Plant cultivation methods, plant cultivation kits, methods for producing plant seedlings, and rooting promoters for plants.

Abstract

To enable plants to be cultivated properly in over a long period of time in hydroculture, while reducing the workload required during the cultivation.SOLUTION: A method for cultivating plants by hydroculture involves culturing a nitrification bacteria-containing nutritious solution, which incorporates an organic nitrogen source containing organic nitrogen and a microbial source containing nitrification bacteria, to prepare a nitrification culture solution. Prior to starting the cultivation of plants by hydroculture, pre-culture is performed with a solution containing the nitrification culture solution, which serves as a cultivation liquid for the plants. Following the pre-culture, the cultivation liquid is replaced with a solution free of the nitrification culture solution.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a method for cultivating plants, a plant cultivation kit, a method for producing plant seedlings, and a rooting promoter for plants. [Background technology]

[0002] Conventionally, various methods have been known for cultivating plants. Generally, when cultivating plants using soil, inorganic nutrients are produced through the action of bacteria such as nitrifying bacteria present in the soil, using organic matter in the soil and organic fertilizers added to the soil to carry out ammonia conversion and nitrification. In addition, as a cultivation method that does not use soil, methods using cultivation solutions or microbial carriers containing microorganisms including nitrifying bacteria are known (see, for example, Patent Documents 1 and 2, and Non-Patent Documents 1 and 2). Thus, even in methods using cultivation solutions or microbial carriers containing microorganisms, it is possible to continuously produce inorganic nutrients from organic fertilizers, etc., through the action of microorganisms, just as in the case of using soil, and to grow various plants, including vegetables, well. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 6156821 [Patent Document 2] Patent No. 5392800 [Non-patent literature]

[0004] [Non-Patent Document 1] Shinohara, "The Birth of Designer Soil Technology," Chemistry and Biology, 59 (3), 144-150, 2021. [Non-Patent Document 2] Makoto Shinohara et al., "Microbial mineralization of organic nitrogen into nitrate to allow the use of organic fertilizer in hydroponics", Soil Science and Plant Nutrition, 57(2), 2011, [online] [Retrieved January 13, 2023], Internet<https: / / www.tandfonline.com / doi / full / 10.1080 / 00380768.2011.554223> [Overview of the project] [Problems that the invention aims to solve]

[0005] In addition to the methods using soil or soil-like media (hereinafter also referred to as "soil, etc.") described above, there is a cultivation method known as hydroculture, which involves planting plants in a porous material called hydroballs. Similar to hydroponics, this method involves growing plants by providing water and liquid fertilizer without using organic fertilizers, etc. Because it does not use soil, it is possible to cultivate plants hygienically by suppressing the generation of insects and odors, and is particularly suitable for indoor plant cultivation. However, in this method that does not use soil, the growth conditions are limited because nitrification using organic fertilizers, etc. cannot be utilized, and nutrient deficiencies are likely to occur. In order to grow plants in good condition for a long period of time, complicated tasks such as controlling the amount and timing of supplemental fertilization with inorganic fertilizers may be necessary. For this reason, there has been a desire for a technology that can cultivate plants well for a long period of time in hydroculture without soil, etc., while suppressing the need for complicated tasks during cultivation such as supplemental fertilization. Furthermore, there has been a desire for a technology that can provide such hydroculture more simply. [Means for solving the problem]

[0006] This disclosure can be implemented in the following forms: (1) According to one embodiment of the present disclosure, a method for cultivating plants by hydroculture is provided. This method for cultivating plants by hydroculture involves cultivating a nitrifying culture solution containing an organic nitrogen source containing organic nitrogen and a microbial source containing nitrifying bacteria to produce a nitrifying culture solution, performing pre-culture using a solution containing the nitrifying culture solution as the cultivation solution to be given to the plants when starting the cultivation of plants by hydroculture, and after the pre-culture, changing the cultivation solution to a solution that does not contain the nitrifying culture solution. According to this method of cultivating plants, by performing pre-culture using a nitrifying culture solution at the start of hydroponics, it becomes possible to cultivate plants successfully for a longer period while reducing the need for additional fertilization and other tasks during cultivation in the subsequent hydroponics. (2) In the above-described method of cultivating plants using hydroculture, artificial growing medium containing ion exchange resin nutrients may be used as the artificial growing medium for hydroculture. With such a configuration, it is possible to obtain a high effect of promoting good plant growth while suppressing the excessive administration of inorganic fertilizers. (3) In the above-described method of cultivating plants by hydroculture, a soil-containing nutrient solution may be prepared by culturing an organic nitrogen source containing organic nitrogen and at least one of bark compost and leaf mold, and the part of a plant body having a cut surface that includes the cut surface may be brought into contact with the soil-containing nutrient solution to obtain a plant seedling that has grown roots from the part including the cut surface, and the pre-culture may be performed using the obtained plant seedling. With this configuration, rooting of the plant body can be promoted by bringing the plant body into contact with the soil-containing nutrient solution, making it possible to produce rooted plant seedlings for use in the pre-culture described above more quickly and at a lower cost. (4) According to another embodiment of the present disclosure, a plant cultivation kit for hydroculture is provided. This plant cultivation kit for hydroculture comprises an artificial growing medium for use in hydroculture, plant seedlings for cultivation by hydroculture, an organic nitrogen source containing organic nitrogen, a microbial source containing nitrifying bacteria, and a nitrification culture solution obtained by culturing a nitrifying bacteria-containing nutrient solution. This type of plant cultivation kit makes it easy to implement the hydroculture method with pre-culture described above, and when using hydroculture, it reduces the need for intermediate tasks such as fertilizing, making it possible to cultivate plants well for a longer period of time. (5) According to yet another embodiment of the present disclosure, a method for producing a plant seedling is provided. This method for producing a plant seedling involves culturing a soil-containing nutrient solution comprising an organic nitrogen source containing organic nitrogen and at least one of bark compost and leaf mold to produce a soil culture solution, and bringing a portion of a plant body having a cut surface, including the cut surface, into contact with the soil culture solution to obtain a plant seedling that has grown roots from the portion including the cut surface. This method for producing plant seedlings promotes root development by bringing the plant body into contact with soil culture solution, making it possible to produce rooted plant seedlings more quickly and at a lower cost. (6) According to yet another embodiment of the present disclosure, a plant rooting stimulant is provided. This plant rooting stimulant comprises a soil culture solution obtained by culturing a soil-containing nutrient solution comprising an organic nitrogen source containing organic nitrogen and at least one of bark compost and leaf mold. With this form of plant rooting stimulant, rooting of the plant can be promoted by bringing the part of the plant containing the cut surface into contact with the rooting stimulant. This disclosure can be implemented in various forms other than those described above, for example, in the form of a method for producing plant seedlings for hydroponics, a method for processing plant seedlings to be used for hydroponics, or a method for rooting plants. [Brief explanation of the drawing]

[0007] [Figure 1] An explanatory diagram showing how to cultivate plants using hydroponics. [Figure 2] An explanatory diagram showing the method for preparing plant seedlings. [Figure 3A] An explanatory diagram showing the ion concentrations of each ion in the culture medium CM1-CM4 for D18. [Figure 3B]Explanatory drawing showing the pH of culture media CM1 to CM4 of D18. [Figure 4A] Explanatory drawing showing the ion concentrations of culture media CM1 to CM4 of D27. [Figure 4B] Explanatory drawing showing the pH of culture media CM1 to CM4 of D27. [Figure 5] Explanatory drawing showing the state of change of ion concentrations in culture media CM1 to CM4. [Figure 6] Explanatory drawing showing the results of photographing aromaticus seedlings over time. [Figure 7A] Explanatory drawing showing the results of measuring the above-ground fresh weight after approximately 6 months. [Figure 7B] Explanatory drawing showing the results of measuring the number of branches after approximately 6 months. [Figure 7C] Explanatory drawing showing the results of calculating the total length of each branch after approximately 6 months. [Figure 7D] Explanatory drawing showing the results of measuring the number of large green leaves after approximately 6 months. [Figure 7E] Explanatory drawing showing the results of determining the ratio of yellowed large leaves after approximately 6 months. [Figure 8] Explanatory drawing showing the state of D18 aromaticus seedlings on the 22nd day from the start of cultivation. [Figure 9A] Explanatory drawing showing the results of measuring the total length of the main roots on the 22nd day. [Figure 9B] Explanatory drawing showing the results of calculating the average length of the main roots on the 22nd day. [Figure 9C] Explanatory drawing showing the results of measuring the number of main roots on the 22nd day. [Figure 10] Explanatory drawing showing the state of D27 aromaticus seedlings on the 23rd day from the start of cultivation. [Figure 11A] Explanatory drawing showing the results of measuring the total length of the main roots on the 23rd day. [Figure 11B] Explanatory drawing showing the results of calculating the average length of the main roots on the 23rd day. [Figure 11C] Explanatory drawing showing the results of measuring the number of main roots on the 23rd day.

Modes for Carrying Out the Invention

[0008] A. First Embodiment: Figure 1 is an explanatory diagram showing a method of cultivating plants by hydroculture according to the first embodiment. In this embodiment of plant cultivation, when starting hydroculture, a nitrifying culture solution described later is used as the cultivation solution, and then the cultivation solution is changed to a solution that does not contain the nitrifying culture solution. Here, hydroculture is a type of plant cultivation method in which artificial growing medium is used instead of soil, and plant seedlings that have rooted in this artificial growing medium are planted and given water or water containing inorganic liquid fertilizer without using organic fertilizer. As the artificial growing medium, porous materials with aeration and water retention properties such as inorganic foam (hydroballs) made by firing clay at high temperature and expanding it, zeolite, and foamed resin can be used, and below, cultivation methods using such artificial growing medium will be collectively referred to as hydroculture.

[0009] When implementing the hydroculture method for cultivating plants according to this embodiment, first, plant seedlings to be cultivated by hydroculture are prepared (step T100). Various plants can be used as plants to be cultivated by hydroculture. Since hydroculture is a method suitable for indoor cultivation, aromatic plants and ornamental plants can be suitably used, for example. Because hydroculture does not use soil, it is a method that allows for hygienic cultivation by suppressing the generation of insects and odors, and the cultivation method of this embodiment, in particular, minimizes the need for special operations for cultivation other than providing a nutrient solution such as water at a relatively low frequency. For this reason, aromatic plants that can be placed in living spaces such as around a desk to enjoy the fragrance on a daily basis can be suitably used. There are no particular restrictions on aromatic plants, and various aromatic plants can be used, for example, Lamiaceae plants such as aromaticus, rosemary, lavender, lemon balm, mint, thyme, clary sage, and marjoram, Geraniaceae plants such as geraniums, and Myrtaceae plants such as tea tree, eucalyptus, and myrtle. In particular, aromatic plants, rosemary, rose geranium, and orange geranium are preferred because they are inherently resistant to insects and easy to cultivate hygienically.

[0010] In step T100 described above, it is sufficient to prepare rooted plant seedlings. Rooted plant seedlings can be prepared by using the cutting technique, a common method for propagating plants, by inserting a part of a plant with a cut surface, such as a cut stem or leaf tip, into vermiculite or water to induce rooting. Alternatively, the part of the plant with the cut surface may be brought into contact with a nitrified culture solution obtained by culturing a soil-containing nutrient solution to induce rooting. The method of inducing rooting by contact with a nitrified culture solution will be explained in detail later. Furthermore, rooted plant seedlings can also be prepared by removing the soil from plant seedlings that were previously planted in soil.

[0011] In addition to preparing the plant seedlings in step T100 described above, a nitrifying culture solution containing nitrifying bacteria is cultured to prepare a nitrifying culture solution to be used at the start of hydroculture (step T110). The nitrifying bacteria-containing nutrient solution is a liquid containing an organic nitrogen source containing organic nitrogen and a microbial source containing nitrifying bacteria. The organic nitrogen source containing organic nitrogen can contain various organic substances (organic nitrogen) that can be targeted by nitrification by nitrifying bacteria, i.e., various proteins, protein decomposition products, peptides, amino acids, etc. Specifically, for example, organic fertilizers and organic waste derived from various plants and animals can be used. The organic nitrogen source is not particularly limited, but since the nitrifying culture solution prepared using the organic nitrogen source will be used in hydroculture in a subsequent step, it is desirable to suppress the contamination of the cultivation solution given to plants in hydroculture with undesirable organic substances due to the use of an organic nitrogen source. For this reason, it is desirable that the organic nitrogen source be a liquid with a low content of organic substances that are not easily consumed in nitrification in step T110. Specifically, for example, corn steep liquor (CSL) can be suitably used. The amount of organic nitrogen source added to the nitrifying bacteria-containing nutrient solution can be appropriately set within a range where the amount of organic nitrogen remaining in the resulting nitrifying culture solution is within an acceptable limit, taking into consideration the type of microbial source used and the culture conditions such as the culture time of the nitrifying bacteria-containing nutrient solution.

[0012] The microbial source used in step T110 can be any type of material, as long as it contains nitrifying bacteria capable of nitrifying organic nitrogen sources. For example, soils such as leaf mold, peat moss, and potting soil, or composts such as bark compost can be used. When using soil or compost as the microbial source, the amount of microbial source added to the nitrifying bacteria-containing nutrient solution is preferably 3 g / L or more, and more preferably 5 g / L or more, from the viewpoint of obtaining sufficient nitrification. Furthermore, from the viewpoint of suppressing the contamination of the hydroculture cultivation solution with impurities due to the microbial source, it is preferably 50 g / L or less, and more preferably 20 g / L or less. A nitrifying bacteria-containing nutrient solution can be prepared by suspending the above-described organic nitrogen source and microbial source in water.

[0013] The cultivation of the nitrifying bacteria-containing nutrient solution in step T110 should be set under conditions that allow sufficient nitrification targeting organic nitrogen in the organic nitrogen source to proceed. For example, the nitrite ions (NO2) in the nitrified culture solution obtained by culturing the nitrifying bacteria-containing nutrient solution. - ) and nitrate ions (NO3 - The concentration of at least one of the following is ammonium ion (NH4 + The conditions should be such that the concentration of nitrite ions (NO2) in the nitrification culture medium becomes higher than the above. - ) and nitrate ions (NO3 - The concentration of at least one of the following is ammonium ion (NH4 + The concentration of ) is preferably twice or more, and more preferably three times or more. The specific incubation period is preferably 12 days or more, and more preferably 15 days or more. It is also preferably 30 days or less, and more preferably 25 days or less. The incubation temperature is preferably 18°C ​​or higher, more preferably 20°C or higher. It is also preferably 35°C or lower, and more preferably 30°C or lower. The incubation conditions can be aerobic, and it is desirable to perform aeration by means of an air pump or shaking.

[0014] After preparing the nitrification culture solution in step T110, hydroculture is started using this nitrification culture solution and the plant seedlings prepared in step T100 (step T120). That is, as a pre-culture when starting hydroculture, hydroculture is performed using a solution containing the nitrification culture solution described above as the growing solution to be given to the plants. As the growing solution, only the nitrification culture solution may be used, or a solution may be used in which other additives are added to the nitrification culture solution. As additives, inorganic liquid fertilizers (chemical fertilizers) or vitality enhancers containing vitamins and minerals can be used. In addition, root rot preventatives (for example, silicate clay such as Million A or zeolite) or ion exchange resin nutrients may be added to artificial growing media such as hydroballs. This can enhance the effect of cultivating plants well by improving plant growth and color retention. In particular, it is preferable to use ion exchange resin nutrients. Ion exchange resin nutrients are made by adding nutrients (inorganic fertilizers) to a gel-like ion exchange resin. In addition to its function as a fertilizer, ion exchange resin nutrients decompose waste products in the growing solution through ion exchange, and by suppressing fluctuations in the pH of the growing solution through ion exchange, they can suppress inhibition of plant growth and also function as a root rot preventative. While excessive use of the inorganic fertilizers contained in such ion exchange resin nutrients may actually hinder their effectiveness, combining pre-culture using nitrified culture solution with ion exchange resin nutrients makes it possible to achieve a high level of effectiveness in promoting good plant growth while suppressing excessive administration of inorganic fertilizers.

[0015] In step T120, the pre-culture using nitrified culture medium is preferably performed for at least two weeks, and more preferably for at least three weeks, in order to fully obtain the effects of pre-culture. Furthermore, from the viewpoint of minimizing the time until transition to the original hydroculture, it is preferably performed for eight weeks or less, and more preferably for five weeks or less.

[0016] After pre-culture using nitrifying culture solution in step T120, the hydroculture solution is changed to one that does not contain nitrifying culture solution, and hydroculture is performed (step T130). In other words, the plant transitions to general hydroculture. In step T120, water or water with the previously described additives added can be used as the cultivation solution for the plant seedlings. Alternatively, the previously described root rot inhibitors and ion exchange resin nutrients may be added to artificial growing media such as hydro balls.

[0017] According to the plant cultivation method of this embodiment, configured as described above, a solution containing nitrified nutrient solution is used as the cultivation solution to be given to the plants at the start of hydroculture, and then the cultivation solution is changed to a solution that does not contain nitrified nutrient solution. Therefore, by performing preculture using nitrified nutrient solution at the start of hydroculture, the need for additional fertilization and other work during cultivation can be reduced when performing general hydroculture without using soil or organic fertilizers. Furthermore, it becomes possible to cultivate plants well over a long period of time by improving plant growth and color retention.

[0018] While the technique of applying chemical fertilizers when practicing hydroponics is generally known, when using chemical fertilizers, for example, liquid fertilizers require repeated application (top dressing), and when using fertilizers contained in carriers such as resins, it is necessary to mix the fertilizer into the artificial growing medium and continue to provide fertilizer. When using a solution containing nitrifying culture solution as the growing solution, as in this embodiment, the use of chemical fertilizers as described above can be eliminated or reduced. In other words, the work of applying chemical fertilizers is reduced, and the risk of excessive chemical fertilizer application is suppressed, allowing for better plant growth for a longer period.

[0019] Furthermore, by utilizing the plant cultivation method of this embodiment, the need for work during cultivation is reduced, and it is possible to manufacture hydroculture products (products in which plant seedlings are planted in a container that holds artificial growing medium for hydroculture) that can be cultivated successfully for a long period of time. Such hydroculture products can be manufactured and sold, for example, after the pre-culture in step T120, with the growing solution changed to a solution that does not contain nitrifying nutrient solution. In this way, consumers who purchase the above product can enjoy hydroculture for a long time with reduced effort required for cultivation. Alternatively, the hydroculture product may be manufactured and sold in the state in which the pre-culture in step T120 is performed, that is, with nitrifying nutrient solution used as the growing solution. In this case, consumers who purchase the above product can enjoy hydroculture for a long time with reduced effort required for subsequent cultivation by changing the hydroculture growing solution to a normal growing solution that does not contain nitrifying nutrient solution after purchase.

[0020] B. Second Embodiment: As a second embodiment, a plant cultivation kit for hydroculture will be described below. The plant cultivation kit of the second embodiment comprises an artificial growing medium for hydroculture, plant seedlings for cultivation by hydroculture, and the nitrification culture solution described above. The plant seedlings may be included in the kit in a hydroponic state, for example, but it is preferable to include them in a hydroculture state, that is, with the plant seedlings planted in a container that holds the artificial growing medium for hydroculture. This allows the user of the kit to immediately perform hydroculture without having to transplant the plant seedlings. Furthermore, the plant cultivation kit may also include an ion exchange resin nutrient solution, and if the plant seedlings are provided in a hydroculture state, the ion exchange resin nutrient solution may be mixed into the artificial growing medium for hydroculture beforehand.

[0021] As described above, if the kit includes plant seedlings in a hydroponic state, the hydroponic solution can be water or a general-purpose solution containing inorganic liquid fertilizer or a plant tonic. In this case, the kit should include instructions that the user should perform a pre-culture using the nitrifying culture solution included in the kit for a certain period of time when starting to use the kit. With this configuration, the effects of the cultivation method described in the first embodiment can be obtained by using the kit.

[0022] Furthermore, if the kit includes plant seedlings in a hydroponic state as described above, the hydroponic nutrient solution may be a nitrified nutrient solution. In other words, the kit may include plant seedlings in a pre-culture state. In this case, the kit should be accompanied by instructions to replace the hydroponic nutrient solution with water or a general nutrient solution containing inorganic liquid fertilizer or a plant tonic. Alternatively, the kit may be accompanied by instructions to perform a pre-culture using the nitrified nutrient solution provided in the kit for a certain period of time prior to replacing the nutrient solution as described above. Even with such a configuration, the effects of the cultivation method described in the first embodiment can be obtained by using the kit.

[0023] C. Third Embodiment: Figure 2 is an explanatory diagram showing a method for producing plant seedlings according to the third embodiment. The method for producing plant seedlings according to the third embodiment is a method for obtaining rooted plant seedlings. The method for producing plant seedlings according to the third embodiment can be used to produce plant seedlings for hydroculture, and can be suitably implemented, for example, as the step of preparing plant seedlings in step T100 of the plant cultivation method according to the first embodiment. Alternatively, the method for producing plant seedlings according to the third embodiment may be used as a method for producing seedlings for cuttings used to propagate plants by cuttings.

[0024] In carrying out the method for producing plant seedlings according to the third embodiment, first, a plant body having a cut surface for rooting is prepared (step T200). Various plants to which the cutting technique can be applied can be used as the plant to obtain rooted plant seedlings. It is generally known that rooting during cuttings occurs through a common mechanism in which auxin, a type of plant hormone, is secreted from the cut surface of the cutting, and the action of auxin promotes the formation of callus on the cut surface and the differentiation of roots. The plant whose rooting is promoted by the method for producing plant seedlings according to the third embodiment is not particularly limited as long as it is a plant that can be made to root as described above, and can be suitably used. Aromatic plants suitable for hydroculture, such as Aromaticus, rosemary, rose geranium, and orange geranium described above, can all be used for the above-mentioned rooting purpose.

[0025] In addition to preparing the plant bodies in step T200 described above, a soil-containing nutrient solution is cultured to produce a soil culture solution used to promote root growth (step T210). The soil-containing nutrient solution is a liquid containing an organic nitrogen source containing organic nitrogen, and at least one of bark compost and leaf mold. As the organic nitrogen source containing organic nitrogen, the same organic nitrogen source contained in the nitrifying bacteria-containing nutrient solution used in step T110 of the first embodiment can be used.

[0026] As described above, the soil-containing nutrient solution contains at least one of bark compost and leaf mold, which are sources of microorganisms. The combined amount of bark compost and leaf mold added to the soil-containing nutrient solution is preferably 3 g / L or more, and more preferably 5 g / L or more, from the viewpoint of obtaining sufficient rooting activity as described later. Furthermore, the above amount is preferably 50 g / L or less, and more preferably 20 g / L or less. The cultivation period in step T210 is preferably 12 days or more, more preferably 15 days or more. Furthermore, it is preferably 30 days or less, and more preferably 25 days or less. The cultivation temperature is preferably 18°C ​​or higher, more preferably 20°C or higher. Furthermore, it is preferably 35°C or lower, and more preferably 30°C or lower. The cultivation conditions are preferably aerobic conditions, and aeration may be performed by aeration using an air pump or shaking.

[0027] After preparing the nitrification culture solution in step T210, the portion of the plant body prepared in step T200, including the cut surface, is brought into contact with the soil culture solution obtained in step T210 (step T220). The method of bringing the plant body into contact with the soil culture solution is not particularly limited as long as it does not inhibit rooting of the plant body, but for example, a method of immersing the above portion of the plant body in the soil culture solution can be employed. By bringing the plant body into contact with the soil culture solution as described above, a plant seedling with roots growing from the portion including the cut surface is obtained (step T230).

[0028] With this configuration, the rooting of the plant can be promoted by bringing the plant body into contact with the soil culture solution during the rooting process. Therefore, when selling plant seedlings grown using hydroponics, for example, or when propagating plants by cuttings, it becomes possible to produce rooted plant seedlings more quickly and at a lower cost.

[0029] As described above, the soil culture solution used to promote plant rooting is thought to contain substances that promote plant rooting (hereinafter also referred to as rooting-promoting substances). That is, in the process of culturing the soil-containing nutrient solution in step T210, rooting-promoting substances are generated, and it is thought that plant rooting can be promoted by using a soil culture solution containing such rooting-promoting substances. As will be described later, since a rooting-promoting effect is observed even when using a soil culture solution that has been sterilized by heating, it is thought that the rooting-promoting substances are substances that are not deactivated by heating and are not, for example, living microorganisms. Furthermore, the reaction in which nitrification proceeds in the soil-containing nutrient solution, which contains an organic nitrogen source and soil as a microbial source, and generates nitrate nitrogen and nitrite nitrogen, also proceeds when using microbial sources other than bark compost and leaf mold. However, as will be described later, the rooting-promoting effect observed in culture solutions obtained using other types of microbial sources is not seen in the soil culture solution of this embodiment. Therefore, it is thought that the rooting-promoting substances are substances different from the nitrate nitrogen and nitrite nitrogen produced by nitrification. As described above, a rooting-promoting effect has been observed, so the solution containing the soil culture solution of the third embodiment can be used as a rooting agent to promote rooting of the plant by bringing it into contact with the cut surface of the plant.

[0030] D. Impossible or impractical circumstances: In the plant cultivation kit according to the second embodiment, the nitrification culture solution included in this plant cultivation kit is specified by the manufacturing method as "obtained by culturing a nitrifying bacteria-containing nutrient solution containing an organic nitrogen source and a microbial source." Here, the nitrifying bacteria-containing nutrient solution and the nitrification culture solution obtained by culturing it are thought to contain a very large variety of organic and inorganic substances and microorganisms. In addition, there is a possibility that many unknown components are also included. Here, the effect obtained by pre-culturing plants with the nitrification culture solution is recognized to be at least as good as, or better than, that obtained when using an ion exchange resin nutrient solution containing chemical fertilizers, as will be described later, and it is inferred that the nitrate nitrogen and nitrite nitrogen produced by nitrification that proceeds by culturing the nitrifying bacteria-containing nutrient solution influence the above effect. However, the proportions of nitrate nitrogen, nitrite nitrogen and ammonia nitrogen contained in each nitrification culture solution in the examples described later, in which the effect was confirmed, differed greatly, and it was difficult to observe a specific trend between the composition of nitrogen compounds and the effect obtained. Furthermore, as will be discussed later, using nitrification culture solution and chemical fertilizer (ion exchange resin nutrient solution) in combination during pre-culture further improves the growth of hydrocultured plants after pre-culture. However, the degree of improvement in growth cannot be said to be simply a result of adding a certain effect compared to using nitrification culture solution alone, in terms of various evaluation items. Therefore, it is thought that various effects related to improving plant growth are obtained through the complex combination of various components contained in the nitrification culture solution, in addition to the nitrogen compounds produced by nitrification. Analyzing and identifying the components contained in the nitrification culture solution, which has a complex composition, and confirming the effects of pre-culture with various combinations would require an excessive amount of time and effort. Therefore, at the time of filing the application, it can be said that it is impossible, or at least not practical, to directly identify the nitrification culture solution by its structure or properties.

[0031] In the plant rooting promoter according to the third embodiment, the soil culture solution contained in this rooting promoter is specified by the manufacturing method, such as "obtained by culturing a soil-containing nutrient solution that includes an organic nitrogen source and at least one of bark compost and leaf mold." Here, the soil-containing nutrient solution and the soil culture solution obtained by culturing it are thought to contain a very large number of types of organic matter, inorganic matter, microorganisms, etc. Furthermore, it is possible that many unknown components are also included. Here, as previously mentioned, the rooting-promoting substance contained in the soil culture solution is presumed to be a substance that is not deactivated by heating and is a substance different from nitrate nitrogen and nitrite nitrogen produced by nitrification, but it is unknown whether it is a single component or multiple components present in a specific ratio. For this reason, it is thought that analyzing and identifying the components contained in the soil culture solution with a complex composition and confirming the presence or absence of rooting-promoting effect of each component individually or in combination of multiple components would require an excessive amount of time and effort. Therefore, at the time of filing the application, it can be said that it is impossible or not at all practical to directly identify the soil culture solution by its structure or properties. [Examples]

[0032] <Preparation of nitrification culture solution and soil culture solution> The progression of nitrification was investigated by culturing a combination of an organic nitrogen source containing organic nitrogen and a candidate microbial source containing nitrifying bacteria. Here, corn steep liquor (manufactured by Sakata Seed Corporation, product name "Nature Aid", hereinafter referred to as "CSL") was used as the organic nitrogen source. As candidate microbial sources, the following four materials, SO1 to SO4, including soil, compost, and fermented plant matter, were used. "SO1" was mature compost with charcoal (manufactured by Kyowa Kaihatsu Co., Ltd.), "SO2" was a material commercially available as insect rearing mat (product name "Premium Fermented Mat", manufactured by Mitani Co., Ltd.) that was fermented at high temperature using decayed broadleaf wood as the main raw material, "SO3" was leaf mold with bark compost (manufactured by Setogahara Hanaen Co., Ltd.), and "SO4" was a culture medium blended with black peat and white peat (product name "Super Mix A", manufactured by Sakata Seed Corporation).

[0033] The specific culture procedure is as follows. First, 5 L of RO water (water filtered through a reverse osmosis membrane) was put into an 8-L plastic bucket, and further, 5 g of CSL (final concentration 1 g / L) and 25 g of any one of the materials SO1 to SO4 put in a net (final concentration 5 g / L) were added to prepare nutrient solutions NS1 to NS4. Then, an air stone (Ibuki air stone, 30φ series, 30φ×78, manufactured by King砥石 Co., Ltd.) connected to an air pump (Nissho Air Pump Silent β-120, manufactured by Marukan Co., Ltd.) was put into each of the nutrient solutions NS1 to NS4, and while performing aeration, the culture was carried out under light conditions of 25°C, 16 h Light (6:00 - 22:00) / 8 h Dark (22:00 - 6:00). After the start of the culture, 5 g of CSL was additionally added on the 1st and 2nd days. In addition, during the above-described culture process, since the liquid volume decreased due to evaporation or the like, RO water corresponding to the decreased liquid volume was added every 2 to 3 days. By culturing the nutrient solutions NS1 to NS4, culture solutions CM1 to CM4 were obtained.

[0034] After the start of the culture using the nutrient solutions NS1 to NS4, on the 11th, 18th, 27th, 31st, and 35th days after the start, various ion concentrations and the like were measured as component measurements for the culture solutions CM1 to CM4. The ammonium ion (NH4 + ) concentration was measured using a Reflectoquant ammonium test (manufactured by Kanto Chemical Co., Inc., product numbers: 16892-1M; 16977-1M; 16899-1M, Reflectoquant is a registered trademark), the nitrite ion (NO2 - ) concentration was measured using a Reflectoquant nitrite test (manufactured by Kanto Chemical Co., Inc., product numbers: 16973-1M; 16732-1M), the nitrate ion (NO3 - ) concentration was measured using a Reflectoquant nitrate test (manufactured by Kanto Chemical Co., Inc., product numbers: 16971-1M; 16995-1M), the phosphate ion (PO4 3- ) concentration was measured using a Reflectoquant phosphate test (manufactured by Kanto Chemical Co., Inc., product number: 16978-1M), and the pH was measured using a Reflectoquant pH test (manufactured by Kanto Chemical Co., Inc., product number: 16996-1M) with a simple reflection photometer (manufactured by Kanto Chemical Co., Inc., RQ Flex 20).

[0035] Figure 3A is an explanatory diagram showing the results of measuring the concentrations of each of the above-mentioned ions in culture media CM1-CM4 on day 18 after the start of cultivation (hereinafter also referred to as "D18"). Figure 3B is an explanatory diagram showing the results of measuring the pH of culture media CM1-CM4 on D18. Figure 4A is an explanatory diagram showing the results of measuring the concentrations of each of the above-mentioned ions in culture media CM1-CM4 on day 27 after the start of cultivation (hereinafter also referred to as "D27"). Figure 4B is an explanatory diagram showing the results of measuring the pH of culture media CM1-CM4 on D27. Figure 5 shows the concentrations of ammonium ions (NH4) in each of culture media CM1-CM4. + ) concentration, nitrite ion (NO2 - ) concentration, and nitrate ion (NO3 - This is an explanatory diagram showing the changes in concentration. The horizontal axis shows the number of days elapsed since the start of culture, and the vertical axis shows the concentration of each ion.

[0036] As shown in Figure 5, in all culture solutions, the ammonium ion concentration reached its maximum around the 11th day after the start of cultivation. Subsequently, the nitrite ion and nitrate ion concentrations increased in culture solutions CM1, CM3, and CM4, suggesting that nitrification occurred. From the above, it was confirmed that various commercially available horticultural materials, including soil and compost, such as materials SO1, SO3, and SO4, can be used as a source of microorganisms containing nitrifying bacteria. Material SO2 is a commercially available material for insect rearing, made from decaying broadleaf wood treated with high-temperature fermentation, and although it is made from fermented plant material, it could not be used as a source of microorganisms containing nitrifying bacteria. Hereafter, culture solutions CM1, CM3, and CM4 will also be referred to as nitrified culture solutions CM1, CM3, and CM4. Culture solution CM3 will also be referred to as soil-containing culture solution CM3.

[0037] Comparing these nitrification culture solutions CM1, CM3, and CM4, nitrification culture solutions CM1 and CM4 showed higher nitrite and nitrate ion concentrations compared to nitrification culture solution CM3, suggesting that nitrification proceeded more actively. Furthermore, nitrification culture solutions CM1 and CM4 showed a steeper increase in nitrite and nitrate ion concentrations compared to nitrification culture solution CM3, and the nitrite and nitrate ion concentrations peaked earlier, suggesting that nitrification became more active at an earlier stage after the start of culture (see Figures 3A, 4A, and 5).

[0038] <Effects of preculture using nitrification medium> Using nitrifying culture solutions CM3 and CM4, which exhibit different timings of nitrification activation, we performed preculture of plants according to the cultivation method shown in Figure 1 and investigated the effects on hydroculture after preculture. For preculture, we used nitrifying culture solutions CM3 and CM4 on day 27 (D27) after the start of cultivation.

[0039] Aromaticus seedlings were used as the plant seedlings. In process T100, Aromaticus was cut approximately 5 cm from the leaf tip, and Rootone (Sumitomo Chemical Garden Co., Ltd.), a plant growth regulator for promoting root development, was applied to the cut end. The seedlings were then inserted into vermiculite and cultured at room temperature with appropriate watering to produce rooted seedlings. Subsequently, silicate clay was spread on the bottom of a hydroculture pot (bottom-watering pot) with a diameter of approximately 9 cm as a root rot preventative, washed with tap water, and three types of hydroballs (medium and small hydrocorn (Miura Gardening Co., Ltd.), and Seramis Granules (Yokohama Ueki Co., Ltd.)) mixed in a 1:1:1 ratio were added. Rooted Aromaticus seedlings of similar size were planted in each of these hydroculture pots. When ion exchange resin nutrients (IC) were added, approximately 2.5 cc of ion exchange resin nutrients was mixed with the hydroballs in the case of the 9 cm pot. In step T110, as previously described, nitrification culture solutions CM3 and CM4 of D27 were prepared.

[0040] As described above, Aromatics seedlings planted in hydroculture pots were subjected to a one-month hydroculture (pre-culture of process T120) using nitrifying nutrient solutions CM3 and CM4 as the growing medium. After that, the growing medium was changed to tap water (which does not contain nitrifying nutrient solutions), and hydroculture of process T130 was performed. Processes T120 and T130 were performed at room temperature (approximately 25°C). In the pre-culture of process T120, nitrifying nutrient solution was added when it ran out from the bottom of the hydroculture pot. In process T130, after replacing the growing medium with tap water, tap water was used to irrigate the hydroculture pot when the water ran out from the bottom. In the control group, which did not use nitrifying nutrient solutions CM3 and CM4, the pre-culture of process T120 was not performed, and tap water was used as the growing medium, with tap water being used to irrigate the hydroculture pot when the water ran out from the bottom.

[0041] Figure 6 is an explanatory diagram showing the results of photographing Aromatics seedlings over time after starting hydroponics in process T130. Figure 7A is an explanatory diagram showing the results of cutting the above-ground part of the plant and measuring its fresh weight approximately 6 months after starting hydroponics in process T130. Figure 7B is an explanatory diagram showing the results of measuring the number of branches (total number of main branches and sub-branches) of the plant after 6 months. Figure 7C is an explanatory diagram showing the results of measuring the length of each branch and calculating its sum after 6 months. Figure 7D is an explanatory diagram showing the results of measuring the number of green large leaves (referring to leaves with a length in the long axis direction of 17 mm or more and a length in the horizontal axis direction of 12 mm or more; the same applies hereinafter) after 6 months. Figure 7E is an explanatory diagram showing the results of measuring the number of yellowed large leaves after 6 months and calculating their ratio to the total number of large leaves.

[0042] Here, cultivation was performed with a sample size of 2 (n=2) for each cultivation condition. In each figure, "CM3" is written when preculture was performed using nitrifying culture solution CM3, "CM4" is written when preculture was performed using nitrifying culture solution CM4, and "CM(-)" is written when no preculture with nitrifying culture solution was performed. In addition, "IC(+)" is written when ion exchange resin nutrients were added to the hydroballs, and "IC(-)" is written when no ion exchange resin nutrients were added. In Figures 7A to 7E, the error bars indicate the standard error (SE).

[0043] As shown in Figures 6 and 7A to 7E, it was confirmed that pre-culture using nitrifying culture solution resulted in vigorous plant growth and maintained leaf color for approximately 6 months during subsequent hydroculture, and that this effect was equivalent to or better than that achieved when using ion exchange resin nutrients. Furthermore, it was confirmed that when pre-culture using nitrifying culture solution, mixing ion exchange resin nutrients with hydroballs (artificial growing medium) and using ion exchange resin nutrients in combination significantly enhances the effect of improving plant growth and maintaining leaf color.

[0044] <Promoting root growth using soil culture solution> Among the nitrification culture solutions described above, nitrification culture solutions CM1 and CM3, which produce a particularly large amount of nitrate ions that plants can directly utilize as a nitrogen source, were used, and their effect on root development in plant seedlings was investigated according to the plant seedling preparation method shown in Figure 2. The nitrification culture solutions used were nitrification culture solutions CM1 and CM3 on day 18 from the start of cultivation (D18), when the nitrate ion concentration was highest, nitrification culture solutions CM1 and CM3 on day 27 from the start of cultivation (D27), and autoclaved nitrification culture solutions CM1 and CM3 from D27 at 121°C for 20 minutes (hereinafter referred to as CM1 (sterilized) and CM3 (sterilized)). Hereafter, CM1 from D18, CM1 from D27, and CM1 (sterilized) will be collectively referred to as "CM1 etc.," and CM3 from D18, CM3 from D27, and CM3 (sterilized) will be collectively referred to as "CM3 etc."

[0045] Aromaticus seedlings were used as the plant seedlings. In step T200, the Aromaticus seedlings were cut approximately 5 cm from the leaf tip. In step T210, as previously described, nitrification nutrient solutions CM1 and CM3 were prepared. In step T220, the portion of the Aromaticus seedling including the cut surface was immersed in nitrification nutrient solutions CM1 and CM3 in 50 mL plastic tubes (Falcon tubes) and cultured at room temperature. In the control group, where nitrification nutrient solutions CM1 and CM3 were not used, the plant seedlings cut as described above were immersed in approximately 45 mL of water in 50 mL plastic tubes (Falcon tubes) and cultured at room temperature.

[0046] Figure 8 is an explanatory diagram showing images of Aromaticus seedlings 22 days after the start of rooting cultivation, when seedlings were prepared using D18 CM1, D18 CM3, and water, respectively. Figure 9A is an explanatory diagram showing the results of measuring the total taproot length of each D18 plant seedling 22 days after the start of cultivation. Figure 9B is an explanatory diagram showing the results of calculating the average taproot length of each D18 plant seedling 22 days after the start of cultivation. Figure 9C is an explanatory diagram showing the results of measuring the number of taproots of each D18 plant seedling 22 days after the start of cultivation. Here, "taproot" refers to the root that grows directly from the stem.

[0047] Figure 10 is an explanatory diagram showing images of Aromaticus seedlings 23 days after the start of rooting culture, when seedlings were prepared using D27 CM1, D27 CM3, and water, respectively. Figure 11A is an explanatory diagram showing the results of measuring the total main root length of each D27 plant seedling 23 days after the start of culture. Figure 11B is an explanatory diagram showing the results of calculating the average main root length of each D27 plant seedling 23 days after the start of culture. Figure 11C is an explanatory diagram showing the results of measuring the number of main roots of each D27 plant seedling 23 days after the start of culture.

[0048] In Figures 8 and 9A-9C, the rooting conditions using CM1 and water have a sample size of 6 (n=6), while the rooting conditions using CM3 have a sample size of 4 (n=4). In Figures 10 and 11A-11C, the sample size is 5 (n=5) for each rooting condition. In Figures 9A-9C and 11A-11C, the error bars indicate the standard error (SE).

[0049] Figure 9A also shows the results of multiple comparisons using the Mann-Whitney U test and Bonferroni correction to determine whether there was a significant difference in the total length of the main roots measured under the three conditions described above. Here, if the p-value is less than 0.0167 and a significant difference is found, different letters a or b are used to distinguish them; if no significant difference is found, the same letter is used. Figures 9B, 9C, 11A, and 11B also show the results of multiple comparisons using the Tukery-Kramer test to determine whether there was a significant difference in each measurement result from rooting under the three conditions described above. In Figures 9B, 9C, and 11A, if the p-value is less than 0.05 and a significant difference is found, different letters a or b are used to distinguish them; in Figure 11B, if the p-value is less than 0.001 and a significant difference is found, different letters a or b are used to distinguish them. Furthermore, in all of the figures, the same letter is used to indicate no statistically significant difference.

[0050] As shown in the figures above, nitrified culture solution CM3 (soil culture solution CM3) was found to have a rooting-promoting effect in terms of the total length of the main roots and the average length of the main roots. Here, nitrified culture solution CM1, which has high concentrations of nitrate ions and nitrite ions similar to nitrified culture solution CM3, did not show the same rooting-promoting effect as nitrified culture solution CM3. Therefore, it is thought that the active substance that exhibits the rooting-promoting effect in nitrified culture solution CM1 is different from the nitrogen source produced by nitrification, or is not composed solely of the nitrogen source produced by nitrification. Furthermore, as shown in Figures 10 and 11A to 11C, "CM3 (sterilized)," which is nitrified culture solution CM3 that has been autoclaved, also exhibits the same rooting-promoting effect as nitrified culture solution CM3. Therefore, it is thought that the active substance that exhibits the rooting-promoting effect is a substance that is not easily deactivated by heating, and is not, for example, a living microorganism.

[0051] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-mentioned problems, or to achieve some or all of the above-mentioned effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

[0052] This disclosure can also be implemented in the following forms: [Application Example 1] A method of cultivating plants using hydroponics, A nitrification culture solution is prepared by culturing a nitrifying bacteria-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and a microbial source containing nitrifying bacteria. When starting the cultivation of plants using hydroponics, pre-culture is performed using a solution containing the nitrification culture solution as the growing solution to be given to the plants. After the pre-culture, the cultivation solution is changed to a solution that does not contain the nitrification culture solution. Methods for cultivating plants. [Application Example 2] A method for cultivating plants by hydroponics as described in Application Example 1, For use in hydroponics, artificial growing media containing ion exchange resin nutrients are used. Methods for cultivating plants. [Application Example 3] A method for cultivating plants by hydroponics as described in Application Example 1 or 2, A soil culture solution is prepared by culturing a soil-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and at least one of bark compost and leaf mold. By bringing the portion of a plant body having a cut surface, including the cut surface, into contact with the soil culture solution, a plant seedling with roots growing from the portion including the cut surface is obtained. The preculture process is carried out using the obtained plant seedlings. Methods for cultivating plants. [Application Example 4] This is a plant cultivation kit for hydroponics, Artificial growing medium used in hydroponics, Plant seedlings for hydroponics cultivation, A nitrification culture solution obtained by culturing a nitrifying bacteria-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and a microbial source containing nitrifying bacteria, A plant cultivation kit that includes [the following items]. [Application Example 5] A method for producing plant seedlings, A soil culture solution is prepared by culturing a soil-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and at least one of bark compost and leaf mold. By bringing the portion of a plant body having a cut surface, including the cut surface, into contact with the soil culture solution, a plant seedling with roots growing from the portion including the cut surface is obtained. Method for preparing plant seedlings. [Application Example 6] It is a rooting stimulant for plants, It contains a soil culture solution obtained by culturing a soil-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and at least one of bark compost and leaf mold. A rooting stimulant for plants.

Claims

1. A method of cultivating plants using hydroponics, A nitrification culture solution is prepared by culturing a nitrifying bacteria-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and a microbial source containing nitrifying bacteria. When starting the cultivation of plants using hydroponics, pre-culture is performed using a solution containing the nitrification culture solution as the growing solution to be given to the plants. After the pre-culture, the cultivation solution is changed to a solution that does not contain the nitrification culture solution. Methods for cultivating plants.

2. A method for cultivating plants by hydroculture as described in claim 1, For use in hydroponics, artificial growing media containing ion exchange resin nutrients are used. Methods for cultivating plants.

3. A method for cultivating plants by hydroculture as described in claim 1, A soil culture solution is prepared by culturing a soil-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and at least one of bark compost and leaf mold. By bringing the portion of a plant body having a cut surface, including the cut surface, into contact with the soil culture solution, a plant seedling with roots growing from the portion including the cut surface is obtained. The preculture process is carried out using the obtained plant seedlings. Methods for cultivating plants.

4. This is a plant cultivation kit for hydroponics, Artificial growing medium used in hydroponics, Plant seedlings for hydroponics cultivation, A nitrification culture solution obtained by culturing a nitrifying bacteria-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and a microbial source containing nitrifying bacteria, A plant cultivation kit that includes [the following items].

5. A method for producing plant seedlings, A soil culture solution is prepared by culturing a soil-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and at least one of bark compost and leaf mold. By bringing the portion of a plant body having a cut surface, including the cut surface, into contact with the soil culture solution, a plant seedling with roots growing from the portion including the cut surface is obtained. Method for preparing plant seedlings.

6. It is a rooting stimulant for plants, It contains a soil culture solution obtained by culturing a soil-containing nutrient solution that includes an organic nitrogen source containing organic nitrogen and at least one of bark compost and leaf mold. A rooting stimulant for plants.

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