Methods for producing agricultural products and methods for producing soil

Abstract

To provide a method for producing crops that is capable of producing crops while utilizing a desirable soil for cultivating the crops, and also provide a method for producing the soil.SOLUTION: A method for producing crops includes irradiating an aqueous solution of sodium lactate with atmospheric-pressure plasma to prepare a plasma-activated sodium lactate solution, and supplying the plasma-activated sodium lactate solution to the soil to increase its bacterial count, while growing crops in the soil. The method for producing crops also increases the amount of available phosphorus in the soil while growing the crops.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technical field of this specification relates to methods for producing crops and soil using plasma. [Background technology]

[0002] Plasma technology is applied in the fields of electricity, chemistry, and materials science. Within a plasma, in addition to charged particles such as electrons and ions, ultraviolet light and radicals are generated. It has been discovered that these have various effects on biological tissues, including sterilization.

[0003] Furthermore, it has become clear that plasma is also effective in promoting crop growth. For example, Patent Document 1 discloses a technology for promoting rice growth by irradiating rice with atmospheric pressure plasma. Patent Document 2 discloses a method for producing a plant growth promoter in which chitosan is dissolved in lactic acid and the pH is adjusted to 3.0 to 7.0. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-18278 [Patent Document 2] Japanese Patent Application Publication No. 2-49704 [Overview of the project] [Problems that the invention aims to solve]

[0005] Incidentally, bacteria in the soil often have a positive effect on crop growth. In the technologies described in Patent Documents 1 and 2, the condition of the soil in which the crops are grown is unclear.

[0006] The problem to be solved by the technology described in this specification is to provide a method for producing agricultural crops and a method for producing soil that can produce agricultural crops while using soil that is favorable for growing agricultural crops.

Means for Solving the Problem

[0007] In the first aspect Methods for increasing soil bacterial counts are: Irradiate an aqueous sodium lactate solution with atmospheric pressure plasma to produce a plasma-activated aqueous sodium lactate solution, and supply the plasma-activated aqueous sodium lactate solution to the soil. The number of bacteria in the soil is increased by supplying a plasma-activated sodium lactate aqueous solution to the soil while growing crops in the soil.

[0008] In this Increase in soil bacteria count method, the number of bacteria in the soil, which is important for producing agricultural crops, is increased. As a result, the growth of agricultural crops is promoted, and fruits and the like of agricultural crops grow large.

Effects of the Invention

[0009] In this specification, a method for producing agricultural crops and a method for producing soil that can produce agricultural crops while using soil that is favorable for growing agricultural crops are provided.

Brief Description of the Drawings

[0010] [Figure 1] FIG. 1.A is a cross-sectional view showing the configuration of a first plasma generation device, and FIG. 1.B is a diagram showing the shape of an electrode. [Figure 2] FIG. 2.A is a cross-sectional view showing the configuration of a second plasma generation device, and FIG. 2.B is a diagram showing the shape of an electrode. [Figure 3] It is a table (Part 1) showing the components in each soil. [Figure 4] It is a table (Part 2) showing the components in each soil. [Figure 5] It is a table showing seven types of aqueous solutions used in Experiment B. [Figure 6] It is a table showing the properties and components of each aqueous solution. [Figure 7] It is a table showing the number of bacteria cultured in an LB medium mixed with each aqueous solution. [Figure 8] This table shows the total number of bacteria grown in soil mixed with each aqueous solution. [Figure 9] This table shows the soil composition after cultivating Japanese mustard spinach in soil supplied with each aqueous solution. [Figure 10] This is a graph showing the growth rate of Brassica rapa. [Figure 11] This is a graph showing the growth rate of spinach. [Figure 12] This is a graph showing the growth rate of chili peppers. [Figure 13] This is a table showing the fruit weight of chili peppers. [Figure 14] This is a graph showing the fruit weight of chili peppers. [Figure 15] These are photographs comparing the growth stages of spinach plants. [Figure 16] These are photographs comparing the growth stages of chili pepper fruits. [Modes for carrying out the invention]

[0011] The following describes specific embodiments, using a method of producing agricultural products as an example, with reference to the diagrams. Note that the dimensions of the plasma generator are illustrative, and values ​​outside the given range may be used.

[0012] (First embodiment) The first embodiment will now be described. In the crop production method of the first embodiment, atmospheric pressure plasma is directly irradiated onto the crop. Therefore, the plasma irradiation device used for irradiating the crop will be described first.

[0013] 1. Plasma device 1-1. First Plasma Generator Figure 1.A is a cross-sectional view showing the schematic configuration of the plasma generator P10. Here, the plasma generator P10 is a first plasma generator that ejects plasma in a point-like manner. Figure 1.B is a diagram showing the detailed shapes of electrodes 2a and 2b of the plasma generator P10 in Figure 1.A.

[0014] The plasma generator P10 comprises a housing 10, electrodes 2a and 2b, and a voltage application unit 3. The housing 10 is made of a sintered body made from alumina (Al2O3). The housing 10 is cylindrical in shape. The inner diameter of the housing 10 is 2 mm to 3 mm. The thickness of the housing 10 is 0.2 mm to 0.3 mm. The length of the housing 10 is 10 cm to 30 cm. Gas inlets 10i and gas outlets 10o are formed at both ends of the housing 10. The gas inlet 10i is for introducing gas to generate plasma. The gas outlet 10o is an irradiation unit for irradiating the outside of the housing 10 with plasma. The direction of gas movement is indicated by the arrows in the figure.

[0015] Electrodes 2a and 2b are a pair of opposing electrodes positioned opposite each other. The length of electrodes 2a and 2b in the direction of their opposing surfaces is smaller than the inner diameter of the housing 10, for example, about 1 mm. As shown in Figure 1.B, electrodes 2a and 2b each have numerous recesses (hollows) H formed on their opposing surfaces. Therefore, the opposing surfaces of electrodes 2a and 2b have a finely textured surface. The depth of these recesses H is about 0.5 mm.

[0016] Electrode 2a is located inside the housing 10, near the gas inlet 10i. Electrode 2b is located inside the housing 10, near the gas outlet 10o. Therefore, the plasma generator P10 introduces gas from the opposite side of the opposing surface of electrode 2a and ejects gas from the opposite side of the opposing surface of electrode 2b. The distance between electrodes 2a and 2b is, for example, 24 cm. The distance between electrodes 2a and 2b may be smaller than this.

[0017] The voltage application unit 3 is for applying an AC voltage between electrodes 2a and 2b. The voltage application unit 3 uses a commercial AC voltage of 60Hz, 100V, steps it up to 9kV, and then applies the voltage between electrodes 2a and 2b.

[0018] When a rare gas such as argon is introduced through the gas inlet 10i and a voltage is applied between electrodes 2a and 2b by the voltage application unit 3, plasma is generated inside the housing 10. As shown by the shaded area in Figure 1.A, the region where plasma is generated is called the plasma generation region P. The plasma generation region P is covered by the housing 10.

[0019] 1-2. Second Plasma Generator Figure 2.A is a cross-sectional view showing the schematic configuration of the plasma generator P20. Here, the plasma generator P20 is a second plasma generator that ejects plasma in a linear manner. Figure 2.B is a partial cross-sectional view of the plasma generation region P of the plasma generator P20 in Figure 2.A, perpendicular to the longitudinal direction.

[0020] The plasma generator P20 comprises a housing 11, electrodes 2a and 2b, and a voltage application unit 3. The housing 11 is made of a sintered body using alumina (Al2O3) as the raw material. Gas inlets 11i and numerous gas outlets 11o are formed at both ends of the housing 11. The gas inlets 11i have a slit shape with the left-right direction in Figure 2.A as their longitudinal direction. The slit width from the gas inlets 11i to directly above the plasma generation region P (width in the left-right direction in Figure 2.B) is, for example, 1 mm.

[0021] The gas outlet 11o is an irradiation section for irradiating the outside of the housing 11 with plasma. The gas outlet 11o is cylindrical or slit-shaped. In the case of a cylindrical shape, the gas outlet 11o is formed in a straight line along the longitudinal direction of the plasma generation region. The inner diameter of the gas outlet 11o is in the range of 1 mm to 2 mm. In the case of a slit shape, it is preferable that the slit width of the gas outlet 11o be 1 mm or less. This ensures the formation of a stable plasma. The gas inlet 11i is configured to introduce gas in a direction that intersects the line connecting electrodes 2a and 2b.

[0022] The electrodes 2a, 2b and the voltage application unit 3 are the same as those in the plasma generator P10 shown in Figure 1. Similarly, a voltage is applied between electrodes 2a and 2b using commercial AC voltage. This allows the plasma to be ejected in a straight line.

[0023] Furthermore, by arranging these plasma generators P20, which eject plasma in a straight line, in a row in the left-right direction as shown in Figure 2.B, plasma can be ejected planarly over a certain rectangular area.

[0024] 2. Plasma generated by a plasma generator The plasma generated by plasma generators P10 and P20 is non-equilibrium atmospheric pressure plasma. Here, atmospheric pressure plasma refers to plasma with a pressure within the range of 0.5 atmospheres to 2.0 atmospheres.

[0025] In this embodiment, Ar gas is mainly used as the plasma generating gas. Within the plasma generated by the plasma generators P10 and P20, electrons and Ar ions are naturally produced. The Ar ions generate ultraviolet light. Furthermore, since this plasma is released into the atmosphere, it generates oxygen radicals, nitrogen radicals, and other similar substances.

[0026] The plasma density of this plasma is 1 × 10⁻⁶ 14 cm -3 The above 1 x 10 17 cm -3 The following range applies. Note that the plasma density in the plasma generated by dielectric barrier discharge is 1 × 10⁻⁶. 11 cm -3 The above 1 x 10 13 cm -3It is as follows. Therefore, the plasma density of the plasma generated by the plasma generators P10 and P20 is approximately three orders of magnitude greater than the plasma density of the plasma generated by dielectric barrier discharge. Therefore, more Ar ions are generated inside this plasma. As a result, the amount of radicals and ultraviolet rays generated is also large. Note that this plasma density is approximately equal to the electron density inside the plasma.

[0027] And the plasma temperature at the time of generating this plasma is within the range of approximately 1000K or more and 2500K or less. Also, the electron temperature in this plasma is higher than the gas temperature. Moreover, although the electron density is in the range of 1×10 14 cm -3 or more and 1×10 17 cm -3 or less, the gas temperature is within the range of approximately 1000K or more and 2500K or less. The temperature of this plasma is the temperature in the plasma generation region P where the plasma is generated. Therefore, by setting different conditions for the plasma conditions and the distance from the gas jet outlet to the object, the plasma temperature at the position of the object can be set to room temperature.

[0028] 3. Method for manufacturing plasma-activated aqueous solution 3-1. Aqueous solution preparation step First, a first aqueous solution is prepared. The first aqueous solution refers to the aqueous solution before being irradiated with plasma. The first aqueous solution contains sodium L-lactate, sodium chloride, potassium chloride, and calcium chloride.

[0029] 3-2. Plasma irradiation step Next, the atmospheric pressure plasma generated in the plasma generation region by the plasma-activated aqueous solution manufacturing apparatus PM is irradiated onto the first aqueous solution. The distance between the liquid surface and the plasma jet outlet when irradiating the plasma is, for example, 3 mm. Also, this distance may be changed within the range of, for example, 0.1 cm or more and 3 cm or less. The plasma density in the plasma generation region is 1×10 14 cm -3 or more and 1×10 17 cm-3 The following range applies. Furthermore, the plasma temperature in this plasma is approximately between 1000K and 2500K. However, at the liquid surface, this plasma temperature can be lowered to around room temperature (approximately 300K). These plasma conditions are shown in Table 1. These conditions are merely examples.

[0030] [Table 1] Condition Numerical range Liquid level-spout distance 0.1cm or more 3cm or less Plasma density 1 × 10⁻⁶ 14 cm -3 The above 1 x 10 17 cm -3 below Plasma temperature: 1000K or higher, 2500K or lower

[0031] In this way, by irradiating the first aqueous solution with atmospheric pressure plasma, the first aqueous solution is converted into the second aqueous solution. It is thought that the components of the first aqueous solution react with radicals and other substances derived from the plasma upon irradiation with atmospheric pressure plasma. In addition, the amount of nitrite ions and nitrate ions in the aqueous solution increases. It is thought that the components of the first aqueous solution also react with these ions and other substances. This second aqueous solution is a plasma-activated aqueous solution.

[0032] The plasma density of atmospheric pressure plasma is, for example, 2 × 10⁻⁶. 16 cm -3 The irradiation time of atmospheric pressure plasma is, for example, 30 seconds to 600 seconds. The volume of the first aqueous solution when irradiating with atmospheric pressure plasma is, for example, 10 ml to 1000 ml.

[0033] In this case, the plasma density-time product per unit volume in the second aqueous solution is 6 × 10⁻⁶. 14 sec·cm -3 ·ml -1 The above 1.2 × 10 18 sec·cm -3 ·ml -1The following applies. Here, the plasma density-time product per unit volume is (plasma density) × (irradiation time) / (volume of the first aqueous solution). In other words, the plasma density-time product per unit volume is the amount of plasma products irradiated onto the first aqueous solution per unit volume.

[0034] 4. Effects of plasma-activated aqueous solution The plasma-activated aqueous solution of the first embodiment is obtained by irradiating an aqueous solution containing L-sodium lactate with plasma. More specifically, it is obtained by irradiating a first aqueous solution containing L-sodium lactate, sodium chloride, potassium chloride, and calcium chloride with atmospheric pressure plasma. This plasma-activated aqueous solution increases the number of bacteria in the soil that grow crops. Because the soil is activated, the quality of crops grown in that soil is high. For example, they have high nutritional value.

[0035] 5. Method for producing agricultural products using plasma-activated aqueous solution The method for producing agricultural products according to the first embodiment includes an aqueous solution preparation step of preparing a first aqueous solution containing sodium L-lactate, a plasma irradiation step of irradiating the first aqueous solution with atmospheric pressure plasma to produce a second aqueous solution, and an aqueous solution supply step of supplying the second aqueous solution to the soil in which the agricultural products are grown.

[0036] 5-1. Aqueous solution preparation process In the aqueous solution preparation step, a first aqueous solution containing L-sodium lactate, sodium chloride, potassium chloride, and calcium chloride is prepared.

[0037] 5-2. Plasma Irradiation Process Next, a plasma irradiation process is performed. In this process, atmospheric pressure plasma is irradiated onto the first aqueous solution to create the second aqueous solution.

[0038] 5-3.Aqueous solution supply process Next, the aqueous solution supply process is carried out. In this process, the second aqueous solution is supplied to the soil of the crops. At this time, the second aqueous solution is added at a concentration of 5 to 100 times the total volume. The plasma density-time product per unit volume of the aqueous solution supplied to the soil is 6 × 10⁻⁶. 11 sec·cm -3 ·ml -1 The above 2.4 × 10 17 sec·cm -3 ·ml -1 The following applies. The dilution ratio of this second aqueous solution is preferably between 12.5 and 50 times. Of course, fertilizer and water are also supplied separately to the soil of the crops.

[0039] In this way, a plasma-activated sodium lactate aqueous solution is produced by irradiating an aqueous sodium lactate solution with atmospheric pressure plasma, and this plasma-activated sodium lactate aqueous solution is supplied to the soil to increase the number of bacteria in the soil while promoting crop growth. This makes it possible to increase the available phosphorus in the soil while promoting crop growth.

[0040] 6. Variations 6-1. Plasma-activated sodium lactate aqueous solution The first aqueous solution is preferably a sodium lactate aqueous solution containing L-sodium lactate. The first aqueous solution does not need to contain sodium chloride or the like. The plasma-activated sodium lactate aqueous solution is obtained by irradiating a sodium lactate aqueous solution containing L-sodium lactate with atmospheric pressure plasma. The plasma-activated sodium lactate aqueous solution is supplied to the soil.

[0041] 6-2. Sodium lactate aqueous solution that has not been irradiated with plasma. Alternatively, a sodium lactate aqueous solution that has not been irradiated with plasma may be supplied to the soil. In this case, the sodium lactate aqueous solution is supplied to the soil, increasing the number of bacteria in the soil while promoting the growth of crops.

[0042] 6-3. Soil Production Methods In the crop production method of the first embodiment, the total number of bacteria in the soil increases. Therefore, the technology of the first embodiment can be used in soil production methods. Even after crop production, the total number of bacteria and nutrients in the soil remain high, so this soil can be reused for the production of other crops.

[0043] 6-4. Miniaturized Plasma Generator Plasma generators P10, P20, etc., may be further miniaturized. By sufficiently miniaturizing them, a pen-type plasma generator can be manufactured. Even in that case, a plasma density equivalent to that of plasma generators P10 and P20 can be obtained.

[0044] 6-5. Freezing process Furthermore, a freezing step may be performed to preserve the second aqueous solution. The freezing step is performed after the plasma irradiation step and before the aqueous solution supply step. In the freezing step, the second aqueous solution is frozen in a range of -196°C to 0°C. Specifically, it is stored in a freezer. For example, a refrigerator for biological experiments (e.g., a BioFreezer GS-5203KHC manufactured by Nippon Freezer Co., Ltd.) can be used as the freezer.

[0045] The storage temperature of the second aqueous solution frozen in this freezer is within the range of -28°C to -14°C. However, the storage temperature of the second aqueous solution is not limited to this range. Any normal freezing temperature is acceptable. For example, within the range of -196°C to 0°C. Preferably, it is between -196°C and -10°C. More preferably, it is between -150°C and -20°C. Even more preferably, it is between -80°C and -30°C.

[0046] This freezing process allows for the preservation of the plasma-activated aqueous solution. Therefore, the frozen plasma-activated aqueous solution can be thawed before being supplied to the soil for agricultural products.

[0047] 6-6. Combinations The above variations may be combined as appropriate.

[0048] (Second embodiment) A second embodiment will now be described. In the second embodiment, the plasma-activated aqueous solution of the first embodiment is not used. Instead, in the second embodiment, atmospheric pressure plasma is directly irradiated onto the crops. The atmospheric pressure plasma apparatus can be the same as that of the first embodiment. Therefore, the differences from the first embodiment will be described.

[0049] 1. Methods of producing agricultural products 1-1. Plasma Irradiation Process In this plasma irradiation process, atmospheric pressure plasma is directly irradiated onto the region of the crop containing the growth point. Here, the growth point is located near the tip of the plant stem and is the area where cell division is actively occurring. The distance between the plasma irradiation port and the crop's growth point is, for example, between 0 cm and 10 cm. Furthermore, the plasma irradiation port should be directed towards the crop's growth point.

[0050] The plasma density is the same as in the first embodiment. The plasma irradiation time is, for example, 30 seconds or more and 600 seconds or less. For example, the plasma density of atmospheric pressure plasma is 2 × 10⁻¹⁶ 16 cm -3 Therefore, the plasma density-time product, which is the product of the plasma density and irradiation time of atmospheric pressure plasma, is 6 × 10⁻⁶. 17 sec·cm -3 The above 1.2 × 10 19 sec·cm -3 The following applies:

[0051] In this way, atmospheric pressure plasma is irradiated onto crops in the process of growing from the soil, increasing the number of bacteria in the soil and promoting crop growth.

[0052] 2. The effect of directly irradiating crops with plasma. By irradiating the region containing the growth point of a crop with atmospheric pressure plasma, the amount of polyphenols contained in the crop increases, as will be described later. More specifically, the polyphenol that increases is anthocyanin. Therefore, people who eat this crop will become healthier.

[0053] In this way, by directly irradiating the region containing the growth point of a crop with atmospheric pressure plasma, atoms, molecules, ions, and radicals derived from nitrogen or oxygen atoms are supplied to the growth point of the crop. As a result, it is predicted that the crop spontaneously enhances its antioxidant activity in response to such external stimuli. Consequently, it is thought that a large amount of antioxidants such as polyphenols are produced in the fruit.

[0054] 3. Variant Modifications of the first embodiment may be combined. [Examples]

[0055] (Experiment A) 1. Strawberry growth and soil Strawberries were grown under various conditions, and the soil composition was examined. Table 2 shows the soil growing conditions. Soil 1 is soil after strawberries were grown in soil with added fertilizer. Soil 2 is soil in which strawberries were grown in soil with added fertilizer, and plasma was also irradiated to the growth points of the strawberries. Soil 3 is soil after strawberries were grown in soil with added fertilizer and distilled water. Soil 4 is soil after strawberries were grown in soil with added fertilizer and Lactec (registered trademark). Soil 5 is soil after strawberries were grown in soil with added fertilizer and PAL. Soil 6 is the original soil, with no added fertilizer and not used for strawberry growth.

[0056] Lactec® is a lactated Ringer's solution containing L-sodium lactate, sodium chloride, potassium chloride, and calcium chloride. PAL is Lactec® irradiated with plasma.

[0057] Direct plasma irradiation and PAL supply were performed three times a week. The plasma irradiation time for direct irradiation was 120 seconds. The plasma irradiation time for PAL production was 300 seconds. The plasma density of the plasma irradiation device for direct irradiation and the plasma irradiation device for PAL production was 2 × 10⁻⁶16 cm -3 That was the case.

[0058] [Table 2] Soil 1 Control plot Fertilizer Strawberry Soil 2 Direct irradiation treatment area Fertilizer + plasma irradiation Strawberry Soil 3 Distilled water treatment area Fertilizer + distilled water Strawberry Soil 4 Lactec treatment area Fertilizer + Lactec Strawberry Soil 5 PAL treated area Fertilizer + PAL Strawberry Soil 6 Original soil None None

[0059] 2. Soil composition Figure 3 is a table (part 1) showing the components of each soil type. The columns indicating those that meet the recommended values ​​are shown in darker shades.

[0060] As shown in Figure 3, the total bacterial count in soil 2, which was directly irradiated with plasma, was 2.11 billion cells / g, which was approximately 3.8 times the total bacterial count in soil 6. The total bacterial count in soil 5, which was supplied with PAL, was 1.96 billion cells / g, which was approximately 3.6 times the total bacterial count in soil 6. The total bacterial count in soil 2 was approximately 1.35 times the total bacterial count in the control soil 1, and the total bacterial count in soil 5 was approximately 1.26 times the total bacterial count in soil 1. When plasma is used, as in soils 2 and 5, the total bacterial count becomes very high.

[0061] On the other hand, the total bacterial counts in soil 3, to which distilled water was added, and soil 4, to which Lactec® was added, were 860 million / g and 850 million / g, respectively. In these soils, the increase in the total bacterial count was not very large.

[0062] In terms of phosphorus cycle activity evaluation, soil 2, which was directly irradiated with plasma, is the most preferable. Soils 3 and 5 contain the most total carbon atoms. Soil 3 has the highest total phosphorus content. Soil 5 is the most preferable for total potassium and meets the recommended value criteria.

[0063] Figure 4 is a table (part 2) showing the composition of each soil type.

[0064] As shown in Figure 4, soil 5, which was supplied with PAL, contained a very high amount of available phosphorus at 1145 mg / kg. In soils 1-4 and 6, the amount of available phosphorus decreased compared to the original soil. There were not significant differences in other components.

[0065] 3. Summary of the experiment Thus, soil 2, which was directly irradiated with plasma, and soil 5, which was supplied with PAL, contain a very large number of bacteria. For this reason, soils 2 and 5 are favorable for growing crops, as bacteria play an important role in crop growth. Thus, a dramatic increase in the total number of bacteria is rare. Therefore, it is suggested that there may be some kind of interaction between the strawberry seedlings and the bacteria in the soil.

[0066] (Experiment B) 1. Experimental Method Distilled water, sodium lactate aqueous solution (non-PAW), and plasma-activated sodium lactate aqueous solution (PAW) were prepared, and these solutions were supplied to the soil to grow plants. Three types of aqueous solutions were prepared by diluting the sodium lactate aqueous solution (non-PAW) and plasma-activated sodium lactate aqueous solution (PAW) to 12.5, 25, and 50 times, respectively. The plasma irradiation device was the same as that used in Experiment A. The plasma irradiation time was 300 seconds. These solutions were supplied to the soil every other day.

[0067] Figure 5 is a table showing the seven types of aqueous solutions used in Experiment B. As shown in Figure 5, "C" is distilled water and is the control group. "T-1" is a 27 mM sodium lactate aqueous solution diluted 12.5 times. "T-2" is a 27 mM sodium lactate aqueous solution diluted 25 times. "T-3" is a 27 mM sodium lactate aqueous solution diluted 50 times.

[0068] "T-4" is a plasma-activated sodium lactate aqueous solution (PAW) obtained by diluting a 27 mM sodium lactate aqueous solution irradiated with atmospheric pressure plasma 12.5 times. "T-5" is a plasma-activated sodium lactate aqueous solution (PAW) obtained by diluting a 27 mM sodium lactate aqueous solution irradiated with atmospheric pressure plasma 25 times. "T-6" is a plasma-activated sodium lactate aqueous solution (PAW) obtained by diluting a 27 mM sodium lactate aqueous solution irradiated with atmospheric pressure plasma 50 times.

[0069] 2. Experimental Results 2-1. Properties and components of aqueous solutions Figure 6 is a table showing the properties and components of each aqueous solution. As shown in Figure 6, the pH tends to approach 7 as the aqueous solution is diluted. The electrical conductivity (EC) decreases as the aqueous solution is diluted. The total organic carbon (TOC) and total carbon (TC) also decrease as the aqueous solution is diluted.

[0070] 2-2. Bacterial growth in culture medium Figure 7 is a table showing the number of bacteria cultured in LB medium mixed with each aqueous solution. The number of Bacillus subtilis and Escherichia coli was highest in LB medium mixed with "T-4". The growth-promoting effect of plasma-activated sodium lactate aqueous solution (PAW) tends to be higher than that of sodium lactate aqueous solution (non-PAW). Furthermore, the growth-promoting effect tends to decrease with increasing dilution ratio.

[0071] 2-3. Growth of bacteria in soil Figure 8 is a table showing the total number of bacteria grown in soil mixed with each aqueous solution. Figure 8 shows the total number of bacteria in the initial state, after one week, and after two weeks. As shown in Figure 8, when sodium lactate aqueous solution (non-PAW) is used, the total number of bacteria tends to decrease from the initial state. On the other hand, when plasma-activated sodium lactate aqueous solution (PAW) is used, the total number of bacteria increases from the initial state. The rate of increase in the total number of bacteria is similar from T-4 to T-6. Among these, the rate of increase in the total number of bacteria was greatest when T-4 was used.

[0072] 2-4. Soil composition after cultivation Figure 9 is a table showing the soil composition after cultivating komatsuna (Japanese mustard spinach) in soil supplied with each aqueous solution. The amount of each component in the soil treated with plasma-activated sodium lactate aqueous solution (PAW) tends to be higher than the amount of each component in the soil treated with sodium lactate aqueous solution (non-PAW). Furthermore, the amount of each component tends to be higher as the dilution ratio decreases. Note that soil T-4 contains the highest amount of each component.

[0073] 2-5. Growth rates of crops in various aqueous solutions 2-5-1. Brasika Lapa Figure 10 is a graph showing the growth rate of Brasika Rapa. The horizontal axis of Figure 10 represents the type of aqueous solution supplied to the soil. The vertical axis of Figure 10 represents the fresh weight of Brasika Rapa. The vertical axis is normalized with distilled water used as 100%. The fresh weights were heaviest in the following order: T-4 (163%), T-5 (155%), T-6 (153%), T-1 (152%), T-2 (148%), and T-3 (140%).

[0074] The fresh weight of Brassica rapa grown in soil supplied with plasma-activated sodium lactate solution (PAW) was more than 150% heavier than that of Brassica rapa grown in soil supplied with distilled water.

[0075] The fresh weight of Brassica rapa grown in soil supplied with plasma-activated sodium lactate solution (PAW) was heavier than that of Brassica rapa grown in soil supplied with non-PAW sodium lactate solution.

[0076] Furthermore, the fresh weight of Brassica rapa grown in soil supplied with sodium lactate solution (non-PAW) was heavier than that of Brassica rapa grown in soil supplied with distilled water.

[0077] 2-5-2. Spinach Figure 11 is a graph showing the growth rate of spinach. The horizontal axis of Figure 11 represents the type of aqueous solution supplied to the soil. The vertical axis of Figure 11 represents the fresh weight of the spinach. The vertical axis is normalized with the case using distilled water set to 100%. The fresh weights were heaviest in the following order: T-4 (129%), T-5 (122%), T-1 (122%), T-2 (112%), T-6 (108%), and T-3 (104%).

[0078] The fresh weight of spinach grown in soil supplied with plasma-activated sodium lactate solution (PAW) was more than 108% heavier than the fresh weight of spinach grown in soil supplied with distilled water.

[0079] The fresh weight of spinach grown in soil supplied with plasma-activated sodium lactate solution (PAW) tends to be heavier than that of spinach grown in soil supplied with sodium lactate solution (non-PAW).

[0080] Furthermore, the fresh weight of spinach grown in soil supplied with sodium lactate solution (non-PAW) was heavier than that of spinach grown in soil supplied with distilled water.

[0081] 2-5-3. Chili peppers Figure 12 is a graph showing the growth rate of chili peppers. The horizontal axis of Figure 12 represents the type of aqueous solution supplied to the soil. The vertical axis of Figure 12 represents the fresh weight of the chili peppers. The vertical axis is normalized with distilled water used as 100%. The fresh weights were heaviest in the following order: T-4 (134.5%), T-5 (131%), T-1 (119%), T-2 (118%), T-6 (108%), and T-3 (101%).

[0082] The fresh weight of chili peppers grown in soil supplied with plasma-activated sodium lactate solution (PAW) was more than 108% heavier than that of chili peppers grown in soil supplied with distilled water.

[0083] The fresh weight of chili peppers grown in soil supplied with plasma-activated sodium lactate solution (PAW) tends to be heavier than that of chili peppers grown in soil supplied with sodium lactate solution (non-PAW).

[0084] Furthermore, the fresh weight of chili peppers grown in soil supplied with sodium lactate solution (non-PAW) was heavier than that of chili peppers grown in soil supplied with distilled water.

[0085] Figure 13 is a table showing the fruit weight of chili peppers. In the cases of T-1 and T-4, there were 3 fruits, and in all other cases, there were 2 fruits.

[0086] Figure 14 is a graph showing the fruit weight of chili peppers. The horizontal axis of Figure 14 represents the type of aqueous solution supplied to the soil. The vertical axis of Figure 14 represents the average fruit weight of chili peppers.

[0087] As shown in Figures 13 and 14, the average fruit weight of the chili peppers was significantly heavier in the case of T-4 compared to the other cases. In the case of T-5, there were 2 fruits, and in the case of T-1, there were 3 fruits, but the total fruit weight in T-5 was heavier than the total fruit weight in T-1.

[0088] 2-6. Photographs 2-6-1. Spinach Figure 15 shows photographs comparing the growth stages of spinach plants. The spinach leaves are largest in the order of T-4, T-1, and C.

[0089] 2-6-2. Chili peppers Figure 16 shows photographs comparing the degree of growth of chili pepper fruits. The left side of Figure 16 shows chili pepper fruits grown in soil supplied with a sodium lactate solution (non-PAW). The right side of Figure 16 shows chili pepper fruits grown in soil supplied with a plasma-activated sodium lactate solution (PAW).

[0090] 3. Summary of the experiment Crops grown in soil supplied with plasma-activated sodium lactate solution (PAW) grow remarkably well. Crops grown in soil supplied with sodium lactate solution (non-PAW) also grow larger than usual.

[0091] (Note) The method for producing crops in the first embodiment involves irradiating an aqueous solution of sodium lactate with atmospheric pressure plasma to produce a plasma-activated aqueous solution of sodium lactate, supplying the plasma-activated aqueous solution of sodium lactate to the soil, and growing crops in the soil while increasing the number of bacteria in the soil.

[0092] The method for producing crops in the second embodiment involves increasing the available phosphorus in the soil while growing the crops.

[0093] The third embodiment of the method for producing crops involves irradiating crops growing in the soil with atmospheric pressure plasma to increase the number of bacteria in the soil while promoting crop growth.

[0094] The fourth embodiment of the soil production method involves irradiating an aqueous sodium lactate solution with atmospheric pressure plasma to produce a plasma-activated aqueous sodium lactate solution, supplying the plasma-activated aqueous sodium lactate solution to the soil, and increasing the number of soil bacteria while growing crops in the soil.

[0095] The fifth embodiment of the soil production method involves supplying an aqueous sodium lactate solution to the soil and increasing the number of bacteria in the soil while growing crops in the soil.

[0096] The sixth embodiment of the soil production method involves irradiating crops growing in the soil with atmospheric pressure plasma, thereby increasing the number of bacteria in the soil while allowing the crops to grow in the soil. [Explanation of symbols]

[0097] P10, P20... Plasma generators 10, 11... Enclosure 10i, 11i... Gas inlet 10°, 11°... Gas nozzle 2a, 2b...electrodes P...Plasma generation area H... Hollow

Claims

1. Plasma-activated sodium lactate aqueous solution is produced by irradiating an aqueous sodium lactate solution with atmospheric pressure plasma. The aforementioned plasma-activated sodium lactate aqueous solution is supplied to the soil. To increase the number of bacteria in the soil by supplying the plasma-activated sodium lactate aqueous solution to the soil while growing crops in the soil. A method for increasing the number of soil bacteria, including [specific method / details].

2. In the method for increasing the number of soil bacteria according to claim 1, To increase the available phosphorus in the soil by supplying the plasma-activated sodium lactate aqueous solution to the soil while growing the crops. A method for increasing the number of soil bacteria, including [specific method / details].

3. A method for producing crops, wherein the number of bacteria in the soil is increased using the method for increasing the number of soil bacteria described in Claim 1 or Claim 2, and crops are grown in the soil to produce the crops.

4. A method for producing soil in which the number of bacteria has been increased using the method for increasing the number of soil bacteria described in Claim 1 or Claim 2.

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