JPH03259021A - Portable soil sterilizing method by hot water and device therefor - Google Patents

Abstract

PURPOSE:To improve the controlling effect on insect pests in soil by sprinkling water from a moving boiler moving on a field, covering and shielding to soil surface with a heat insulating sheet and sterilizing the soil. CONSTITUTION:A boiler body 1 is moved to a desired place by a handcart 3 and a water feed port 4 of the body 1 is connected to a water feed hose and, simultaneously, a water-sprinkling hose 18 arranged on the soil S is connected through a lengthening hose 15 to a discharge port 10. Then the hose 18 and soil S are covered and shielded with a heat insulating sheet 22 and the body 1 is operated by an operating panel 13 and hot water heated to about 80 deg.C is sprinkled from a hot water charging hole 20 through the discharge port 10 and hose 18 to permeate the hot water into the soil S. Then, sprinkling of the hot water is continued until soil temperature in the position 20-30cm deeper from the surface of the soil becomes >=55 deg.C to sterilize the soil.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is a method for treating soil contaminated with a high density of soil pathogens and nematodes by moving a portable boiler to a destination and spraying hot water on the soil surface. The present invention relates to a portable hot water soil disinfection method and device in which soil disinfection is performed by arranging a hose, covering the top with a heat insulating sheet, and spraying hot water from the sprinkler hose.

[Conventional technology]

For control in fields contaminated with soil pathogens and nematodes at high densities, chemical and physical soil disinfection methods that directly reduce pathogens and nematodes are generally used. These methods mainly involve steam disinfection and soil fumigants such as chloropicrin.

[Problem to be solved by the invention]

Soil disinfection using steam disinfection or chloropicrin is as follows:
It is not necessarily a panacea; steam disinfection may actually accelerate the development of certain pathogenic bacteria. One of the reasons for this is that antagonistic microorganisms are also sterilized indiscriminately.

As a countermeasure, an air-mixed steam disinfection method has been developed that mixes air with steam to lower the temperature and suppress the sterilization of antagonistic microorganisms. However, like steam disinfection, this method requires large-scale equipment and underground piping to ensure sufficient penetration of the steam, and is still not commonly used because it requires a lot of expense and labor. Not popular.

The present invention was made in order to solve the above-mentioned problems. A relatively small-scale mobile boiler is used to move to a destination, place a hot water hose on the soil surface, and disinfect the hot water hose and disinfect the soil. The above problem can be solved by covering the top of the soil with a thermal insulation sheet such as a synthetic resin film and spraying hot water on the soil surface, allowing it to penetrate into the soil and disinfecting the soil slowly. The purpose of the present invention is to provide a portable hydrothermal soil disinfection method and device.

[Means to solve the problem]

In order to achieve the above object, the present invention provides (1) moving a mobile boiler to a field to be disinfected, extending a hot water hose from the boiler and placing it on the soil surface; The soil surface in the area where the hot water is sprayed from the hot water hose is covered with a thermal insulation sheet made of synthetic resin film.

Seal the area tightly and spray hot water of approximately 80°C from a sprinkler hose to penetrate into the soil. Spray hot water until the soil temperature reaches 55°C or higher at a depth of 20 to 30 (2) below the soil surface. (2) A portable boiler that is mounted on a trolley that can be moved freely around the field and has a water inlet, hot water outlet, fuel tank, etc. A heat-resistant #1 hot water hose is removably connected to the discharge port and placed on the soil surface to be disinfected, and the soil surface within the spray area of this hot water hose and the hot water sprayed from the hot water hose is almost kept confidential. A portable hot water soil disinfection device comprising: a heat insulating sheet made of a translucent or heat-absorbing synthetic resin that covers the surface of the soil;

[For production]

By using the method and device described above, the present invention enables a mobile boiler to be moved to a desired place where soil is to be disinfected, places a hot water hose on the soil to be disinfected, covers the top with a heat insulating sheet, and heats the water from the hot water hose. The desired control effect can be achieved by a simple operation and work of spraying water and permeating it into the soil.

In addition, the heat-insulating sheet prevents the hot water temperature from decreasing during disinfection, increasing sterilization efficiency, and promoting the use of solar heat. It can be used as is to increase crop productivity.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings and tables.

In FIG. 1, reference numeral 1 denotes a boiler body, 2 a fuel tank for storing fuel for the boiler, and these are mounted on a loading platform 3a of a hand truck 3. The hand truck 3 has a pair of left and right front wheels 3c and a pair of left and right rear wheels 3d, each consisting of a handle 3b1 and casters that stand upward from the rear end of the loading platform 3a. It is now able to run and move freely on the ground.

The boiler body l is provided with a water supply port 4, a drain port 5, a pressure reducing valve 6, a safety valve 7, etc. on one side, a hot water discharge pipe 8 is connected to the other side, and a pulp A hot water pump II is provided in the hot water discharge pipe 8 in the middle of the hot water discharge pipe 8 to pressurize the hot water.

In addition, the boiler main body l is provided with an exhaust pipe 12 that projects upwardly at the upper end, and an operation panel 13 that is provided with an operation switch, an operation lamp, a combustion lamp, a temperature setting knob, etc. on the side. ing. Further, although not shown, the boiler body I is provided with a water pump, a water meter, etc.

Two discharge ports IO are provided for the hot water discharge pipe 8, and a heat resistant and flexible extension hose 15 is provided at each discharge port IO. A joint 16 provided at one end is connected and extended toward the field. As shown in FIGS. 2 to 4, the G-ind I7 provided at the other end of the extension hose I5 is placed on the surface of the soil S to be disinfected. A jacket I9 provided at the base end of a synthetic resin hot water hose 18 that has heat resistance and can be wound onto a hose reel (not shown) is connected.

A large number of hot water outlet holes 20, 20, .

These hot water tapping holes 20, 20... are provided at alternate heights in the length direction of the hot water hose 18, and the hole diameter is 1 m) The interval between the holes is about 12□□□. The spacing between the holes may be changed as appropriate. In addition, the water sprinkling hose 18 is provided with a seal 21 at its end, and two hoses are arranged in parallel at a predetermined interval on the surface of the soil S to be disinfected. It's also good. The hose diameter of the hot water hose 18 is 3.4 mm, and the length of each hose is 10 to 20 m.
The diameter and length of this hose may be changed as appropriate, and the terminal ends of a plurality of hot water hoses 18 may be connected to each other in a loop to circulate hot water. .

The spraying range of hot water sprayed from the sprinkling hose I8 and the sprinkling hole 20 of the sprinkling hose 18 arranged on the surface of the soil S, that is, the surface of the soil S to be disinfected, has translucency or heat absorption. The heat insulating sheet 22 made of a synthetic resin film has a substantially airtight covering. This heat insulation sheet 22
The film sheet may be a film sheet normally used for mulch cultivation, and the means for tightly covering the grass may be the same as the conventionally known means of pressing the periphery of the sheet with soil from the field.

In addition, the work of pressing the area around this sheet with soil from the field is
It is recommended to use a well-known machine for laying mulch film.

In a portable hydrothermal soil disinfection device with such a configuration,
In addition to greenhouses with steam or hot water heating equipment such as boilers, glass rooms, vinyl houses, and rain shelters without such equipment are widely applied to cultivation, small-scale outdoor cultivation, etc. Move the boiler body 1st class to the disinfection destination. A water supply hose from a water supply or the like is connected to the water supply port 4 of the boiler body 1, and a hot water hose 18 placed on the soil S to be disinfected is connected to the discharge port IO via the extension hose 15. Next, the upper side of the hot water hose 18 and the soil S to be disinfected is covered almost confidentially with a heat insulating sheet 22, and the boiler main body l is operated by the operation panel 13, and the temperature and flow rate of the hot water discharged from the discharge port 10 are , the hot water is sprayed from the outlet hole 20 of the hot water hose 18 by controlling the pressure and the like. At this time, the temperature of the hot water sprayed from the tapping hole 20 is about 80° C., and this hot water gradually permeates into the soil S. Then, hot water is continued to be sprayed until the soil temperature at a depth of 20 to 30 degrees below the soil surface reaches 55°C or higher, and when that temperature is reached, the operation of the boiler body is stopped and soil disinfection work is started. finish. In this example, the process was completed in about 1 to 1.5 hours on soil S with a width of 75 e- and a length of 10 m, the amount of hot water sprayed was about 68 J/l, and the consumption of kerosene was 1.
It was 10.5-1.1'//.

These numbers are affected by boiler capacity, outside temperature, water temperature, soil temperature, soil moisture, sunlight, etc.

For pathogenic bacteria that are distributed deep into the soil, it is necessary to cultivate the soil to a depth of 400 cm or more and continue spraying hot water until the temperature of the lower layer 25 to 30 cm reaches 55°C or higher.

After the disinfection work is completed, disconnect the sprinkling hose 18 from the discharge port IO of the boiler main body L, and remove the sprinkling hose 18 from one side of the moisturizing sheet 22 by sliding it over the top surface of the soil S, for example. Wind it onto a hose reel. Then, the water sprinkling hose 18 together with the boiler body 1 is moved to a place where the next soil disinfection work is to be performed, and the same work is carried out. On the other hand, the sterilized soil S from which the hot water hose 18 was removed
The extraction hole of the hot water hose 18 of the heat insulation sheet 22 is sealed, and the soil temperature raised by the hot water is maintained for a long time to enhance the disinfection effect. Soil S disinfected in this way has
When seeds are sown or crop seedlings are transplanted, the heat insulating sheet 22 can be used as is as a mulch film to increase yields.

Regarding the increase in soil temperature due to the soil disinfection method described above, FIG. 5 shows the temperature increase and duration of each soil layer. As is clear from this graph, temperatures of 55°C or higher persisted for more than 3 hours in soil layers 5 (to) and 10 cffi, especially at 20 cffi.
It lasted for more than 5 hours in the lower layer of cm.

The hot water that penetrated the soil and cooled it remained in the soil pores and was pushed down by the hot water that was continuously sprayed and injected from the soil surface. Therefore, a high temperature zone progressed from the surface to the lower layer.

Regarding tomato wilt, pathogens in the remaining roots of diseased plants are treated at 55°C for 3 to 4 hours, and at 60 to 65°C for 1.5 hours.
They were almost completely killed by immersion treatment at 70°C for 1 hour, 75°C for 25 minutes, and 80°C for 15 minutes (see Table 1). In the treatment in the diseased field, the tomato set diet and the disease onset after 5 months showed a diseased plant rate of 20% and a death rate of 6%, whereas in the chloropicrin and untreated plots, the diseased plant rate and death rate were 100%. A remarkable control effect was observed (see Table 4).

Other soil filamentous fungi were isolated at a high rate even after 6 hours at 55°C (see Table 2).

The onset of soybean black root rot was significantly reduced by treating the diseased surface with hot water at 55° C. for 1 hour (see FIG. 6FIIJ and FIG. 7). Root nodules were also formed in soybeans grown in treated soil at 55°C for 1 hour.

Regarding spinach wilt, soil disinfection was carried out in the affected fields, and in the plots where Benten No. 1 (uncoated seeds) was sown, the untreated plots showed almost 100% infection rate, but after hot water treatment The diseased strain rate was lower in the chloropicrin-treated area than in the chloropicrin-treated area, indicating a high efficacy. In the plots sown with Solomon (fungicide-coated seeds), the hydrothermal treatment showed almost the same control effect as the chloropicrin treatment (see Figure 9).

Soil was collected from infected fields after hot water treatment, and the number of bacteria was investigated using the plate dilution method. The isolation rate of filamentous fungi from the soil in the chloropicrin disinfection area was extremely low, but the isolation rate from the soil in the hydrothermal treatment area was 1/10 that of the untreated area, indicating that many filamentous fungi were alive. It shows that there is. There was almost no difference in the number of bacteria between the treatment sections (see Table 3).

Regarding nematodes, all plant-parasitic nematodes (
Although not detected, self-active nematodes were also detected in the heat-treated soil (see Figure 8).

From the above results, the disinfection method according to the present invention showed a slow bactericidal effect, and the survival rate of useful soil microorganisms was relatively high.

Regarding the effects of hydrothermal treatment on the growth of crops, when sowing or transplanting 1 to 5 days after hydrothermal treatment, there was almost no growth disorder observed in radish, Chinese cabbage, spinach, tomato, or soybean, and there was no effect of high humidity. I couldn't see it.

〔Effect of the invention〕

As explained above, according to the portable hot water soil disinfection device of the present invention, the mobile boiler is moved to the desired place where the soil is to be disinfected, the hot water hose is placed on the soil to be disinfected, and the area above is kept warm. With simple operation and work, cover with a sheet and spray hot water from a sprinkler hose to penetrate and inject into the soil.
The desired control effect on soil insect pests can be achieved.

In addition, the thermal sheet prevents the hot water temperature from decreasing during disinfection, increasing sterilization efficiency, and promoting the use of solar heat. It can be used as is as a film to increase crop productivity. Furthermore, it is economical as it allows for efficient disinfection work at low cost.

[Brief explanation of drawings]

Figure 1 is an enlarged side view of the mobile boiler and hot water hose according to the present invention, and Figure 2 shows the hot water hose placed on the soil surface and the hot water hose and the soil surface to be disinfected covered with a heat insulating sheet. Plan view, Figure 3 is the same side view, Figure 4 is the second view.
A cross-sectional view taken along the line A-A in the figure, Figure 5 is a graph showing the increase in soil temperature and its sustained state after spraying hot water, and Figure 6 shows the state of disease development in soybean in artificially contaminated soil treated with hot water. graph,
Figure 7 is a graph showing the disease state of soybean on a contaminated field treated with hot water, Figure 8 is a graph showing the effect on nematodes, and Figure 9 is a graph showing the effect of hot water disinfection on spinach wilt. (a) is the case of Benten 1, and (b) is the case of Solomon. 1... Boiler body, 2... Fuel tank, 3...
Hand truck, 4... Water supply port, 5... Drain port, 6.
...Pressure reducing valve, 7...Safety valve, 8...Hot water discharge pipe, 9
...Pulp, lo...Discharge port, 11...Hot water pump, 12...Exhaust pipe, 13...Operation panel, 14.18
．． 17.19... Di1 India, I5... Extension hose, 18... Hot water supply hose, 20... Hot water outlet, 21...
- Seal, 22... Heat insulation sheet, S... Soil.

Claims (2)

[Claims] (1) Move the mobile boiler to the field to be disinfected, extend the hot water hose from this boiler and place it on the soil surface, and spread the hot water sprayed from this hot water hose and the hot water hose. The soil surface is covered and sealed with a thermal insulation sheet made of synthetic resin film, and hot water of approximately 80°C is sprayed from a sprinkler hose to permeate into the soil, and the soil is heated downward from the soil surface.
A portable hot water soil disinfection method characterized by continuing to spray hot water until the soil temperature at a depth of 0 to 30 cm reaches 55°C or higher. (2) A mobile boiler that is mounted on a trolley that can be moved freely around the field and has a water inlet, hot water outlet, fuel tank, etc., and the soil that is to be disinfected is removably connected to the boiler's hot water outlet. A heat-resistant hot water hose placed on the surface,
A portable system characterized by comprising the water sprinkling hose and a heat insulating sheet made of a translucent or heat-absorbing synthetic resin that almost secretly covers the soil surface in the area where the hot water is sprayed from the sprinkling hose. Hydrothermal soil disinfection equipment.