JP2019146521A - Plant cultivation method - Google Patents

Abstract

To provide a plant cultivation method that can increase the iron content of leaf vegetable.SOLUTION: A plant cultivation method is a method for cultivating leaf vegetable while supplying nutritious liquid. Assuming that a period from dissemination until the day before a-th day is a first period, a period after a-th day until the day before b-th day is a second period, a period after b-th day until a harvest day is a third period, in the second period, nutritious liquid having pH3.5 or more and 4.9 or less to which iron is added by 0.5 ppm or more and 10.0 ppm or less is supplied as nutritious liquid, and in the third period, nutritious liquid having pH3.5 or more and 4.9 or less to which iron is added by 5.0 ppm or more and 100.0 ppm or less is supplied.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a plant cultivation method for cultivating leafy vegetables, and particularly to a method for cultivating a plant (leafy vegetables) that increases the iron content of leafy vegetables.

  Iron is a substance necessary for the production of hemoglobin in the human body, and iron deficiency and iron deficiency anemia due to deficiency have been regarded as one of the serious health problems all over the world for many years. In order to eliminate iron deficiency, it is most effective to eat foods rich in iron. For this reason, attempts have been made to contain a large amount of iron in various crops.

  For example, Patent Document 1 (Japanese Patent Laid-Open No. 2008-301733) discloses a method for producing a sprout having a high iron content by spraying an aqueous iron salt solution such as iron citrate during cultivation.

  However, when plants such as vegetables, especially leaf vegetables, whose cultivation period from seeds is longer than that of sprout are cultivated by the method of Patent Document 1, there is a problem that growth failure occurs.

  Patent Document 2 (Japanese Patent Laid-Open No. 2017-060426) cultivates leafy vegetables using a normal prescription culture solution for hydroponics, and has an iron content higher than that of the normal prescription culture solution only for a specific period before harvesting. A hydroponic cultivation method for cultivating leafy vegetables with many high iron-containing culture solutions is disclosed.

However, although the method of Patent Document 2 increases the iron content in the plant body, the drainage standard for wastewater related to factories or business establishments where the average amount of discharged water per day is 50 m ³ or more is far greater. It uses a high concentration iron-containing culture solution that exceeds the concentration, and the drainage treatment cost is high, and its feasibility is poor from the economical point of view. Furthermore, there is a risk that leaf vegetables will die from overdose.

  Thus, in the prior art, a technique for efficiently cultivating leafy vegetables containing a large amount of iron has not been established.

JP 2008-301733 A JP 2017-060426 A

  An object of this invention is to provide the cultivation method of the plant which can raise the iron content of leaf vegetables efficiently and simply.

  As a result of intensive studies in view of the above-mentioned problems, the present inventors set the pH of the nutrient solution in the range of 3.5 to 4.9 in the growth stage by supplying the nutrient solution and cultivating the leaf vegetables. The present inventors have found that the above problems can be solved by using a nutrient solution having an appropriate iron content and adding iron to the nutrient solution at least twice or more, and have completed the present invention.

  That is, in the plant cultivation method of the present invention, the first period is from the sowing to the day before the a day, the second period is from the a day to the day before the b day, and the third period is from the b day to the harvest date. In the second period, a nutrient solution having a pH of 3.5 or more and 4.9 or less to which 0.5 ppm or more and 10.0 ppm or less of iron is added as a nutrient solution is supplied. In the third phase, iron is supplied as a nutrient solution in an amount of 5.0 ppm or more. This is a plant cultivation method for supplying a nutrient solution having a pH of 3.5 or more and 4.9 or less added at 100.0 ppm or less. However, a is 7 (days) or more and 25 (days) or less, and (b-a) is 2 (days) or more and 60 (days) or less. Thus, in the second period when the roots of the plants settle, the nutrients of iron are added by adding a small amount of iron of 0.5 ppm or more and 10.0 ppm or less to the nutrient solution of pH 3.5 or more and 4.9 or less. Absorption capacity can be increased, and in the third phase thereafter, it is suitable for leaf vegetables by adding iron of 5.0 ppm to 100.0 ppm to a nutrient solution having a pH of 3.5 to 4.9. Stress can be applied and iron can be effectively contained.

  In one embodiment of the present invention, a is 7 (days) or more and 25 (days) or less.

  In one aspect of the present invention, in the middle of the third period, injection of fresh water into the nutrient solution is started.

  In one embodiment of the present invention, the fresh water is tap water or well water.

  In one aspect of the present invention, in the middle of the third period, iron is added to the nutrient solution to increase the iron concentration in the nutrient solution within a range of 99.0 ppm or less.

  In one aspect of the present invention, a fixed planting panel plate having a large number of planting holes is disposed on a cultivation bed having a gradient, and a seedling pot is placed on the cultivation bed through the planting hole, The nutrient solution is supplied to the upper surface side of the bottom surface of the cultivation bed to hydroponic the leaf vegetables.

  In one mode of the present invention, a plurality of ridges extending in the gradient direction are provided on the upper surface of the cultivation bed, the ridges are located below the planting holes, and the ridges The space is a groove, and the seedling pot is placed on the ridge, and the nutrient solution is poured into the groove.

  In one aspect of the present invention, a hydrophilic sheet is disposed on the upper surface side of the bottom surface of the cultivation bed.

  In one aspect of the present invention, the leafy vegetables are Ominae, Brassicaceae, Amaryllidaceae, Apiaceae, Lamiaceae, Amaranthaceae, Asteraceae, or Rubiaceae.

  According to the plant cultivation method of the present invention, the pH of the nutrient solution is set to a specific range, and by using a nutrient solution having an iron content according to the growth stage of leafy vegetables, iron is excessively administered to the nutrient solution. Without being able to effectively increase the iron content contained in leafy vegetables.

It is a perspective view of a cultivation bed. It is sectional drawing of the convex part of FIG. It is sectional drawing of the cultivation bed during plant cultivation. It is a top view explaining cultivation facilities.

  Hereinafter, the present invention will be described in more detail. However, the present invention is not limited to the following embodiments as long as the effects of the present invention are achieved.

  The leafy vegetables cultivated by the plant cultivation method of the present invention are preferably Ominae family, Brassicaceae family, Amaryllidaceae family, Apiaceae family, Lamiaceae family, Amaranthaceae family, Asteraceae family, or Azaza family, and spinach is particularly preferred.

  The plant cultivation method of the present invention uses a nutrient solution cultivation method for cultivating leafy vegetables by supplying a nutrient solution according to the cultivation period. Thereby, it is easy to manage various nutrients contained in leafy vegetables such as iron, and there is an advantage that there is less concern about diseases caused by cultivation in soil.

  In addition, hydroponics is divided roughly into three systems. The first method is hydroponics, and the crop is cultivated by supplying nutrients from the culture solution in the culture tank without using any soil. A 2nd system grows a crop by spraying a culture solution on a root by spray cultivation. The third method is to give a culture solution to a crop through a solid medium and aim at stable production by the buffering action of the solid medium. The plant cultivation method of the present invention is not particularly limited, and any method can be used, but hydroponics and spray cultivation are preferred because the iron distribution in the nutrient solution can be made more uniform.

  Moreover, since supply of oxygen and circulation of nutrient solution are easily performed, it is more preferable that the nutrient solution cultivation in the plant cultivation method of the present invention is a thin film hydroponics type (NFT). In addition, the preferable form of the cultivation bed for performing oxygen supply and nutrient solution effectively is mentioned later.

  In the present invention, the nutrient solution refers to water containing a plurality of fertilizers or a single fertilizer.

  The nutrient solution used in the present invention preferably contains at least nitrate nitrogen, phosphoric acid and potassium. The content of nitrate nitrogen is preferably in the range of 8.0 to 25.0 me / L, and more preferably in the range of 10.0 to 20.0 me / L. The phosphoric acid content is preferably in the range of 3.0 to 7.0 me / L, and more preferably in the range of 4.0 to 6.5 me / L. Moreover, it is preferable that content of potassium is the range of 3.0-14.0 me / L, and it is more preferable that it is the range of 5.0-12.0 me / L. It is preferable for growth of leafy vegetables to make nitrate nitrogen, phosphoric acid, and potassium contained in the nutrient solution within the above ranges.

  The nutrient solution is not particularly limited, and a common liquid fertilizer diluted with water can be used. For example, liquid fertilizer “High Tempo” sold by Mitsubishi Chemical Agridream Co., Ltd., “OAT House Fertilizer Series” manufactured by OAT Agrio Co., Ltd., “Sumitomo Liquid Fertilizer” manufactured by Sumitomo Chemical Co., Ltd., etc. should be used. Can do.

  In the plant cultivation method of the present invention, the pH of the nutrient solution in the second and third periods is 3.5 or more and 4.9 or less, preferably more than 3.5 and less than 4.9, more preferably more than 3.7. It is less than 4.7, more preferably 4.0 or more and 4.5 or less. By making the pH of the nutrient solution smaller than the upper limit of the above range, the leafy vegetables can be effectively absorbed with iron. In addition, from the second period where the growth of the plant is accelerated, in the third period when the iron concentration of the nutrient solution is increased, there is an advantage that the growth of the plant is not inhibited by increasing the pH of the nutrient solution above the lower limit of the above range. .

  Although the pH measurement of a nutrient solution will not be specifically limited if the objective can be achieved, For example, it can measure by the glass electrode method. The pH of the nutrient solution can be adjusted by adding sulfuric acid, nitric acid, or phosphoric acid.

  In the plant cultivation method of the present invention, iron added to the nutrient solution may be various iron compounds such as ethylenediaminetetraacetic acid (EDTA) iron chelate and citric acid iron chelate. The form of iron may be trivalent iron or divalent iron. The iron may be iron powder.

  Especially, in the plant cultivation method of this invention, it is preferable to use the iron chelate of EDTA from a viewpoint that it is cheap, is easily available, and is easy to use.

  In the plant cultivation method of the present invention, the method of adding iron to the nutrient solution is not particularly limited, and iron may be added directly to the nutrient solution, and the iron is dissolved in the nutrient solution or water in advance and the aqueous solution. In this state, it can be added to the nutrient solution. The latter addition method is preferred in terms of making the iron distribution in the cultivation nutrient solution more uniform.

  Moreover, even if the form of iron when it is added to the nutrient solution is a powder or an aqueous solution, a prescribed amount of iron may be added directly to a normal cultivation nutrient solution, and iron is added to the liquid fertilizer stock solution in advance. Then, after stirring and mixing, it may be added to the nutrient solution.

  In the present invention, the amount of iron added means the content of iron in the nutrient solution when iron is added to the nutrient solution. Specifically, it is obtained by dividing the total amount of iron obtained from the product of the amount of iron-containing liquid to be added and the iron concentration by the amount of nutrient solution to which the iron-containing liquid is added. In addition, in the thin film hydroponic type (NFT), this iron addition amount matches the iron concentration in the nutrient solution tank measured immediately after the addition. The concentration of iron in the nutrient solution can be measured, for example, by ICP emission spectrometry.

  In the entire cultivation period N (days) from sowing to harvesting of leafy vegetables, the present inventors are the first period from the sowing to the (a-1) day, and from the a day to the (b-1) day. The second period, from the b-th day to the harvest day is divided from the third period, and a is 7 (days) to 25 (days) and (b-a) is 2 (days) to 60 (days). And it finds that leaf vegetables absorb iron effectively and iron content in leaf vegetables increases by adding iron to a nutrient solution in the 2nd period in the middle of cultivation, and the 3rd period after that, respectively. It was. The plant cultivation method of the present invention is based on such knowledge, and preferably the first period in which iron is not added to the nutrient solution and the amount of iron added to the nutrient solution is 0.5 ppm or more and 10.0 ppm or less. There are two periods and a third period in which the amount of iron added to the nutrient solution is 5.0 ppm or more and 100.0 ppm or less.

  In the plant cultivation method of the present invention, it is preferable that iron is not added to the nutrient solution at the initial stage of cultivation, that is, the first period from the sowing to the (a-1) day. Here, not adding iron means not adding iron to the nutrient solution. In addition, the trace amount iron derived from liquid fertilizer may be contained in the nutrient solution. Further, a small amount of iron may be added to the nutrient solution during this first period.

  When N is the total number of cultivation days from sowing to harvest date, a is N / 2 (days) or less, that is, a is preferably 50% or less of N, more preferably 45% or less. Although a (day) changes with the plant species and climate to grow, specifically, it is 1 or more, preferably 5 or more, especially 7 or more, especially 10 or more. Further, a (day) is preferably 50 or less, particularly 40 or less, particularly 30 or less. For example, in spinach, the preferable range of a (day) is 5 or more, particularly 7 or more, and 30 or less, particularly 20 or less.

  In the present invention, the first period and the second period are separated by setting a as the above range, so that the second period is reached when the roots of the plant are established and the nutrient absorption capacity is increased, and the iron in the nutrient solution is effective. Can be absorbed.

  In the second period from the a day to the (b-1) day, the above amount of iron is added to the nutrient solution. As described above, the amount of iron added in the second phase is 0.5 ppm or more, preferably 1.0 ppm or more, and more preferably 1.5 ppm or more. By making the amount of iron added in the second period within the above range, the plant roots can be absorbed and the nutrient absorption capacity can be increased, so that the plant can absorb the iron in the nutrient solution and the plant iron content. Can be increased efficiently. Further, the amount of iron added in the second period is 10.0 ppm or less, preferably 9.0 ppm or less, and more preferably 8.0 ppm or less. By setting the amount of iron added in the second period to be in the above range, it is possible to prevent a rapid increase in iron concentration and death in the plant in leafy vegetables, and the growth of the plant is healthy and the yield can be secured. .

  The second period from the a day to the (b-1) day, that is, the period of (b-a) is set according to the crop and the climate, but is 2 (days) to 60 (days) , Preferably 5 (days) or more, and preferably 50 (days) or less. For example, in the case of spinach, it is preferably 2 (days) or more, particularly 5 (days) or more, preferably 50 (days) or less, particularly 30 (days) or less.

  In the present invention, it is preferable that after the second period, iron is added to the nutrient solution within the range of the amount added in the third period and the third period is started. The beginning of the third period is the b day from sowing, and the end of the third period is the harvest day. The number of days in the third period is 1 day or more, particularly 2 days or more, and preferably 20 days or less, particularly 15 days or less.

The amount of iron added in the third stage is 5.0 ppm or more, preferably 6.0 ppm or more, more preferably 7.0 ppm or more. The amount of iron added in the third period is preferably 1.0 ppm or more and more preferably 3.0 ppm or more than the amount of iron added in the second period. By setting the amount of iron added in the third period to be in the above range, leafy vegetables can be moderately stressed and iron can be effectively absorbed.

  On the other hand, the amount of iron added in the third stage is 100.0 ppm or less, preferably 60.0 ppm or less, and more preferably 30.0 ppm or less. The difference from the amount of iron added in the second period in the third period is preferably 99.0 ppm or less, more preferably 60.0 ppm or less, and particularly 10.0 ppm or less. By making the amount of iron added in the third phase the above upper limit, the concentration of iron in the nutrient solution is within the drainage standard, and there is no need to install a special filtration device. Can also be put to practical use.

  In the present invention, in the second period and the third period, iron may be added only once at the beginning, or may be added a plurality of times at different addition times. Moreover, you may add continuously. Even when it is added a plurality of times or continuously, the iron concentration in the nutrient solution after the addition is set to be within the addition range of the second period or the third period.

  In addition, in the second period or the third period, when iron is added one or more times to the nutrient solution, the iron concentration in the nutrient solution is highest immediately after the addition, and then the iron is absorbed by the plant, Decrease gradually.

  In the present invention, as in Example 1 described later, in the third period, the injection of fresh water into the nutrient solution may be started and the fresh water injection may be continued until the harvest date. When the nutrient solution is circulated and supplied by the equipment shown in FIGS. 1 to 4 described later, the amount of fresh water injected per day is preferably 1% or more, particularly 5% or more of the amount of water held in the circulation system. By injecting fresh water at a rate equal to or greater than the lower limit, stress can be applied to leafy vegetables and the iron absorption capacity in the third stage can be increased. Moreover, in order to reduce the damage to a plant body, it is preferable that the amount of fresh water injected per day is 99% or less, preferably 60% or less of the amount of water held in the circulation system.

  As this fresh water, tap water or well water is suitable. Even after the start of fresh water injection, the concentration of iron in the circulating nutrient solution is preferably in the range of the iron concentration in the third stage, and the pH is preferably 3.5 or more and 4.9 or less.

  In the present invention, as in Examples 2 and 3 to be described later, in the middle of the third period, all of the nutrient solution to be circulated by the equipment of FIGS. 1 to 4 to be described later is drained, and a nutrient solution in which iron is added to fresh water is newly added. The total amount of the nutrient solution may be replaced by adjusting to. According to this, a great stress can be given to leaf vegetables and iron absorption ability can be improved more effectively. The iron concentration of the iron-added nutrient solution after the replacement may be the same as the iron concentration of the iron-added nutrient solution before the replacement, but is preferably higher than that before the replacement. The concentration is more preferably 1.5 times or more, and further twice or more. Moreover, considering the drainage standard, it is preferably 100 times or less, more preferably 50 times or less of the iron concentration of the iron addition nutrient solution before replacement.

  There are a circulation type and a non-circulation type in how to supply the nutrient solution, and it is not particularly limited. However, the present invention provides a uniform distribution of iron in the nutrient solution, and is sufficiently and uniformly supplied to the roots of the plant. Then, it is preferable to grow leaf vegetables with the cultivation apparatus which circulates and cultivates nutrient solution like the installation of FIGS.

  In the circulation type hydroponic cultivation method, in order to reduce the nitric acid concentration in the nutrient solution, that is, to reduce the nitric acid concentration in the plant body, as described above, water injection or water change may be performed in the third period. preferable. Water injection or water replacement is, for example, a method of gradually adding new nutrient solution or fresh water while circulating the nutrient solution as in Example 1, or temporarily stopping the supply of nutrient solution as in Examples 2 and 3 Then, after replacing the water in the nutrient solution tank (child tank) with the fresh water added with iron, there is a method of starting the supply of the nutrient solution again. In particular, the water exchange is preferably a method in which the supply of the nutrient solution is once again stopped, the plant is stressed, and then the supply of the nutrient solution is started again. Thereby, absorption of the nutrient solution containing only iron can be accelerated | stimulated and the iron content of leaf vegetables can be increased. At the same time, the sugar content and the ascorbic acid content can be increased. Therefore, when adding a nutrient solution in water injection or water change, a nutrient solution containing only iron is preferable.

  In the present invention, in the second period and the third period, a cultivation bed having a gradient is used as a cultivation device, and the nutrient solution is supplied to the upper surface side of the bottom surface of the cultivation bed to hydroponic the leaf vegetables. Is preferred.

  On the cultivation bed having a gradient of the cultivation apparatus, a fixed planting panel plate having a large number of planting holes is disposed, and a seedling root pot is placed on the cultivation bed through the planting hole. The nutrient solution is supplied to the upper surface side of the bottom surface to hydroponic the leaf vegetables. A space is created between the planted panel board and the bottom of the cultivation bed. This space becomes a moisture space.

  Preferably, a plurality of ridges extending in the gradient direction are provided on the upper surface of the cultivation bed, the ridges are located below the planting holes, and the ridges are between the ridges. The seedling pots are placed on the ridges, and the nutrient solution is poured into the ridges. Moreover, it is preferable that a hydrophilic sheet is disposed on the upper surface side of the bottom surface of the cultivation bed, and the nutrient solution is supplied to the upper surface side of the bottom surface of the cultivation bed so that the leaf vegetables are hydroponically cultivated.

  By using such a cultivation device, the nutrient solution can be circulated at a certain flow rate on the upper surface side of the bottom surface of the cultivation bed, the iron distribution in the nutrient solution becomes uniform, and is sufficient for the root of the plant body And uniformly supplied. Thereby, iron can be efficiently supplied to the roots of plants.

  The cultivation apparatus may include a temperature adjusting unit that holds a nutrient solution to be supplied within a preset temperature range and a concentration adjusting unit for the nutrient solution.

  The temperature adjusting means can maintain the temperature of the circulating nutrient solution within a preset range throughout the year. The temperature adjusting means includes a temperature sensor that detects the temperature in the nutrient solution tank, a heat exchanger that is disposed in the nutrient solution tank and exchanges heat with the nutrient solution, and a heat medium that supplies the heat medium to the heat exchanger A supply line (temperature adjustment line) and a control valve that is interposed in the heat medium supply line and controls the supply amount of the heat medium to the heat exchanger by a detection signal from the temperature sensor can be used.

  The concentration adjusting means includes one or a plurality of stock solution tanks for storing stock solutions (liquid fertilizer solutions) of different types and concentrations, and a transfer line for sending the stock solution in each stock solution tank to the nutrient solution tank by a pump. And the density | concentration of the circulating nutrient solution can be adjusted by comprising from the three-way selector valve (open / close valve) etc. intervened in these transfer lines.

  It is preferable that a ridge is formed on the upper surface of the cultivation bed under the planting hole of the fixed planting panel. The width of the ridge is determined by the diameter of the seedling pot used. If the width of the ridge is narrower than the diameter of the seedling basin, the seedling basin may be displaced from the bowl-shaped convex part and tilted. Preferably, the width of the ridge is larger than the diameter of the seedling pot used, and more preferably smaller than the width of 4 mm added to the diameter of the seedling pot.

  The nutrient solution flowing on the upper surface of the cultivation bed flows through the concave stripes between the convex stripes of the cultivation bed. The seedling root pot inserted into the planting hole is placed on the upper surface of the ridge. Since the seedling root pot is not washed by the flow of the nutrient solution, it is possible to prevent the culture medium of the seedling root pot from collapsing or the medium from flowing out.

  According to this cultivation bed, it is possible to generate roots having two different forms and functions: an underwater root that grows in water and a wet root that is maintained in a moisture space and has a large number of root hairs. Underwater roots absorb mainly fertilizer and water in the nutrient solution, and wet roots absorb oxygen directly from the moisture space.

  According to this cultivation method, it is possible to cultivate a plant without relying only on dissolved oxygen in the nutrient solution, and the roots of the plant do not fall into oxygen deficiency even in cultivation in the high temperature period where dissolved oxygen tends to be insufficient.

  The suitable structure of this cultivation bed is demonstrated with reference to FIGS. Moreover, the cultivation apparatus provided with this cultivation bed is shown in FIG.

  As shown in FIGS. 1 to 3, a large number of planting holes 52 are drilled in the fixed planting panel 51 formed of lightweight foamed polystyrene. The size of the planting panel 51 is 600 mm wide, 1000 mm deep, and 35 mm thick, for example. Although the shape of the planting hole 52 may be an inverted conical shape, it is better to use a cylindrical shape having the same upper and lower diameters, and the size is larger than the diameter of the seedling pot 54 used. The interval between the planting holes 52 is determined as an appropriate interval for crop cultivation. For example, in the case of spinach, assuming that the size of the fixed planting panel 51 is as described above, a total of 45 cylindrical planting holes 52 having a diameter of 27 mm are arranged in a diamond shape at intervals of 118 mm.

  The cultivation bed 53 on which the above-described planted panel plates 51, 51 are placed on the upper surface is molded with a lightweight foamed polystyrene, like the planted panel plate 51. In the illustrated example, the two fixed planting panel plates 51 and 51 are supported by stepped portions 59 and 59 formed on both sides of the cultivation bed 53 and a receiving portion 60 formed at the center of the upper surface. An example of the size of the cultivation bed 53 is 1260 mm in width, 1000 mm in depth, and 100 mm in height of the side wall.

  A plurality of rows of ridges 56 that are continuous in the longitudinal direction are formed on the bottom surface of the cultivation bed 53 that is directly below the planting hole 52 of the planting panel 51. The nutrient solution L flows down into the groove 55 between the protrusions 56 and 56. The height of the ridges 56 is determined by the relationship with the depth of the nutrient solution L, and the width of the ridges 56 is determined by the diameter of the seedling pot 54 used. If the height of the ridges 56 is too low, it is not preferable because the seed pot 54 placed on the ridges 56 may be washed with the nutrient solution L. It is not preferable because the distance from the liquid surface of L is too far, and the water supply to the seedling root pot 54 is insufficient and the growth is delayed. If the width of the ridge 56 is narrower than the diameter of the seedling basin 54, the seedling basin 54 may fall off the hook-like ridge 56 and tilt. Desirably, the height of the ridge 56 is about 2 to 3 mm higher than the depth of the nutrient solution L, and the width of the ridge 56 is larger than the diameter of the seedling root pot 54 to be used. It is more preferable that the width is smaller than the width of 4 mm added to the diameter. The interval between the ridges 56 is equal to the interval between the planting holes 52.

  Preferably, a plurality of cultivation beds 53 are continuously provided in the longitudinal direction and installed so as to have a gradient of about 1/50 to 1/150. In this case, as shown in FIG. 2, the entire upper surface of the continuous cultivation bed 53 is covered with a plastic sheet 57 to prevent water leakage at each continuous installation place. On the plastic sheet 57, cloth, paper, etc. A hydrophilic sheet 58 is preferably laid. This hydrophilic sheet 58 is for pumping up the liquid by capillary action.

  As shown in FIG. 3, the planting panel 53 is placed on the cultivation bed 53, and the seedling pot 54 is dropped from the planting hole 52. The seedling root pot 54 is placed on the ridge 56 of the cultivation bed 53 facing directly below the planting hole 52. Next, the nutrient solution L is allowed to flow from the upstream side of the cultivation bed 53 toward the downstream side in the recess 55. When the flow rate of the nutrient solution L is 10 liters / minute per cultivation bed, the liquid level in the groove is about 2 to 3 mm. This is about half the height of the ridge 56. A moisture space having a height of about 25 mm is formed between the lower surface of the planting panel 51 and the liquid surface of the nutrient solution L in the groove.

  In the above description, the cultivation bed 53 is made of foamed synthetic resin, but using various plate-like or plate-like members in which convex and concave stripes are alternately formed in parallel, such as synthetic resin corrugated plates. Also good.

  As illustrated in FIG. 4, the cultivation apparatus that can be used in the present invention has a parent tank 86 that stores diluted nutrient solution, and at least one or more child tanks 73 that supply the nutrient solution from the parent tank 86. It is preferable that at least one cultivation bed 53 to which the nutrient solution is supplied from the child tank 73 is disposed.

  A liquid fertilizer stock solution in a stock solution tank (not shown) and water such as fresh water are supplied to the parent tank 86 from pipes 84 and 95 with supply control valves 84a and 85a to prepare a nutrient solution having a predetermined concentration. A nutrient solution having a predetermined concentration prepared in the parent tank 86 is distributed and supplied to each child tank 73 via a pump 87, a pipe 88, a three-way valve 89, a flow meter 90 and a ball tap 91. A water supply pipe 92 is connected to the three-way valve 89, and water from the pipe 92 can be supplied to the child tank 73 by switching the three-way valve 89. The liquid in each child tank 73 is supplied to each cultivation bed 53 via a pump 74 and a pipe 75.

  In FIG. 4, a plurality of the cultivation beds 53 are arranged and leaf vegetables are cultivated. The plurality of cultivation beds 53 are supplied with the nutrient solution prepared in the parent tank 86 through the child tank 73. Thereby, the nutrient solution (dilution nutrient solution) of the uniform density | concentration prepared with the parent tank 86 can always be supplied to each cultivation bed 53. FIG.

  In FIG. 4, a cultivation bed group 62 is formed by arranging a plurality of cultivation bed rows 61 (four rows in the drawing) in which a plurality of cultivation beds 53 are arranged in one row with a gradient. One child tank 73 is attached to one cultivation bed group 62.

  In the cultivation apparatus of FIG. 4, iron is preferably added to the child tank 73.

  As shown in FIG. 4, by providing the child tank 73 for each cultivation bed group 62, it is possible to manage the nutrient solution cultivated in the child tank 73 with a relatively small amount. When the harvesting is completed, it is preferable that the nutrient solution used for one cultivation bed group 62 is discarded and cultivation is started with a new nutrient solution.

  As a result, the vegetables that are cultivated in the next period without being affected by secretions from the roots (organic acids, etc.) or detachment of the epidermis cells of the roots that have flowed into the nutrient solution due to cultivation of the first crop, Stable cultivation becomes possible.

  In the conventional method, the nutrient solution is cultivated by supplying the nutrient solution to each cultivation bed using a common tank, so the nutrient solution used is to reuse the nutrient solution while adding a new nutrient solution each time. As a result, the secretion from the roots and the epidermis cells of the roots accumulate, and as the cultivation is repeated, growth inhibition called self-poisoning occurs.

Moreover, even in the case of the conventional method, it is possible to renew all of the nutrient solutions, but since it is an operation to replace all the nutrient solutions in the tank and each cultivation bed at the same time, it is necessary to discard a large amount of the nutrient solution at the same time. During this work, all vegetables cannot be grown.
As a result, during this time, vegetables cannot be shipped, and there is a problem that regular vegetables cannot be shipped.

  In FIG. 4, the nutrient solution used in one cultivation bed group 62 is returned to the child tank 73 that has supplied the nutrient solution to each cultivation bed 53 of the cultivation bed group 62 via the pipe 76 to circulate the nutrient solution. . The nutrient solution is additionally supplied from the parent tank 86 into the child tank 73 by the ball tap 91 or the like, and the nutrient solution in the child tank 73 is kept constant.

  In FIG. 4, while the cultivation is continued in some of the cultivation bed groups 62, the other cultivation bed groups 62 are cleaned for each cultivation bed group 62 such as cleaning (cleaning after harvesting is completed). The process can be advanced.

  Moreover, also when a pathogenic microbe generate | occur | produces in one cultivation bed group 62, the infection of the pathogenic microbe to the other cultivation bed group 62 can be suppressed. That is, since the nutrient solution is not returned to the parent tank 86, the contamination stops only in the closed circuit (cultivation bed group 62) that circulates the nutrient solution.

  Water can be introduced into each child tank 73 via a water supply pipe 92 and a three-way valve 89. By switching from supplying nutrient solution to supplying water in the later stage of cultivation of leaf vegetables grown in each cultivation bed group 62, the fertilizer concentration of the nutrient solution circulating through the child tank 73 and the cultivation bed 53 can be reduced. . As a result, it is possible to gradually reduce the amount of nitric acid in the plant in the latter stage of cultivation, and leaf vegetables can be harvested with the amount of nitric acid reduced.

  When nitric acid in a plant body is taken into the human body, it combines with amide nitrogen to produce nitrosamine. By lowering the fertilizer concentration of the nutrient solution in the later stage of cultivation, the nitric acid concentration in the plant body can be reduced. In addition, by reducing the concentration of nitrogen, phosphoric acid, and potash in the nutrient solution used in the later stages of cultivation, the burden on the environment can be greatly reduced even when the nutrient solution is discarded after harvesting is completed. Can do.

[Basic conditions (cultivation equipment, nutrient solution and nutrient solution flow rate)]
The cultivation bed shown in FIGS. 1 to 3 having a gradient of 1/100 has a fixed planting panel plate having 270 planting holes, and a hydrophilic sheet is arranged on the upper surface side of the bottom surface of the cultivation bed. On the bottom of the cultivation bed, as a normal cultivation nutrient solution, nutrient solution concentration: EC 3.0 dS / m, nutrient solution temperature: 20 ° C., nitrate nitrogen; 14.0 me / L, phosphoric acid: 4.0 me / L, potassium A nutrient solution of 10.0 me / L was allowed to flow at a flow rate of 10 liters per minute. The total amount of nutrient solution flowing in the child tank and through the cultivation bed (the amount of liquid retained in the circulation system) was 50 L.

[Method of adding iron]
An aqueous solution of EDTA iron chelating agent (iron concentration 13% by mass) was supplied to the child tank.

[Method for measuring pH of nutrient solution]
It was measured by the glass electrode method.

[Iron content measurement]
About each Example and the comparative example and its control, the measurement of the iron content of a sample was measured using the ICP emission-spectral-analysis apparatus (made by Seiko Electronics). In each of the examples and comparative examples, three or more strains × 3 samples were harvested.

<Comparative Example 1>
In Comparative Example 1, the cultivation period N (day) was 35 (day), a was 11 (day), and b was 32 (day). In the first period from the sowing to the 10th day, the seeds of spinach were sown in a seedling root pot and nurtured with a seedling raising device.
In the second period from the 11th day to the 31st day after sowing, in Comparative Example 1, a seedling pot having a spinach seedling that has passed 11 days after sowing is planted in the cultivation bed, and spinach is grown under the basic conditions. Cultivated. In the third period until the harvest date, on the 32nd day after sowing, 54.0 ppm of iron was added for cultivation and harvested on the 35th day. In Comparative Example 1, no pH adjustment was performed, and the pH of the nutrient solution in the second period and the third period was 5.6 to 7.9.

<Comparative Example 2>
In Comparative Example 2, the cultivation period N (day) was 35 (day), a was 11 (day), and b was 32 (day).
In the first period from sowing to the 10th day, and in the second period from the 11th day after sowing to the 31st day, Comparative Example 2 was cultivated in the same manner as Comparative Example 1.
In the third period from the 32nd day after sowing to the harvest date, cultivation was continued in the same manner as in Comparative Example 1 except that 29.0 ppm of iron was added and the cultivation was continued on the 35th day. Harvested to the eyes.
In Comparative Example 2, no pH adjustment was performed, and the pH of the nutrient solution in the second period and the third period was 5.6 to 7.9.

<Comparative Example 3>
In Comparative Example 3, the cultivation period N (day) was 27 (day), a was 11 (day), and b was 18 (day).
In Comparative Example 3, the first period until the 10th day after sowing was cultivated in a seedling device in the same manner as in Comparative Example 1.
Comparative Example 3 is then the 11th day after sowing, until the 17th day as the second stage, and at the same time as performing the planting on the 11th day after sowing, 5.0 ppm of iron was added (first addition), Further, on the 14th day after sowing, 5.0 ppm of iron was added (second addition).
From the 18th day after sowing, in the third period until the harvest date, iron was added to the added concentration of 9.0 ppm on the 18th day, the 21st day, and the 24th day (the third to fifth additions). .

  In Comparative Example 3, supply of nutrient solution from the parent tank 86 to the child tank 73 was stopped 24 days after sowing, and fresh water injection was started at a rate of 15 L / day instead. Thereafter, fresh water was continuously added until harvesting, and harvesting was performed on the 27th day. The pH of Comparative Example 3 was not particularly adjusted until 18 days after sowing, and was pH 5.6 to 7.9. The third period after the 18th day after sowing was adjusted with dilute sulfuric acid so that pH = 5.0.

<Comparative Example 4>
In Comparative Example 4, the cultivation period N (day) was 27 (day), a was 11 (day), and b was 21 (day). Moreover, the comparative example 4 was cultivated with the seedling raising apparatus by the method similar to the comparative example 1 in the 1st period until the 10th day after sowing. Then, from 11th day after sowing to the 20th day as the second period, at the same time as planting on the 11th day after sowing, 5.0 ppm of iron was added (first addition), and 14 days after sowing. On day 18 and day 18, 5.0 ppm of iron was added (the second and third additions). In Comparative Example 4, the pH was not particularly adjusted until the 18th day after sowing, and the nutrient solution was pH 5.6 to 7.9. The pH of the liquid was adjusted to 5.5.
Thereafter, in the third period from the 21st day after sowing until the harvest date, iron was added to the addition concentration of 11.0 ppm on the 21st and 24th days (4th and 5th addition). In Comparative Example 4, on the 24th day after sowing, the supply of nutrient solution from the parent tank 86 to the child tank 73 was stopped, and instead, fresh water injection was started at a rate of 15 L / day. After that, fresh water was added until harvest. The nutrient solution of Comparative Example 4 in the third period was adjusted to pH 5.5 and harvested on the 27th day.

<Example 1>
In Example 1, the cultivation period N (day) was 26 (day), a was 11 (day), and b was 18 (day).
In Example 1, the first period from sowing to the 10th day was cultivated in a seedling device in the same manner as in Comparative Example 1. Thereafter, in the second period from the 11th day to the 17th day after sowing, 5.0 ppm of iron was added (first addition) at the same time as planting on the 11th day after sowing, and dilute sulfuric acid was used. The pH was adjusted to 4.0 and the second phase was started. Further, on the 14th day after sowing, 5.0 ppm of iron was added (second addition). In the third period from the 18th day after sowing to the harvest date, iron was added at a concentration of 9.0 ppm after addition (the third addition) on the 18th day after sowing, at pH = 4.0. The third period has started. On the 21st day after sowing, supply of the nutrient solution from the parent tank 86 to the child tank 73 was stopped, and injection of fresh water adjusted to pH 4.0 at a rate of 15 L / day was started instead. Further, iron was added at 9.0 ppm on the 21st and 25th days after sowing (the fourth and fifth additions). Thereafter, fresh water was continuously added until harvesting, and harvesting was performed on the 26th day.

<Example 2>
In Example 2, the cultivation period N (day) was 33 (day), a was 11 (day), and b was 18 (day).
In Example 2, the first period from sowing to the 10th day was cultivated in a seedling raising apparatus in the same manner as in Example 1. Thereafter, in the second period from the 11th day to the 17th day after sowing, the second period was performed in the same manner as in Example 1 except that the pH of the nutrient solution was adjusted to 4.5 using dilute sulfuric acid. The first iron addition on the 11th day and the second iron addition on the 14th day were performed. Thereafter, in the third period from the 18th day after sowing until the harvest date, iron was added to 9.0 ppm on the 18th and 21st days (the third and fourth additions). On the 24th day after sowing, the supply of the nutrient solution was stopped, and the inside of the nutrient solution tank (child tank) was switched to a newly prepared (unused) iron-added nutrient solution having an iron concentration of 10.0 ppm (thereby, the 24th day) The fifth iron addition was performed on the eyes.) And cultivation was performed. Thereafter, harvesting was carried out on the 33rd day. Other conditions were the same as in Example 1.

<Example 3>
In Example 3, the cultivation period N (day) was 38 (day), a was 11 (day), and b was 18 day.
In Example 3, cultivation was performed in the same manner as in Example 2 in the first period from the sowing to the 10th day and in the second period from the 11th day to the 17th day after the sowing. From the 18th day after sowing, in the third period until the harvest date, water was changed and iron was added in the same manner as in Example 2, and cultivation was carried out until the 38th day for harvesting. That is, cultivation was performed in the same manner as in Example 2 except that the cultivation period N (days) and the third period were longer than those in Example 2. The pH of the second and third periods was 4.5, and the iron addition concentration and addition timing were the same as in Example 2.

  Table 1 shows the analysis results of the iron content in the harvested spinach.

  The addition amount of iron described in Table 1 is the iron concentration in the nutrient solution tank (child tank) immediately after iron is added to the nutrient solution. Moreover, the control plot of each Example and the comparative example was cultivated, respectively. In the control group, the pH was not adjusted (pH 5.6 to 7.9), and a nutrient solution containing no iron other than liquid fertilizer was supplied. The control group of Comparative Example 1-4 and Example 1 was similarly cultivated for water change. On the other hand, the control plots of Examples 2 and 3 were cultivated without changing water. The iron content ratio is the ratio of the iron content of spinach harvested from each control group to 100%.

  As shown in Table 1, the spinach of Examples 1 to 3 had an iron content increased by a factor of 2 or more, and the effect of the plant cultivation method in the present invention was demonstrated. In particular, Examples 2 and 3 were cultivated in such a manner that the supply of nutrient solution (fresh water containing only iron) was temporarily stopped and the plant was stressed, and then the supply of the nutrient solution was started again. Was found to increase significantly. In addition, according to the comparison between Comparative Examples 1 and 2 and each Example, by adding iron multiple times and gradually increasing the iron concentration, effectively without excessive administration of iron to the nutrient solution It has been demonstrated that the iron content of leafy vegetables can be increased. Furthermore, according to comparison between Comparative Examples 3 and 4 and each Example, it was demonstrated that the iron content of leafy vegetables can be significantly increased by lowering the pH of the nutrient solution to less than 4.9.

  Furthermore, when the sucrose content in the spinach of Example 2 was measured using an ICP emission spectroscopic analyzer (manufactured by Seiko Electronics), it was found that the content was increased 42 times. Similarly, when the spinach of Example 3 was also measured, the sucrose content was increased 48 times.

  Moreover, when the content of vitamin C in the spinach of Example 2 was measured by high performance liquid chromatography, it was found to increase 1.9 times. When the spinach of Example 3 was also measured, the vitamin C content was increased 2.7 times.

  As a result, the pH of the nutrient solution is set within a specific range, and the content of sucrose and vitamin C contained in the leaf vegetable is increased by using a nutrient solution having an iron content according to the growth stage of the leaf vegetable. It was demonstrated that In particular, in Examples 2 and 3, where the supply of nutrient solution was once stopped and the plant was stressed, and then cultivated by the method of starting the supply of nutrient solution again, the increase in sucrose and vitamin C content It was remarkable.

53 Cultivation Bed 61 Cultivation Bed Row 62 Cultivation Bed Group 73 Child Tank 86 Parent Tank 90 Flow Meter 91 Ball Tap

Claims (9)

A method for cultivating leafy vegetables by supplying nutrient solution,
The first period from sowing to the day before a day, the second period from the a day to the day before the b day, the third period from the b day to the harvest date,
In the second phase, as a nutrient solution, a nutrient solution having a pH of 3.5 or more and 4.9 or less to which iron is added at 0.5 ppm or more and 10.0 ppm or less is supplied.
In the third period, a plant cultivation method for supplying a nutrient solution having a pH of 3.5 or more and 4.9 or less to which iron is added in an amount of 5.0 ppm to 100.0 ppm as a nutrient solution.
However, a is 7 (days) or more and 25 (days) or less, and (ba) is 2 (days) or more and 60 (days) or less.   The plant cultivation method according to claim 1, wherein the a is N / 2 or less (N: days from sowing to harvesting date).   3. The plant cultivation method according to claim 1 or 2, wherein infusion of fresh water into the nutrient solution is started in the middle of the third period.   4. The plant cultivation method according to claim 3, wherein the fresh water is tap water or well water.   In the middle of the third period, iron is added to the nutrient solution to increase the iron concentration in the nutrient solution within a range of 99.0 ppm or less. On the cultivation bed with a gradient, place a fixed planting panel with many planting holes,
Place the seedling root pot on the cultivation bed through the planting hole,
The plant cultivation method according to any one of claims 1 to 5, wherein the nutrient solution is supplied to the upper surface side of the bottom surface of the cultivation bed to hydroponic the leaf vegetables. A plurality of ridges extending in the gradient direction are provided on the upper surface of the cultivation bed,
The ridge is located below the planting hole,
Between the ridges is a groove,
Place the seedling pot on the ridge,
The plant cultivation method according to claim 6, wherein the nutrient solution is allowed to flow through the recess.   The plant cultivation method according to claim 6 or 7, wherein a hydrophilic sheet is disposed on the upper surface side of the bottom surface of the cultivation bed.   The plant cultivation method according to any one of claims 1 to 8, wherein the leafy vegetables are Ominae, Brassicaceae, Amaryllidaceae, Apiaceae, Lamiaceae, Amaranthaceae, Asteraceae, or Rabbitaceae.

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