Plant growing media and powders

Abstract

To provide a plant cultivation medium that has good separation from plant roots and can firmly maintain its shape as a growing medium. [Solution] The present invention relates to a growing medium for plants, comprising mother particles and particles having a plurality of protrusions on the surface of the mother particles, wherein the volume-average particle size of the particles is 0.50 mm or more and 5.00 mm or less.

Description

Technical Field

[0001] The present disclosure relates to a powder used as a growing medium for plants and the like, and a medium for plant cultivation.

Background Art

[0002] In recent years, due to abnormal weather and water shortages caused by global warming, conventional open-field cultivation has become difficult. Therefore, protected horticulture agriculture that enables stable planned production of agricultural crops has attracted attention. Among them, in particular, hydroponics cultivation, which does not use soil for cultivating crops, has no continuous cropping obstacles, is easy to control the cultivation environment and nutrient water management, is easy to automate, and has high cleanliness of harvested products and fertilizer efficiency, is increasing. Conventionally, as a solid medium for hydroponics cultivation, media such as urethane sponges and rock wool have been used. When removing plants cultivated from the medium, the roots are entangled with the medium and cannot be easily separated, and the roots remain in the medium, making it difficult to reuse, resulting in high running costs and problems in its disposal.

[0003] Therefore, in Patent Document 1, the use of a capillary water absorption carrier made of a compression-molded polypropylene synthetic fiber resin that does not allow plant roots to pass through is proposed. However, although this capillary water absorption carrier is easy to separate from plant roots, due to the weak interaction between the carriers, when cultivation is carried out, the shape as a medium cannot be maintained, and the plants may tilt or collapse.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] This disclosure aims to solve the above-mentioned problems. Specifically, it aims to provide a powder that can be used as a growing medium for plants, etc., that has good separability from plant roots and can firmly maintain its shape as a growing medium. It also aims to provide a growing medium for plants containing such a powder. [Means for solving the problem]

[0006] The inventors of the present invention conducted intensive studies to solve the above problems and found that the above problems can be solved by a plant cultivation medium containing mother particles and particles having multiple protrusions on the surface of the mother particles. This disclosure relates to a growing medium for plants, comprising a mother particle and a plurality of particles having a plurality of protrusions on the surface of the mother particle, wherein the volume-average particle size of the particles is 0.50 mm or more and 5.00 mm or less. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a powder that can be used as a growing medium for plants, etc., that has good separability from plant roots and can firmly maintain its shape as a growing medium, and a growing medium for plants containing the powder. [Modes for carrying out the invention]

[0008] The embodiments of this disclosure will be described in more detail below, but the invention is not limited to these embodiments. Unless otherwise specified, the notations "XX or greater and YY or less" or "XX to YY" that represent a numerical range mean a numerical range that includes the lower and upper limits.

[0009] The plant cultivation medium of this disclosure contains particles having multiple protrusions on their surface. The presence of multiple protrusions increases the frictional force between particles, making it easier to maintain the shape of the medium, thereby enabling firm support for the growing body of a plant.

[0010] Furthermore, if the volume-average particle size of the particles is less than 0.50 mm, the gaps between the particles become smaller, resulting in insufficient aeration and poor separation from plant roots. If the volume-average particle size is greater than 5.00 mm, the gaps between particles become larger, reducing capillary action, which can lead to insufficient water retention and instability of the culture medium. Therefore, the volume-average particle size of the particles is preferably 0.50 mm or more and 5.00 mm or less, more preferably 0.50 mm or more and 2.00 mm or less, and more preferably 1.00 mm or more and 1.50 mm or less.

[0011] As described above, we believe that a powder containing mother particles and particles having multiple protrusions on the surface of the mother particles, with a volume-average particle size of 0.50 mm to 5.00 mm, allows for good separation from plant roots and maintains its shape as a culture medium.

[0012] The individual components that make up the powder and their manufacturing methods will be explained in more detail. <Mother particle> As the material for the mother particles of this disclosure, either organic or inorganic materials can be used as long as they do not dissolve in water, but from the viewpoint of ease of manufacture, thermoplastic resins are preferred. Examples of thermoplastic resins include polyvinyl acetate, polystyrene, polyethylene, polypropylene, polyacrylic acid, polymethacrylic acid, polyester, polyamide, polyethylene terephthalate, polylactic acid, polyurethane, etc., which can be used individually or in combination of two or more. When using two or more resins in combination, they can be used as a mixture of different resins, a melt-blended mixture of different resins, or a copolymer. There are no particular limitations on the method for producing the mother particles of this disclosure, but for example, the mother particles can be obtained by crushing a lump of the mother particle material, melting and extruding it, then cooling and cutting it.

[0013] <Materials for raised parts> As the material of the convex portion of the present disclosure, any organic or inorganic substance can be used as long as it does not dissolve in water. Also, either a hydrophilic material or a hydrophobic material may be used, but from the viewpoints of water retention and support of the plant body, a hydrophilic material is more preferable. When it is a hydrophilic material, a liquid cross-linking force acts between the particles, enabling the support to be strengthened and the water retention to be improved.

[0014] The volume average particle size of the convex portion material is preferably 0.10 mm or more and 0.80 mm or less. By the volume average particle size of the convex portion material being within the above range, it is possible to achieve both air permeability and water retention. More preferably, a porous body with an average pore diameter of 10.00 μm or less is preferred. By being a porous body, the water retention is improved. Also, since the separability from plant roots is improved when the average pore diameter is 10.00 μm or less, it is preferred.

[0015] Examples of the material of the convex portion of the present disclosure include hydrophobic materials such as polyester, polystyrene, polyethylene, polypropylene, polylactic acid, polyamide, polyurethane, polycarbonate, silicone resin, etc., cellulose, cellulose acetate, carboxymethyl cellulose, polyacrylic acid, polyvinyl alcohol, activated carbon, smoked charcoal, silica, soda glass, vermiculite, perlite, zeolite, radiolite, etc. Among them, from the viewpoints of cost and availability, it is preferably cellulose, smoked charcoal, vermiculite, perlite, zeolite, or radiolite.

[0016] <Method for producing powder> Regarding the formation of the convex portions present on the surface of the mother particles, there are no particular restrictions. For example, the above mother particles and the material for forming the convex portions are mixed in a container and heated to fuse and fix the convex portions on the surface of the mother particles. After cooling, the excess convex members are sieved to produce the powder of the present disclosure.

[0017] <Powder having the particles of the present disclosure> The powder containing the particles of the present disclosure preferably has an average value of the shape factor SF2 of 180 or more and 300 or less. When SF2 is within this range, it is easy to maintain the shape as a medium, and the separability from plant roots is also improved。 Furthermore, the average number of protrusions per particle (N , , , ,

[0019] , ) of the powder containing the particles of the present disclosure is preferably 3.00 or more. When the average number of protrusions (N P ) is 3.00 or more, it is easy to achieve both air permeability and water retention。 The maximum average diameter of the protrusions of the powder containing the particles of the present disclosure is preferably 0.10 mm or more and 0.80 mm or less. More preferably, it is 0.2 mm or more and 0.7 mm or less. By having the volume average particle diameter of the protrusion material within the above range, it is possible to achieve both air permeability and water retention。

[0018] <Plant cultivation medium> The plant cultivation medium of the present disclosure contains the powder of the present disclosure. By containing the powder of the present disclosure, the water retention, air permeability, supportability of the plant body, and separability from plant roots are improved。 The plant cultivation medium of the present disclosure may contain only the powder of the present disclosure, or may contain any components other than the powder of the present disclosure. The optional components are not particularly limited as long as they are natural soil components and known components used in artificial media. Examples include rock wool, perlite, peat moss, wood powder, sawdust, leaf mold, chitin, chitosan, agar, and gellan gum。 When the plant cultivation medium of the present disclosure contains optional components, the content of the powder of the present disclosure is, for example, 50% by mass or more, preferably 90% by mass or more, based on the total mass of the solid components contained in the medium. Note that the solid components mean components other than the water contained in the medium。 The plant body cultivated using the plant cultivation medium of the present disclosure is not particularly limited and can be applied to any plants such as herbs, flowers, and woody plants。

[0019] Hereinafter, the measurement method of the powder containing the particles of the present disclosure will be described。 <Calculation method of volume average particle diameter and average of shape factor SF2> The volume-average particle size of the powder in this disclosure is measured using an optical microscope with appropriately adjusted magnification. From the obtained image, 100 particles are arbitrarily selected, and their perimeter and area are calculated using an image analysis device (Nireco Corporation, LUZEX® AP). The equivalent diameter of a circle is calculated from the obtained area, and the volume-average particle size is calculated by calculation. The shape factor SF2 is calculated using the following formula, and its average value is taken as the average of the shape factor SF2. SF² = (perimeter of the particle) 2 / (Particle area) × 1 / (4 × π) × 100

[0020] <Analysis of the protruding part> For the analysis of the protrusions of the powder described herein, the particles were embedded in a photocurable resin D800 (JEOL Ltd.), and then a 100 nm thick cross-section was prepared using an ultrasonic ultramicrotome (Leica, UC7) at a cutting speed of 1 mm / s. The obtained cross-section was observed using the STEM mode of a TEM (JEOL, JEM2800) to confirm whether or not the protrusions were porous. In the case of a porous material, the diameter of the pores in the porous material is measured from secondary electron images obtained by scanning electron microscopy (SEM) observation of the particle surface. (Method for obtaining secondary electron images of particles) Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Acceleration voltage: 1.0kV WD: 2.5~5.5mm (adjust as needed) Aperture Size: 30.0 μm Detection signal: SE2 (secondary electrons) Observation magnification: 500 to 50,000 times (adjust as needed) Resolution: 1024 x 768 pixels Pretreatment: Particles are scattered onto carbon tape (Pt deposition is not performed). From the obtained secondary electron images, the longest diameter of 100 pores in the porous material on the particle surface is measured, and the arithmetic mean is taken as the average diameter of the pores.

[0021] <Number of protrusions (N) P How to calculate the average of ) Number of protrusions (N) P The method for calculating the average of the protrusions (N) is as follows: First, cross-sectional images are obtained from an X-ray CT scanner. From the obtained cross-sectional images, 100 particles are arbitrarily selected, and the number of protruding parts of those particles is calculated using an image analysis device (Nireco Corporation, LUZEX® AP). The number of protruding parts is calculated using the measurement parameter "Number of protruding parts (NO PROJ)" in LUZEX® AP, and the average value is used to calculate the number of protrusions (N) P ) is the average.

[0022] <Maximum average diameter of the protrusion> The maximum average diameter of the protrusions is measured using a digital microscope (KH-8700, manufactured by Hirox Co., Ltd.). Particles with protrusions were observed at 100 random locations, the maximum diameter of each protrusion was measured, and the maximum average diameter was calculated from the average value. [Examples]

[0023] Examples of the powder used as a growing medium for plants and other organisms according to this disclosure, and growing media for plants, will be described. <Example of manufacturing parent particle 1> • Bisphenol A ethylene oxide (2.2 molar adduct): 50.0 molar parts • Bisphenol A propylene oxide (2.2 molar adduct): 50.0 molar parts Terephthalic acid: 90.0 molar parts • Trimellitus anhydride: 10.0 moles 100 parts by mass of the monomer constituting the above polyester unit was mixed with 500 ppm of titanium tetrabutoxide in a 5-liter autoclave. A reflux condenser, moisture separator, N2 gas introduction tube, thermometer, and stirring device were attached to the autoclave, and the condensation polymerization reaction was carried out at 230°C while introducing N2 gas into the autoclave. The reaction time was adjusted to achieve the desired softening point. After the reaction was complete, the material was removed from the container, cooled, pulverized, and sieved to obtain mother particle 1 with a volume-average particle size of 1.02 mm. Mother particle 1 had an acid value of 30, a softening point Tm of 130°C, and a glass transition temperature Tg of 57°C.

[0024] <Example of manufacturing mother particles 2-8> In the example of preparing parent particle 1, parent particles 2 to 8 were obtained in the same manner, except that the volume-average particle size was changed as shown in Table 1.

[0025] [Table 1]

[0026] <Example of manufacturing of protruding material 1> The convex material 1 was obtained by sieving commercially available Viscopearl PD-3002 (manufactured by Rengo Co., Ltd.). The physical properties of the obtained convex material 1 are shown in Table 2.

[0027] <Manufacturing examples of convex materials 2 and 10> Rice husk charcoal (manufactured by Togawa Heiwa Farm Co., Ltd.) was crushed in a coffee mill and sieved to obtain convex materials 2 and 10. The physical properties of the obtained convex materials 2 and 10 are shown in Table 2.

[0028] <Manufacturing examples of protruding materials 3-7> In the example of manufacturing material 2 for the protruding part, materials 3 to 7 were obtained in the same manner except that the rice husk charcoal was changed as shown in Table 2. The physical properties of the obtained materials 3 to 7 are shown in Table 2.

[0029] <Manufacturing examples of convex materials 8 and 11> In the example of manufacturing material 1 for the protrusions, materials 8 and 11 were obtained in the same manner except that Viscoparl PD-3002 was changed as shown in Table 2. The physical properties of the obtained materials 8 and 11 are shown in Table 2.

[0030] <Example of manufacturing of the protruding material 9> 0.62 parts by mass of sodium phosphate was added to 180 parts by mass of deionized water and dissolved and stirred. After heating to 65°C, a solution of 0.24 parts by mass of sodium chloride dissolved in 20 parts by mass of deionized water was added all at once. 0.20 parts by mass of 1% sodium dodecylbenzenesulfonate was added to the resulting mixture to prepare an aqueous medium containing the dispersion. To the above aqueous medium, 100.00 parts by mass of styrene, 1.00 part by mass of divinylbenzene, and 0.35 parts by mass of t-butyl peroxypivalate (25% toluene solution) were added, and then the mixture was dissolved and dispersed under stirring to form a suspension. Next, the reaction was carried out at 70°C for 5 hours under stirring at 200 rpm. After the polymerization reaction was complete, the temperature inside the container was raised to 100°C and distillation was performed for 4 hours. After the distillation was complete, the contents were cooled to 25°C and removed from the container, then acid washed, dehydrated, dried, and classified to obtain the convex material 9. The physical properties of the obtained convex material 9 are shown in Table 2.

[0031] [Table 2]

[0032] <Example of Particle 1 Production> To obtain the above-mentioned mother particle 1, 70.0 parts by mass was mixed with 210.0 parts by mass of convex material 1 (Viscopearl PD-3002 (manufactured by Rengo Co., Ltd.)) in a container and heated at 100°C for 5 hours to fix the Viscopearl PD-3002 to the surface of the mother particle 1. Subsequently, the unfixed Viscopearl PD-3002 was sieved through a 1.0 mm mesh to obtain particle 1. The physical properties of particle 1 are shown in Table 3.

[0033] <Manufacturing examples for particles 2-20 and 22-23> In the production of particle 1, particles 2-20 and 22-23 were obtained in the same manner, except that the mother particle 1 and Viscopar PD-3002 were changed as shown in Table 3. The physical properties of particles 2-20 and 22-23 are shown in Table 3.

[0034] <Example of Particle 21 Production> 70.0 parts by mass of mother particle 1 was mixed with 1000 parts by mass of sodium chloride (manufactured by Kishida Chemical Co., Ltd.) in a container, and heated at 100°C for 5 hours. After that, the unadhered sodium chloride was sieved through a 1.0 mm mesh, the adhered sodium chloride was washed with water, and the mixture was dried to obtain particle 21 with multiple protrusions on its surface. The physical properties of the obtained particle 21 are shown in Table 3.

[0035] <Example of Particle 24 Production> In the same manner as in the production example of mother particle 1, after the condensation polymerization reaction was completed, the material was cooled and pulverized, and then fed from the metering feeder into the hopper using a twin-screw extruder equipped with a hopper and a metering feeder, where it was melt-kneaded. At this time, the cylinder temperature of the extruder was set to 100°C. The molten mixture was extruded in a string-like form from a strand die, cooled in a cooling water bath, and then cut with a pelletizer to obtain particles 24 with a volume-average particle size of 1.50 mm. The physical properties of the obtained particles 24 are shown in Table 3.

[0036] [Table 3] The evaluation method performed on the obtained particles is described below. The evaluation results are shown in Table 4.

[0037] <Water retention test> 100 mL of particles were weighed and immersed in tap water for 24 hours to reach a saturated water content. The particles were then packed into a 25 mm diameter separator with a 100-mesh stainless steel screen, left for 24 hours, and gravity water was allowed to flow through. The mass of the obtained sample was measured (denoted as wet mass a), and subsequently dried under reduced pressure at 40°C for 24 hours. The mass before and after drying was measured (denoted as dry mass b). From the obtained masses of a and b, the dry-mass-based moisture content (ab) / b × 100 (%) was calculated and used as an indicator of water retention. A: Moisture content of 60% or more B: Moisture content is 40% or more but less than 60% C: Moisture content is between 15% and less than 40% D: Moisture content is 5% or more but less than 15% E: Moisture content less than 5%

[0038] <Porosity measurement> Similar to the water retention test, after allowing gravity-fed water to flow down, a 100 mL sample was collected in a cylindrical container while maintaining its shape as much as possible, and the porosity was measured using a digital volume measurement device (DIK-1150, manufactured by Daiki Rika Kogyo Co., Ltd.). A: Void ratio of 45% or more B: Void ratio is 35% or more but less than 45% C: Void ratio is 30% or more but less than 35% D: Void ratio is 20% or more but less than 30% E: Void ratio less than 20% If the void ratio is 30% or higher, it can be considered to have good ventilation.

[0039] <Shape retention test> Similar to the water retention test, after allowing gravity-fed water to flow down, particles were packed into a 100 mL sample cylinder to form the culture medium. After lightly pressing down on the top surface, the container was inverted and placed on a flat tray. Then the container was lifted and the culture medium was removed. The shape of the culture medium was then visually inspected immediately after removal and after one hour to evaluate whether the shape of the culture medium was maintained. A: The container maintains its shape both immediately after removal and one hour later. B: The container maintains its shape immediately after removal, but after one hour, part of its shape has collapsed. C: The container maintains its shape immediately after removal, but does not maintain its shape after one hour. D: Immediately after removal, the container's shape was partially distorted, and after one hour, the container no longer maintained its shape. E: The container does not maintain its shape immediately after being removed. The results suggest that if the container maintains its shape immediately after removal, it has a high ability to maintain its shape and can adequately support the plant.

[0040] <Separation Test> After setting a non-woven fabric under the seedling panel of the Green Farm Cube hydroponic cultivation kit (manufactured by Ewing Co., Ltd.), water-soaked particles were filled in as a growing medium for plants. Frilly lettuce seeds were sown on top, stored in the dark for 3 days to germinate, and then cultivated for 14 days at a temperature of 22-23°C and humidity of 40-50% with a cycle of 16 hours of light and 8 hours of darkness. Hyponex (registered trademark: liquid fertilizer manufactured by Hyponex Japan Co., Ltd.) was used as liquid fertilizer, diluted 500 times. After cultivation, the growing medium was removed from the seedling bed panel, gently shaken in the air, and then the frilly lettuce was shaken in a container of water to check whether the growing medium could be separated from the roots. A: After gently shaking it in the air, the separation was achieved by shaking it several times in water. B: After gently shaking it in the air, the separation was achieved by shaking it ten times in water. C: After gently shaking it in the air, separation was achieved by shaking it dozens of times in water. D: After gently shaking in the air and then shaking dozens of times in water, the separation was incomplete. Separation was achieved by letting it stand for 10 minutes and then shaking it again. E: After gently shaking in the air and then shaking dozens of times in water, the separation was incomplete, and even after letting it stand for 10 minutes and then shaking, separation was not possible.

[0041] [Examples 1-21] In Examples 1 to 21, the above evaluation was performed using particles 1 to 21, respectively. The evaluation results are shown in Table 4.

[0042] [Comparative Examples 1-3] In Comparative Examples 1 to 3, the above evaluation was performed using particles 22 to 24, respectively. The evaluation results are shown in Table 4.

[0043] [Table 4]

[0044] Examples 1 to 21 yielded favorable results in all evaluation items. On the other hand, Comparative Examples 1 to 3 showed inferior results compared to the examples in at least one of the above evaluation items. Based on the above results, this disclosure provides a powder that can be used as a growing medium for plants, etc., that has good separability from plant roots and can firmly maintain its shape as a growing medium, and a growing medium for plants containing the powder.

[0045] This embodiment includes the following configuration. (Composition 1) The particle includes a parent particle and a particle having a plurality of protrusions on the surface of the parent particle, The volume-average particle size of the aforementioned particles is 0.50 mm or more and 5.00 mm or less. Growing medium for plants. (Configuration 2) When the aforementioned plant cultivation medium was measured with an image analysis device, The average value of the shape factor SF2 of the aforementioned particles is between 180 and 300. The number of protrusions per particle (N P The average of ) is 3.00 or higher. The plant growing medium described in Composition 1. (Composition 3) The plant growing medium according to configuration 1 or 2, wherein the aforementioned protrusions are formed of a hydrophilic material. (Composition 4) The aforementioned protrusion is made of a porous material, The average diameter of the pores in the porous material is 10.00 μm or less. A growing medium for plants as described in any one of items 1 to 3. (Composition 5) A plant growing medium according to any one of the four items, wherein the protrusions are formed of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite. (Composition 6) The particle includes a parent particle and a particle having a plurality of protrusions on the surface of the parent particle, The volume-average particle size of the aforementioned particles is 0.50 mm or more and 5.00 mm or less. powder. (Composition 7) When the aforementioned powder is measured with an image analysis device, The average value of the shape factor SF2 of the aforementioned particles is between 180 and 300. The number of protrusions per particle (N P The average of ) is 3.00 or higher. The powder described in composition 6. (Composition 8) The powder according to configuration 6 or 7, wherein the convex portion is formed of a hydrophilic material. (Composition 9) The aforementioned protrusion is made of a porous material, The average diameter of the pores in the porous material is 10.00 μm or less. The powder described in any one of items 6 to 8. (Composition 10) The powder according to any one of claims 6 to 9, wherein the protrusions are formed of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite.

Claims

1. The particle includes a parent particle and a particle having a plurality of protrusions on the surface of the parent particle, The volume-average particle size of the aforementioned particles is 0.50 mm or more and 5.00 mm or less. Growing medium for plants.

2. When the aforementioned plant cultivation medium was measured with an image analysis device, The average value of the shape coefficient SF2 of the aforementioned particles is 180 or more and 300 or less. The number of protrusions per particle (N Ｐ The average of ) is 3.00 or higher. The plant growing medium according to claim 1.

3. The plant growing medium according to claim 1 or 2, wherein the convex portion is formed of a hydrophilic material.

4. The aforementioned protrusion is made of a porous material, The average diameter of the pores in the porous material is 10.00 μm or less. A growing medium for plants according to claim 1 or 2.

5. The plant growing medium according to claim 1 or 2, wherein the protrusions are formed of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite.

6. The particle includes a parent particle and a particle having a plurality of protrusions on the surface of the parent particle, The volume-average particle size of the aforementioned particles is 0.50 mm or more and 5.00 mm or less. powder.

7. When the aforementioned powder is measured with an image analysis device, The average value of the shape coefficient SF2 of the aforementioned particles is 180 or more and 300 or less. The number of protrusions per particle (N Ｐ The average of ) is 3.00 or higher. The powder according to claim 6.

8. The powder according to claim 6 or 7, wherein the convex portion is formed of a hydrophilic material.

9. The aforementioned protrusion is made of a porous material, The average diameter of the pores in the porous material is 10.00 μm or less. The powder according to claim 6 or 7.

10. The powder according to claim 6 or 7, wherein the protrusions are formed of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite.

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