JP5140571B2 - Hydroponics method of leaf vegetables - Google Patents

Description

The present invention relates to a hydroponic cultivation method for leafy vegetables that have excellent taste and are less likely to discolor even after long-term storage after harvesting.

In recent years, the demand for raw vegetable salad using raw vegetables has increased. Fresh vegetable salads such as Sunny lettuce and leaf lettuce that eat leaves are mainly used. For fresh vegetable salads, the freshness of the leaf vegetables used is required. However, most of the leaf vegetables sold in general are leaf vegetables cultivated in the open ground. Leafy vegetables cultivated in the open field are not cultivated in a bacterially controlled environment, so there are many cases where bacteria in the soil adhere to them, and when stored raw, they turn brown during storage and are difficult to keep. There is a tendency. Therefore, hydroponics that are cultivated in a controlled environment are attracting attention.

Hydroponics includes submerged hydroponics that are cultivated by filling the nutrient solution, thin-film hydroponics that is cultivated by shallowly feeding the nutrient solution, and spray hydroponics that is cultivated by spraying the nutrient solution. Since submerged hydroponics and thin-film hydroponics immerse the roots in the nutrient solution, they tend to cause respiratory problems, and various hydroponics by spray hydroponics have been proposed. For example, Japanese Patent Application Laid-Open No. 5-123069 (Patent Document 1) discloses a method in which a nutrient solution is made into a mist of 5 μm or less and is sent to the planting bed together with air, and Japanese Patent Application Laid-Open No. 2006-67999 (Patent Document 2) includes 50 μm A method of spraying the following nutrient solution mist intermittently has been proposed.

However, the proposed method has a problem in that it is large in terms of equipment in order to make the nutrient solution into a predetermined ultrafine mist, and in view of maintenance of the equipment, there is a problem that productivity is inferior in terms of cost. In addition, spray hydroponics using the above-mentioned very fine mist nutrient solution has a problem that growth is delayed and not economical. Moreover, depending on the nutrient solution used in spray hydroponics, a product with good taste may not be obtained, and further improvement is desired.

Japanese Patent Laid-Open No. 5-123069 JP 2006-67999 A

Therefore, an object of the present invention is to provide a hydroponic cultivation method for leafy vegetables that are excellent in taste and that do not change color even after long-term storage after harvesting.

In order to achieve the above object, the present inventors have conducted intensive research on the entire cultivation process of hydroponics. As a result, if the specific hydroponic cultivation is performed for a specific period and the use method and concentration of the nutrient solution used for hydroponic cultivation are specified, it is surprisingly excellent in taste and discolored even after long-term storage after harvesting. It has been found that difficult leaf vegetables can be obtained, and the present invention has been completed.

That is, the present invention
This is a hydroponics method for leafy vegetables in which the seedlings are grown for 4 to 13 days by first submerged hydroponics, for 20 to 8 days by spray hydroponics, and then for 1 to 3 days by second submerged hydroponics. The spray hydroponic solution uses a mist of nutrient solution having an average size of 70 to 180 μm. Containing salt, the concentration of each nutrient solution is the electric conductivity excluding the water-soluble calcium salt, 0.7-1.3 mS / cm, 0.3-0.7 mS / cm, 0.1-0. Hydroponics method of leafy vegetables that is 4 mS / cm,
It is.

According to the present invention, since leaf vegetables that are excellent in taste and are hard to discolor even after long-term storage after harvesting are obtained, there is a further increase in demand for, for example, raw vegetable salads that use raw leaf vegetables as food ingredients. Be expected.

The present invention will be described in detail below. Hydroponics refers to a cultivation method that does not require a solid medium such as soil. Hydroponics includes submerged hydroponics that are cultivated by filling the nutrient solution, thin-film hydroponics that is cultivated by shallowly feeding the nutrient solution, and spray hydroponics that is cultivated by spraying the nutrient solution. In the hydroponics method of the present invention, seedlings after seedling are cultivated in the order of first submerged hydroponic, spray hydroponic, and second submerged hydroponic.

The object of the hydroponics method of the present invention is leafy vegetables. Leaf vegetables are vegetables which eat the part of a leaf, and in this invention, as long as it is a vegetable which can be planted and grown on the growth panel, any thing may be sufficient. Examples of such leafy vegetables include sunny lettuce, leaf lettuce, spinach, salad vegetables, frilled ice, Japanese mustard vegetables, and pak choi.

The first aspect of the hydroponics method for leafy vegetables of the present invention is to perform cultivation by the first submerged hydroponic, spray hydroponic and second submerged hydroponic for a specific period. Specifically, the seedlings after raising are cultivated in the first submerged hydroponics for 4 to 13 days, preferably 5 to 12 days, spray hydroponics for 20 to 8 days, preferably 17 to 10 days, and then the second Cultivate for 1 to 3 days by submerged hydroponics. In addition, since it is necessary to grow the leaf vegetables of this invention so that it can be harvested, although it depends on the kind of leaf vegetables, it is preferable to carry out the total period of liquid-type hydroponic and spray hydroponic for 20 to 30 days. The seedling is a period from seeding of leaf vegetable seeds to transplanting to a transplanting panel in order to start the first submerged hydroponics.

If the first submerged hydroponics period is shorter than the above range, the growth of roots may be delayed, and leaves may be deflated during spray hydroponics, and if it is long, the taste of leaf vegetables is inferior. If the spray hydroponics period is shorter than the above range, the taste of leafy vegetables is inferior. In addition, if the second submerged hydroponics period is shorter than the above range, the taste of leafy vegetables may be inferior, and if it is longer, the lower leaves are yellowed and there are not many bad leaves.

The second feature of the hydroponics method of leafy vegetables of the present invention is that, in addition to the cultivation order and period, the cultivation method by spray hydroponics sprays a nutrient solution misted to a specific size. Specifically, a misted nutrient solution having an average size of 70 to 180 μm, preferably 70 to 150 μm, is sprayed. If the size of the misted nutrient solution is smaller than the above range, growth is delayed and it is not economical. On the other hand, when the size of the misted nutrient solution is larger than the above range, the taste of leafy vegetables is inferior.

Furthermore, in the hydroponics method for leafy vegetables of the present invention, the nutrient solution contains a water-soluble calcium salt, and each nutrient solution concentration of the first submerged hydroponic, spray hydroponic, and second submerged hydroponic is water-soluble. A third feature is that the electrical conductivity excluding the calcium salt has a specific ratio. Specifically, each nutrient solution concentration of the first submerged hydroponic, spray hydroponic, and second submerged hydroponic is the electrical conductivity excluding the water-soluble calcium salt, and 0.7 to 1.3 mS, respectively. / Cm, 0.3 to 0.7 mS / cm, 0.1 to 0.4 mS / cm, preferably 0.8 to 1.2 mS / cm, 0.4 to 0.6 mS / cm, 0, respectively. .2 to 0.3 mS / cm.

The water-soluble calcium salt contained in the nutrient solution of the present invention is indispensable for growing leafy vegetables as a kind of mineral. The water-soluble calcium salt is not particularly limited as long as it is soluble in water, and examples thereof include calcium chloride, calcium phosphate, calcium nitrate, calcium lactate, and calcium acetate. The concentration of the water-soluble calcium salt in the nutrient solution may be a concentration that is usually used in hydroponics, and specifically, is about 0.6 to 2.5 mS / cm in terms of electrical conductivity.

In the hydroponic cultivation method of the present invention, the nutrient concentrations of the first submerged hydroponic, spray hydroponic, and second submerged hydroponic are the electrical conductivities excluding the water-soluble calcium salt, respectively. 7 to 1.3 mS / cm, 0.3 to 0.7 mS / cm, and 0.1 to 0.4 mS / cm, and preferably 0.8 to 1.2 mS / cm and 0.4 to 0. 0, respectively. 6 mS / cm, 0.2 to 0.3 mS / cm. Moreover, this invention made the density | concentration of the nutrient solution of each cultivation process low except the water-soluble calcium salt as cultivation progressed with the 1st submerged hydroponic, the spray hydroponics, and the 2nd submerged hydroponics. Is preferably used because leaf vegetables with better taste are easily obtained. When the nutrient solution concentrations of the first submerged hydroponic, spray hydroponic, and second submerged hydroponic are higher than the above ranges, the taste of leaf vegetables is inferior. On the other hand, when each nutrient solution concentration of the first submerged hydroponic and spray hydroponics is lower than the above range, leaf vegetables that can be delayed in growth become small, and the nutrient solution concentration of the second submerged hydroponic is within the above range. If it is lower, yellowing of the lower leaves proceeds, which is not preferable.

The method for cultivating leafy vegetables of the present invention is to perform the above-mentioned specific hydroponics for a specific period, and by specifying the use method and concentration of the nutrient solution used for hydroponics, the reason is not clear, but the test examples described later As shown in the figure, leaf vegetables that are less likely to discolor even when stored for a long period of time are obtained compared to commercially available spray hydroponic leaf vegetables.

Next, typical cultivation methods of the present invention will be described in detail. Note that the present invention is not limited to this. First, seeds of leaf vegetables are sown on a nursery bed such as a urethane mat at regular intervals (for example, 1 to 5 cm). The sowed urethane mat is transferred to a nursery shelf in a vat and soaked in a nutrient solution containing a water-soluble calcium salt to grow the seedling. Although the nutrient solution depends on the type of leaf vegetable, the concentration of the water-soluble calcium salt is about 0.6 to 2.5 mS / cm in terms of electrical conductivity, and the concentration of the nutrient solution excluding water-soluble calcium is the electrical conductivity. It is good to use a thing of about 0.5-2.0 mS / cm in conversion.

The seedling on the raised urethane mat is transplanted to the transplanting panel, and the first submerged hydroponics of the present invention is started. For the transplantation, it is preferable to use the urethane mat cut into a predetermined size for each seedling, and the cut urethane mat is transplanted into the hole of the transplant panel. Since the transplanting panel is used for a period until the seedlings are transplanted and grown to a certain extent until they are planted on the growing panel, it is preferable to use a panel having more holes than the growing panel at regular intervals. Specifically, for example, the size of 600 × 900 mm used in the embodiment and having 120 holes can be used.

The first submerged hydroponics of the present invention needs to be performed for 4 to 13 days, preferably 5 to 12 days. In addition, the first submerged hydroponics is not limited as long as it is a generally performed method using a panel. For example, the first submerged hydroponics is performed by, for example, cultivating a transplanting panel floating on the water surface of the nutrient solution. Good to do. Moreover, as for the nutrient solution used by the 1st submerged hydroponics, the density | concentration of the nutrient solution except a water-soluble calcium salt is 0.7-1.3mS / cm, Preferably 0.8-1 in conversion of electrical conductivity. It is necessary to use one of 2 mS / cm. The specific concentration of the water-soluble calcium salt in the nutrient solution used in the first submerged hydroponics is preferably about 0.6 to 2.5 mS / cm in terms of electrical conductivity. The first submerged hydroponic cultivation of the present invention is carried out on the transplanting panel. If necessary, leafy vegetables grown to some extent during the first submerged hydroponics are planted from the transplanting panel to the growing panel. Then, the first submerged hydroponics may be continued with the planted growth panel.

Next, leaf vegetables planted on the growth panel are cultivated by spray hydroponics. Since the growth panel is a panel used until harvesting, a panel having holes at intervals suitable for growth until harvesting is used. Specifically, for example, the size of 600 × 900 mm used in the embodiment and having 24 holes or 32 holes can be used.

The spray hydroponics of the present invention is carried out for 20 to 8 days, preferably 17 to 10 days, and it is necessary to use a mist nutrient solution having an average size of 70 to 180 μm, preferably 70 to 150 μm. Further, the nutrient solution used in spray hydroponics is 0.3 to 0.7 mS / cm, preferably 0.4 to 0.6 mS / cm, in terms of electrical conductivity excluding the water-soluble calcium salt. There is a need. Moreover, as a specific density | concentration of the water-soluble calcium salt in the nutrient solution used by spray hydroponics, it is good to use a thing about 0.6-2.5mS / cm in conversion of electrical conductivity.

Finally, leafy vegetables are cultivated by second submerged hydroponics. In the second submerged hydroponics, it is preferable to provide a space of 2 to 15 cm, more preferably 3 to 10 cm between the growth panel and the nutrient solution so that oxygen can be absorbed from the roots. The second submerged hydroponics of the present invention needs to be performed for 1 to 3 days. The nutrient solution used in the second submerged hydroponics of the present invention is 0.1 to 0.4 mS / cm, preferably 0.2 to 0.3 mS in terms of electrical conductivity excluding the water-soluble calcium salt. / Cm must be used. Moreover, as a specific density | concentration of the water-soluble calcium salt in the nutrient solution used by the 2nd submerged hydroponics, it is good to use a thing about 0.6-2.5mS / cm in conversion of electrical conductivity.

Hereinafter, the hydroponics method for leafy vegetables of the present invention will be specifically described based on Examples and Comparative Examples. The present invention is not limited to these.

[Example 1]
One piece of leaf lettuce was sown on each 300 × 600 mm urethane mat divided into 300, and the urethane mat was transferred to a vat and immersed in a nutrient solution containing calcium chloride and allowed to grow for 10 days. The nutrient solution is fertilizer that does not contain water-soluble calcium salt (Otsuka Chemical Co., Ltd., trade name “Otsuka House S1”) diluted with water to have an electrical conductivity of 1 mS / cm, and calcium chloride is added. The electrical conductivity was 2 mS / cm (the concentration of calcium chloride was 1 mS / cm in terms of electrical conductivity).

The seedlings on the raised urethane mat were cut into sections and transplanted to a transplanting panel having a size of 600 × 900 mm and 120 holes. And the transplanting panel transplanted to the water surface of the nutrient solution was floated, and the first submerged hydroponics was performed for 7 days. The nutrient solution is fertilizer that does not contain water-soluble calcium salt (Otsuka Chemical Co., Ltd., trade name “Otsuka House S1”) diluted with water to have an electrical conductivity of 1 mS / cm, and calcium chloride is added. The electrical conductivity was 2 mS / cm (the concentration of calcium chloride was 1 mS / cm in terms of electrical conductivity).

Next, the leaf lettuce grown by the first submerged hydroponics was planted in a growth panel having a size of 600 × 900 mm and having 24 holes. Then, a sprayed hydroponics was carried out for 14 days by spraying a misted nutrient solution having an average size of 120 μm from the lower side of the growth panel. The nutrient solution is a fertilizer that does not contain water-soluble calcium salt (Otsuka Chemical Co., Ltd., trade name “Otsuka House S1”) diluted with water to an electrical conductivity of 0.5 mS / cm, and calcium chloride. Was added to obtain an electric conductivity of 2 mS / cm (the concentration of calcium chloride was 1.5 mS / cm in terms of electric conductivity).

Finally, leaf lettuce grown by spray hydroponics was cultivated for 2 days by second submerged hydroponics while being planted on the growth panel, and then harvested. The nutrient solution is fertilizer that does not contain water-soluble calcium salt (trade name “Otsuka House S1” manufactured by Otsuka Chemical Co., Ltd.) diluted with water to an electrical conductivity of 0.25 mS / cm, and further calcium chloride Was added to obtain an electrical conductivity of 2.0 mS / cm (the concentration of calcium chloride was 1.75 mS / cm in terms of electrical conductivity). The second submerged hydroponics was performed by providing a space about 5 cm apart between the growth panel and the nutrient solution.

Twenty strains of harvested leaf lettuce were sampled and evaluated for taste, and all the strains were excellent in taste.

[Example 2]
Salad vegetables were cultivated in the same manner as in Example 1. As a result, the harvested salad vegetables were evaluated for taste in the same manner as in Example 1. As a result, all the strains were excellent in taste.

[Example 3]
About frill ice, it cultivated by the method similar to Example 1 except having raised the seedling for 15 days. As a result, when the harvested frilled ice was evaluated for taste as in Example 1, all the strains were excellent in taste.

[Test Example 1]
The influence on the taste of leafy vegetables by the cultivation days of the first submerged hydroponic, spray hydroponic and second submerged hydroponic was investigated. That is, in Example 1, each cultivation day was changed to the number of days in Table 1, and the leaf lettuce harvested by the same method as in Example 1 was evaluated.

<Evaluation criteria for taste>
A: Excellent B: Good B: Slightly inferior
X: Inferior in taste.
-:Unrated

From Table 1, the leaf vegetables grown in the first submerged hydroponics for 4 to 13 days, in the spray hydroponics for 20 to 8 days, and in the second submerged hydroponics for 1 to 3 days are harvested with excellent taste. It is understood that In particular, leaf vegetables cultivated in the first submerged hydroponics for 5 to 12 days, in the spray plowing for 17 to 10 days, and in the second submerged hydroponics for 1 to 3 days were excellent. In addition, No. which cultivated the first submerged hydroponics for less than 4 days. In the case of No. 1, the growth of the roots was delayed and the leaves were deflated during spray hydroponics. Moreover, No. which cultivated the second submerged hydroponics for longer than 3 days. In FIG. 7, many bad leaves due to yellowing of the lower leaves were observed.

[Test Example 2]
The influence of the size of the misted nutrient solution used in spray hydroponics on the taste of leafy vegetables was investigated. That is, in Example 1, the size of the misted nutrient solution was changed to the size shown in Table 2 (average size), and the leaf lettuce harvested by the same method as in Example 1 was evaluated. In addition, the thing of the test example 1 was used for the evaluation criteria of sweetness.

From Table 2, it is understood that those sprayed with a misted nutrient solution having an average size of 70 to 180 μm are excellent in taste. In particular, leaf vegetables using a misted nutrient solution having an average size of 70 to 150 μm were excellent. In addition, the thing using the thing smaller than 70 micrometers on average was delayed in growth.

[Test Example 3]
The influence on the taste of leafy vegetables by the difference in the concentration (excluding water-soluble calcium salt) of each nutrient solution used in the first submerged hydroponic, spray hydroponic and second submerged hydroponic was investigated. That is, in Example 1, the concentration of nutrient solution (excluding calcium chloride) used in each cultivation was changed to the concentration shown in Table 3, and leaf lettuce harvested by the same method as in Example 1 was evaluated. The evaluation criteria used were those of Test Example 1. Moreover, the numerical value in a table | surface is the value which converted the density | concentration (except calcium chloride) of an actual nutrient solution into electrical conductivity, and a unit is "mS / cm".

From Table 3, the concentration (excluding the water-soluble calcium salt) of each of the first submerged hydroponic, spray hydroponic, and second submerged hydroponic is 0.7 to 1.3 mS / cm, 0 It is understood that those using concentrations of 3 to 0.7 mS / cm and 0.1 to 0.4 mS / cm are excellent in taste. In particular, the concentration of each nutrient solution (excluding the water-soluble calcium salt) is 0.8 to 1.2 mS / cm, 0.4 to 0.6 mS / cm, and 0.2 to 0.3 mS / cm, respectively. It was excellent. In addition, No. In No. 7, many bad leaves due to yellowing of the lower leaves were observed. 9 grew slowly and became small.

[Test Example 4]
What was obtained with the cultivation method of this invention confirmed that it was hard to discolor even if it stored for a long time after a harvest. That is, as a target product, the commercially available spray hydroponic leaf lettuce and the product of the present invention obtained in Example 1 were stored in a refrigerator at 5 ° C., and discoloration over time was observed.

<Evaluation criteria for discoloration>
(Double-circle): It has not discolored and is favorable.
○: The cut edge and the leaf at the bottom have slightly discolored, but are determined to be good.
Δ: Lower leaf changed to light brown.
X: The leaf turned into light brown spread.

From Table 4, it is understood that the product of the present invention is hardly discolored even after long-term storage after harvesting.

Claims (1)

This is a hydroponics method for leafy vegetables in which the seedlings are grown for 4 to 13 days by first submerged hydroponics, for 20 to 8 days by spray hydroponics, and then for 1 to 3 days by second submerged hydroponics. The spray hydroponic solution uses a mist of nutrient solution having an average size of 70 to 180 μm. Containing salt, the concentration of each nutrient solution is the electric conductivity excluding the water-soluble calcium salt, 0.7-1.3 mS / cm, 0.3-0.7 mS / cm, 0.1-0. A hydroponic cultivation method of leafy vegetables characterized by being 4 mS / cm.