JP2015039303A - Nutrient liquid cultivation method and nutrient liquid cultivation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alternative means for natural sand used for hydroponics.SOLUTION: A raised floor-type cultivation bed filled with a granular inorganic culture medium is prepared, and while a culture solution is supplied to the inorganic culture medium, in a nutrient liquid cultivation method for cultivating a plant so that the root system of the plant can be expanded, a cooled ground product of molten slag of refuse incineration ash is used as the granular inorganic culture medium.

Description

  The present invention relates to a method for hydroponically cultivating a plant while supplying a culture solution to a granular inorganic medium, and similarly to an apparatus for hydroponically cultivating a plant.

  Hydroponic cultivation is a method for cultivating a plant while not using the soil that was essential in conventional plant cultivation, and supplying the ingredients conventionally supplied from the soil as a culture solution together with water. Hydroponic cultivation is classified into a method using a medium instead of soil and a method not using a medium (hydroponics, spray plowing). The culture medium that substitutes for the soil is classified according to the type of material (organic, inorganic or natural product, artificial product) and shape (granular, fibrous, etc.).

Hydroponics is characterized by the fact that plants can be cultivated regardless of soil conditions or even in places where there is no soil. Moreover, there is substantially no problem mainly caused by soil such as continuous cropping failure, and even if a problem occurs, it is easy to solve. Furthermore, it is possible to provide a high-floor type cultivation floor at a position higher than the ground or an indoor floor surface in indoor cultivation, thereby reducing the burden of cultivation work.
The advantages of hydroponic cultivation as described above are effective as countermeasures against the decrease in the number of agricultural workers, aging, and the decrease in farmland, which have become serious problems in recent agriculture. In hydroponic culture, the cultivation area is increasing year by year.

  As an inorganic culture medium for hydroponics, natural pebbles, natural sand, or rock wool is used. Sand is relatively superior in water retention compared to reki and relatively superior in water permeability compared to rock wool. Moreover, the root system of a plant can extend | expand easily in sand rather than the case of reki or rock wool. Therefore, it is suitable for cultivation of leaf materials (for example, salad vegetables, tangy vegetables, komatsuna) that are promoted and shipped in a short period of time. In addition, root vegetables (eg, radish, carrot, potato) can be cultivated in the sand medium.

Due to the above advantages, the hydroponics using natural sand as an inorganic medium is also increasing year by year.
Recently, however, the collection of natural sand has been severely restricted due to environmental problems, making it difficult to use sand. Natural sand having water permeability suitable for plant cultivation has limited places where it can be collected.

  Patent Document 1 discloses an invention relating to a rock wool molded product and a method for producing the same (name of the invention). The rock wool molded body is composed of fibers (F) and aggregates (S) (FIG. 1 and description of symbols). Fiber is produced from slag melted from rock (0002). Aggregates are porous particles produced by foaming slag (0013).

Patent document 1 is disclosing the culture medium for plant cultivation as a use of a rock wool molded object (0001). It also discloses that the fibers or aggregates of rock wool moldings are produced using incinerated ash molten slag discharged from a garbage incineration plant as a main raw material (claims 2 and 3).
However, Patent Document 1 does not particularly describe the technical advantage of using incinerated ash molten slag discharged from a garbage incineration plant as a main raw material. Patent Document 1 only describes that “leads to effective use of a large amount of waste waste” (0003).

JP 2003-55 A

An object of the present invention is to provide an alternative means of natural sand used in hydroponics.
An object of the present invention is also to provide a method for hydroponically cultivating a plant while supplying the culture solution to a granular inorganic medium containing materials other than natural sand, and also an apparatus for hydroponically cultivating the plant. .

  The present invention provides a stilt type cultivation bed filled with a granular inorganic medium, and cultivates the plant so that the root system of the plant extends in the inorganic medium while supplying the culture solution to the inorganic medium. It is a liquid culture method, Comprising: The hydroponic culture method characterized by using the cooling ground material of the molten slag of refuse incineration ash as said granular inorganic culture medium is provided.

The granular inorganic medium may consist only of a cooled and pulverized product of molten slag of garbage incineration ash.
The granular inorganic medium may be a mixture of a cooled pulverized product of molten slag of garbage incineration ash and natural sand. However, the ratio of the cooled and pulverized material of the molten slag of refuse incineration ash in the above mixture is preferably 30% by mass or more. The ratio of the cooled and pulverized product of the molten incinerated ash slag in the mixture is preferably 40 to 95% by mass, and more preferably 45 to 90% by mass.
The thickness of the inorganic medium is preferably 10 to 30 cm, and more preferably 15 to 20 cm.

  The present invention is a nourishing liquid cultivation apparatus comprising a stilt cultivation bed filled with a granular inorganic medium and a liquid supply device attached to the cultivation bed and supplying a culture solution to the cultivation bed, There is also provided a hydroponic cultivation apparatus characterized in that the culture medium is a cooled and ground product of molten slag of garbage incineration ash.

A drainage port for discharging the culture solution from the cultivation bed may be provided on the bottom surface of the cultivation bed.
The above-mentioned stilt type cultivation floor may consist of a container and a plurality of supports attached to the container.

  The inventor has sought a substitute for natural sand used as a granular inorganic medium in hydroponics. As a result, it was possible to obtain a granular inorganic medium that can be used in the same manner as natural sand in hydroponics by cooling and further pulverizing the molten slag of garbage incineration ash. That is, the present inventor succeeded in cultivating a plant in the same manner as when natural sand is used by using a cooled and ground product of molten slag of garbage incineration ash as a granular inorganic medium. A good result can be obtained in the same manner even when a cooled pulverized product of molten incinerated ash slag is used in combination with natural sand.

  As described above, Patent Document 1 discloses that a fiber or aggregate of a rock wool molded body is manufactured using incinerated ash molten slag discharged from a garbage incineration plant as a main raw material. Conventionally, the fibers and aggregates of rock wool molded bodies have been manufactured from slag obtained by melting rock. Patent Document 1 proposes replacing conventional slag obtained by melting rock with incinerated ash molten slag.

In the present invention, instead of natural sand, molten slag of refuse incineration ash is cooled and pulverized for use. It was completely unexpected that a result similar to that obtained using natural sand was obtained even when a cooled pulverized product of molten slag of refuse incineration ash completely different from natural sand was used.
According to the present invention, hydroponics using a granular inorganic medium can be carried out even when it becomes difficult to obtain natural sand.

It is a photograph which shows the cultivation floor which consists of a pot for sowing. It is a photograph which shows the state which filled the cultivation floor which consists of a pot for sowing with the cooling ground material of the molten slag of refuse incineration ash. It is the photograph which shows the state which the seed of the Ching ginger vegetable sown in the pot germinated. It is a photograph which shows the state of the seedling which 15 days passed after sowing. It is a photograph which shows the state which planted the seedling. It is the photograph which shows the Chinggen vegetables which 12 days passed after planting. It is the photograph which shows the Chinged vegetables which 20 days passed after planting. It is a photograph which shows the gentian vegetables which grew up using ideal sand in a reference example, and 12 days passed after planting.

[Cooled slag of waste incineration ash and mixture with natural sand]
More than 5 million tons of garbage incineration ash are discharged annually in Japan. Cooled (and further ground if necessary) molten slag of incineration ash is used as material for concrete, road pavement, and land improvement.
In the production of slag, waste incineration ash is melted at high temperature. The treatment temperature in the latest garbage treatment facility is 1200 ° C. or higher (generally 1200 to 1300 ° C.). At such a high temperature, organic matter such as plastic remaining in the garbage incineration ash is completely burned and decomposed. Low boiling point metals such as lead also volatilize. Furthermore, at a high temperature of 1200 ° C. or higher, dioxins are also completely decomposed (99.9% or higher).

  As described above, the molten incinerated ash slag produced in the latest waste disposal facility does not substantially contain harmful components and can be used for plant cultivation.

The composition of the main elements (mg / kg) contained in the molten slag of incineration ash is as follows (Characteristics of coke bed blast furnace, Takehiko Hirata et al., Proceedings of Sanitation Engineering Symposium, 5: 107-110, (See November 1, 1997).
(1) Si: 170000, (2) Ca: 170000,
(3) Al: 55000, (4) Mg: 27000,
(5) Na: 26000, (6) Fe: 23000,
(7) K: 12000, (8) S: 5200,
(9) Cu: 1700, (10) Zn: 880,
(11) Cl: 600, (12) Pb: 28

The molten slag is cooled as it is without performing any special treatment (fibrosis treatment, foaming treatment).
In the present invention, a cooled pulverized product of molten slag of refuse incineration ash is used in place of natural sand or together with natural sand. In the granular inorganic medium used for hydroponics, adjustment of water permeability is important. Therefore, when pulverizing the cooled product of molten slag, it is preferable to pulverize the cooled product to the extent that water permeability similar to that of natural sand preferably used for hydroponics is obtained.
The average particle size of the cooled pulverized product of the molten incinerated ash slag is preferably 100 to 5000 μm, more preferably 200 to 2000 μm, and most preferably 500 to 1000 μm.

  The particle size distribution is preferably as nonuniform as possible. It is preferable that particles of 40% by mass or more are included outside the range of average particle size ± 12% (0.88 × average particle size to 1.12 × average particle size), and particles of 50% by mass or more are included. More preferably, it contains 55% by mass or more of particles. Further, it is preferable that particles of 15% by mass or more are included outside the range of average particle size ± 38% (0.62 × average particle size to 1.38 × average particle size), and particles of 20% by mass or more. Is more preferable, and it is most preferable that particles of 25% by mass or more are included.

  A cooled pulverized product of molten slag of refuse incineration ash or a mixture thereof with natural sand, that is, a granular inorganic medium used in the present invention has water permeability suitable for plant cultivation. A specifically preferable water permeability is determined according to the type of plant to be cultivated. As a general guideline, in the following permeability test, the time for the water level to drop from a location 6 cm from the sand surface (11 cm from the lower end of the tube) to a location 1 cm from the sand surface (6 cm from the lower end of the tube) is 3 to 80. Seconds are preferred, 5 to 40 seconds are more preferred, and 7 to 20 seconds are most preferred.

(Water permeability test)
(1) A glass tube having an inner diameter of 13 mm and a length of 30 cm is prepared. Mark 5 cm, 6 cm, and 11 cm from the bottom of the glass tube.
(2) Cut the Kimwipe into a circle having a diameter of 3 cm, apply the center of the circle to the lower end of the glass tube to cover the lower end of the glass tube, and adhere the Kimwipe on the side of the glass tube. This will cover the lower end of the glass tube with Kimwipe.
(3) Pour sand from the lower end of the glass tube to a point of 5 cm. Shake the glass tube up, down, left, and right to see if the top of the sand matches the 5cm point from the bottom of the glass tube, and adjust the amount of sand as needed.
(4) Pour water from the top of the glass tube. After confirming that most of the water has flowed out from the lower end of the glass tube through the sand, pour water again from the top of the glass tube. Repeat this 3 times to allow water to blend in the sand.
(5) Pour water from the upper part of the glass tube so that the water surface is located about 20 cm from the sand surface (25 cm from the lower end of the tube).
(6) Measure the time (seconds) for the water level to drop from a location 6 cm (11 cm from the lower end of the tube) to a location 1 cm (6 cm from the lower end of the tube) from the sand surface.

The particle size and water permeability of the cooled pulverized product of the molten slag of incineration ash can be adjusted by the pulverization time and pulverization conditions of the molten slag cooled product. In addition, when using a mixture of cooled pulverized slag of waste incinerated ash and natural sand as a granular inorganic medium, the particle size and water permeability can be adjusted by changing the mixing ratio of the two. Can do.
When the mixture of the cooled pulverized product of molten incinerated ash slag and natural sand is used as the granular inorganic medium, the ratio of the cooled pulverized product of molten incinerated ash slag in the mixture is preferably 30% by mass or more. 40 to 95% by mass is more preferable, and 45 to 90% by mass is most preferable.

[High-floor cultivation floor]
In the present invention, a raised floor cultivation floor is employed. The stilt type is a method in which the cultivation floor is installed at a position higher than the ground or the indoor floor surface in indoor cultivation. The main advantage of stilts is improved work efficiency. Further, by isolating from the ground, invasion of various phytotoxicity, microorganisms, viruses, etc. from other media is suppressed. Furthermore, productivity can also be improved by making a cultivation floor into a multistage structure. Stilted floors are widely used as one of the advantages of hydroponics.
The height at which the cultivation floor is installed is determined in consideration of the main purpose of work efficiency. The optimal height for work varies depending on the type of plant to be cultivated and the cultivation worker (not only humans but also machines). Moreover, even if it is the same plant, the optimal height for work may differ in the cultivation initial stage and a harvesting stage. In such a case, the height of the cultivation floor may be changed.

The height of the cultivation floor (height from the ground or indoor floor surface in indoor cultivation to the upper surface of the medium in the cultivation floor) is generally 50 to 100 cm.
As a means for installing the cultivation floor at a high position, there are a gantry method and a suspension method. In the present invention, any method can be adopted. However, in the present invention using the cooled pulverized material of molten slag of garbage incineration ash or natural sand, the weight of the cultivation bed tends to be larger than other hydroponics. The gantry method is more suitable for cultivated floors that are heavy. In the case of the gantry method, the stilt type cultivation floor is composed of a container and a plurality of (usually an even number of four or more) struts attached to the container.

The size of the cultivation floor is basically determined according to the type of plant to be cultivated.
As will be described later, the culture solution is generally supplied from a tube to the cultivation bed. Therefore, it is preferable that the shape of the cultivation floor is a rectangle having a long direction along the tube. The rectangular length (long side along the tube) is preferably 30 to 2500 cm, more preferably 60 to 1000 cm, and most preferably 120 to 200 cm. The side of the rectangle (the short side perpendicular to the tube) is preferably 20 to 200 cm, and more preferably 50 to 100 cm. A plurality of rectangular cultivation beds may be connected in the vertical direction. The length in the case of connection can be 70 m or more.

The depth of the cultivation bed (thickness of the inorganic medium) is preferably 10 to 30 cm, and more preferably 15 to 20 cm. In the present invention, the cultivation bed can be made deeper than the conventional inorganic medium (generally 7 to 10 cm deep) using natural sand. By deepening the cultivation floor, it becomes possible or easy to grow root vegetables and fruit vegetables.
The upper limit of the depth of the cultivation floor depends on the loading limit (generally about 400 kg / m ² ) of the raised floor cultivation floor. The specific gravity of natural sand containing water is about 1.7. The specific gravity of the cooled pulverized product of the molten incinerated ash slag or the mixture of it and natural sand is also the same value. Therefore, when the depth of the cultivation floor is 15 cm, the weight is about 250 kg / m ² .

When using the cultivation floor from the seed sowing stage (for sowing cultivation bed), it is configured as an aggregate of pots (9 × 18 pots in Example 1 described later) obtained by subdividing the cultivation floor into seeds. May be.
The bottom surface of the cultivation floor preferably has air permeability and drainage as long as the cooled pulverized product of the molten slag of garbage incineration ash does not flow out. Therefore, the mesh sheet which has air permeability and drainage can be used for the bottom face of a cultivation floor.

[Liquid supply device]
A liquid supply device that supplies the culture solution to the cultivation floor can be attached to the cultivation floor. However, in small-scale cultivation, a culture solution may be supplied manually without providing an apparatus.
The culture solution is generally supplied to the cultivation bed by drip through a tube (microtube, drip tube). The culture solution is usually supplied in a non-circulating manner (non-circulating type). When providing a plurality of tubes on the cultivation floor, the interval between the tubes is preferably 10 to 50 cm.

In the liquid supply device, the prepared culture solution is stored in the culture solution tank and then supplied to the tube through the supply pipe, and the liquid fertilizer and water are mixed in a diluter and supplied as they are. There is a method of supplying to a tube via a liquid pipe. Either method can be adopted in the present invention.
An electric conductivity (EC) sensor, a pH sensor, or a water level measuring device may be attached to the culture medium tank. In addition, in order to replenish the components of the culture solution according to the values of these sensors (adjusting the EC and pH values), a stock solution tank, a stock solution supply pump, and a conduit for supplying the stock solution can be attached.

A moisture content sensor may be attached to the cultivation floor, and the amount of water supplied may be controlled by an automatic irrigation control device (irrigation controller) according to the measured value.
A filter, a flow meter, a pressure reducing valve, or an electromagnetic valve may be attached to the liquid supply pipe serving as the culture medium supply path.

[Cultivated plant]
The present invention is particularly suitable for cultivation of leafy vegetables, root vegetables or fruits.
As described above, conventional hydroponics using natural sand is mainly used for cultivation of leafy vegetables. In the present invention, since the cultivation floor can be deeper than before, it is possible to cultivate root vegetables and fruits that need to be deeply rooted by the cultivated plant.

Common leafy vegetables are plants from the family Asteraceae (eg, lettuce, salad vegetables, sengiku), Brassicaceae (eg, cabbage, Chinese cabbage, Chingen vegetables, Komatsuna, watercress), and red crustaceae (eg, spinach). It is. Leafy vegetables include herbs. Herbs are typically plants of the family Apiaceae (eg, parsley, chervil, dill) and Lamiaceae (eg, basil, mint, sage, thyme).
Root vegetables include plants of the Brassicaceae (eg, radish, turnip), celery (eg, carrot), asteraceae (eg, burdock), convolvulaceae (eg, sweet potato), and eggplant (eg, potato) It is.
As fruits, rose family (eg, strawberry), cucurbitaceae (eg, melon, cucumber), and eggplant (eg, tomato) plants are suitable for hydroponics.

[Culture medium]
The composition of the culture solution is the same as the culture solution used for normal hydroponics.
Below, the range of the composition (unit: me / liter) of nitrogen, phosphorus, potassium, calcium, and magnesium is shown for main leafy vegetables and fruits.

───────────────────────────────────
Leafy vegetables N (Nitric acid equivalent) P (Phosphoric acid equivalent) K Ca Mg
───────────────────────────────────
Lettuce 5.4 to 7.1 1.3 to 2.7 3.0 to 4.4 1.6 to 2.2 0.9 to 2.0
Salad vegetables 11.9-20.5 3.6-5.5 7.2-11.5 3.6-7.1 1.8-3.2
Watercress 4.0-11.4 2.7-4.9 3.1-7.4 0.9-3.0 0.9-3.3
Spinach 9.6 ~ 19.3 2.4 ~ 4.9 4.7 ~ 11.3 3.6 ~ 9.1 2.4 ~ 4.4
───────────────────────────────────
Strawberries 3.4-10.8 1.5-3.6 2.2-6.0 0.9-3.7 1.0-2.7
Melon 8.0〜18.8 2.0〜4.4 4.0〜 6.4 4.0〜8.4 2.0〜4.0
Cucumber 13.0 ~ 13.1 3.0 ~ 4.4 5.3 ~ 5.7 5.7 ~ 7.0 2.6 ~ 3.0
Tomato 7.0 ~ 13.9 2.0 ~ 4.0 4.0 ~ 8.9 3.0 ~ 9.5 2.0 ~ 4.0
───────────────────────────────────

[Environmental management]
Either a sunlight or an artificial light source can be used as the light source. Generally, sunlight is used for outdoor cultivation, and an artificial light source is used for indoor cultivation. Sunlight and artificial light sources may be used in combination. Moreover, when plants that do not like strong sunlight are cultivated outdoors, a light shielding means such as a light shielding curtain may be used.
In indoor cultivation, carbon dioxide supply means, temperature, humidity or air flow rate adjusting means may be installed.

[Consecutive works]
Hydroponic culture is characterized by the difficulty of continuous cropping failures. In particular, in cultivation using a granular inorganic medium as in the present invention, the granular inorganic medium can be reused after washing. By washing and reusing the medium, the problem of continuous cropping problems can be almost completely solved. Therefore, in the present invention, a substantially unlimited number of continuous operations are possible.

[Example 1]
(From sowing to raising seedlings)
The molten slag of refuse incineration ash having the above-described elemental composition was cooled and pulverized to obtain a cooled pulverized product of molten slag having the following particle size distribution. The average particle size was 803 μm.

300 to 500 μm: 15% by mass
500 to 700 μm: 15% by mass
700 to 900 μm: 41% by mass
900-1100 μm: 15% by mass
1100 to 1300 μm: 12% by mass
1300 μm or more: 2% by mass

A cultivated floor composed of a sowing pot (9 × 18 = 162) shown in FIG. 1 was filled with a cooled pulverized product of molten slag of refuse incineration ash. Cooled pulverized material was able to create a good quality cultivation bed like natural sand, except that the particles were horny and the point pressure was slightly painful compared to sand. The state filled with the cooled pulverized product is shown in FIG.
A hole having a diameter of 1 cm and a depth of 1 cm was made in each pot, and seeds of chingen vegetables were sown in each hole. Medium (cooled pulverized product of molten slag of garbage incineration ash) was put in the hole, and light pressure was applied by hand. When watering, most (150/162) germinated. The germinated state is shown in FIG.
When seedlings were grown for 15 days while spraying the culture solution, seedlings could be grown in the same manner as in the case of natural sand (reference example described later). The temperature of the culture medium was almost the same as that of natural sand (only 1 ° C lower). The state of the seedling after 15 days is shown in FIG.

[Example 2]
(From planting to shipping)
Two cultivated beds having a length of 180 cm, a width of 60 cm, and a depth of 15 cm were connected in the vertical direction, and a cooled pulverized product of molten slag of garbage incineration ash was filled as a medium. The cultivation bed was installed in a stilt type so that the upper surface of the culture medium had a height of 70 cm.
As with normal sand cultivation, the first fertilizer was applied and left for 24 hours.
The seedlings grown in Example 1 were planted in a single cultivation bed with 27 strains (3 × 9 =), a total of 54 plants. The state where the seedlings are planted is shown in FIG.
Cultivation was carried out in the same manner as normal sand cultivation. Fig. 6 shows the tangy vegetables that have passed 12 days after the planting, and Fig. 7 shows the tangy vegetables that have passed 20 days after the planting.
As a result, as with the cultivation using ideal sand (the following reference example), it was possible to cultivate tangy vegetables.

[Reference Example 1]
Natural sand was sieved, classified by particle size, and mixed again to prepare artificially ideal sand. The mixing ratio was 10% by mass for particles having a particle size of 100 to 300 μm, 70% by mass for particles having a particle size of 300 to 500 μm, and 20% by mass for particles having a particle size of 1000 to 4000 μm.
Using this ideal sand, cultivation was carried out in the same manner as in Examples 1 and 2, and used for comparison.
FIG. 8 shows a tangy vegetable that has been cultivated in the same manner as in Example 2 and 12 days have passed since the planting.

In the present invention, a cooled pulverized product of molten slag of incineration ash is used instead of or together with natural sand used for hydroponics. According to the present invention, even when a cooled pulverized product of molten slag of garbage incineration ash is used, it has become possible to cultivate a plant in the same manner as when natural sand is used.
Thereby, even if it becomes difficult to collect natural sand, the same hydroponics can be carried out.

Claims (4)

  A nourishing hydroponics method that cultivates a plant so that the root system of the plant grows in the inorganic medium while preparing an elevated bed filled with a granular inorganic medium and supplying the culture liquid to the inorganic medium. A hydroponic cultivation method using a cooled and pulverized product of molten slag of garbage incineration ash as the granular inorganic medium.   The hydroponic cultivation method according to claim 1, wherein the granular inorganic medium consists only of a cooled and ground product of molten slag of garbage incineration ash.   The granular inorganic medium is a mixture of a cooled pulverized product of molten incinerated ash slag and natural sand, and a ratio of the cooled pulverized product of molten slag of incinerated ash in the mixture is 30% by mass or more. Item 4. The hydroponics method according to item 1.   A nourishing liquid cultivation device comprising a stilt cultivation bed filled with a granular inorganic medium and a liquid supply device attached to the cultivation floor and supplying the culture liquid to the cultivation floor, wherein the granular inorganic medium is garbage incinerated A hydroponic cultivation apparatus, which is a cooled pulverized product of molten slag of ash.