JP2024057137A - Cold-climate planting maintenance device, cold-climate planting maintenance method, and cold-climate athletic facility turf management method - Google Patents

Abstract

[Problem] We develop a technology to prevent damage to plants directly below a heating sheet that comes into direct contact with the planting surface when laid over the planting. [Solution] A cold-climate planting conservation device for protecting plantings in cold climates, equipped with a conservation sheet body equipped with a three-dimensional net structure and an air-permeable/water-permeable planting heating sheet, and a control panel for adjusting the temperature of the heating sheet, in which the conservation sheet body is arranged in the order of the three-dimensional net structure and the air-permeable/water-permeable planting heating sheet from the planting surface side upward, and the temperature of the heating sheet is controlled by the control panel. [Selected drawing] Figure 2

Description

The present invention relates to technology for preserving plantations in cold regions. In particular, it relates to technology for maintaining turf at sports facilities in cold regions.

In soccer stadiums in areas with heavy snowfall, such as Hokuriku, Tohoku, and Hokkaido, snow that has accumulated on the grass needs to be removed when games are held from winter to spring. In recent years, the start of the J-League season has been brought forward, making snow melting and snow removal an urgent issue for soccer stadiums in areas with heavy snowfall. Even in stadiums outside of heavy snowfall areas, there are concerns about the impact of snowfall the day before or on the day of a game, freezing of the planted soil and planting surfaces, and frost. When snow accumulates on the grass, the snow acts as an insulator and keeps the ground temperature at about 5°C, so the temperature does not drop to the point where the grass dies due to frost damage. Instead, if snow is removed in winter, the grass may be exposed to low temperatures and die, so care must be taken to maintain the ground temperature at a level that does not cause the grass to die after snow removal and to nurture the grass.
Therefore, there is a need to develop technology that can remove snow that has accumulated on the lawn or melt falling snow so that it does not accumulate, while also maintaining the temperature of the planting soil and planting surface to prevent the grass from dying.

For example, Patent Document 1 (JP Patent Publication 10-306405A) discloses a method for heating the soil for growing grass by circulating a heat medium such as hot water through pipes that have been buried in the ground beforehand. A similar method is also used in which electric heating wires are buried in the ground to heat the soil for growing grass. However, it is difficult to install a heat medium later in a facility such as a stadium that is already in operation.
Patent Document 2 (JP 2000-197415 A) discloses a soccer field and the like equipped with watering equipment and heating equipment installed on the grass surface to be melted snow or the grass surface to be prevented from accumulating, and melting snow or preventing snow accumulation by using either the watering equipment or the heating equipment, or by using both equipment together, depending on the snowfall or snow accumulation conditions.

Patent document 3 (JP Patent Publication 61-78624 A) discloses an insulation mat for raising seedlings, in which a core material made of polyurethane foam heat-retaining material, insulating material, waterproof material, or other material is covered with a covering material to provide weather resistance, waterproofing, etc.
Patent Document 4 (Japanese Utility Model Application Laid-Open Publication No. 6-52433) discloses a covering sheet for protecting lawns in winter, which is made of a cloth sheet woven using synthetic resin monofilaments for the warp and synthetic resin flat yarns that have been subjected to aluminum vapor deposition for the weft, in which the wefts are woven adjacent to each other and the warp threads are woven at a density at least twice that of the weft threads, thereby ensuring breathability to prevent the lawn from suffocating and heat retention for curing.
In addition, Patent Document 5 (JP 2019-183493 A) discloses a method for heating planting soil using a planting heating sheet having a plurality of heater units and a connecting means for connecting the heater units to each other.

Japanese Patent Application Laid-Open No. 10-306405 JP 2000-197415 A Japanese Patent Application Laid-Open No. 61-78624 Japanese Utility Model Application Publication No. 6-52433 JP 2019-183493 A

When a heating sheet is laid over a planting surface, the plant may be damaged where the sheet comes into direct contact with the planting surface. The present invention aims to develop a technology that prevents damage to the plant directly below the sheet caused by the sheet coming into direct contact with the planting surface when the sheet is laid over the planting.

1. A conservation sheet body including a three-dimensional net structure, an air-permeable/water-permeable sheet, and a heating sheet;
A control panel that adjusts the temperature of the heating sheet,
A cold region planting conservation device for protecting plantings in cold regions, comprising:
The conservation sheet body is arranged in the following order from the planting surface side to the upper side: a three-dimensional net structure, a breathable and water-permeable sheet, and a heating sheet.
A cold climate plantation conservation device characterized by controlling the temperature of the heating sheet using a control panel.
2. The cold climate plantation conservation device according to 1., characterized in that an air-permeable and water-permeable sheet is integrally provided on the upper surface side of the three-dimensional net structure.
3. The cold climate plantation conservation device according to 1. or 2., characterized in that a temperature sensor is attached between the planting surface and the heating sheet or on the surface of the heating sheet, and the control panel performs control based on the temperature detected by the temperature sensor.
A method for preserving plantations in cold climates by installing the cold climate plantation preservation device described in 4.1.
A method for preserving plantations in cold climates, comprising covering the plantations in the cold climates in the order of a three-dimensional net-like structure, an air-permeable and water-permeable sheet, and a heating sheet, and then adjusting the control panel to control the temperature.
5. The method for preserving cold-climate plantations according to 4., wherein the cold-climate plantations are turf grass provided in a sports facility.
6. The cold climate plantation conservation method according to 5., characterized in that the temperature of the heating sheet is controlled so as to maintain the temperature of the turf surface at 0 to 8°C.
7. The cold region plantation conservation method according to 5., wherein the sports facility is any one of a ball game stadium (such as a soccer field, baseball field, or rugby field), an athletics field, and a golf course (including a golf driving range).

1. According to the present invention, by installing a three-dimensional net structure between the planting surface and the heating sheet, snow falling from above is melted by the heat of the sheet, and the meltwater is allowed to permeate through, maintaining the temperature and humidity around the plants at a level that will not cause the plants to wither and die, thereby preventing low-temperature damage and high-temperature damage to the plants and keeping them in a healthy state.
2. The cold climate planting conservation device of the present invention places a three-dimensional net structure on the planting surface in a cold climate, provides a heating sheet via an air-permeable and water-permeable sheet, and heats the heating sheet to increase heat retention and protect the planting from damage caused by low temperatures. The air-permeable and water-permeable sheet can be provided integrally with the upper surface of the three-dimensional net structure. Alternatively, it can be provided separately. In addition, the heating sheet on the outside melts snow, so there is no need to remove snow. By using the cold climate planting conservation device of the present invention in sports facilities, the sports facilities can be used in the winter even in cold climates. In particular, the usability of the facilities can be improved in facilities for ball games such as soccer fields using grass, golf courses, and golf driving ranges.
In the present invention, winter refers to a period when the cold damages the planting of the target such as grass (for example, when low temperatures cause the growth rate of grass to decrease or growth disorders of stems and leaves to occur), and is different from winter on the calendar. For example, when a cold wave or snow falls in spring and the grass is adversely affected by the cold, this corresponds to winter in the present invention, and when a similar condition occurs in autumn, this corresponds to winter in the present invention. When adverse effects of the cold on grass are expected in spring or autumn, the present invention can be applied preventively. Therefore, the present invention is used during the winter in cold regions, but can also be used as a preventive measure during spring and autumn when cold air or snowfall is expected.
3. In the present invention, the space inside the three-dimensional mesh structure between the planting surface and the heating sheet is heated by the heat transmitted from the underside of the heating sheet, and the three-dimensional mesh structure covered with the breathable and water-permeable sheet keeps the warm air in the space inside the three-dimensional mesh structure, so that even in the harsh winter, the temperature of the space formed by the three-dimensional mesh structure and the ground surface does not drop to a level that would cause frost damage to plants.
Both the three-dimensional mesh structure and the breathable/water-permeable sheet have water permeability, and meltwater can seep into the planting soil without stagnating, so the space inside the three-dimensional mesh structure does not become overly humid and the plants do not become steamy.
Even if the temperature of the three-dimensional network structure itself rises, the plants will not suffer from high temperature damage because only the fibers of the three-dimensional network structure are in contact with the plants.
4. If the grass surface of a sports facility freezes in winter, the grass roots will be cut, so it is necessary to keep the soil at a temperature that does not freeze. In this invention, the temperature of the grass surface is controlled at about 5°C to 0°C, so the grass can be kept healthy and able to withstand sports such as soccer. The temperature of the heating sheet can be controlled to about 10°C to 5°C to keep the grass surface at this temperature.
By laying the planting conservation device in areas where the grass is easily damaged by low temperatures during the winter and promoting grass growth, the grass can be finished uniformly over the entire ground.
5. In soccer stadiums in cold regions or areas with heavy snowfall, the effort and cost of removing snow can be reduced when playing matches in winter. If snowfall or frost damage is predicted before a match and it is in doubt whether the match will be held, the plant protection device can be removed to allow the match to be held without delay.
By installing the plant conservation device on the grass, it is possible to melt snow and warm the ground, so it can be installed in stadiums with natural grass fields, both new and existing.

FIG. 1 is a diagram showing an overview of a cold climate planting conservation device. FIG. 2 is a diagram showing a cross-sectional configuration of a cold region planting conservation device. FIG. 1 shows an example of installation of a cold climate planting conservation device. A diagram showing the effect of installing a cold region planting conservation device.

The present invention is a cold climate planting conservation device for protecting plantings in cold climates, comprising a three-dimensional net structure, a conservation sheet body with a heating sheet, and a control panel for adjusting the temperature of the heating sheet. The conservation sheet body is arranged in the order of the three-dimensional net structure and the planting heating sheet from the planting surface side upward, and the temperature of the heating sheet is controlled by the control panel. It is preferable to provide an air-permeable/water-permeable sheet integrally or separately on the upper surface of the three-dimensional net structure to enhance the heat retention function.
In the present invention, a three-dimensional net-like structure made of artificial fibers such as polyester is placed on a planting surface, the surface of the three-dimensional net-like structure is covered with a breathable and water-permeable sheet that is permeable to water and has heat retention properties, and then a heating sheet is laid on top of that.The heating sheet does not come into direct contact with the planting surface, and an appropriate temperature space is formed on the planting surface, thereby preventing damage to the plants directly below the sheet and keeping plantings such as grass healthy.
When electricity is applied to the heating sheet placed on top of the three-dimensional mesh structure covered with the breathable and water-permeable sheet, the surface of the sheet becomes about 10°C, making it possible to melt falling snow. In addition, the heat transmitted from the underside of the heating sheet warms the space inside the three-dimensional mesh structure between the planting surface and the heating sheet to about 5°C. At this time, the three-dimensional mesh structure is covered with the breathable and water-permeable sheet, and the warmed air is kept in the space inside the three-dimensional mesh structure, so that even in the harsh winter, the temperature of the space formed by the three-dimensional mesh structure and the ground surface will not drop to a level that would cause frost damage to plants, even if there is no accumulated snow.
Heating sheets made of surface heating elements using conductive fibers, etc., also need to pass through melting snow water, so they are water permeable. The water permeability of the heating sheet can be either entirely or partially.
There is no limit to the size of the three-dimensional net structure and the breathable/water-permeable sheet, and they can be rolled up or folded and spread out over a large exercise field. On the other hand, the heating sheet is deployed over a large area by connecting units of several tens of centimeters to one meter square. Since heat is released from between the heating sheet units, a breathable/water-permeable sheet that can widely cover the planting surface is placed on the underside of the heating sheet to maintain heat in the space formed by the three-dimensional net structure.
In addition, since a space is formed by the breathable/water-permeable sheet and the three-dimensional mesh structure, the heating sheet placed on top of it can maintain the temperature within the space even if it is placed with a gap.
Both the three-dimensional net structure and the breathable/permeable sheet have excellent water permeability, and meltwater does not stagnate but penetrates into the planting soil, so the space inside the three-dimensional net structure does not become too humid and the plants do not become steamy. Even if the temperature of the three-dimensional net structure itself rises, the plants do not suffer from high-temperature damage because only the fibers are in contact with the plants.
When laying the heating sheet on top of the planting surface, a three-dimensional mesh structure is placed between the planting surface and the heating sheet, and this is covered with a breathable, water-permeable sheet that has excellent water permeability and heat retention. This makes it possible to melt snow falling from above with the heat of the sheet surface, while maintaining the temperature and humidity in the space around the plants at a level that will not cause the plants to wither or die.

The following describes a method of preserving plants by laying a planting heating sheet over the planting surface during the winter to melt snow and prevent the plants from dying due to frost damage.
The main target plant of the present invention is grass planted on sports grounds such as soccer fields.
Soccer stadiums used for the J.League have a two-month winter curing period, from early December when the J.League finishes until mid-February when the next season begins. In winter, soccer stadiums lay a highly permeable and heat-retaining curing sheet on the grass during the curing period to prevent the grass from being damaged by low temperatures. In contrast, in stadiums in areas with heavy snowfall, snow is left to pile up on the grass, and the snow acts as insulation to prevent the grass from dying due to freezing damage. Snow removal begins about 10 days before the start of the new season.
Therefore, in this invention, in stadiums located in heavy snowfall areas, a heating sheet for planting is installed on the grass after the J League games have finished in order to melt the snow that falls and to protect the grass from withering due to exposure to low temperatures.
The present invention can be used not only in soccer fields, but also in athletics stadiums, baseball fields, rugby fields, golf courses, golf driving ranges, and the like.

An example of the installation of the cold region planting conservation device is shown in Figure 1. Figure 2 shows the cross-sectional configuration of the cold region planting conservation device shown in Figure 1.
In the present invention, the three-dimensional network structure 2 is installed on a lawn surface (planted surface) 6. If snow has accumulated on the lawn at this time and this impedes the work, the snow must be removed before the installation work can be carried out.
The three-dimensional net structure to be installed is made of artificial fibers such as polyester, has water permeability, and is about 20 to 50 mm thick.
After that, the surface and sides of the three-dimensional net structure 2 are covered with a breathable/water-permeable sheet 3 that has excellent breathability and water permeability and heat retention. The breathable/water-permeable sheet is a sheet that has appropriate gaps to ensure water permeability and breathability, and also has heat retention. When covering the three-dimensional net structure with the breathable/water-permeable sheet, the breathable/water-permeable sheet is laid out about 100 to 200 mm wider than the three-dimensional net structure, and the breathable/water-permeable sheet is fixed to the grass by inserting a U-shaped stopper pin or the like into the end of the breathable/water-permeable sheet. After that, a heating sheet 4 that generates heat when electricity is applied is placed on the breathable/water-permeable sheet 3. At that time, in order to prevent the heating sheet 4 from scattering, a U-shaped stopper pin (not shown) or the like is driven in to fix it to the planting surface, thereby forming the cold region planting conservation device 10.

The temperature sensor 52 is disposed at an appropriate location when the three-dimensional mesh structure 2 is laid out, and is connected to the control panel 5 by a sensor cable 53. The heating sheet 4 and the control panel 5 are connected by a cable 51.
The control panel adjusts the current output to the heating sheet, and electricity is passed through the heating sheet during the curing period. Temperature control is based on the temperature detected by the installed temperature sensor, and electricity is controlled during the winter curing period so that the grass surface is kept at 0-5°C. In this way, during the winter curing period, the lower surface of the sheet is heated to about 10°C, melting falling snow, and the space in the three-dimensional net-like structure is also heated to about 0-5°C, allowing the grass to be cured without dying.
The temperature sensors can be located on the top and bottom surfaces of the heating sheet, the bottom surface of the breathable and water-permeable sheet, inside the three-dimensional net structure, or on the grass surface.

Preparations for the opening of the season begin two days or the day before a match. After the power is turned off, the heating sheets, breathable and water-permeable sheets, and three-dimensional mesh structures are removed, and the exposed grass surface is lightly mowed and prepared for the match.
During the winter curing period, meltwater is able to seep in without stagnating, keeping the planting soil moderately dry and the roots of the grass do not rot and can maintain the same root condition as before winter, making it possible to provide grass in a condition suitable for playing.
After the game, depending on the weather conditions, if snowfall is predicted, the three-dimensional net structure, the breathable/water-permeable sheet, and the heating sheet can be laid on the grass again to prevent snow from accumulating. Also, if snow is unlikely to fall and the temperature is predicted to gradually rise, only the breathable/water-permeable sheet can be laid on the grass.
In this way, by simply attaching and detaching relatively lightweight materials such as a heating sheet that heats up when electricity is passed through it, a breathable and water-permeable sheet, and a three-dimensional mesh structure, it is possible to provide a turf that can be used for games in a short period of time without the need to remove snow after each game.

<Three-dimensional network structure>
The three-dimensional net structure is a material made by forming plastic fibers such as polyethylene or polystyrene, which are processed like springs, into a three-dimensional shape and shaping them into a mat. The mat has many voids within it, giving it high breathability and water permeability, and the fibers are self-supporting, so it has high load-bearing capacity, will not be crushed by snow accumulation, and can maintain an appropriate space. In the present invention, a mat with a thickness of 10 to 70 mm can be used. Larger width and length are more suitable, but are determined in relation to handling and storage.
For example, the configuration of a three-dimensional network structure is disclosed in Japanese Patent Application Laid-Open Nos. 2001-328153 and 2001-145422.

<Breathable and water-permeable sheet>
The air-permeable/water-permeable sheet is made of woven fabric, nonwoven fabric, or dense mesh sheet, for example, a sheet made of plastic fibers such as polyethylene compressed into a mesh shape.
Transparent fabrics allow light to penetrate the grass and planted areas covered with the sheet, helping to maintain their greenery. They also have high breathability, allowing the water that transpire from the plants to evaporate without being trapped inside the sheet, preventing the grass and planted areas from becoming steamy.
For example, the present sheet illustrated in Japanese Utility Model Laid-Open Publication No. 6-52433 can be used.

<Warming sheet>
The heating sheet can use a surface heating element. The heating part that is energized is sealed and not exposed. The heating sheet disclosed in JP 2019-183493, which was previously proposed by the present inventor, can be used. In this proposal, the ladder structure is formed by connecting 1m square heating elements.
The structure relating to the current flow and heat generation is not described here because it is known as a planar heating element and is disclosed, for example, in JP 2017-224397 A.

<Control panel>
The control panel is an electric control panel for passing electricity through the heated sheet. It is controlled based on the temperature detected by the temperature sensor. For example, if the outside temperature is within the expected range, the heat output (= amount of electricity) of the heated sheet is kept constant, and if it becomes unexpectedly low, the temperature sensor detects it and increases the amount of electricity, so there is no need to constantly perform variable control.
The temperature sensor can be attached to the top and bottom of the heating sheet, or it can be placed on the grass surface. The sensor can be placed in multiple locations, not just one, and the control can be performed according to the location depending on the conditions such as shade and wind.
If a temperature sensor is attached to the surface of the heating sheet, a preventive control method can be implemented in which the output is controlled by detecting whether the temperature of the sheet surface is rising or falling.

A test area was set up at the end of the year in a section of a natural grass ground in Sapporo, and a test was conducted by placing a heating sheet on the grass until the following February. There was already about 60 cm of snow on the test area, so the snow on the grass was removed before setting up the 12 ^m2 test area. Figures 3 and 4 show the state of the test area.
Three Endlenmats (manufactured by Maeda Kosen Co., Ltd., width 300 mm x length 2,000 mm x thickness 30 mm) were laid on the snow-removed lawn surface 6 as the three-dimensional mesh structure 2, and San Sunscreen (manufactured by Nippon Wide Cross Co., Ltd.) was laid to cover the front and sides as the breathable/water-permeable sheet 3. At this time, the breathable/water-permeable sheet 3 was laid about 100 to 200 mm wider than the three-dimensional mesh structure 2 so that the breathable/water-permeable sheet 3 covered the sides of the three-dimensional mesh structure 2 as well, and the ends were fixed to the lawn with locking pins.
Next, a planting heating sheet 4 (width 900 mm x length 1,800 mm) was placed on top of the air-permeable and water-permeable sheet 3, in which a fiber that generates heat when electricity is applied is sandwiched between transparent PET sheets. To prevent the heating sheet 4 from scattering, six holes were drilled at the end of the heating sheet 4, and a stopper pin was inserted to fix it to the grass surface. The cable 51 of the heating sheet 4 was connected to a control panel, which is a power source not shown in the figure. The amount of electricity output was adjusted while checking the surface temperature of the heating sheet 4, and the temperature sensor was used to detect whether the temperature of the sheet surface was tending to drop or rise below 5°C so that the temperature under the air-permeable and water-permeable sheet was about 5°C, and the output was controlled and electricity was applied.

Under these conditions, the melting of the falling snow and the condition of the grass were observed over time, and temperature sensors (not shown) were placed on the underside of the breathable and water-permeable sheet 4, inside the three-dimensional mesh structure sheet 2, and on the surface of the grass 6 to measure the temperature changes at each location.
During the test, a total of 292 cm of snow fell in Sapporo (according to AMeDAS weather data), and at the end of the test, there was nearly 100 cm of snow on the natural grass ground, but no snow had accumulated on the sheet (see Figure 4).

When the test was completed, the sheet was removed and the condition of the grass was observed (see Figure 4 (b)). It was confirmed that the grass was maintained in a healthy state, with no signs of discoloration of the grass leaves due to low temperatures or rotting of the stems and leaves due to excessive moisture. The surface of the base soil did not freeze, meltwater penetrated without stagnating, and the soil moisture content from the surface to -7 cm was about 20-25%, maintaining conditions suitable for grass growth. The temperatures measured at each point were 5.4°C (-4.0 to 19.5°C) on the surface under the breathable and water-permeable sheet on average, 5.3°C (-2.5 to 19.5°C) on average in the space inside the three-dimensional net structure, and 3.5°C (-0.5 to 10.5°C) on the grass surface on average. The temperature of the grass surface, which particularly affects grass growth, did not fall significantly below freezing, and the grass was kept at a temperature that would not cause frost damage.

Furthermore, to confirm whether the turf had the quality suitable for soccer after the heating sheet 4 was removed, the surface hardness of the turf was checked using a CREG Impact Soil Tester in accordance with the method prescribed by FIFA. The average of five measurements was 106.2 CIV (105-107 CIV), which was within the range of 80-120 CIV that is set as the surface hardness suitable for soccer.
Prior to this test, a snow melting test was conducted by laying a heating sheet directly on the grass without the three-dimensional mesh structure. In that test, the grass was heated while still wet with melting snow at the points where the sheet and the grass were in contact, and the grass became steamy, decreasing its density and causing the grass surface to harden.
It has become clear that the present invention satisfies the requirements of a soccer field for playing matches.
From the above, it has become clear that by placing a three-dimensional mesh structure covered with a breathable and water-permeable sheet on the grass and then laying a heating sheet on top of it, snow can be prevented from accumulating throughout the winter, the temperature of the space within the three-dimensional mesh structure and the grass surface can be maintained at a moderate level, and the grass can be maintained in a condition suitable for playing soccer.
It has become clear that the present invention satisfies the requirements of a soccer field for playing matches.

Reference Signs List 1: Maintenance sheet body 2: Three-dimensional net structure 3: Breathable/water-permeable sheet 4: Heating sheet 5: Control panel 51: Cable 52: Temperature sensor 53: Sensor cable 6: Lawn surface 61: Grass 7: Snow cover 10: Cold region planting maintenance device

Claims (7)

A conservation sheet body including a three-dimensional net structure, an air-permeable and water-permeable sheet, and a heating sheet;
A control panel that adjusts the temperature of the heating sheet,
A cold region planting conservation device for protecting plantings in cold regions, comprising:
The conservation sheet body is arranged in the following order from the planting surface side to the upper side: a three-dimensional net structure, a breathable and water-permeable sheet, and a heating sheet.
A cold climate plantation conservation device characterized by controlling the temperature of the heating sheet using a control panel. The cold climate planting conservation device according to claim 1, characterized in that a breathable and water-permeable sheet is integrally provided on the upper surface side of the three-dimensional net structure. A cold climate planting conservation device as described in claim 1 or 2, characterized in that a temperature sensor is attached between the planting surface and the heating sheet or on the surface of the heating sheet, and the control panel performs control based on the temperature detected by the temperature sensor. A method for preserving plantations in cold climates by installing the cold climate plantation preservation device according to claim 1,
A method for preserving plantations in cold climates, comprising covering the plantations in the cold climates in the order of a three-dimensional net-like structure, an air-permeable and water-permeable sheet, and a heating sheet, and then adjusting the control panel to control the temperature. The method for preserving cold-climate plantings according to claim 4, characterized in that the cold-climate plantings are grass installed in sports facilities. The cold climate planting conservation method according to claim 5, characterized in that the temperature of the heating sheet is controlled so as to maintain the temperature of the grass surface at 0 to 8°C. 6. The cold region planting conservation method according to claim 5, wherein the sports facility is any one of a ball game stadium, an athletics stadium, and a golf course.