JPH07250578A - Water-supplying method to soil on dry land - Google Patents

Abstract

PURPOSE:To provide a method for afforesting a dry land by supplying water to dry soil without depending on a specific water resource, e.g. rain water, river or subsoil water and keeping it in the soil. CONSTITUTION:A solid surface 1 contacting the atmosphere is cooled below the dew-point by natural radiational cooling or an artificial cooling means and vapor in the atmosphere is made to condense on the solid surface 1. The condensed water is collected from the solid surface l and supplied to soil wherein the soil is treated with a humectant in advance so that the supplied water is efficiently kept in it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supplying water to soil in a dry area, and more specifically, to rehydrate the soil in a dry area by changing the water content in the soil necessary for plant growth to the water vapor in the atmosphere. The present invention relates to a method of replenishing water to a soil in an arid area to be retained in the soil after being obtained from

[0002]

2. Description of the Related Art The difficulty of growing plants in arid areas is mainly due to the fact that the soil in the areas does not have enough water to grow the plants. Therefore, the most important issue for greening arid areas is where and how to obtain water, supply it to the soil, and keep the water in the soil so that it does not dissipate. .

Conventionally, there are known a method of transporting river water to a dry land and supplying it to the soil in order to obtain water, and a method of pumping underground water from the dry land by a deep well and spraying it on the soil. However, in order to carry out these methods, of course, the presence of appropriate rivers and underground water is necessary, and it is not practical in arid areas where rivers or underground water that can be used geographically or geologically cannot be found. . In addition, even if it can be put to practical use, there is a problem that a huge cost is required for equipment for water intake and water transportation.

[0004] There is also known a method of covering the surface of the soil to prevent the evaporation of water in the soil. This method has the advantage of effectively utilizing the water once supplied, but it is positive from the outside. Lacks a means to take water into the soil,
It is difficult to bring arid soil to the condition necessary for plant growth by this method alone.

Therefore, there has been a strong demand for the emergence of a practical and economical method for supplying water to dry soil and efficiently retaining the water in the soil in order to green the dry land.

[0006]

The present invention has been made under the above background, and provides a useful method for replenishing soil in arid land with water necessary for plant growth to provide greening in the arid area. For the purpose of contributing, more specifically, to provide a series of methods for recovering water vapor contained in the atmosphere and supplying it to the soil, and further effectively retaining the supplied water in the soil. To do.

[0007]

Means for Solving the Problems That is, in the present invention, when water necessary for plant growth is given to soil in an arid region, the solid surface in contact with the atmosphere is cooled to a temperature below the dew point, It is characterized in that steam is condensed on the solid surface, the condensed water is collected from the solid surface and supplied to the soil, and the water retention agent is added to the soil in advance to effectively retain the supplied condensed water. .

The inventor of the present invention pays attention to water vapor inexhaustibly present in the atmosphere as a source of water supply to the dry land, without relying on rainwater originally present in the dry land or a specific water source such as river or underground water. Then, we studied earnestly how to obtain this water vapor as condensed water, and after supplying condensed water to the dry soil, devised a method to efficiently retain this water in the dry soil. The present invention has been achieved by finding that plants can be grown sufficiently.

When the solid surface in contact with the atmosphere is cooled to a temperature below the dew point, water vapor in the atmosphere is condensed on the solid surface to obtain condensed water. As a method of cooling a solid surface, the present inventor first conducted an experiment as follows in consideration of utilizing radiative cooling by a natural phenomenon. That is, a solid plate having a size as shown in FIG. 1 is manufactured using materials of stainless steel and plastic, and the solid plate is placed at a certain distance from the surface of the earth, and the angle of the cooling surface with respect to the sky is measured by using the device as shown in FIG. After fixing variously, it was left to stand through the night of high emissivity, the water vapor was condensed on the surface of the solid plate, the condensed water was collected, and the weight was measured.

As a result, the amount of condensed water collected varies depending on various conditions, but in the case of a large amount, it reached to 6 g or more per one solid plate per day. The amount of condensed water is most easily affected by weather conditions, and the larger the surface temperature of the solid plate is lower than the dew point temperature, and the longer the state is, the larger the amount of condensed water is. On the other hand, it was found that when the wind blowing on the surface of the solid plate was strong, the water once condensed was vaporized and volatilized, and the collected amount was reduced.

Further, it has been found that not only the weather conditions but also the material of the solid plate, the surface shape, the installation angle with respect to the sky and the surface of the earth, and the like cause a large change in the amount of condensed water collected.

That is, although there is a difference in the amount due to the difference in the conditions, it is possible to collect the water vapor in the atmosphere as condensed water by subjecting the solid plate of the size shown in FIG. 1 to radiative cooling for one day. Was confirmed. Therefore, by enlarging this solid plate, increasing the number of sheets, and stacking the days,
It is possible to actually supply water to the soil to acquire water that contributes to the growth of plants.

In order to cool the solid surface more effectively, artificial cooling means can be used. For example, if a thermoelectric element utilizing the Peltier effect is used as a solid plate and brought into contact with the atmosphere, and the thermoelectric device is energized by a general industrial power source or a solar cell, the solid plate is cooled independently of weather conditions. At temperatures below the dew point, water vapor in the atmosphere condenses on the solid surface and condensed water is obtained. If the sensor is used to automatically and automatically adjust the cooling temperature of the solid surface to an appropriate temperature according to the temperature and humidity of the atmosphere, condensed water can be efficiently obtained.

The condensed water condensed on the solid surface is separated from the solid surface by the action of gravity or external force such as vibration, if necessary, and is collected in a storage container or the like through a conduit such as a hose and dried. Used as water for soil supply.

The soil in the arid land is often a soil having extremely low water absorption capacity such as sand sand, and by the above-mentioned measures, it is obtained from the water vapor in the atmosphere as condensed water, and the water supplied at all times passes through the soil. It is difficult to use for growing plants. The present inventor has experimentally confirmed that it is effective to add a water retention agent having high hydrophilicity and a property of retaining water once absorbed to soil as a measure for improving the problem, and Applied

As the water retention agent, a substance which does not have a harmful effect on plants and has no adverse effect on the environment is required. In addition, if the substance itself easily dissolves in water by water retention, the effect is not sustainable. From such a viewpoint, a hydrophilic organic polymer compound is suitable as the water retention agent of the present invention. Among the hydrophilic organic polymer compounds, N-acetylglucosamine or a condensate of glucosamine, chitin or chitosan, which is a natural product or a chemical structure close to that of a natural product and is easy to harmonize with the environment, is preferable because of its excellent water retention property.

To add the water retention agent to the soil, a method of directly spraying a powdery water retention agent, a method of previously dispersing or dissolving the water retention agent in water and supplying this water to the soil, and further adding the water retention agent to the soil. In order to fully support the
Any method such as a method of adding a water retention agent to the mixture and adding the mixture to the soil may be used, and the method is not limited.

[0018]

EXAMPLES The present invention will be described below with reference to examples.

Example 1 A solid plate 1 of stainless steel and acrylic having a length of 20 cm × width of 30 cm × thickness of 0.3 cm shown in FIG. 1 was cooled by a device as shown in FIG. 2 at a height of 17 to 37 cm from the ground surface. Two
Was tilted at an angle of about 35 degrees with respect to the sky, faced with the pillars 3, fixed by the columns 3, and left for one day.

Water vapor in the atmosphere is cooled by radiative cooling to the cooling surface 2
After being condensed, the obtained condensed water slipped off from the cooling surface by its own weight and was collected in the water collecting bottle 6 through the water receiving hole 4 and the water guiding pipe 5. The weight of the condensed water collected in this water collecting bottle was measured. At the same time, the surface temperature of the cooling surface 2 during water capturing is measured by the surface thermometer 7
The temperature and humidity of the atmosphere were measured with a thermo-hygrometer to calculate the dew point temperature with time, and the radiation balance on the surface was measured with a radiation balance meter.

The above experimental results were as follows. A day B day Amount of condensed water collected by the stainless steel solid plate 1 g 8 g Amount of condensed water collected by the acrylic solid plate 0.2 g 3 g The temperature difference value obtained by subtracting the dew point temperature of the atmosphere from the surface temperature of the solid plate is used overnight. Graphs plotted over time are shown in FIGS. 3 and 4. 5 and 6 are graphs in which the radiation balance on the surface of the earth is plotted overnight.

On the B-th day, the degree of negative temperature difference is larger than on the A-th day, that is, the surface temperature of the solid plate is lower than the dew point temperature and the time width is large. This is because B day is more than A day.
This is in line with the fact that the radiation balance on the surface is negative. Therefore, as described above, the amount of collected condensed water on day B is larger than the amount of collected condensed water on day A.

In the case of the stainless solid plate and the acrylic solid plate, the former has a larger amount of condensed water. Water vapor condenses on the acrylic solid plate to the same extent as on the stainless solid plate, but it flows down,
Since the collection was not carried out smoothly, the amount of condensed water collected was small.

Example 2 In the apparatus of FIG. 2 used in Example 1, a stainless plate was used as the solid plate 1, and a plurality of 4 cm × 4 cm thermoelectric elements 8 and radiator plates 9 were provided on the back side of this stainless plate as shown in FIG. Each piece was attached, and the stainless steel plate was cooled in the atmosphere while controlling the temperature of this thermoelectric element with a power supply and a current control circuit. The surface temperature of the cooling surface and the temperature and humidity of the atmosphere were measured in the same manner as in Example 1. The surface temperature could be kept 8 to 10 ° C lower than the atmospheric temperature.

FIG. 8 shows a graph in which a value obtained by subtracting the dew point temperature of the atmosphere from the surface temperature of the solid plate is plotted with time.
The amount of condensed water collected during this period was 25 g.

Example 3 An experimental slab of a test soil prepared by mixing chitin powder as a water retention agent in a sand sand soil and a comparative soil prepared by not mixing it was prepared and placed adjacent to the outdoors, and each of them was treated with low molecular weight chitosan. Western grass seeds were sown and the growth conditions of the seeds after one month were compared and observed under the same weather conditions such as rainfall.

The results are as shown in FIG. 9. Although the growth of western lawn was observed in the test soil stalk 10 containing chitin powder, the comparison soil slab 11 containing no chitin powder was observed.
No growth was observed in. That is, the water-retaining effect of chitin powder appears, and if the main side is combined with the method of supplying condensed water to the soil from the water vapor in the atmosphere according to Example 1 or 2, the scale-up of a vast dry land is performed. It is possible to replenish water effectively to the soil, which is a useful greening measure for dry land.

[0028]

The solid surface in contact with the atmosphere is cooled to a temperature below the dew point to condense water vapor in the atmosphere onto the solid surface, and the condensed water is collected from the solid surface and supplied to the soil. The present invention, in which a water retention agent is added to hold the supplied condensed water, is capable of effectively replenishing and retaining the moisture from the water vapor inexhaustibly present in the dry land, which is an epoch-making method. Is.

It is extremely significant as an effective remedial measure for the global environment to be able to contribute to the greening of arid areas by securing water without relying on a small amount of rainwater or a specific water source such as a river or an underground water.

[Brief description of drawings]

FIG. 1 is a schematic view of a solid plate according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an apparatus for condensing and collecting water vapor in the atmosphere according to an embodiment of the present invention.

FIG. 3 is a graph in which the temperature difference obtained by subtracting the dew point temperature of the atmosphere from the surface temperature of the solid plate on day A is plotted all day and night.

FIG. 4 is a graph in which the temperature difference obtained by subtracting the dew point temperature of the atmosphere from the surface temperature of the solid plate on day B is plotted all day and night.

FIG. 5 is a graph in which the radiation balance of the ground surface on day A is plotted all day and night.

FIG. 6 is a graph in which the radiation balance of the ground surface on day B is plotted all day and night.

FIG. 7 is a schematic view of a stainless steel plate to which a thermoelectric element and a heat dissipation plate according to an embodiment of the present invention are attached.

FIG. 8 is a graph plotting the temperature difference obtained by subtracting the dew point temperature of the atmosphere from the surface temperature of the stainless steel plate in one embodiment of the present invention in which a stainless steel plate is artificially cooled using a thermoelectric element, over a day and night. is there.

FIG. 9 is an observation view comparing the seed growth situation one month after sowing seeds of Western turf in a soil prepared by mixing chitin powder, which is a water retention agent, in a sand sand soil with a control example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid plate 2 Cooling surface 3 Strut 4 Water receiving hole 5 Water guide pipe 6 Water collection bottle 7 Surface thermometer 8 Thermoelectric element 9 Radiator plate 10 Chitin powder-mixed soil ridge 11 Comparative soil ridge

Claims (5)

[Claims] 1. When giving water required for plant growth to soil in a dry land, the solid surface in contact with the atmosphere is cooled to a temperature below the dew point to condense water vapor in the atmosphere onto the solid surface.
The condensed water is collected from the solid surface and supplied to the soil, and a water retention agent is added to the soil in advance to effectively retain the supplied condensed water. Method. 2. The method for replenishing water to soil in a dry land according to claim 1, wherein the solid surface in contact with the atmosphere is cooled to a temperature below the dew point by natural radiative cooling. 3. The method for replenishing water to soil in a dry land according to claim 1, wherein the solid surface in contact with the atmosphere is cooled to a temperature below the dew point by an artificial cooling means. 4. The method for replenishing water to soil in a dry land according to claim 3, wherein the artificial cooling means is a cooling means using a thermoelectric element. 5. The method for replenishing water to soil in a dry land according to claim 1, 2, 3 or 4, wherein the water retention agent is chitin or chitosan.