JP7840583B2 - Tank-mounted liquid fertilizer application device - Google Patents

Description

This invention relates to a device for applying liquid fertilizer to soil.

The liquid component of livestock manure, a stagnant part of the circulation of livestock waste within rural areas, is a resource with low-cost fertilizer components, and its use has been explored in pastures and paddy fields. However, in field crops where large amounts of chemical fertilizer are used, the benefits of using livestock manure have been limited because conventional application methods result in a low rate of fertilizer component substitution and make it difficult to apply sufficient amounts. Furthermore, in Honshu, conventional machinery for applying liquid fertilizer using livestock manure is large and has not been adopted. Therefore, there is a need to establish a cultivation system that enables fertilizer substitution by maximizing the use of local organic resources such as livestock manure. This requires the introduction of technologies to suppress ammonia volatilization of fertilizer components that can be used as a substitute for fertilizer, and technologies that enable large-scale application into the soil, compatible with small tractors used in Honshu.

Traditionally, slurry and digestate, which are the liquid components of livestock manure and its fermentation residues, have been applied to farmland by spreading them on the surface using slurry tanker spreaders or slurry tanker spreaders mounted on tractors. This method has resulted in application rates of 40 t/ha or less. If the application rate exceeds this, the slurry will accumulate on the surface, and if the terrain is sloped or due to rain, phosphorus and bases will be washed out of the field. Furthermore, in Honshu, the use of conventional large implements and application methods that generate odors has been impossible. For this reason, several technologies for applying liquid fertilizer into the soil using slurry injectors have been proposed.
Patent Document 1 discloses an application method that suppresses odor generation by applying liquid fertilizer to deep within the soil using a work machine that inserts slurry into the grooves left by the claw marks of two subsoiler blades. However, because the application is done in two rows of fixed width and the mechanism does not allow for adjustment of the application amount, the application amount tends to be uneven, making it difficult to introduce into the field for the purpose of replacing fertilizer.
Patent Document 2 discloses a fertilizer and seeding device using a slurry tanker that enables fertilization and seeding by injecting slurry into the shallow layer of the soil cutting section; Patent Document 3 discloses a slurry flow rate control device used in the shallow-layer slurry injector of Patent Document 2; and Patent Document 4 discloses a slurry flow rate control device for the shallow-layer slurry injector of Patent Documents 2 and 3. Although all of these technologies enable application in multiple units, the insertion depth into the soil is shallow, and because application is performed by multiple injectors arranged at regular intervals, the width of the machine becomes long, causing problems when the machine is moved.
Patent document 5, non-patent document 1, and non-patent document 2 all disclose devices for applying livestock manure to soil by cutting up the soil and spreading it on top of the cuts.

These conventional technologies make it difficult to apply large quantities of liquid fertilizer, such as livestock manure slurry or digestate, deep into the soil. Furthermore, there is no disclosure of equipment designed to be compatible with small tractors.

Japanese Patent Publication No. 2000-224909 Japanese Patent Publication No. 2003-38007 Japanese Patent Publication No. 2003-38012 Japanese Patent Publication No. 2003-38013 Japanese Patent Publication No. 2008-109886

"Shallow-type slurry injector, miniaturized version III, with high odor suppression effect and work efficiency," [online], [searched November 20, 2023], Internet <https://www.naro.go.jp/project/results/laboratory/nilgs/2005/nilgs05-06.html> "Everyone's Agricultural Plaza Top Page > Handy Guide to Farm Work > Machinery > Soil Preparation > Soil Preparation (1) Compost Spreading Work", [online], [Accessed November 20, 2023], Internet <https://www.jeinou.com/benri/machine/soil/2011/03/311310.html>

The conventional technologies described above have the following problems:
(1) The technology to apply large quantities of liquid fertilizer, such as livestock manure slurry and digestate, to deep layers of the soil requires the use of large tractors or large tank trucks and is not a technology that can be used with small tractors.
(2) Because large machinery is used, the mechanical mobility of the application unit is poor as a construction method.
(3) Although there are buried objects such as stones and gravel at the site, the application unit is not structured to deal with them.
(4) Not only is there no disclosure of a method for evenly distributing liquids such as liquid fertilizer in any amount, but there is also no disclosure of a method for reducing impure solids contained in liquids such as liquid fertilizer.

In light of the above situation, the present invention provides a liquid fertilizer application device or method that can be operated even with a small tractor and that can apply a large amount of liquid fertilizer to the deep layers of the soil.

To achieve the above objectives, the present invention provides the following configuration.
1) Aspects of the present invention are:
A liquid fertilizer application device for applying liquid fertilizer to a field towed by a tractor,
A liquid fertilizer tank for storing liquid fertilizer,
A soil cutting section comprising a shaping lifting plate and two shaping cutting blades connected in a substantially V-shape with the shaping lifting plate interposed therebetween,
The soil cutting section is fixed to the lower part, the liquid fertilizer tank is fixed to the upper part, and the frame is detachably connected to the tractor,
It has a liquid fertilizer insertion pipe fixed around the shaping cutting blade and communicating with the liquid fertilizer tank,
As the soil cutting section progresses through the soil, crushed soil suitable for fertilization is formed inside the roughly V-shape formed by the two shaping cutting blades , and the two shaping cutting blades themselves form two grooves in the soil , while at the same time, the liquid fertilizer in the liquid fertilizer tank flows out from the liquid fertilizer insertion pipe into each of the two grooves and is applied to the crushed soil formed inside the two shaping cutting blades .
2) In the above embodiment,
The frame connects the tractor to the shaped cutting blade frame which fixes the shaped cutting blade.
The invention includes a point linkage connection frame, and is characterized in that the construction depth of the soil cutting section can be adjusted within a range of 0 to 50 cm by changing the angle of the shaped cutting blade frame relative to the three-point linkage connection frame using a hydraulic cylinder that connects the shaped cutting blade frame and the three-point linkage connection frame.
3) In the above embodiment,
The system is characterized by being able to have one to three of the aforementioned soil cutting sections in a row.
4) In the above embodiment,
The liquid fertilizer insertion tube is positioned along the shaping cutting blade, either inside, outside, or on the rear side opposite to the direction of travel, or a combination of these positions, and
The shaping cutting blade is inserted into the soil, and the outlet of the liquid fertilizer insertion pipe is positioned in the soil.
5) In the above embodiment,
The liquid fertilizer outlet of the liquid fertilizer insertion pipe is positioned perpendicular to the side surface of the portion of the shaped cutting blade that is not inserted into the soil, while the shaped cutting blade is inserted into the soil.
6) Aspects of the present invention are:
A liquid fertilizer application device is integrally equipped with a liquid fertilizer tank, a liquid fertilizer insertion pipe communicating with it, a soil cutting section comprising a shaping lifting plate and two shaping cutting blades connected in a roughly V-shape with the shaping lifting plate interposed therebetween, and a frame to which the soil cutting section is fixed at the bottom and the liquid fertilizer tank is fixed at the top and detachably connected to a tractor. By having the tractor tow the device, the soil cutting section is advanced in the soil, forming a roughly V-shaped, soft, crushed soil inside the two shaping cutting blades , while the two shaping cutting blades themselves form two grooves in the soil. Liquid fertilizer that flows out into each of the two grooves from the liquid fertilizer insertion pipe, which is positioned along the side of each shaping cutting blade or the rear side opposite to the direction of advancement, is applied to the soft, crushed soil formed inside the two shaping cutting blades .

A liquid fertilizer application device or method that can be operated even with a small tractor, enabling the application of large quantities of liquid fertilizer to deep layers of the soil.

Figure 1(a) is a schematic side view showing the configuration of the liquid fertilizer application device according to the present invention, and Figure 1(b) is a schematic front view of the soil cutting section. Figure 2 is a schematic front view of the liquid fertilizer application apparatus according to the present invention. Figure 3(a) is a schematic plan view of the distribution container in the liquid fertilizer distributor. Figure 3(b) is a schematic side view of the liquid fertilizer distributor. Figure 4(a) is a schematic plan view of a distribution container equipped with four distribution plates. Figure 4(b) is a schematic plan view of a distribution container equipped with two distribution plates. Figure 5 shows the liquid fertilizer insertion pipe located behind the soil cutting section and the shaping cutting blade, where (a) is a schematic front view, (b) is a schematic side view, and (c) is a schematic rear view. Figure 6(a) schematically shows the state of the soil when the liquid fertilizer insertion tube is placed behind the shaping cutting blade for application, and Figure 6(b) is an illustrative diagram showing the state of the soil after liquid fertilizer application. Figure 7 shows the liquid fertilizer insertion pipe located inside the soil cutting section and the shaping cutting blade, where (a) is a schematic front view, (b) is a schematic side view, and (c) is a schematic rear view. Figure 8(a) schematically shows the condition of the soil when the liquid fertilizer insertion tube is placed inside the shaping cutting blade for application, and Figure 8(b) is an illustrative diagram showing the condition of the soil after liquid fertilizer application. Figure 9 shows the liquid fertilizer insertion pipe located outside the soil cutting section and the shaping cutting blade, where (a) is a schematic front view, (b) is a schematic side view, and (c) is a schematic rear view. Figure 10(a) schematically shows the state of the soil when the liquid fertilizer insertion tube is placed outside the shaping cutting blade for application, and Figure 10(b) is an illustrative diagram showing the state of the soil after liquid fertilizer application. Figure 11(a) is a schematic front view showing how the liquid fertilizer is applied when the outlet of the liquid fertilizer insertion pipe is positioned toward the side of the shaping cutting blade, and Figure 11(b) is an illustrative diagram showing the state of the soil after liquid fertilizer application with this arrangement. Figure 12 is a table showing the concentration distribution of inorganic nitrogen in the soil in Example 1. Figure 13 is a table showing the results of measuring the amount of ammonia gas volatilized from the ground surface in Example 2. Figure 14 is a table showing the concentration distribution of inorganic nitrogen in the soil in Comparative Example 1.

The liquid fertilizer application device M according to the present invention will be described with reference to Figure 1.
The liquid fertilizer applicator M is detachable from the tractor and can be towed by the tractor. In this specification, the forward direction F shown in Figure 1 refers to the direction in which the liquid fertilizer applicator M is connected to the tractor, i.e., the direction of travel of the liquid fertilizer applicator M. The direction opposite to the forward direction F is referred to as the rear direction R.
The liquid fertilizer application device M includes a liquid fertilizer tank 17 for storing liquid fertilizer 30, a soil cutting section 25 (see Figure 1(b)) comprising a shaping lifting plate 21 and two shaping cutting blades 20 connected in a roughly V-shape with the shaping lifting plate 21 in between, and a frame to which the soil cutting section 25 is fixed at the bottom and the liquid fertilizer tank 17 is fixed at the top and which is detachably connected to a tractor.

This frame primarily includes a three-point linkage frame 12, which is a subframe for connecting to the tractor via a so-called three-point linkage; a shaped cutting blade frame 14, which is a subframe for fixing the shaped cutting blade 20; and a liquid fertilizer tank frame 16, which is a subframe for fixing the liquid fertilizer tank 17. Each subframe is described for illustrative purposes only; they may be manufactured separately, or the whole or parts of the frame may be manufactured as a single unit.

The liquid fertilizer application device M is connected to the tractor using a so-called three-point linkage system, and therefore includes a three-point linkage connection frame 12. In the front view shown in Figure 2, the frame 12 has a top linkage connection section 10 at the top center, and two lower linkage connection sections 11 on either side of it.

The three-point linkage frame 12 is rotatably connected to the shaping cutting blade frame 14 on the rear R side. The connecting cutting blade frame 14 has a shaping cutting blade holder 15 for supporting the shaping cutting blade 20.

As shown in Figure 1(b), in a front view of the soil cutting section 25, two shaping cutting blades 20 are connected to form a roughly V-shape. The connection point of the two shaping cutting blades 20 has a base of a certain width, where a shaping lifting plate 21 is installed between the two shaping cutting blades 20. As shown in Figure 1(a), the shaping cutting blades 20 are curved in a side view, and the shaping lifting plate is installed to rise from the front F side to the rear R side. Due to this shape, when the liquid fertilizer application device M is towed by a tractor and the shaping cutting blades 20 and shaping lifting plate 21 inserted into the soil move forward, the soil 1 inside this series of shaping cutting blades 20 is lifted by the shaping lifting plate, and then lowered again after the shaping cutting blades have passed, causing it to be crushed. For example, as shown by the horizontal hatching in Figure 6(a), a roughly V-shaped crushed soil 2 is formed in the front view of the figure. This crushed soil 2 is soft and pliable, making it easy for the liquid fertilizer 30 to penetrate within its area.

The liquid fertilizer application device M can also handle buried objects when applying fertilizer to deep soil layers. Buried objects such as stones up to a certain size can pass through the roughly V-shaped opening formed by the two shaping cutting blades 20. Furthermore, the liquid fertilizer application device M is equipped with a mechanism that prevents damage to the device and tractor by preventing the shaping cutting blades 20 and the shaping lifting plate 21 from colliding with a large object. This is achieved by breaking a safety pin (not shown), allowing the blades to lift to the surface without resisting the force, thus preventing damage to the device and the tractor.

The liquid fertilizer application device M can be equipped with one to three soil cutting sections 25. Figure 2 shows an example of a liquid fertilizer application device M equipped with three soil cutting sections 25. Even when multiple soil cutting sections 25 are provided, they can be arranged at any desired intervals.

The three-point linkage frame 12 and the shaping cutting blade frame 14 are rotatably connected via a hydraulic cylinder 13. This hydraulic cylinder 13 can be operated using the tractor's hydraulic system, and its extension and retraction allows the angle of the shaping cutting blade frame relative to the three-point linkage frame to be changed, thereby adjusting the inclination of the shaping cutting blade frame 14 relative to the soil surface. This operation allows for adjustment of the insertion depth of the shaping cutting blade 20 into the soil and its subsequent retrieval from the soil. This adjustment using the hydraulic cylinder 13 allows the cutting depth to be adjusted within a range of 0 to 50 cm.

A liquid fertilizer tank frame 16 is fixed to the upper part of the shaping and cutting blade frame 14. A liquid fertilizer tank 17 for storing liquid fertilizer 30 is fixed to the upper part of the liquid fertilizer tank frame 16. For example, as shown in Figure 2, one liquid fertilizer tank 17 can be provided on each side when viewed from the front. The fixing of the liquid fertilizer tank 17 to the liquid fertilizer tank frame 16 is not particularly limited as long as it can withstand the vibrations of agricultural work, but it is preferable that the liquid fertilizer tank 17 itself be installed in a way that allows for easy attachment and detachment.
Liquid fertilizer 30 refers to liquids such as the slurry of manure, which is livestock waste, the fermented digestate, which is the fermented liquid of manure, or prepared liquid fertilizer.

The liquid fertilizer application device M is equipped with a liquid fertilizer insertion pipe 37 for ultimately applying the liquid fertilizer 30 to the soil.
Preferably, the liquid fertilizer insertion tubes 37 are fixedly installed around each of the shaping cutting blades 20. In this case, two liquid fertilizer insertion tubes 37 are provided for a single soil cutting section 25, and six liquid fertilizer insertion tubes 37 are provided for a triple soil cutting section 25 (see Figure 2).
By adjusting the position of the shaping and cutting blade frame 14 or the soil cutting section 25 using the hydraulic system described above, the position of the liquid fertilizer insertion pipe 37, which is fixed in position relative to the shaping and cutting blade 20, is also adjusted.

As the liquid fertilizer application device M is towed by the tractor, the soil cutting section 25 moves through the soil 1, crushing the soil in a roughly V-shape, while simultaneously applying the liquid fertilizer 30 from the liquid fertilizer tank into the crushed soil 2 via the liquid fertilizer insertion pipe 37.
By applying liquid fertilizer 30 into the gaps of the soft soil through the liquid fertilizer insertion pipe 37 within the crushed soil 2, the liquid fertilizer 30 can be completely buried so that it is not exposed to the surface of the soil 1, i.e., not exposed to the atmosphere, thus preventing the volatilization of ammonia, a nitrogen fertilizer component, into the atmosphere. This increases the utilization rate of nitrogen fertilizer.

For example, when the soil cutting section 25 is inserted into the soil to a construction depth of 50 cm, the distance between the two shaped cutting blades 20, which form a roughly V shape, near the ground surface becomes about 60 cm, and each shaped cutting blade 20 itself forms a groove (gap) about 5 cm wide in the soil down to the deep layer. When viewed from the front (viewpoint in Figure 2), the formation of soft, crushed soil 2 of this size increases the upper limit of the application amount.
In the crushed soil 2 thus formed, the area at a depth of approximately 1 cm to 50 cm becomes the mid-to-deep application area for liquid fertilizer. The aforementioned grooves (gaps) of approximately 5 cm formed on both sides of the mid-to-deep application area for liquid fertilizer can be used to apply liquid fertilizer 30 into the crushed soil 2. By adjusting the soil cutting section 25 from 1 to 3 consecutive sections, it becomes possible to apply up to 20 t/10a of liquid fertilizer 30 into the soil.

To distribute liquid fertilizer 30 from the liquid fertilizer tank 17 to multiple liquid fertilizer insertion pipes 37, the liquid fertilizer application device M can be equipped with a liquid fertilizer distributor 31 between the liquid fertilizer tank 17 and the liquid fertilizer insertion pipes 37 (see Figures 1 and 2).

The liquid fertilizer distributor 31 will be explained using Figure 3. As shown in Figure 3(b), the liquid fertilizer distributor 31 comprises a distribution container 60 and a distribution container lid 63. The distribution container 60 has a cylindrical shape with a bottom surface 61.
A transport pipe 32 is provided as a passage for the liquid fertilizer 30 connecting the liquid fertilizer distributor 31 and the liquid fertilizer tank 17 (see Figures 1(a) and 3(b)). The transport pipe 32 is connected to a hole opening in the center of the distribution container lid 63, and the liquid fertilizer 30 is injected from the liquid fertilizer tank 17 into the distribution container 60 by its own weight.
At this time, to prevent the liquid fertilizer 30 from leaking out of the dispensing container 60, the dispensing container lid 63 and the dispensing container 60 are tightly sealed together, for example, with a dispensing container lid fastener 64.

As shown in Figure 3(a), the interior of the distribution container 60 includes a rotating shaft 66 rotatable by a motor 65 (see Figures 1(a) and 3(b)) located on the underside of the distribution container 60, a plurality of holes 62 provided on the bottom surface 61 at equal angular intervals and equidistant from the rotating shaft 66, a plurality of distribution plates 68 extending from the rotating shaft 66 to the vicinity of the inner surface of the distribution container 60 and evenly partitioning the interior of the distribution container 60, and distribution plate blades 67 provided on the vertically upper edge of each distribution plate 68, i.e., the edge on the side of the liquid fertilizer inlet 69. The distribution plates 68 and distribution plate blades 67 may be manufactured as a single unit or as separate components. It is preferable that the number of distribution plates equals the number of holes 62. More preferably, the number of holes 62 equals the number of liquid fertilizer insertion pipes 37.

Each distribution plate 68 is positioned at an angle of approximately 1 to 30 degrees in the rotational direction from a plane perpendicular to the bottom surface 61 of the distribution container 60. Therefore, as shown in Figure 3(a), the side surfaces of the distribution plates 68 are visible in a plan view.

The liquid fertilizer distributor 31 and the liquid fertilizer insertion pipe 37 are connected by liquid fertilizer distribution hoses 36. One end of each liquid fertilizer distribution hose 36 connected to each liquid fertilizer insertion pipe 37 is installed in the respective holes 62, as shown in Figure 3(b).

As the rotating shaft 66 rotates, the distribution plate 68 rotates, and the angled distribution plate blades 67 cut through impurities in the liquid fertilizer 30 injected from the liquid fertilizer inlet 69. This rotational action ensures that an equal amount of liquid fertilizer 30 flows into the distribution container 60, which is partitioned by the distribution plate, and then flows through the holes 62 in the bottom surface 61 to the respective liquid fertilizer distribution hoses 36.

The dispensing container lid 63 is provided with a transparent container window 70 that allows visibility into the inside of the dispensing container 60 (Figure 3(b)). This allows observation of the rotation of the aforementioned rotating shaft 66, the process of cutting the liquid fertilizer 30, and the distribution status of the liquid fertilizer 30. For example, a container window 70 of the size shown can be provided at the position indicated by the dashed line in Figure 3(a).

In the example shown in Figure 3(a), six holes 62 are provided, and the internal space of the distribution container 60 is divided into six sections by six distribution plates 68. In this case, as shown in Figure 2, it is assumed that the container will be used primarily for six liquid fertilizer insertion pipes 37 installed on each of the three shaping cutting blades 20 of the triple soil cutting section 25. As a variation, Figure 4(a) shows an example where four holes 62 are provided, and the internal space of the distribution container 60 is divided into four sections by four distribution plates 68. In this case, it is assumed that the container will be used primarily for four liquid fertilizer insertion pipes 37 installed on each of the two shaping cutting blades 20 of the double soil cutting section 25. Another variation, Figure 4(b), shows an example where two holes 62 are provided, and the internal space of the distribution container 60 is divided into two sections by two distribution plates 68. In this case, it is assumed that the container will be used primarily for two liquid fertilizer insertion pipes 37 installed on each of the three shaping cutting blades 20 of the single soil cutting section 25.

The liquid fertilizer distributor 31 itself can be widely used in devices that distribute liquid fertilizer containing impurities into multiple pipes, and can be used regardless of the size of the device.

As shown in Figure 1, the liquid fertilizer application device M is equipped with a valve 40 that enables the start/stop of the supply of liquid fertilizer 30 injected from the liquid fertilizer tank 17 to the liquid fertilizer distributor 31.
By adjusting this valve to a degree such as fully open, 3/4 open, half open, or 1/4 open, the flow rate of the injected liquid fertilizer 30 can be adjusted.
The valve opening and closing mechanism can be operated manually, by the extension and retraction of a hydraulic cylinder, by an electric valve (shutter type), or by a combination thereof.
In addition, in order to apply fertilizer at an appropriately planned rate, the flow rate of the liquid fertilizer may be adjusted, for example, by the travel speed of the tractor towing the liquid fertilizer application device M, rather than by adjusting it with a valve.

In the following, several embodiments regarding the position in which the liquid fertilizer insertion pipe 37 is arranged will be described.
In one embodiment, as shown in Figures 1 and 5, the liquid fertilizer insertion tube 37 can be positioned along the rear side of the two shaping cutting blades 20 that form a roughly V shape. The liquid fertilizer insertion tube 37 may be positioned so as to be in contact with the shaping cutting blades 20, or it may be positioned along the shaping cutting blades 20 with a gap between them, as shown in Figure 1(a). However, it is desirable that their relative positions be fixed when applying liquid fertilizer. In particular, it is desirable that the liquid fertilizer insertion tube 37 be fixed so that the depth in the soil at the outlet 38 at the tip does not change when applying liquid fertilizer.
To securely position the liquid fertilizer insertion pipe 37, a fixing member 39 provided on the molding cutting blade holder 15 may be used, for example, as shown in Figures 5(b) and 5(c). It is sufficient that the liquid fertilizer insertion pipe 37 is positioned in a stable location even during agricultural work; fixing members may be provided in other locations, or other fixing methods may be used.
The configuration or method of arranging the liquid fertilizer insertion tube 37 along the molding cutting blade 20, and the fixing member 39, are common to other embodiments described later.

As the liquid fertilizer application device M is towed by the tractor, the shaping cutting blades 20 move through the soil 1 in the leftward direction from the viewpoint shown in Figure 5(b), and in the forward direction from the viewpoints shown in Figures 5(a) and 6. As shown in Figure 6, the soil 1 inside the two shaping cutting blades 20, which form a roughly V-shape, becomes crushed soil 2. Liquid fertilizer 30, flowing from a liquid fertilizer insertion pipe installed on the rear side of the shaping cutting blades 20, can be applied to the gaps left by the shaping cutting blades 20 as they pass through the soil 1.

Figure 6(b) shows the state of the roughly V-shaped crushed soil 2 after the liquid fertilizer 30 has been applied according to this embodiment. Because the liquid fertilizer 30 is completely buried in the soil, the volatilization of volatile components such as ammonia, which are major fertilizer components, can be suppressed.

In another embodiment, as shown in Figure 7, the liquid fertilizer insertion pipe 37 can be positioned along the inside of the two shaping cutting blades 20, which form a roughly V-shape. In this case, as shown in Figure 8, the liquid fertilizer 30 flowing out of the liquid fertilizer insertion pipe 37 can be applied to the lower part of the crushed soil 2 by flowing down the shaping cutting blades 20 due to surface tension.

In another embodiment, as shown in Figure 9, the liquid fertilizer insertion pipe 37 can be positioned along the outside of the two shaping cutting blades 20, which form a roughly V-shape. In this case, as shown in Figure 10, the liquid fertilizer 30 flowing out from the liquid fertilizer insertion pipe 37 can be applied to the lower part of the crushed soil 2 by flowing down the shaping cutting blades 20 due to surface tension.

In yet another embodiment, as shown in Figure 11, when the soil cutting section 25 is inserted into the soil, the liquid fertilizer insertion pipe 37 can be positioned such that the outlet 38 at the tip of the liquid fertilizer insertion pipe 37 is perpendicular to the side surface of the portion of the shaped cutting blade 20 that is not inserted into the soil. The side surface of the shaped cutting blade 20 may be either the inside or outside of the shaped cutting blade 20, which forms a roughly V shape from the viewpoint shown in Figure 11(a).
In this case, the liquid fertilizer 30 that flows out from the liquid fertilizer insertion pipe 37 collides with the side surface of the shaping cutting blade 20, as shown in Figure 11(a), resulting in a scattered liquid fertilizer application as shown in Figure 11(b). The liquid fertilizer 30 easily penetrates the softened crushed soil 2.

The aforementioned components, particularly the liquid fertilizer application device M as an integrated implement equipped with a liquid fertilizer tank, have connections and dimensions that allow it to be towed even by a small tractor, thus ensuring overall mechanical mobility. This makes it possible to apply liquid fertilizers such as livestock manure slurry and digestate without using a tank truck.
In addition, the shaping cutting blade 20 creates a soft, crushed soil 2 with numerous roughly V-shaped cracks in a front view (viewpoint in Figure 2), which is constructed over a wide area down to the deep layers of the soil. The crushed soil 2, continuously formed by the movement of the liquid fertilizer application device M, not only allows for the application of liquid fertilizer to the deep layers, but also enables the application of large quantities of fertilizer.

Furthermore, as described above, the application of fertilizer into the soil by the liquid fertilizer insertion pipe 37, which is positioned along the side surface of the shaping cutting blade 20, enables effective application to deep layers of the soil.
By applying fertilizer using the liquid fertilizer application device M, surface exposure of the liquid fertilizer 30 can be prevented, thereby preventing the volatilization and runoff of ammonia from the liquid fertilizer 30, which generates unpleasant odors. This prevents not only surface exposure when applying large amounts of liquid fertilizer, but also uneven distribution of the liquid fertilizer due to terrain, resulting in the application of large quantities of liquid fertilizer into the soil while maintaining uniformity.
Since the liquid fertilizer application device M is equipped with a three-point linkage frame 12 that can be connected to an existing tractor, and can utilize an existing liquid fertilizer tank 17, the present invention can be implemented at a relatively low cost.

The contents disclosed above can also be understood as an invention for a method of applying liquid fertilizer 30. That is, by having a tractor tow a liquid fertilizer application device M which integrally comprises the above-mentioned components, the soil cutting section is advanced in the soil, forming a roughly V-shaped, soft soil inside it, and the liquid fertilizer 30 in the liquid fertilizer tank 17 is applied into the soft soil from the liquid fertilizer insertion pipe 37 which is arranged along the side of each shaping cutting blade or the rear side opposite to the direction of advancement.
By using the aforementioned liquid fertilizer distributor 31 in this liquid fertilizer application device M, impurities in the liquid fertilizer 30 are cut off, and an equal amount of liquid fertilizer 30 flows into each liquid fertilizer insertion pipe 37.

[Example 1]
Examples of the present invention are shown below.
A deep soil application section for liquid fertilizer 30 was set up, assuming a liquid fertilizer application device M (see Figure 5) in which a liquid fertilizer insertion pipe 37 is installed on the rear side of the shaping cutting blade 20. The distribution of ammonia nitrogen in the soil during deep soil application was measured, and the results of the cross-sectional distribution of the components are shown in Figure 12.
The test conditions are as follows:
- Test date: March 29, 2023 - Test location: Kuroboku soil field at the Rural Engineering Research Division, Tsukuba City, Ibaraki Prefecture - Tractor used: Kubota SMZ76 76 horsepower half-crawler tractor - Implement used: As a test trial, a small liquid fertilizer applicator M having three V-shaped molded cutting blades 20 was used, and test application was carried out with an insertion depth of 40 cm per molded cutting blade 20.
• Liquid fertilizer used: Methane fermentation digestate (livestock manure-based)
Ammonia nitrogen concentration: 0.17%
• Application method: Subsurface application using the liquid fertilizer application device M according to the present invention. • Application rate: 8 t/10 a
- Chemical fertilizer (nitrogen equivalent): equivalent to 13.6 kgN/10a

As shown in Figure 12, the concentration of ammonia nitrogen in the soil application plots of this embodiment increased with depth, indicating that the liquid fertilizer 30 was applied to the soil without exposure even in the surface layer at a depth of 0-10 cm. Furthermore, there was no immediate movement of ammonia components from the application area to the surrounding area after application, suggesting that the ammonia was retained at the application site.

[Example 2]
A deep soil application section for liquid fertilizer 30 was set up, assuming a liquid fertilizer application device M (see Figure 9) in which the liquid fertilizer insertion pipe 37 is installed outside the shaping and cutting blade 20. The amount of ammonia gas volatilized from the ground surface after liquid fertilizer application was measured, and the results are shown in Figure 13 as the ammonia gas volatilization rate.
The test conditions are as follows:
• Test date: March 29, 2023 • Test location: Kuroboku soil field at the Rural Engineering Research Division, Tsukuba City, Ibaraki Prefecture • Tractor used: Kubota SMZ76 76 horsepower half-crawler tractor • Liquid fertilizer used: Methane fermentation digestate (livestock manure-based)
Ammonia nitrogen concentration: 0.17%
• Application method: 1) Soil application using the liquid fertilizer application device M according to the present invention
2) Surface application to the ground surface using conventional technology: Application rate: 8 t/10a (the same amount for both the subsurface application area and the surface application area)
- Chemical fertilizer (nitrogen equivalent): equivalent to 13.6 kgN/10a

As shown in Figure 13, the ammonia gas volatilization rate in the soil application plot using the liquid fertilizer application device M according to the present invention was zero. This indicates that ammonia gas volatilization can be suppressed by applying the liquid fertilizer 30 into the soil and completely covering it with soil.

[Comparative Example 1]
Figure 14 shows the results of measuring the distribution of ammonia nitrogen in the soil after applying liquid fertilizer 30 to the soil surface, assuming a conventional surface application method, and presenting a cross-sectional distribution map of the components.
The test conditions are as follows:
• Test date: March 29, 2023 • Test location: Kuroboku soil field at the Rural Engineering Research Division, Tsukuba City, Ibaraki Prefecture • Application method: Manual application • Liquid fertilizer used: Methane fermentation digestate (livestock manure-based)
Ammonia nitrogen concentration: 0.17%
• Application location: Surface application to the ground surface • Application rate: 8 t/10a (same amount for both surface application and subsurface application)
- Chemical fertilizer (nitrogen equivalent): equivalent to 13.6 kgN/10a

As shown in Figure 14, the area with the highest concentration of ammonia nitrogen in the conventional surface application method was the surface layer at a depth of 0-10 cm, meaning that most of the concentration was at the surface. Immediately after application, there was no nutrient movement to the lower layers, creating conditions conducive to the volatilization of ammonia gas.

As shown in Figure 13, the ammonia gas volatilization rate in the conventional surface application plot is high after application, and although it gradually decreases, it continues for a relatively long period. As long as liquid fertilizer 30 is present on the soil surface, ammonia gas volatilization continues, contributing to the reduction of nitrogen components.

The combinations of arrangement of liquid fertilizer insertion pipes or the arrangement of each shaping cutting blade 20, the arrangement relationships of each component in the liquid fertilizer application device M, the piping method between each component, the piping material, the method of fixing the liquid fertilizer insertion pipe 37, the method of fixing the liquid fertilizer tank, the size of the tank, etc., are all examples and do not limit the scope of the invention to the extent that the objective of the present invention can be realized. Regarding the liquid fertilizer application device, method, and liquid fertilizer distributor disclosed above, the combinations described herein are also included in the scope of disclosure to the extent that they are included in the claims.

1 Soil 2 Crushed soil 10 Top link connection 11 Lower link connection 12 Three-point link connection frame 13 Hydraulic cylinder 14 Molding cutting blade frame 15 Molding cutting blade holder 16 Liquid fertilizer tank frame 17 Liquid fertilizer tank 20 Molding cutting blade 21 Molding lifting plate 25 Soil cutting section 30 Liquid fertilizer 31 Liquid fertilizer distributor 32 Transport pipe 36 Liquid fertilizer distribution hose 37 Liquid fertilizer insertion pipe 38 Outlet 39 Fixing member 40 Valve 60 Distribution container 61 Bottom surface 62 Hole 63 Distribution container lid 64 Distribution container lid fastener 65 Motor 66 Rotating shaft 67 Distribution plate blade 68 Distribution plate 69 Liquid fertilizer inlet 70 Container window M Liquid fertilizer application device F Front R Rear

Claims (6)

A liquid fertilizer application device for applying liquid fertilizer to a field towed by a tractor,
A liquid fertilizer tank for storing liquid fertilizer,
A soil cutting section comprising a shaping lifting plate and two shaping cutting blades connected in a substantially V-shape with the shaping lifting plate interposed therebetween,
The soil cutting section is fixed to the lower part, the liquid fertilizer tank is fixed to the upper part, and the frame is detachably connected to the tractor,
It has a liquid fertilizer insertion pipe fixed around the shaping cutting blade and communicating with the liquid fertilizer tank,
A liquid fertilizer application device characterized in that, as the soil cutting section progresses in the soil, crushed soil suitable for fertilization is formed inside the roughly V-shape formed by the two shaping cutting blades , and the two shaping cutting blades themselves form two grooves in the soil , while at the same time, the liquid fertilizer in the liquid fertilizer tank flows out from the liquid fertilizer insertion pipe into each of the two grooves and is applied to the crushed soil formed inside the two shaping cutting blades . The liquid fertilizer application device according to claim 1, characterized in that the frame includes a molded cutting blade frame for fixing the molded cutting blade and a three-point linkage frame for connecting to the tractor, and the depth of the soil cutting section can be adjusted within a range of 0 to 50 cm by changing the angle of the molded cutting blade frame relative to the three-point linkage frame using a hydraulic cylinder connecting the molded cutting blade frame and the three-point linkage frame. The liquid fertilizer application device according to claim 1, characterized in that it can be equipped with one to three soil cutting sections. The liquid fertilizer insertion tube is positioned along the shaping cutting blades, either inside, outside, or on the rear side opposite to the direction of travel, or in a combination thereof, and
The liquid fertilizer application device according to claim 1, characterized in that the shaping cutting blade is inserted into the soil and the outlet, which is the outlet for the liquid fertilizer in the liquid fertilizer insertion pipe, is positioned in the soil. The liquid fertilizer application device according to claim 1, characterized in that, with the shaping cutting blade inserted into the soil, the outlet of the liquid fertilizer insertion pipe, which is the outlet for the liquid fertilizer, is positioned perpendicular to the side surface of the portion of the shaping cutting blade not inserted into the soil. A method of applying liquid fertilizer by towing a liquid fertilizer application device, which integrally comprises a soil cutting section having a liquid fertilizer tank, a liquid fertilizer insertion pipe communicating with it, a shaping lifting plate and two shaping cutting blades connected in a substantially V-shape with the shaping lifting plate in between, and a frame to which the soil cutting section is fixed at the bottom and the liquid fertilizer tank is fixed at the top and detachably connected to a tractor, thereby advancing the soil cutting section in the soil, forming a substantially V-shaped, soft, crushed soil inside the two shaping cutting blades , and the two shaping cutting blades themselves forming two grooves in the soil, while applying liquid fertilizer that flows into each of the two grooves from the liquid fertilizer insertion pipe, which is positioned along the side of each shaping cutting blade or the rear side opposite to the direction of advancement, to the soft, crushed soil formed inside the two shaping cutting blades .