JPH0356689B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention connects a porous pipe equipped with a large number of capillary-like pores with a required hydraulic permeability and anti-air permeability (withstand pressure) to a water source whose water level can be adjusted. The water pipe is connected to a riser pipe that is supported upright in parallel with the water pipe, and the water pipe, the riser pipe, and the porous pipe are buried in the cultivation soil so that the porous pipe is located within the root group area of the cultivated crop. , the water level of the water source is set lower than the porous pipe so as to give a set negative pressure to the water inside the porous pipe, and the negative pressure difference between the inside and outside of the porous pipe causes water to flow from the porous pipe to the cultivated crop. This is a negative pressure differential irrigation method characterized by seeping into the root group area.

Due to these characteristics, this irrigation method automatically and continuously reliably supplies the necessary and sufficient amount of water for the successful cultivation of crops, adapting to changes in the weather and the growth stage. This can be done very economically and efficiently.

Conventional irrigation methods for crops include sprinkler method, porous pipe method (hereinafter referred to as watering irrigation),
Methods such as the border method, contour method, basin method, furrow method, drip method (the above are surface irrigation), open drain method, underdrain method, (the above are underground irrigation) are known, and these methods When the water in the soil is consumed, pressurized water is sprayed from a nozzle, forming raindrop-shaped,
Irrigation methods include spraying water, pouring water over the soil surface of the field and allowing it to penetrate into the soil, or flooding the soil surface with water, or directly supplying water to the root zone of crops through capillary rise. These methods all involve replenishing water from above ground, on the surface of the ground, or underground. However, when fertilizing crops under this type of water management, it is necessary to constantly monitor the moisture status of the soil. In addition, it is necessary to investigate each dimension in order to determine the amount of irrigation water, and investigating and determining each of these dimensions requires a great deal of effort and effort, both technically and economically. ,
The reality is that we are forced to waste time and money,
For example, methods of watering plants from above using sprinklers or porous hoses require a large amount of water to sufficiently irrigate the root zone, and there is also a large amount of water loss due to evaporation, making use of limited water resources. Even with the drip method, which was developed to eliminate the disadvantage of excessive waste - a method in which water pipes are built along the cultivated plants and a regulated amount of water drops are dripped around the roots of the plants - there is still no water from the water pipes. Not only is it difficult to adjust the amount of water dripped, but there is also considerable loss due to evaporation.Furthermore, an electrical control device is required to adjust the amount of water to maintain an appropriate moisture level in the root zone in terms of time and location. Irrigation methods that use a single water level adjustment tank for both water supply and water supply have the disadvantage that it is difficult to irrigate the crop root group with even water.

In addition, in the early stages when the soil is not sufficiently moist, water is sent from a high-pressure water supply tank to a water pipe, and after the soil is sufficiently moist, the height is approximately the same as that of a water pipe, or at a lower height that takes into account the strength of the negative pressure in the soil. An underground irrigation method has also been proposed that involves switching to a low-pressure water supply tank with a water level of If a pipe equipped with this is applied, water can be supplied from the inside of the pipe to the outside only when the water pressure inside the water permeable pipe is positive pressure water of 0 pressure (zero pressure) or higher. This is because when the water pressure inside the permeable pipe is set to negative pressure, the permeable pipe is generally not strictly breathable, so it is not possible to constantly prevent outside air in the soil from entering the pipe. First, the outside air that has entered the pipe blocks the flow of water, making water supply impossible. Therefore, unless a suitable air permeability is strictly provided to the water permeable pipe, water in the water permeable pipe can be continuously supplied only under positive pressure, whether high or low. In addition, compared to conventional irrigation methods, it only drastically reduces the amount of water consumed, and cannot guarantee the normal growth of crops, resulting in water saturation (full of water).
Moreover, since the water supply does not stop, the normal growth of crops is inhibited, and in some cases, they may even die, so this has the fatal drawback of not being able to guarantee the normal growth of cultivated crops at all times. It was hot.

The present invention has been newly developed by eliminating all the above-mentioned drawbacks of conventional irrigation methods, and
In order to maintain a uniform and appropriate moisture condition within the crop root zone, it can be self-controlled by increasing or decreasing the set negative pressure of the porous pipe and the moisture negative pressure within the crop root zone. It is an extremely economical and efficient irrigation method that does not require any control equipment.

The principle and embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the principle of the present invention, in which 1 is a Marriott water supply system, 4 is a water level adjustment tank, and 10 is a water supply system.
is a porous pipe, and is connected to the riser pipe 8 that is connected to the water supply pipe 7 that communicates with the water level adjustment tank 4 that communicates with the water supply device buried in the soil at a certain depth from the ground surface G, L. The porous tubes 10 are connected via vinyl tubes 9. A crop c having a root group b is grown in a field a. The moisture in the soil of field a decreases due to water absorption by root group b of crop c and water consumption due to soil surface evaporation, and the negative pressure of moisture in the soil increases, causing the effective root group b of crop c to decrease. A porous pipe 10 buried in the soil in the water supply area c is saturated with water, and the water pressure inside the pipe 10 is set to a certain negative pressure hp (in the drawing, the positive pressure is at position B in the soil, and the negative pressure is 0 (zero)). If we set the standard water level (equivalent to the groundwater level there) and set the negative pressure above the water column (the height of the water column), then the negative pressure hs of moisture C in the soil (in the drawing, the negative pressure of C is higher than that of A). There is a negative pressure difference Δh between the negative water pressure hp in the porous pipe 10
(hs - hp) occurs, and by generating this negative pressure difference Δh, moisture movement occurs between the porous pipe 10 and the soil mass in the water supply area, but the negative pressure of moisture C in the soil
When hs is larger than the water negative pressure hp in the porous pipe 10, water is supplied from the porous pipe 10 into the soil. The present invention carries out the desired water supply based on this principle, and the porous pipe 10 directly receives the negative pressure in the soil, and in an attempt to eliminate the negative pressure difference Δh, the porous pipe 10 supplies water to the crop roots in the soil. It supplies moisture to Group C.

3 and 4 show an embodiment of the present invention based on the above principle. Water is supplied from a float level switch (which has the same function as the Marriott water supply system) to the water level adjustment tank 4 via the water meter 2, water supply pipe 3, and deflection pipe 15, and the water level adjustment tank 4 is raised and lowered by a jack 6. Let it be whatever you want. A water pipe 7 is installed from the water level adjustment tank 4 via a flexible pipe 14, and a required number (two in the drawing) of riser pipes 8 are vertically supported in parallel to the water pipe 7. They are placed on the same horizontal line, and a porous pipe 10 is connected to each head of the pipe through a vinyl pipe 9, a rubber stopper 11, and a socket 12. Next, all porous pipes are buried on the same horizontal line. Therefore, no matter how many riser pipes 8 are installed upright and supported on the water pipe 7, each riser pipe 8
Since each head of can be aligned horizontally,
Since the buried depth of each porous pipe 10 connected to each of these riser pipes 8 and buried in the soil can be made constant, the water level can be adjusted accurately, and therefore each root of cultivated crop c can be Moisture can be evenly and evenly supplied to group b from each porous tube 10. Water level adjustment tank 4 is a flexible pipe 15
Since it is connected to the water supply device by the flexible pipe 14 and is connected to the water supply pipe 7 by the flexible pipe 14, it can be raised and lowered by the jack 6. Pressure difference Δh
Irrigation can be performed by setting the negative pressure difference as explained with reference to FIG. As shown in Figure 3, the water level adjustment tank 4, which is a water source whose water level can be adjusted, → the water pipe 7 → the riser pipe (water supply branch pipe) 8 →
The porous pipes 10 form one set, so that the water pressure in the water level adjustment tank 4 and the riser pipe 8 is always constant. In addition, since the porous pipes 10 connected and arranged one by one from each riser pipe 8 are all independent, even if air bubbles enter one of them, it is only necessary to adjust that part. Since there is no change in the water supply throughout the porous pipe 10, the embedding and adjustment work of the porous pipe 10 and the setting of the negative pressure can be performed extremely easily. In the figure, 13 is a detection cup (tensiometer) for detecting pressure.

Since the present invention automatically and continuously supplies water, the set negative pressure can be adjusted twice or more during the crop cultivation period.
Experiments have revealed that irrigation can be done only three times, demonstrating that irrigation operations during the cultivation period are labor-saving and can significantly save water.

The porous pipe 10 adopted in the present invention must have a water permeability coefficient in the range of 10 ^-4 to ^{10 -5} cm/s, and an anti-air permeability (air permeability pressure) of 100 cm-H ₂ O or more. For example, alumina is used as the main raw material, clay is used as a solvent, and fine natural organic powder is mixed in.
It is made of unglazed porcelain sintered at a high temperature of 1400 to 1600℃, and due to sintering, extremely fine capillary-like pores that are invisible to the naked eye are created when the natural organic powder is combusted and vaporized. The porous tube 10 is made to have a function in which water is leached out by a negative pressure difference between the inside and outside of the porous tube 10. Therefore, when the pressure on the outer circumferential side of the porous pipe 10 is lower than the pressure inside the porous pipe 10, the water inside the porous pipe 10 leaches out due to the pressure difference between the inside and outside, and the soil a is not moistened to a saturated state. , because it has the ability to absorb water, the buried porous pipe 10
The soil around water pipe 7 is under the influence of absorption of leached water and is under negative pressure.
Even without applying positive pressure to the water inside the porous tube 10, due to the water absorption action of the soil itself, the water inside the porous tube 10 leaches into the soil, diffuses and infiltrates, and reaches the crop root zone b, causing the crop roots to Between the porous tube 10 and the crop root group area, since infiltrated moisture is absorbed by the group,
The hydraulic gradient created in the soil between the porous tube 10 and the crop root zone ensures that the crop is constantly supplied with the necessary and sufficient amount of water.

According to the results of experiments, the range of the negative pressure set in the present invention is 1.0 to 1.5 in terms of -10 to -30 cmH (water column height) -pF, and higher negative pressures, e.g. There is no need to set -100cm or -400cm or -2.0 or 2.6 as a pF value.

That is, as shown in Fig. 5, the range of negative pressure set in the present invention is -10 to -30 cmH (water column height) - pF.
The largest number of coordinates (small black circles) could be seen in the range of 1.0 to 1.5.

In the present invention, the amount of water supplied to crops varies depending on the set negative pressure, so by adjusting the set negative pressure, it is possible to adjust the water distribution (water tension) in the soil. As a result of the experiment, it was demonstrated that by adjusting the set negative pressure, it was possible to supply the necessary amount of water to multiple crops of 1 to 6 plants. In other words, in a water supply area of 1600 cm ² by one porous pipe, we were able to sufficiently supply the maximum required amount of water for 6 plants of lettuce (leaf vegetable), 4 plants of tomato (fruit vegetable), and 2 plants of melon (fruit vegetable). . According to the present invention, for crops on one plot (1,000 square meters) of cultivated land, only a small amount of
It has been demonstrated that approximately 1,500 porous tubes can supply crops with the necessary and sufficient amount of moisture to grow high-quality crops, such as sweet and sticky melons. Therefore, for farmers, labor, effort,
This has the effect of significantly reducing time and costs, and making facility costs extremely economical.

Furthermore, the amount of water constantly supplied by each set negative pressure in the present invention is significantly self-controlled at each set negative pressure, adapting to the growth stage of the crop and weather conditions. The results are as shown in the experimental tables in FIGS. 5 and 6. Therefore, FIGS. 5 and 6 show that by exhibiting this self-regulating function, the present invention adapts well to the growth stage of crops and various weather conditions such as sunny, cloudy, and rainy days, and provides the necessary water supply. This is to demonstrate that it is possible.

The results of a comparative test of the relationship between each irrigation amount and yield of the present invention and the conventional drip method using prince melon as an example of a crop are as shown in the attached table (Part 1). That is, the negative pressure differential irrigation area in which the present invention was implemented was able to save approximately 14% of water in terms of water amount compared to the drip nozzle irrigation area. In addition, in terms of yield, the negative pressure differential irrigation area in which the present invention was implemented had
The yield was approximately 18% higher than in the drip nozzle irrigated area.

As an example of a crop grown according to the present invention, the quality of Andean melon was investigated, and the results were as shown in the attached table (Part 2). That is, it has been found that sweet and sticky Andean melons of excellent quality can be obtained extremely economically and efficiently.

Since the negative pressure differential irrigation method of the present invention has the advantages described above, it can bring about the following remarkable effects compared to conventional irrigation methods.

(A) In the present invention, the water supply is stopped when the negative water pressure in the soil reaches the negative water level (negative pressure) set in the pipe, and the water supply is stopped to prevent water saturation (full water) that is harmful to the growth of cultivated crops. Since this will never occur, normal growth of cultivated crops can be ensured.

(B) The present invention basically uses only a water source with adjustable water level, water pipes, and porous pipes, and is an extremely simple automatic irrigation method, so it can be automated using conventional irrigation methods. There is no need for manual or automatic control devices that use other energy (other than the energy of water), such as electromagnetic properties and moisture detection valves, which have been required in the past, and these can be completely omitted. Therefore, it is extremely economical and efficient.

(C) The present invention allows for the start-up of irrigation without pressurization.
It is a low negative pressure differential irrigation method that does not require the use of any power source and simply utilizes the balance of negative pressure in porous pipes, so many conventional irrigation methods use pressurized water from a pump etc. to start irrigation. It is possible to eliminate the disadvantages of having to use

(D) In implementing the present invention, not only can farmers themselves install a series of water supply facilities, but there is no mechanical inspection of water supply facilities, and it is easy to replace porous pipes and other parts. ,
It is easy to carry out and is extremely economical, but unlike conventional irrigation methods, the cost of supplying and distributing water is extremely high, and on top of that, the construction requires specialized engineers, resulting in a large amount of work. It is possible to eliminate the drawbacks that have been wasting facility costs.

(E) Since the present invention fertilizes multiple crops in a small irrigation area (water supply area) centered on a porous pipe, the degree of effective water utilization is high, and the water permeability of the porous pipe is uniform. The water supply area at any point can be continuously irrigated with the same amount of water, and water is automatically replenished by the balance between the negative pressure in the capillary around the crop root group and the negative pressure in the porous pipe. , only the required amount of water is supplied and there is no excess water in the crop root zone, so the traditional surface irrigation method requires a large amount of water and wastes water resources, and the subsurface irrigation method has the drawbacks of soil quality. It is possible to eliminate all the disadvantages such as those that tend to affect the efficiency of water use.

(F) In the present invention, after setting the negative pressure inside the porous pipe at the start of irrigation, water supply is self-controlled in accordance with the amount of water consumed, and a certain soil moisture range can be ensured, and the amount of water can be adjusted. Setting the negative pressure (how to apply negative pressure) is easy to operate, is not dependent on age or effort, and is more accurate and economical than conventional automatic control methods. Therefore, as in the conventional irrigation system, intermittent irrigation wastes effort, effort, time, and expense for techniques and management such as starting and stopping irrigation, and automatic control of irrigation requires This eliminates all the disadvantages of requiring various expensive equipment such as moisture detectors, pressure transducers, external units, etc.

(G) In the present invention, as mentioned above, the soil moisture is stable and the water supply can be adjusted according to daily changes in weather elements, so the occurrence of pests and diseases due to overhumidity is suppressed and prevented. Since the removal labor is significantly reduced, the soil moisture conditions are not constant as in conventional irrigation methods, and in addition, pests and diseases tend to occur frequently due to weather conditions, and the amount of labor, effort, time, and expense required for spraying chemicals increases. It is possible to eliminate the drawbacks that are extremely wasteful.

(H) In the present invention, as mentioned above, an even and appropriate amount of water is always supplied to each crop, which not only improves the quality and commercialization rate but also improves the quality of fruits and vegetables, especially melons, etc. It is extremely effective in improving the quality of products. Therefore, as with conventional irrigation methods, it is difficult to match the amount of water required by crops with the amount of irrigation, and it is necessary to invest a lot of technology, effort, time, and money to make the quality uniform and commercialize the product. All defects can be removed.

As mentioned above, by applying a porous pipe with the required hydraulic permeability and anti-air permeability (ventilation resistance) to the water supply end, and by setting the water level of the water supply source to a lower level than the porous pipe, The present invention, which has an essential component of appropriately applying a set negative pressure to the moisture within the porous pipe, is extremely economical and efficient as an irrigation method, and has very high practical value.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view schematically showing the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a vertical cross-sectional view of one embodiment, and FIG.
The figure is a longitudinal sectional view of the main part, FIG. 5 is a diagram showing the relationship between irrigation amount and set negative pressure, and FIG. 6 is a diagram showing automatic irrigation adjustment and continuation according to weather conditions. [Explanation of symbols], 1 is Marriott water supply device, 2
is a water meter, 3 is a water supply pipe, 4 is a water level adjustment tank, 5 is a water supply adjustment valve with a float, 6 is a jack,
[4, 5, and 6 work together to realize the functions of the Marriott device], 7 is a water pipe, 8 is a riser pipe,
9 is a vinyl tube, 10 is a porous tube, 11 is a rubber stopper, 12 is a socket, 13 is a detection cup, 14,
15 are all flexible pipes, A is the reference water level for the soil capillary negative pressure hs outside the porous pipe (this is equivalent to the ground water table being there), and B is the set negative pressure hp inside the porous pipe.
The reference water level for , C is the center of the porous pipe, G, L
is the ground surface, a is the field, b is the crop root zone, c is the crop, and Δh is the negative pressure difference (hs-hp).

【table】

【table】

Claims (1)

[Claims] 1. A riser pipe in which a porous pipe equipped with a large number of capillary-like pores with the required hydraulic permeability and air permeability is installed vertically in parallel to a water supply pipe communicating with a water source where the water level can be adjusted. The water pipe, the riser pipe, and the porous pipe are buried in cultivation soil so that the porous pipe is located within the root group of the cultivated crop, and a set negative pressure is applied to the water in the porous pipe. A negative pressure difference characterized in that the water level of the water source is set lower than the porous pipe, and water oozes from the porous pipe into the root group of the cultivated crop due to the negative pressure difference between the inside and outside of the porous pipe. Irrigation method.