JPH0439295B2 - - Google Patents

Description

[Detailed description of the invention]

purpose of invention

[Industrial application field]

The present invention relates to a plant cultivation method that provides water necessary for plant growth through evaporation and condensation, and also provides self-sufficient water for use in applying liquid fertilizers and spraying agricultural chemicals.

[Conventional technology]

It goes without saying that in order to carry out agriculture in dry lands such as deserts and wastelands, means of irrigation must be taken. However, even if irrigation water is available, if the water contains significant amounts of soluble salts, the salts remaining after evaporation will accumulate in the soil and be harmful. Therefore, there is a need for a plant cultivation technique that does not cause such salt damage problems. In addition, warm wastewater generated naturally or as a result of various industrial activities is used to promote plant growth and cultivation, but this heated wastewater contains substances harmful to plants, such as If it contains heavy metals, it cannot be used for cultivation. Therefore, there is also a desire for a technique for cultivating plants while avoiding the influence of these harmful substances. This objective is achieved by applying the supplied water directly into the cultivation soil, allowing it to evaporate and transfer as water vapor into the cultivation soil, where it is condensed and providing the resulting fresh water. The following technologies have been used to achieve this. (a) Seawater is poured into a room with a sloping roof made of a material that allows sunlight to pass through, and exposed to solar heat to generate water vapor.The rising water vapor is cooled on the inner surface of the roof, and the condensed water droplets form on the slope of the roof. Let it flow down and collect it. (b) Methods that utilize fresh water obtained by carrying out industrial processes, for example, when operating a refrigerated air dryer, air contacts cooling pipes and fins of a heat exchanger, water vapor in the air is cooled and condensed water is obtained. It will be done. The above method (a) is practiced because the device has a simple structure, but it is inefficient, and the method (b) is not effective unless special conditions such as high temperature and high humidity are met. Applicants have previously invented and proposed the following plant cultivation method as a technique that is more efficient than method (a). That is, a plant cultivation bed consisting of, in order from the bottom to the top, a water-impermeable layer, a water-permeable layer, a capillary rise blocking layer, and a cultivation soil mainly composed of sand, and the surface is covered with a transpiration prevention sheet. supplying water to the layer through which the water can flow, and evaporating the water while adjusting the groundwater level so that the water does not exceed the capillary rise barrier layer and reach the cultivation soil, causing water vapor to rise in the cultivation soil; Therefore, there is a method (Japanese Patent Application No. 58-52274, JP-A-59-175830) that condenses water vapor to keep the cultivation soil moist to provide the necessary moisture to plants. Furthermore, in this method, by providing a cooling means in the layer of cultivation soil, we developed a method that can ensure self-sufficiency of fresh water necessary for plant growth and control the supply amount (particularly). Hope
59-145666, Special Publication No. 4-3166). In this invention, when the amount of water condensed in the cultivation soil is large, part of it rises due to capillary action and is useful for plant growth, but part of it flows down. If this flowing water can be recovered, it will be possible to obtain the complete water necessary for plant growth, and also to be self-sufficient in the water used for applying liquid fertilizers and spraying pesticides.

[Problems to be solved by the invention]

The purpose of the present invention is to improve the above-mentioned invention to collect and recover condensed water to secure water necessary for cultivating plants, and also to be able to self-sufficient water for applying liquid fertilizer and spraying pesticides. Our goal is to provide a method of cultivating plants that is possible. Composition of the invention

[Means to solve the problem]

As shown in FIG. 1 or 2, the plant cultivation method of the present invention includes, in order from the bottom to the top, a water-impermeable layer, a water-permeable layer, a capillary rise blocking layer, and a cultivation soil such as The water in the plant cultivation bed is made up of a sand layer, a cooling means is provided in the cultivation soil layer, a water collection means is provided in the capillary rise blocking layer, and the surface of the cultivation soil is covered with a transpiration prevention sheet. Supplying hot water to a layer where water can flow, evaporating water and raising water vapor while adjusting the groundwater level so that the water does not exceed the capillary rise blocking layer and reach the cultivation soil, and providing it within the layer of the cultivation soil. The present invention is characterized in that the water vapor is cooled and condensed by the cooling means, and the condensed water generated is collected by the water collecting means, recovered, and utilized. Another aspect of the plant cultivation method of the present invention is that, as shown in FIG. 3, adjacent to the plant cultivation bed, a water-impermeable layer, a water-permeable layer, and A non-cultivation part is provided in the space above the space, and has a cooling means and a water collection means below the non-cultivation part. Hot water is supplied to the layer through which the water can flow to evaporate the water, and the rising water vapor is removed. It is characterized in that it is cooled by the cooling means, and the condensed water is repaired and recovered by the water collecting means for use.

[Effect]

In the embodiment shown in Figure 1, water vapor evaporated from hot water is actively cooled by cooling means provided within the cultivation soil layer, so that it quickly condenses into water in the cultivation soil, and the cultivation soil keep it moist. Water flowing down from the cultivation soil drips onto the water collection means, flows along the slope, and is collected in an external water collection tank. In the embodiment shown in FIG. 2, by actively cooling the cultivation soil with a cooling means provided within the layer,
Water vapor quickly condenses into water on the lower surface of the water collection means located directly below the cultivation soil, and this water flows along the slope of the water collection means and is collected in an external water collection tank. In the embodiment shown in Fig. 3, the water vapor evaporated from the hot water in the non-cultivation area is forcibly cooled by the cooling means, so it is efficiently condensed and collected by the water collecting means, and the water vapor evaporates from the hot water in the non-cultivated area. It flows along the line and is collected outside. In this non-cultivated area, there are fewer factors that affect the heat balance than in the cultivated area, so the desired amount of condensed water can be easily obtained by adjusting the temperature of the hot water, the temperature and flow rate of the refrigerant, etc.

[Embodiment]

As for the cooling means for condensing the rising water vapor, all the above-mentioned descriptions of the invention apply. That is, as the cooling means, it is preferable to use a straight pipe through which the refrigerant passes, or a pipe formed into a coil shape or a hairpin shape as necessary. Depending on the material to be distributed, it is of course necessary to use materials that can withstand it; for example, if seawater is to be flowed through, metal or plastic pipes that are resistant to seawater or have a lining that is resistant to seawater should be used. Adding fins to increase the heat transfer area is very effective. As the refrigerant to be passed through the cooling pipe, if water, seawater, underground can water, etc., whose temperature is lower than the temperature of the hot water supplied to the layer through which water can flow, can be used, it may be used. It is also advantageous to use pad-circulated water of the pad-and-fan method, which is used as one of the methods for cooling and humidifying high-temperature, low-humidity air.
Organic cooling media such as Freon gas may also be used if the power to drive the compressor is available. The larger the temperature difference between the refrigerant and the hot water side, the better, but it is sufficient that the temperature of the refrigerant is about 5 to 10 degrees Celsius lower than the temperature of the hot water. In some cases, it may be advantageous if there is a vaporization facility for LPG, LNG, etc. nearby, and the cold energy can be used. The findings already disclosed also apply to other factors. Just to be sure, the cultivation soil is
Also in the present invention, soil with a particle size distribution that allows water vapor to easily pass through, such as soil mainly composed of sand, is used. Artificial sand such as synthetic vermiculite or resin fibers may also be used. The hot water source may be naturally occurring or industrially produced hot water. A typical example is warm seawater. From the point of view of plant growth, the temperature of hot water in the cultivation area should be approximately 30 to 38℃, but the temperature of the hot water in the non-cultivation area should be 35℃ or higher, preferably
It is most effective to use something close to 40℃. If the temperature is insufficient, but some kind of heat source is easily available, use it to warm up the area slightly. If the project is to be carried out under climatic conditions where the ground temperature differs significantly between daytime and nighttime, it is recommended to take advantage of this fact. For example, as a hot water source, seawater that has been heated by flowing over land heated by solar heat can be used, and as cooling water, seawater that has been cooled by flowing over cold land at night can be used as a cooling water source. Measures can be taken such as storing one or both in a suitable storage tank and using them. The transpiration prevention sheet that covers the surface refers to the plastic sheet used in agriculture under the name mulch sheet. Also, as already disclosed, the water-impermeable layer and the water-permeable layer are formed by concrete or plastic troughs buried above or below ground, and the capillary rise blocking layer is formed by grating and It may also be a space under the cultivation soil held by a cloth, nonwoven fabric, water vapor permeable sheet, etc. spread over it. The layer through which water can flow and the capillary rise blocking layer may be a layer of gravel, and a cloth or nonwoven fabric may be laid thereon to hold the cultivation soil, as in the previously disclosed invention. One of the means for repairing flowing condensed water, which is a feature of the present invention, is to keep the cultivation soil moist with condensed water and to collect the condensed water flowing down from the cultivation soil, as shown in Figure 1. It is made of a material that is suitable for use in water vapor and has the function of collecting water droplets dripping from above while not preventing the rise of water vapor that evaporates from hot water. For example, a perforated plate tray is used. It is also best to have the edges of the holes shallowly bent upwards to prevent the water on the board from falling back into the warm water. Alternatively, the perforated plate may be formed in a corrugated manner so that condensed water flows through the valleys and holes are provided at or near the peaks to allow water vapor to pass through. The tray is tilted to allow water droplets to flow down the slope. Another collection means has a structure suitable for collecting most of the generated condensed water outside the system.
For example, as shown in FIG. 2, a plate without openings is provided directly under the cultivation soil in contact with the cultivation soil, and water condensed on the lower surface of this plate is allowed to flow down along the slope. Another aspect of the present invention, that is, a plant cultivation method in which condensed water is collected in a non-cultivation area, can be said to be a preferred aspect when the present invention is generally applied to a greenhouse or similar equipment. In the example shown in FIG. 3, condensed water is collected only in the non-cultivation section, but it may of course also be collected in the cultivation section. Needless to say, if there is no need to vary the temperature of the hot water between the cultivation section and the non-cultivation section, there is no need for a partition between the cultivation section and the non-cultivation section. The space above the layer through which the water can flow may be filled in its upper part with a packing, in which case the cooling means may be located within the layer of packing. Although FIG. 3 shows a sealed space, it does not necessarily need to be sealed, and even if the upper part is removed, the purpose can be fully achieved. The present invention has various aspects in addition to those described above. For example, in the embodiment shown in FIG. 3, the water collection tray 9 can be a plate without openings as shown in FIG. It is preferable to use one formed integrally with the water collecting means 9.

【Example】

The plant cultivation method of the present invention was carried out in the equipment having the configuration shown in FIG. This equipment has 150 cultivation beds.
It is made using a cultivation container made of acrylic resin with a diameter of mm, and an air layer of 50 to 100 mm is used as a capillary rise blocking layer.
A cultivation soil 5 consisting mainly of sand held by a porous plate 4 is placed on top of it, a cooling pipe 7 is installed at the bottom of the cultivation soil layer, and a cooling pipe 7 is installed above the air layer 3 as a water collection means. A tray 9 made of a perforated plate was installed at an angle, a collection tank 11 was installed outside, and the surface was covered with a transpiration prevention sheet 6. Salt water adjusted to the same salinity as seawater was placed in the bottom of the container, and the temperature was controlled at 35°C using heater 8. A perforated plate was placed with a spatial layer of 30 to 80 mm apart from the warm saline water surface, and a 100 mm thick layer of river sand with an average grain size of 0.2 mm for cultivation was maintained. A stainless steel cooling pipe with an inner diameter of 4 mm, an outer diameter of 6 mm, and a length of 1300 mm was buried at the bottom of the sand layer, and tap water at 14.9°C was flowed as cooling water.
A stainless steel perforated plate with many 5 mm diameter holes was installed at an angle above the space layer. Ten tomato seedlings were planted on the top of the sand layer. The temperature of the lower layer of cultivation soil 5 was 20.5 to 21°C.
The amount of condensed water collected was 44 ml/day. If all the evaporated water were to condense in the sand, the amount of water would be about 80ml/day. The amount of water consumed by tomatoes is 80−44=36ml/day, and the amount of water consumed by this tomato seedling is 2.0
/m ² /day, which is a reasonable value for the amount of transpiration from vegetables. Therefore, in this example, in addition to providing the amount of water required by tomato seedlings, 1.2 times the amount of fresh water was separately collected. Normally, the amount of water used for miscellaneous purposes such as applying liquid fertilizer or spraying pesticides is 30 to 30% of the amount of transpiration from the plant.
It is about 50%. As the seedlings grow, the amount of transpiration will increase, and the amount of condensed water that can be collected will decrease accordingly, but in this example, the amount of externally collected water is sufficient. Effects of the Invention According to the method of the present invention, in addition to enjoying all the benefits of the invention disclosed above, the water necessary for cultivating plants can be obtained from water unsuitable for the growth of plants, and the amount of water used is can be easily controlled by adjusting the hot water temperature, refrigerant temperature and flow rate, heat transfer area of cooling pipes, etc., and excess water can be recovered and used as miscellaneous water for cultivation. It can be used as The structure of the equipment is simple, the construction cost is low, and there are almost no operational problems.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a cultivation bed showing a typical embodiment of the present invention. FIG. 2 is a similar cross-sectional view to illustrate another aspect of the invention. FIG. 3 illustrates a further aspect of the present invention.
It is a sectional view of the cultivation bed which has a non-cultivation part adjacently. 1...Water impermeable layer, 2...Water channel layer, 3
...Air layer (capillary rise blocking layer), 4...Grating, nonwoven fabric, 5...River sand (cultivation soil), 6...
Transpiration prevention sheet (multi), 7... Cooling pipe, 8...
... Heating coil, 9 ... Water collection tray, 10 ... Plant, 11 ... Water collection tank, 12 ... Non-cultivation tank, 13
...Cultivation tank.

Claims (1)

[Scope of Claims] 1. Consists of a water-impermeable layer, a water-permeable layer, a capillary rise blocking layer, and a cultivation soil layer in order from the bottom to the top, and a cooling means is provided within the cultivation soil layer. providing water collection means within the layer of the capillary rise blocking layer;
Supplying hot water to the water-permeable layer of the plant cultivation bed where the surface of the cultivation soil is covered with a transpiration prevention sheet, and adjusting the groundwater level so that the hot water does not exceed the capillary rise blocking layer and reach the cultivation soil layer. while evaporating water to raise water vapor, cooling and condensing the water vapor with a cooling means provided in the layer of the cultivation soil, and collecting and recovering condensed water produced by the water collecting means,
A plant cultivation method characterized by the use of 2. The plant cultivation method according to claim 1, wherein the capillary rise blocking layer is a space under the cultivation soil held by a grating and a cloth, nonwoven fabric, or water vapor permeable sheet spread thereon. . 3. As a water collection means, a tray made of a perforated plate is installed at an angle, and water vapor rises into the cultivation soil through the holes in the perforated plate, where it is cooled and condensed to keep the cultivation soil in a moist state, and drips onto the perforated plate. 2. The method for cultivating plants according to claim 1, wherein the collected water is collected by flowing down along a slope. 4. A patent claim in which, as a water collecting means, a plate without an opening is provided in contact with the cultivation soil and tilted directly below it, and the water condensed and collected on the lower surface of this plate is caused to flow down along the slope and collected. The plant cultivation method according to item 1. 5. The cooling means is a pipe through which a refrigerant flows, and the refrigerant is selected from water at a temperature lower than the temperature of the hot water, seawater, underground water, and an organic heat medium as set forth in claim 1. Plant cultivation method. 6. Claim 1, in which the water-impermeable layer and the water-permeable layer are formed by concrete or plastic gutters installed on the ground or buried underground. Plant cultivation method described in. 7. The method for cultivating plants according to any one of claims 1 to 6, which is carried out by supplying hot water generated naturally or as industrial waste. 8. The method for cultivating plants according to any one of claims 1 to 6, which is carried out under weather conditions in which the soil temperature is significantly different between daytime and nighttime. 9. The method according to any one of claims 1 to 6, which is carried out by supplying seawater, underground water whose temperature has been raised using solar heat, or seawater or underground water which has been heated as necessary. Plant cultivation method. 10 Adjacent to the plant cultivation bed, in order from the bottom to the top, it consists of a water-impermeable layer, a water-permeable layer, and a space above it, with a cooling means in the space and a water collection device below it. providing a means, supplying hot water to the layer through which water can flow to evaporate water, cooling the rising water vapor by the cooling means, collecting and recovering condensed water by the water collecting means, and utilizing it; A plant cultivation method characterized by: