth because the amount of ions contained in the green soil is more suitable for plant growth.

[0014] The green soil according to the present invention preferably has a pH of 5.0 or more and 7.5 or less.

[0015] The green soil according to the present invention, due to such a constitution, has a pH in the range from weakly acidic to neutral, which is more suitable for plant growth, and is therefore more favorable for plant growth.

[0016] The green soil according to the present invention has a cone index of 800 kN / m 2 It is preferable that it is less than 10 ...

[0017] The green soil according to the present invention, due to such a constitution, exhibits hardness that can be used as improved soil and is more suitable for plant growth, and therefore is superior in plant growth.

[0018] The method for producing green soil according to the present invention is a method for producing green soil by adding a soil conditioner containing gypsum dihydrate, alumina cement, and a water absorbent to soil, and the method produces green soil with an electrical conductivity of 500 μS / cm or more and 1000 μS / cm or less, a pH of 5.0 or more and 8.6 or less, and a cone index of 1000 kN / m or less. 2 The soil amendment is added to the soil so that the soil concentration is less than 100%.

[0019] With this configuration, the method for producing green soil according to the present invention can produce green soil that is hard enough for use as improved soil and is excellent for plant growth.

[0020] In the method for producing green soil according to the present invention, the soil improver is added to the entire soil in an amount of 10 kg / m 3 More than 20kg / m 3 It is preferable to add the following:

[0021] With this configuration, the method for producing green soil according to the present invention can produce green soil that is more favorable for plant growth.

[0022] In the method for producing green soil according to the present invention, the electrical conductivity is preferably 600 μS / cm or more and 800 μS / cm or less.

[0023] With this configuration, the method for producing green soil according to the present invention can produce green soil that is more favorable for plant growth.

[0024] In the method for producing green soil according to the present invention, the pH is preferably 5.0 or more and 7.5 or less.

[0025] With this configuration, the method for producing green soil according to the present invention can produce green soil that is more favorable for plant growth.

[0026] In the method for producing green soil according to the present invention, the cone index is 800 kN / m 2 It is preferable that it is less than 10 ...

[0027] With this configuration, the method for producing green soil according to the present invention can produce green soil that is hard enough for use as improved soil and is excellent for plant growth. [Effects of the Invention]

[0028] According to the present invention, it is possible to provide a green soil that exhibits hardness suitable for use as improved soil and is excellent for plant growth, and a method for producing the green soil. DETAILED DESCRIPTION OF THE INVENTION

[0029] The green soil and the method for producing the green soil according to this embodiment will be described below.

[0030] <Green soil> The green soil according to this embodiment includes a soil modifier and soil.

[0031] The electrical conductivity of the green soil according to this embodiment is an index showing the amount of ions contained in the green soil, and the higher the electrical conductivity, the greater the amount of ions. The amount of ions is one index showing the amount of nutrients necessary for plant growth contained in the green soil, and the greater the amount of ions, the greater the amount of nutrients.

[0032] The green soil according to this embodiment has an electrical conductivity of 500 μS / cm to 1000 μS / cm, preferably 600 μS / cm to 800 μS / cm, in order to provide a favorable plant growth environment. If the electrical conductivity exceeds 1000 μS / cm, the amount of ions becomes excessive, which tends to inhibit plant growth. If the electrical conductivity is less than 500 μS / cm, the amount of ions is insufficient for plant growth, which tends to inhibit plant growth. The electrical conductivity can be measured using an electrical conductivity meter at 20±2°C using a supernatant of a green soil suspension prepared at a solid-liquid ratio of 1:5, in accordance with JIS K 0130:2008 "General Rules for Measuring Electrical Conductivity."

[0033] The pH of the green soil according to this embodiment is 5.0 to 8.6, preferably 5.0 to 7.5, and more preferably 5.0 to 7.0, from the viewpoint of providing a favorable growth environment for plants. Green soil with a pH ranging from weakly acidic to neutral is more suitable for plant growth. The pH can be measured using a pH meter in accordance with JGS 0211-2009 "Test Method for pH of Soil Suspension."

[0034] The cone index of the green soil according to this embodiment is an index of the hardness of the green soil, and the higher the cone index, the harder the green soil.

[0035] The green soil according to this embodiment has a hardness that can be used as improved soil, and from the viewpoint of creating a good growing environment for plants, the cone index is 1000 kN / m 2 less than 800 kN / m2 More preferably, it is less than 700 kN / m 2 Cone index is less than 1000kN / m 2 In the above cases, when the seeds of plants sown in the green soil germinate, the shoots and roots that grow from the seeds have difficulty penetrating the green soil, which tends to inhibit plant growth. The cone index is not particularly limited as long as it can be used as improved soil, and may be, for example, 200 kN / m 2 It may be more than 400kN / m 2 The cone index can be measured in accordance with JIS A 1210:2009 "Test method for soil compaction by tamping."

[0036] In the green soil according to the present embodiment, the soil conditioner is preferably added in an amount of 10 kg / m to the entire soil, from the viewpoint of adjusting the electrical conductivity, pH, and corn index to values ​​more suitable for plant growth. 3 More than 20kg / m 3 More preferably, 12 kg / m 3 More than 18kg / m 3 The following is included:

[0037] The soil conditioner includes gypsum dihydrate, alumina cement, and a water absorbent.

[0038] The gypsum dihydrate may be natural, chemically synthesized, or obtained as a by-product of other substances, or may be gypsum dihydrate-containing waste that has been crushed but not heat-treated (so-called recycled gypsum dihydrate).

[0039] As dihydrate gypsum, the Blaine specific surface area is 500 cm 2 / g or more 6000cm 2 / g or less, preferably 1000 cm 2 / g or more 3000cm 2 / g or less can be used.

[0040] The ratio of the mass of gypsum dihydrate to the total mass of the soil conditioner is not particularly limited, and may be, for example, 69.3 mass% or more and 94.1 mass% or less, or 81.0 mass% or more and 87.3 mass% or less.

[0041] Alumina cement contains calcium aluminates such as CaO·Al2O3, CaO·2Al2O3, and 12CaO·7Al2O3 as its main components. Alumina cement also contains minerals such as C3A and C 12 Includes A7, CA, CA2, C4AF, etc. The aforementioned "A" represents Al2O3, "C" represents CaO, and "F" represents Fe2O3.

[0042] In addition, as an alumina cement, the Blaine specific surface area is 2000 cm 2 / g or more 6000cm 2 / g or less. Specifically, the alumina cement that can be used is that described in JIS R 2521:1995 "Physical test methods for alumina cement for refractories."

[0043] The content of alumina cement is preferably 5.3 parts by mass or more and 42.9 parts by mass or less, and more preferably 11.1 parts by mass or more and 17.6 parts by mass or less, relative to 100 parts by mass of gypsum dihydrate.

[0044] Furthermore, the ratio of the mass of alumina cement to the total mass of the soil conditioner is not particularly limited, and may be, for example, 5.0 mass% or more and 29.7 mass% or less, or 2.5 mass% or more and 15.0 mass% or less.

[0045] The water-absorbing agent can be an organic polymer material that absorbs water upon contact with water and forms a liquid with a relatively high viscosity. Specifically, the water-absorbing agent can be one that, when mixed with water to a concentration of 0.25% by mass relative to the total amount of water (total amount of mixed liquid), results in a viscosity of 300 mPa·s or more. The viscosity can be measured using a B-type rotational viscometer in accordance with JIS K 7117-1:1999 "Plastics - Liquid, emulsion, or dispersion resins - Measurement method of apparent viscosity using a Brookfield rotational viscometer."

[0046] The water-absorbing agent may be an anionic, cationic, or nonionic organic polymer material. Specifically, the water-absorbing agent may be at least one selected from the group consisting of any of the above-mentioned polyacrylamide-based polymer materials, polyacrylic acid ester-based polymer materials, polyacrylate-based polymer materials, polymethacrylate-based polymer materials, polymethacrylate-based polymer materials, polyamidine hydrochloride-based polymer materials, polyvinyl alcohol-based polymer materials, polyoxyethylene-based polymer materials, acrylamide-methacrylate ester copolymer materials, and acrylamide-acrylate copolymer-based polymer materials. The water-absorbing agent preferably contains a carboxyl group (-COO) as the dissociation group. - ) or sulfo group (-SO3 - ) anionic polyacrylamide polymer material, and ammonium groups (-NH3 + ) or trimethylammonium group (-N + At least one selected from the group consisting of cationic polyacrylamide polymer materials having (CH3)3) and nonionic polyacrylamide polymer materials can be used.

[0047] The weight-average molecular weight of the water-absorbing agent can be 3 million or more and 20 million or less. When an anionic or nonionic organic polymer material is used as the water-absorbing agent, the weight-average molecular weight of the water-absorbing agent may be 15 million or more and 20 million or less. When a cationic organic polymer material is used as the water-absorbing agent, the weight-average molecular weight of the water-absorbing agent may be 3 million or more and 10 million or less. The weight-average molecular weight of the water-absorbing agent can be measured by GPC (gel permeation chromatography; apparatus used: HLC-8120GPC (manufactured by Tosoh Corporation), columns used: TSKgel G6000HXL and TSKgel G3000HXL (both manufactured by Tosoh Corporation), column temperature: 40°C) using tetrahydrofuran as a solvent and polystyrene as a standard substance.

[0048] The content of the water-absorbing agent is preferably 1.2 parts by mass or more and 5.9 parts by mass or less, and more preferably 2.1 parts by mass or more and 5.9 parts by mass or less, relative to 100 parts by mass of the gypsum dihydrate.

[0049] Furthermore, the mass ratio of the water absorbing agent to the total mass of the soil conditioner is not particularly limited, and may be, for example, 1 mass % or more and 10 mass % or less, or 2 mass % or more and 5 mass % or less.

[0050] The soil to be mixed with the soil improver is not particularly limited, and examples thereof include soil with a moisture content of 20% by mass or more and 30% by mass or less. The moisture content of soil is the "mass of water in soil / mass of solids in soil" expressed in "mass %" and can be measured based on JGS 0121:2009 "Testing Method for Moisture Content of Soil" of the Geotechnical Society of Japan.

[0051] Specific examples of the soil include sandy soil, clayey soil, highly organic soil, Kanto loam, Akaboku soil, Ando soil, Kanuma soil, and the like.

[0052] The soil is not particularly limited, and may be, for example, soil having a cone index of 100 kN / m 2More than 300kN / m 2 The following can be mentioned: The cone index can be measured based on the same method as above.

[0053] The green soil according to this embodiment can be used to grow, for example, komatsuna (Japanese mustard spinach), peas, spinach, asparagus, udo (Japanese burdock root), cauliflower, sunny lettuce, chrysanthemum, celery, takana (Japanese mustard greens), turnip, chives, green onions, Chinese cabbage, parsley, broccoli, mitsuba (Japanese laurel wort), myoga (Japanese ginger), mulukhiyah (mulukhiyah), lettuce, cabbage, lettuce, bok choy, butterbur, kidney beans, edamame (green soybeans), okra, pumpkin, kanpyo (sweet red pepper), cucumber, cowpea, watermelon, sweet corn, broad beans, chili peppers, tomatoes, eggplants, bell peppers, melons, peanuts, strawberries, konjac (apricot), taro, Japanese yam, kobu (Japanese turnip), burdock, radish, onions, carrots, lotus root, taro, ginger, garlic, and potatoes. and pickled radishes; fruits such as grapes, kiwi, peach, fig, plum, persimmon, pear, mandarin orange, apple, chestnut, pineapple, and blueberry; flowers such as gerbera, baby's breath, sweet pea, lisianthus, carnation, chrysanthemum, gladiolus, cineraria, cyclamen, daffodil, statice, stock, geranium, pansy, freesia, poinsettia, Madagascar jasmine, lily, anthurium, cosmos, marigold, saintpaulia, primula, bromeliad, fern, orchid, begonia, and gentian; and trees such as cedar, cypress, Japanese red pine, Japanese black pine, oak, zelkova, bamboo, and camphor.

[0054] The green soil according to this embodiment includes a soil conditioner containing gypsum dihydrate, alumina cement, and a water absorbent, and soil, and has an electrical conductivity of 500 μS / cm or more and 1000 μS / cm or less, a pH of 5.0 or more and 8.6 or less, and a cone index of 1000 kN / m 2 By being less than 100%, the soil exhibits a hardness that can be used as improved soil, while still being excellent for plant growth.

[0055] In addition, in the green soil according to this embodiment, the soil improver is applied in an amount of 10 kg / m to the entire soil. 3 More than 20kg / m3 By including the following, the electrical conductivity, pH, and Cohn's index become values ​​more suitable for plant growth, resulting in better plant growth.

[0056] Furthermore, since the green soil of this embodiment has an electrical conductivity of 600 μS / cm or more and 800 μS / cm or less, the amount of ions contained in the green soil is more suitable for plant growth, making it superior for plant growth.

[0057] The green soil according to this embodiment has a pH of 5.0 or more and 7.5 or less, so that the pH of the green soil is weakly acidic to neutral, which is more suitable for plant growth, and therefore is superior for plant growth.

[0058] The green soil according to this embodiment has a cone index of 800 kN / m 2 By having a hardness of less than 100%, the soil exhibits a hardness that can be used as improved soil, while being more suitable for plant growth, resulting in better plant growth.

[0059] <Method of producing green soil> In the method for producing green soil according to this embodiment, a soil improver is added to soil.

[0060] The soil modifier is the same as that used in the green soil according to the present embodiment.

[0061] The soil is the same as that used for the green soil according to the present embodiment.

[0062] The method for producing green soil according to this embodiment is to produce green soil having an electrical conductivity of 500 μS / cm or more and 1000 μS / cm or less, a pH of 5.0 or more and 8.6 or less, and a cone index of 1000 kN / m 2 The soil conditioner is added to the soil so that the soil concentration is less than 100% and then the soil conditioner and the soil are mixed.

[0063] In the method for producing green soil according to the present embodiment, the soil improver is preferably added at a rate of 10 kg / m relative to the entire soil, from the viewpoint of adjusting the electrical conductivity, pH, and corn index to values ​​suitable for plant growth. 3 More than 20kg / m 3 More preferably, 12 kg / m 3 More than 18kg / m 3 Add the following:

[0064] The electrical conductivity, pH, and corn index are the same as those of the green soil according to the present embodiment.

[0065] In the method for producing green soil according to this embodiment, after mixing the soil improver with the soil, the green soil obtained based on JIS A 1210:2009 "Test method for soil compaction by ramming" may be poured into a formwork and cured. In the method for producing green soil according to this embodiment, the soil and / or green soil may be passed through a sieve to adjust the particle size, if necessary.

[0066] In addition, in the method for producing green soil according to this embodiment, water may be further added depending on the water content of the soil.

[0067] The method for producing green soil according to this embodiment is a method for producing green soil by adding a soil conditioner containing gypsum dihydrate, alumina cement, and a water absorbent to soil, and the green soil has an electrical conductivity of 500 μS / cm or more and 1000 μS / cm or less, a pH of 5.0 or more and 8.6 or less, and a cone index of 1000 kN / m 2 By adding the soil conditioner to the soil so that the soil hardness is less than 0.05g, it is possible to produce green soil that is excellent for plant growth while still exhibiting a hardness that is suitable for use as improved soil.

[0068] The method for producing green soil according to this embodiment can produce green soil that is more favorable for plant growth by making the electrical conductivity of the green soil 500 μS / cm or more and 1000 μS / cm or less.

[0069] In the method for producing green soil according to this embodiment, the pH is set to 5.0 or more and 7.5 or less, so that green soil that is more favorable for plant growth can be produced.

[0070] In the method for producing green soil according to this embodiment, the cone index is 800 kN / m 2 By making the soil hard enough to be used as improved soil, it is possible to produce green soil that is better suited to plant growth.

[0071] The green soil and the method for producing green soil according to the present invention are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. Furthermore, the configurations, methods, etc. of the above-described embodiments may be arbitrarily adopted and combined (the configurations, methods, etc. of one embodiment may be applied to the configurations, methods, etc. of other embodiments), and further, the configurations, methods, etc. of the various modified examples described below may be arbitrarily selected and adopted in the configurations, methods, etc. of the above-described embodiments.

[0072] The present invention includes the following aspects. [1] A soil conditioner comprising dihydrate gypsum, alumina cement, and a water absorbent, and soil; Electrical conductivity is 500 μS / cm or more and 1000 μS / cm or less, pH is 5.0 or more and 8.6 or less, and the cone index is 1000 kN / m 2 Less than 100% green soil [2] The soil conditioner is applied to the entire soil at a rate of 10 kg / m 3 More than 20kg / m 3 The green soil described in [1] below is included. [3] The green soil according to [1] or [2], wherein the electrical conductivity is 600 μS / cm or more and 800 μS / cm or less. [4] The green soil according to any one of [1] to [3], wherein the pH is 5.0 or more and 7.5 or less. [5] The cone index is 800 kN / m 2 The green soil according to any one of [1] to [4], wherein the soil has a density of less than 10 ... [6] A method for producing green soil by adding a soil conditioner containing gypsum dihydrate, alumina cement, and a water absorbent to soil, The electrical conductivity of green soil is between 500μS / cm and 1000μS / cm, the pH is between 5.0 and 8.6, and the cone index is 1000kN / m 2 The method for producing green soil, wherein the soil modifier is added to the soil so that the soil concentration is less than 100%. [7] The soil conditioner is applied to the entire soil at a rate of 10 kg / m 3 More than 20kg / m 3 The following is added to the green soil described in [6]. [8] The green soil according to [6] or [7], wherein the electrical conductivity is 600 μS / cm or more and 800 μS / cm or less. [9] The green soil according to any one of [6] to [8], wherein the pH is 5.0 or more and 7.5 or less.

[10] The cone index is 800 kN / m 2 The green soil according to any one of [6] to [9], wherein the soil has a density of less than 10 ... [Example]

[0073] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0074] <Soil> 233 parts by mass of No. 7 silica sand (Nippon Kogyo Co., Ltd.) was added to 100 parts by mass of powdered clay (Kanto Kasei Co., Ltd., product name: Tochiklay), and mixed while adding water to make the moisture content 25%, resulting in a cone index of 200 kN / m 2 The soil was prepared as follows.

[0075] <Soil conditioner> 1.Materials used ·Dihydrate gypsum: Regenerated dihydrate gypsum (manufactured by Chuo Kankyo Kaihatsu Co., Ltd.) Alumina cement Water absorbent: Anionic polyacrylamide polymer material (viscosity: 700 Pa·s, dissociation group: carboxyl group)

[0076] The above viscosity is the viscosity of a mixed liquid in which the water-absorbing agent is 0.25% by mass with respect to the total amount of the mixed liquid obtained by mixing the water-absorbing agent and water, and was measured using a B-type rotational viscometer (product name: B-type viscometer BL2, manufactured by Toki Sangyo Co., Ltd.) based on JIS K 7117-1:1999 "Plastics - Liquid, emulsion or dispersion resins - Measurement method of apparent viscosity using a Brookfield rotational viscometer." Specifically, the above viscosity was measured by the method shown below.

[0077] First, 1.25g of water-absorbing agent was added to a 1000mL beaker containing 498.75g of water, and the mixture was stirred at 1000rpm with a propeller mixer for 1 hour to obtain a mixed solution. The resulting mixed solution was transferred to a 500mL beaker and placed in the above-mentioned viscometer. The rotating rotor (No. 2 rotor) was immersed in the mixed solution, and the rotation speed was set to 30 revolutions per minute to measure. The reading was recorded, and the viscosity (mP·s) was calculated from the average of two measurements according to a conversion table.

[0078] 2. Preparation of soil conditioner A soil conditioner used to prepare green soil was obtained by mixing 100 parts by mass of gypsum dihydrate with 18.3 parts by mass of alumina cement and 3.7 parts by mass of a water absorbent.

[0079] <Green soil> Example 1 17.9 g of soil conditioner was added to 1.5 L of soil, and the mixture was stirred and mixed for 90 seconds using a soil mixer. After scraping off the soil and soil conditioner adhering to the soil mixer, the mixture was stirred and mixed again for 90 seconds to obtain the green soil of Example 1. The resulting green soil was poured into a φ10 x 12.7 cm PVC formwork in accordance with JIS A 1210:2009 "Test method for soil compaction by ramming," covered with plastic wrap, and cured in a thermostatic chamber at 20°C for 7 days. The resulting cured green soil was crushed and passed through a 2 cm sieve. The green soil that passed through the sieve was used in the vegetation test described below.

[0080] (Comparative Example 1) The green soil of Comparative Example 1 was obtained in the same manner as in Example 1, except that 120.8 g of hemihydrate gypsum (manufactured by Kanto Chemical Co., Ltd.) was used instead of the soil modifier.

[0081] (Comparative Example 2) The green soil of Comparative Example 2 was obtained in the same manner as in Example 1, except that 7.6 g of blast furnace cement type B (manufactured by Sumitomo Osaka Cement Co., Ltd.) was used instead of the soil modifier.

[0082] The electrical conductivity, pH, and corn index of the green soils of Example 1 and Comparative Examples 1 and 2 were measured using the green soils after aging by the methods described below.

[0083] <Electrical conductivity (unit: μS / cm)> Electrical conductivity was measured in accordance with JIS K 0130:2008 "General rules for measuring electrical conductivity." Specifically, a suspension of the aged green soil was prepared by mixing distilled water in a ratio of 1:5 and allowed to stand for 30 minutes. After 30 minutes, the supernatant of the suspension was measured for electrical conductivity at 20±2°C. The electrical conductivity was measured using a portable electrical conductivity meter (Horiba, Ltd. D-210C, electrode used: glass electrode; Horiba, Ltd. 3552-10D). The measurement results are shown in Table 2.

[0084] <ph> The pH was measured in accordance with JGS 0211-2009, "Test Method for pH of Soil Suspension." Specifically, a suspension was prepared by adding 71.2 g of distilled water to 18.8 g of aged green soil and stirring, and then allowed to stand for 30 minutes. After 30 minutes, the electrical conductivity of the supernatant of the suspension was measured. The pH was measured using a portable pH meter (Horiba, Ltd. D-72, electrode used: glass electrode; Horiba, Ltd. 9615S-10D). The measurement results are shown in Table 2.

[0085] <Cone index (unit: kN / m 2 )> In accordance with JIS A 1228:2009 "Cone index test method for compacted soil," a cone penetration test was conducted on the green soil after curing to measure the cone index. The measurement results are shown in Table 2.

[0086] <Vegetation test> The vegetation test was conducted according to the method described in "Methods and Explanations for Cultivation Tests Regarding Harm to Plants (2017)" (Independent Administrative Institution, Agriculture, Forestry and Fisheries Agricultural Materials Inspection Center). Specifically, first, a test container (a pot (Neubauer pot) with an inner diameter of 11.3 cm and a height of 6.5 cm) was filled with water calculated from the following formula (I) so that the amount was 60% of the maximum water capacity described below. 500 mL of green soil that had passed through a sieve was measured using a measuring cylinder and filled into the test container. A total of two test containers filled with the green soil were prepared. The dripping amount, air-dried soil moisture, water content in 100 g of air-dried soil, volume weight of 500 mL of green soil that had passed through a sieve, maximum water capacity, and amount of water added to the test container are shown in Table 1.

[0087]

number

[0088] The maximum water capacity D was determined by the following method. First, a grooved funnel with a diameter of approximately 110 mm was placed on a 100 mL graduated cylinder, and a water-moistened filter paper of type 3 or type 2 with a diameter of approximately 185 mm was placed on the funnel. 100 g of sieved green soil was placed into the filter paper, and 100 mL of water was gently poured onto the surface of the green soil to drip the filtrate. After confirming that the dripping of the filtrate had finished, the maximum water capacity D was calculated using the amount of dripping obtained from the following formula (II).

[0089]

number

[0090] The moisture content B of air-dried soil is the moisture content B' in 100 g of air-dried soil expressed as a percentage.

[0091] The moisture content B' in 100 g of air-dried soil is the difference between the mass (g) of the dried green soil (air-dried soil) obtained by drying the green soil that has passed through a sieve using a dryer and the mass (g) of the green soil that has passed through a sieve before drying.

[0092] Next, 20 holes were drilled at equal intervals in the green soil filled in each test container, and one komatsuna seed was placed in each hole, resulting in a total of 40 komatsuna seeds being sown. The test containers containing the komatsuna seeds were then placed in an outdoor greenhouse, and the komatsuna were grown for 7 days at a temperature of 20±5°C. Seven days after the start of the test, the test containers containing the komatsuna seeds were observed, and the number of komatsuna plants that germinated was counted. The germination rate of the komatsuna was calculated using the following formula (III) and evaluated as follows. The germination rate and evaluation results are shown in Table 2. Germination rate (%) = number of germinated Komatsuna / number of Komatsuna seeds sown x 100 (III) ·evaluation ○: Germination rate 97.5% or more ×: Germination rate less than 97.5%

[0093] [Table 1]

[0094] [Table 2]

[0095] As can be seen from Table 2, the verdant soil of Example 1, which satisfied all of the requirements of the present invention, had a higher germination rate than the verdant soils of Comparative Examples 1 to 5, which did not satisfy the requirements of the present invention. From this, it can be said that the verdant soil of the present invention exhibits hardness suitable for use as improved soil, while also being excellent for plant growth.< / ph>

Claims

1. A soil conditioner including gypsum dihydrate, alumina cement, and a water absorbent, and soil; The electrical conductivity is 500 μS / cm or more and 1000 μS / cm or less, the pH is 5.0 or more and 8.6 or less, and the cone index is 1000 kN / m ２ Less than 100% green soil.

2. The soil improver is 10 kg / m with respect to the entire soil. ３ More than 20kg / m ３ The green soil of claim 1, comprising:

3. The green soil according to claim 1 or 2, wherein the electrical conductivity is 600 μS / cm or more and 800 μS / cm or less.

4. The green soil according to claim 1 or 2, wherein the pH is 5.0 or more and 7.5 or less.

5. The cone index is 800 kN / m ２ The green soil according to claim 1 or 2, wherein the pore size is less than 100 nm.

6. A method for producing green soil by adding a soil improver containing gypsum, alumina cement, and a water absorbent to soil, The electrical conductivity of the green soil is 500 μS / cm or more and 1000 μS / cm or less, the pH is 5.0 or more and 8.6 or less, and the cone index is 1000 kN / m ２ The method for producing green soil, wherein the soil modifier is added to the soil so that the soil concentration is less than 100%.

7. The soil improver is applied to the entire soil at a rate of 10 kg / m ３ More than 20kg / m ３ The method for producing green soil according to claim 6, wherein the following is added:

8. The method for producing green soil according to claim 6 or 7, wherein the electrical conductivity is 600 μS / cm or more and 800 μS / cm or less.

9. The method for producing green soil according to claim 6 or 7, wherein the pH is 5.0 or more and 7.5 or less.

10. The cone index is 800 kN / m ２ The method for producing green soil according to claim 6 or 7, wherein the total amount of water is less than 1000 kJ / kg.

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