Sampling device and method for detecting nitrate content of soil

Abstract

The invention relates to the technical field of nitrate detection soil sampling, and discloses a sampling device for soil nitrate content detection and a method thereof.The sampling device comprises a machine body and a tubular soil sampling part, and the soil sampling part comprises a connecting end fixed to the lower end of the machine body; the pipe section comprises a soil sampling pipe and is connected to the lower end of the connecting end, multiple sections of the pipe section can be connected end to end to extend the length, and the pipe section is internally provided with a cystic protective layer used for wrapping soil and an inner sleeve assembly used for bagging the soil to prevent mixing; and the soil sampling end is connected to the end part of the pipe section at the outermost end and is used for downwards extending into the soil. The elastic bag has an active wrapping effect, when soil is taken, the soil pushes the elastic bag to form an independent bagging layer tightly attached to the outer contour of a soil column, the soil column is wrapped, the outer side of the elastic bag makes contact with a bag layer or the inner wall of a pipe section, a soil sample is kept stable, and disturbance to the soil sample is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of nitrate detection and soil sampling, and in particular to a sampling device and a method for detecting nitrate content in soil. Background Art

[0002] As the core carrier of nitrogen cycle, the content and dynamic changes of soil nitrate directly affect the productivity and nitrogen balance of ecosystems. In the study of temperate grassland ecology, accurate quantification of nitrate balance flux (such as atmospheric deposition, nitrification, denitrification, leaching, etc.) is the key to analyzing the nitrogen cycle mechanism under grazing disturbance.

[0003] At present, when sampling soil, most devices can only obtain mixed samples and cannot achieve multi-depth accurate stratification. Announcement No. CN109000960B discloses a sampling device and method for detecting soil nitrate content, which aims to solve the problems of high labor intensity of soil sampling and inaccurate detection caused by mixing of soil at different depths in the prior art.

[0004] However, there are still the following problems when sampling soil:

[0005] First, when taking soil, the differences in soil conditions, such as plasticity, fluidity, and particle grading, will significantly increase the risk of mixing when taking soil.

[0006] Second, when taking soil, traditional soil samplers have large friction on the tube wall, which easily disturbs the soil sample, resulting in the possibility of mixing of soil layers at different depths, further affecting the detection of nitrate content.

[0007] Third, after the soil layer is taken out, it is necessary to preserve it relatively intact. However, when the soil layer is taken out from the inside of the soil sampler, there is a possibility that the soil layer will be disturbed, and there is also the possibility that the soil layer to be tested is affected by other pollutants and the evaporation of soil moisture. Summary of the invention

[0008] The object of the present invention is to provide a sampling device and method for detecting soil nitrate content, so as to solve the problems raised in the above background technology.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: a sampling device for detecting soil nitrate content, comprising a body and a tubular soil sampling part, wherein the soil sampling part comprises:

[0010] A connecting end, fixed to the lower end of the body;

[0011] The pipe section includes a soil taking pipe connected to the lower end of the connection end. The pipe section can be connected end to end to extend the length. The interior of the pipe section has a bag-shaped protective layer for covering the soil and an inner sleeve component for bagging the soil to prevent mixing;

[0012] The soil-collecting end is connected to the end of the outermost pipe section and is used to extend downward into the soil.

[0013] Furthermore, the connecting end includes a connecting shaft fixed at the lower end of the machine body, and the outer side of the connecting shaft and the outer side of the soil taking pipe are respectively penetrated with a connecting hole 1 and a connecting hole 2, the connecting shaft is sleeved with the soil taking pipe, and the connecting hole 1 and the connecting hole 2 overlap;

[0014] A support shaft passes through the first connection hole and the second connection hole, and a threaded shaft is threadedly connected to the end of the support shaft, and the outer ends of the support shaft and the threaded shaft are expanded outwards;

[0015] The lower end of the soil sampling pipe is also integrally provided with a matching layer, and a penetrating connection hole three is opened on the outer side of the matching layer. The matching layer can be matched with the head end of the soil sampling pipe of the next group, and the connection hole two can overlap with the connection hole three. The matching layer can also be sleeved with the soil sampling end.

[0016] Furthermore, the outer half of the soil sampling pipe is cut to have a sampling outlet, and the pipe section also includes a cover layer, and the cover layer is buckled in the sampling outlet, so that the soil sampling pipe forms a complete pipe body;

[0017] The soil sampling pipe and the inner wall of the cover layer are both provided with corresponding inner cavities, the bag-type protective layer includes a bag layer and a rubber belt, the bag layers are in two groups and are respectively fixed in the corresponding inner cavities on both sides, the soil sampling pipe and the outer side of the cover layer are both provided with air vents, the air vents are connected with the inside of the bag layers on both sides, and the rubber belt is sleeved on the outer side of the soil sampling pipe and the cover layer and covers the air vents.

[0018] Furthermore, elastic metal sheets are fixed to the outer sides of the soil sampling pipe and the cover layer, and the rubber belt is buckled in the metal sheet.

[0019] Furthermore, the bladder layer is made of rubber material and is expandable, and its internal texture extends along the axis of the pipe section.

[0020] Furthermore, the soil sampling pipe and the cover layer are provided with corresponding installation cavities near the inner wall of the lower end, and the upper inner walls of the installation cavities on both sides are provided with blocks, and the inner sleeve assembly includes an inner metal ring, an elastic bag and a rubber tightening ring;

[0021] The inner metal ring is located in the mounting cavities on both sides, and its upper end is clamped by a clamping block. There is a gap between the lower end of the inner metal ring and the inner wall of the lower end of the mounting cavities on both sides. The elastic bag is sleeved on the outside of the inner metal ring from bottom to top, and its end is located in the gap. The rubber shrinking ring is squeezed and sleeved on the outside of the elastic bag, and the outside of the rubber shrinking ring is squeezed against the inner walls of the mounting cavities on both sides. When the soil moves into the pipe section, the elastic bag will be pushed upward and automatically sleeved into the elastic bag.

[0022] Furthermore, the outer side of the elastic bag has a plurality of evenly distributed elastic rings, so that the elastic bag is in a contracted shape.

[0023] Furthermore, the outer side of the cover layer is threadedly connected with bolt 2, and the bolt 2 passes through a block and abuts against the outer side of the inner metal ring. The outer side of the cover layer has bolt 1, which is fixed to the soil sampling pipe through the bolt 1;

[0024] Stopping blocks are provided on the outer sides of the bolt 1 and the bolt 2 to prevent the soil from covering the bolt 1 and the bolt 2.

[0025] Furthermore, the lower end of the soil-taking end is provided with a blade edge, and the blade edge converges inwardly, and the diameter of the blade edge is smaller than the diameter of the pipe section.

[0026] A sampling method for detecting soil nitrate content comprises the following steps:

[0027] Step 1: Tighten the pipe section and the connecting end step by step, and install the soil collecting end at the end;

[0028] Step 2: Check the shrinkage state of the bladder layer and make sure that the rubber band completely covers the air outlet;

[0029] Step 3: pre-install the elastic bag and tie it in the installation cavity with a rubber tie ring;

[0030] Step 4: Press the machine body vertically downward, pierce the soil end into the soil, penetrate layer by layer to the target depth, push the soil into the elastic bag, and the elastic ring tightens the soil sample layer by layer to avoid mixing. The soil squeezes the bag layer to form an air cushion, and the air pressure is released through the rubber belt to reduce disturbance;

[0031] Step 5: Remove the cover layer, take out the elastic bag along the outlet, and take samples in sections according to the elastic ring marks.

[0032] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0033] 1. The elastic bag has an active wrapping effect. When taking soil, the soil pushes the elastic bag to form an independent bagged layer that fits closely to the outer contour of the soil column, completing the coating of the soil column and achieving contact between the outer side of the elastic bag and the bag layer or the inner wall of the pipe section, thereby keeping the soil sample stable and reducing disturbance to the soil sample.

[0034] 2. The elastic bag has the function of actively wrapping while the elastic rings unfold layer by layer. Each circle of the elastic ring limits the relative position of the soil sample to prevent the soil sample from loosening under its own action.

[0035] 3. The capsule layer supports the internal soil column, and the gas is slowly released through the vent holes, which not only reduces the friction resistance of the tube wall and reduces disturbance, but also maintains lateral constraints on the soil column to ensure the integrity of the soil sample.

[0036] 4. When taking soil, bag it to facilitate taking out the soil. It also prevents the soil from being affected by other pollutants and prevents soil moisture from evaporating. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0039] Figure 2 It is a schematic diagram of the decomposed structure of the soil taking part of the present invention;

[0040] Figure 3 It is a schematic diagram of the decomposed structure of the pipe section of the present invention;

[0041] Figure 4 It is a schematic diagram of the exploded structure of the upper end of the pipe section of the present invention;

[0042] Figure 5 This is a schematic diagram of the separation structure of the capsule layer and the soil sampling pipe of the present invention;

[0043] Figure 6 It is a schematic diagram of the exploded structure of the lower end of the pipe section of the present invention;

[0044] Figure 7 The present invention Figure 6 A is a schematic diagram of the partially enlarged structure of the middle part;

[0045] Figure 8 It is a schematic diagram of the exploded structure of the inner sleeve assembly of the present invention;

[0046] Fig. 9 It is a schematic diagram of the structure of the elastic bag of the present invention unfolding downward;

[0047] Fig.10 It is a schematic diagram of the cross-sectional structure of the inner sleeve assembly and its installation position of the present invention;

[0048] Fig.11 It is a schematic diagram of the exploded structure of the soil taking end and the pipe section of the present invention.

[0049] In the figure: 1. body; 2. soil taking part; 3. connecting end; 31. connecting shaft; 32. connecting hole one; 4. pipe section; 41. soil taking pipe; 411. connecting hole two; 412. matching layer; 413. connecting hole three; 414. supporting shaft; 415. threaded shaft; 42. taking outlet; 43. cover layer; 431. bolt one; 432. bolt two; 5. soil taking end; 6. bladder-type protective layer; 61. inner cavity; 62. bladder layer; 63. rubber belt; 64. air outlet; 65. metal sheet; 7. inner sleeve assembly; 71. installation cavity; 72. block; 73. inner metal ring; 74. elastic bag; 741. elastic ring; 75. rubber tightening ring. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] See also Figure 1-Figure 11 , the present invention provides a technical solution: Figure 1 and Figure 2 The present invention discloses a sampling device for detecting nitrate content in soil, comprising a body 1 and a tubular soil sampling part 2. The body 1 is a core component for providing power, which is usually called a gasoline engine power head or a gasoline engine. It is a mature technology and is used to generate a downward impact. The soil sampling part 2 comprises:

[0052] A connecting end 3 is fixed to the lower end of the body 1;

[0053] The pipe section 4, including a soil sampling pipe 41, is connected to the lower end of the connection end 3. The pipe section 4 can be connected end to end to extend the length. The interior of the pipe section 4 has a bag-shaped protective layer 6 for covering the soil and an inner sleeve component 7 for bagging the soil to prevent mixing;

[0054] The soil-collecting end 5 is connected to the end of the outermost pipe section 4 and is used to extend downward into the soil.

[0055] Specifically, the body 1, the connecting end 3, the multi-section or single-section pipe section 4 and the soil sampling end 5 cooperate to form a complete soil sampling device, which can sample the soil downward.

[0056] like Figure 4 and Fig.11The figure shows a schematic diagram of the structure of the upper and lower ends of the pipe section 4. The connecting end 3 includes a connecting shaft 31 fixed to the lower end of the machine body 1. The outer side of the connecting shaft 31 and the outer side of the soil taking pipe 41 are respectively penetrated by a connecting hole 1 32 and a connecting hole 2 411. The connecting shaft 31 is sleeved with the soil taking pipe 41, and the connecting hole 1 32 and the connecting hole 2 411 are overlapped.

[0057] A support shaft 414 runs through the connection hole 1 32 and the connection hole 2 411 , and a threaded shaft 415 is threadedly connected to the end of the support shaft 414 , and the outer ends of the support shaft 414 and the threaded shaft 415 are both expanded outwards;

[0058] The lower end of the soil taking pipe 41 is also integrated with a matching layer 412, and a penetrating connecting hole three 413 is opened on the outer side of the matching layer 412. The matching layer 412 can be matched with the head end of the next group of soil taking pipes 41, and the connecting hole two 411 can overlap with the connecting hole three 413. The matching layer 412 can also be sleeved with the soil taking end 5.

[0059] Specifically, the two ends of the soil taking pipe 41 can be connected end to end to achieve the effect of extension, and the multiple sections of the soil taking pipe 41 can be fixed by the support shaft 414 and the threaded shaft 415 to change the length of the soil taking pipe 41. Since the support shaft 414 is set through, only the soil of the length of the lowest soil taking pipe 41 can be removed each time. The soil taking end 5 is used to drive the soil taking pipe 41 to extend downward. Since the soil taking end 5 is not fixed to the lowest soil taking pipe 41, the soil taking end 5 needs to be taken out additionally after soil taking.

[0060] like Figure 3 As shown, the outer half of the soil sampling tube 41 is cut to have a sampling port 42, and the tube section 4 further includes a cover layer 43, which is buckled into the sampling port 42, so that the soil sampling tube 41 forms a complete tube body. When the soil sample is completed, the cover layer 43 is removed, and the soil sample can be completely taken out horizontally;

[0061] like Figure 4 and Figure 5 As shown, the inner walls of the soil sampling pipe 41 and the cover layer 43 are both provided with corresponding inner cavities 61, the bag-type protective layer 6 includes a bag layer 62 and a rubber belt 63, the bag layer 62 is in two groups and is respectively fixed in the corresponding inner cavities 61 on both sides, the outer sides of the soil sampling pipe 41 and the cover layer 43 are both provided with air vents 64, the air vents 64 are connected with the inside of the bag layers 62 on both sides, and the rubber belt 63 is sleeved on the outer sides of the soil sampling pipe 41 and the cover layer 43 and covers the air vents 64.

[0062] Specifically, when soil enters the soil taking pipe 41, the rubber bag layers 62 on both sides are squeezed to form an annular air cushion, thereby achieving a supporting effect and avoiding a large squeezing force on the outer side of the soil.

[0063] When the bag layer 62 is pressurized, the internal air pressure increases, and the gas is slowly released through the air outlet 64 and the micropores elastically formed by the rubber belt 63. The effect achieved is similar to a "pressure relief valve", which not only reduces the friction resistance of the pipe wall and reduces disturbance, but also maintains lateral constraints on the soil column to ensure the integrity of the soil sample.

[0064] like Figure 4 As shown, elastic metal sheets 65 are fixed to the outside of the soil sampling tube 41 and the cover layer 43, and the rubber belt 63 is buckled in the metal sheet 65. The metal sheet 65 is used to limit the rubber belt 63 to prevent the rubber belt 63 from moving when there is soil on the outside of the soil sampling tube 41, which makes it difficult to cover the air outlet 64.

[0065] The bladder layer 62 is made of rubber and is expandable. Its internal lines extend along the axis of the pipe section 4. The internal lines of the bladder layer 62 extend axially to guide the soil to rise and reduce friction resistance.

[0066] like Figure 6 , Figure 8 , Fig. 9 and Fig.10 As shown, the soil sampling pipe 41 and the cover layer 43 are provided with corresponding installation cavities 71 near the inner walls of the lower ends, and the upper inner walls of the installation cavities 71 on both sides have clamping blocks 72, and the inner sleeve assembly 7 includes an inner metal ring 73, an elastic bag 74 and a rubber tightening ring 75;

[0067] The inner metal ring 73 is located in the mounting cavities 71 on both sides, and its upper end is clamped by the clamping block 72. There is a gap between the lower end of the inner metal ring 73 and the inner wall of the lower end of the mounting cavities 71 on both sides. The elastic bag 74 is sleeved on the outside of the inner metal ring 73 from bottom to top, and its end is located in the gap. The rubber tightening ring 75 is squeezed and sleeved on the outside of the elastic bag 74, and the outside of the rubber tightening ring 75 is squeezed against the inner wall of the mounting cavities 71 on both sides. When the soil moves into the pipe section 4, it will push the elastic bag 74 upward and automatically sleeve into the elastic bag 74.

[0068] Specifically, the elastic bag 74 is manually folded and sleeved on the outside of the inner metal ring 73. It should be noted that when folding, the elastic bag 74 needs to be folded in sequence so that the elastic bag 74 can be unfolded in sequence later. It should be noted that the inner metal ring 73 is limited by bolt 432 and is fixed. The rubber tightening ring 75 and the elastic bag 74 are squeezed on the outside of the inner metal ring 73. When the soil column moves upward, the elastic bag 74 clamped between the rubber tightening ring 75 and the inner metal ring 73 can be pulled out into the gap to achieve the connection of the soil column.

[0069] like Fig. 9 As shown, the outer side of the elastic bag 74 has a plurality of evenly distributed elastic rings 741, so that the elastic bag 74 is in a contracted shape.

[0070] Specifically, when the soil pushes the elastic bag 74, its elastic ring 741 expands layer by layer to form an independent bagged layer that fits closely to the outer contour of the soil column, physically isolating soil at different depths. The rubber tightening ring 75 controls the expansion speed of the elastic bag 74 through the pre-tightening force, so that the expansion speed of the elastic bag 74 corresponds to the extension speed of the soil column.

[0071] like Figure 7 As shown, the outer side of the cover layer 43 is threadedly connected with a second bolt 432, the second bolt 432 passes through a block 72 and abuts against the outer side of the inner metal ring 73, and the outer side of the cover layer 43 has a bolt 431, which is fixed to the soil sampling pipe 41 through the bolt 431;

[0072] The outer sides of bolt 1 431 and bolt 2 432 are both provided with blocking blocks to prevent soil from covering bolt 1 431 and bolt 2 432. It should be noted that soil and impurities can be prevented from entering the driving ends of bolt 1 431 and bolt 2 432, which is convenient for subsequent loosening and opening.

[0073] like Fig.11 As shown, the lower end of the soil-taking end 5 is provided with a blade edge, and the blade edge thereof converges inwardly, and the diameter of the blade edge is smaller than the diameter of the pipe section 4 .

[0074] Specifically, the cutting edge of the soil-taking end 5 is inwardly retracted and has a diameter smaller than the pipe section 4, so that it preferentially cuts into the soil to form a guide hole, thereby reducing the lateral squeezing force when the pipe section 4 penetrates and reducing the compression damage to the original soil.

[0075] A sampling method for detecting soil nitrate content comprises the following steps:

[0076] Step 1: tighten the pipe section 4 and the connecting end 3 step by step, and install the soil collecting end 5 at the end;

[0077] Step 2, check the contraction state of the bladder layer 62 and confirm that the rubber band 63 completely covers the air outlet 64;

[0078] Step 3, pre-install the elastic bag 74 and bind it in the installation cavity 71 with a rubber tightening ring 75;

[0079] Step 4: Press the machine body 1 downward vertically, and the soil taking end 5 penetrates the soil, penetrates the soil layer by layer to the target depth, and the soil is pushed into the elastic bag 74. The elastic ring 741 tightens the soil sample layer by layer to avoid mixing. The soil squeezes the bag layer 62 to form an air cushion, and the air pressure is released through the rubber belt 63 to reduce disturbance.

[0080] Step 5: remove the cover layer 43, take out the elastic bag 74 along the outlet 42, and take samples in sections according to the marks of the elastic ring 741.

[0081] The working principle of the present invention is as follows: since the lower end of the soil-taking end 5 is provided with a blade edge and its diameter is smaller than the diameter of the pipe section 4, the diameter of the soil moving into the soil-taking end 5 when taking soil is smaller than the diameter of the pipe section 4, which can reduce the squeezing force of the pipe section 4 on the soil moving inside the soil, and the soil moving upward from the pipe section 4 will also be clamped by the capsule layers 62 on both sides, ensuring that the soil is columnar and avoiding soil tilting or breaking. In addition, the columnar soil moving upward will be squeezed by the capsule layers 62 on both sides, and the air pressure inside the capsule layer 62 will increase. Since the outer side of the air outlet 64 is blocked by the rubber belt 63, the increase in the air pressure of the capsule layer 62 will cause the gas to move toward the air outlet 64, and the rubber belt 63 plays a role of pressure relief, so that there is air pressure inside the capsule layer 62 but it will not affect the movement of the soil, while keeping the soil moving vertically, reducing the squeezing of the soil and reducing the disturbance of the soil sample.

[0082] Secondly, after the upwardly moving soil extends into the soil sampling end 5, it is first squeezed with the elastic bag 74, so that the end of the elastic bag 74 moves upward to bag the soil. At the same time, the edge of the elastic bag 74 moves out from between the inner metal ring 73 and the rubber tightening ring 75, and covers the soil as it extends upward to complete the bagging of the soil sample. The outer wall of the soil sample is covered by the inside of the elastic bag 74. The elastic bag 74 extends upward with the soil sample, so that the outer side of the elastic bag 74 can be in contact with the sac layer 62 or the inner wall of the pipe section 4, thereby keeping the soil sample stable and reducing disturbance to the soil sample.

[0083] When the elastic bag 74 has the elastic ring 741 , the elastic bag 74 is sleeved on the outside of the soil and in close contact with the soil. Each circle of the elastic ring 741 limits the relative position of the soil sample to prevent the soil sample from loosening due to its own action.

[0084] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0085] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A sampling device for detecting soil nitrate content, comprising a body (1) and a tubular soil sampling portion (2), characterized in that: The soil collecting part (2) comprises: A connecting end (3) fixed to the lower end of the body (1); The pipe section (4) comprises a soil sampling pipe (41) connected to the lower end of the connection end (3); the pipe section (4) can be connected end to end to extend the length of the pipe section; the interior of the pipe section (4) comprises a bag-shaped protective layer (6) for covering the soil and an inner sleeve component (7) for bagging the soil to prevent mixing; A soil extraction end (5) connected to the end of the outermost pipe section (4) and configured to extend downward into the soil; The outer half of the soil sampling pipe (41) is cut to form a sampling outlet (42), and the pipe section (4) further comprises a cover layer (43), wherein the cover layer (43) is buckled into the sampling outlet (42), so that the soil sampling pipe (41) forms a complete pipe body; The inner walls of the soil sampling pipe (41) and the cover layer (43) are both provided with corresponding inner cavities (61); the bag-shaped protective layer (6) comprises a bag layer (62) and a rubber belt (63); the bag layer (62) is in two groups and is respectively fixed in the corresponding inner cavities (61) on both sides; the outer sides of the soil sampling pipe (41) and the cover layer (43) are both provided with air outlet holes (64); the air outlet holes (64) are communicated with the inside of the bag layers (62) on both sides; the rubber belt (63) is sleeved on the outer sides of the soil sampling pipe (41) and the cover layer (43) and covers the air outlet holes (64); The soil sampling pipe (41) and the cover layer (43) are provided with corresponding installation cavities (71) near the inner walls of the lower ends, and the upper inner walls of the installation cavities (71) on both sides are provided with clamping blocks (72). The inner sleeve assembly (7) comprises an inner metal ring (73), an elastic bag (74) and a rubber tightening ring (75), and the outer side of the elastic bag (74) has a plurality of evenly distributed elastic rings (741), so that the elastic bag (74) is in a tightened shape.

2. The sampling device for detecting soil nitrate content according to claim 1, characterized in that: The connecting end (3) comprises a connecting shaft (31) fixed at the lower end of the machine body (1), and the outer side of the connecting shaft (31) and the outer side of the soil taking pipe (41) are respectively penetrated by a first connecting hole (32) and a second connecting hole (411), and the connecting shaft (31) and the soil taking pipe (41) are sleeved and the first connecting hole (32) and the second connecting hole (411) are overlapped; A support shaft (414) passes through the first connection hole (32) and the second connection hole (411), and a threaded shaft (415) is threadedly connected to the end of the support shaft (414), and the outer ends of the support shaft (414) and the threaded shaft (415) are both expanded outwards; The lower end of the soil taking pipe (41) is also integrally provided with a matching layer (412), and a third connecting hole (413) is provided on the outer side of the matching layer (412). The matching layer (412) can match with the head end of the next group of soil taking pipes (41), and the second connecting hole (411) can overlap with the third connecting hole (413). The matching layer (412) can also be sleeved with the soil taking end (5).

3. The sampling device for detecting soil nitrate content according to claim 1, characterized in that: Elastic metal sheets (65) are fixed to the outsides of the soil sampling pipe (41) and the cover layer (43), and the rubber belt (63) is buckled inside the metal sheet (65).

4. The sampling device for detecting soil nitrate content according to claim 1, characterized in that: The bladder layer (62) is made of rubber and is expandable, and its internal texture extends along the axis of the pipe section (4).

5. The sampling device for detecting soil nitrate content according to claim 1, characterized in that: The inner metal ring (73) is located in the mounting cavities (71) on both sides, and its upper end is clamped by the clamping block (72). A gap is formed between the lower end of the inner metal ring (73) and the inner wall of the lower end of the mounting cavities (71) on both sides. The elastic bag (74) is sleeved on the outside of the inner metal ring (73) from bottom to top, and its end is located in the gap. The rubber tightening ring (75) is squeezed and sleeved on the outside of the elastic bag (74), and the outside of the rubber tightening ring (75) is squeezed with the inner wall of the mounting cavities (71) on both sides. When the soil moves into the pipe section (4), it pushes the elastic bag (74) upwards and is automatically sleeved into the elastic bag (74).

6. The sampling device for detecting soil nitrate content according to claim 5, characterized in that: The outer side of the cover layer (43) is threadedly connected with a second bolt (432), the second bolt (432) passes through a clamping block (72) and abuts against the outer side of the inner metal ring (73), and the outer side of the cover layer (43) has a first bolt (431), which is fixed to the soil sampling pipe (41) through the first bolt (431); The outer sides of the bolt 1 (431) and the bolt 2 (432) are both provided with blocking blocks to prevent the soil from covering the bolt 1 (431) and the bolt 2 (432).

7. The sampling device for detecting soil nitrate content according to claim 1, characterized in that: The lower end of the soil-taking end (5) is provided with a blade edge, and the blade edge converges inwards, and the diameter of the blade edge is smaller than the diameter of the pipe section (4).

8. A sampling method for detecting soil nitrate content, characterized in that: The sampling device for detecting soil nitrate content according to any one of claims 1 to 7 comprises the following steps: Step 1: tighten the pipe section (4) and the connecting end (3) step by step, and install the soil collecting end (5) at the end; Step 2, checking the contraction state of the bladder layer (62) to confirm that the rubber band (63) completely covers the air outlet (64); Step 3, pre-install the elastic bag (74) and tie it in the installation cavity (71) with a rubber tightening ring (75); Step 4: vertically press the machine body (1) downward, and the soil taking end (5) penetrates the soil layer by layer to the target depth. The soil is pushed into the elastic bag (74), and the elastic ring (741) tightens the soil sample layer by layer to avoid mixing. The soil squeezes the bag layer (62) to form an air cushion, and the air pressure is released through the rubber belt (63) to reduce disturbance; Step 5: remove the cover layer (43), take out the elastic bag (74) along the outlet (42), and take samples in sections according to the marks of the elastic ring (741).

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