Greenhouse soil culture device and method for combined determination of soil active nitrogen loss and greenhouse gas emission

Abstract

The invention discloses a greenhouse soil culture device and method for combined determination of soil active nitrogen loss and greenhouse gas emission, and belongs to the field of farmland soil environment detection. The device comprises a soil culture column, an ammonia volatilization collecting cover and a greenhouse gas collecting cover, the ammonia volatilization collecting device is characterized in that the ammonia volatilization collecting cover is placed on the soil culture column to form a dynamic circulation chamber, and gas pipes are inserted through two round holes in the top of the ammonia volatilization collecting cover to filter ammonia gas in air and collect soil ammonia volatilization; a greenhouse gas collecting cover is placed on a soil culture column to form a greenhouse gas emission soil culture device, and two round holes in the top of the collecting cover are used for extracting soil greenhouse gas for emission and detecting the temperature in the device respectively; a plastic pipe is inserted into a round hole in the center of the bottom end of the soil culture column to collect the soil nitrogen leaching amount. The device is suitable for greenhouse soil culture experiments with complex factor interaction and large sample size, has hydrological nitrogen collection, and is beneficial to evaluation of the overall nitrogen loss of a soil system.

Description

Technical Field

[0001] The present invention belongs to the field of farmland soil environment monitoring, and in particular relates to a greenhouse soil cultivation device and method for jointly measuring soil active nitrogen loss and greenhouse gas emissions. Background Art

[0002] Soil reactive nitrogen loss and greenhouse gas emissions are influenced by factors such as temperature, irrigation, and soil physical and chemical properties. Using greenhouse soil column cultures, we can clarify the impact of a single explanatory variable, such as fertilization method and amount, on soil reactive nitrogen loss and greenhouse gas emissions while controlling for external factors. Alternatively, we can clarify the contribution of different influencing factors to soil reactive nitrogen loss or greenhouse gas emissions by analyzing the interactive effects of different soil environments and fertilizer management practices on soil reactive nitrogen or greenhouse gas emissions. Currently, there are some combined collection devices for measuring soil greenhouse gas emissions and ammonia volatilization, such as the soil cultivation device for combined measurement of soil greenhouse gases and ammonia volatilization with publication number CN215530342U. However, it lacks insulation treatment, and the extracted greenhouse gas concentration is affected by climate and has large errors, and there is a lack of measurement of hydrological nitrogen (nitrogen leaching); the soil cultivation device for collecting leaching solution, greenhouse gases and ammonia volatilization with publication number CN207133286U has a room temperature detection thermometer pasted on the inside of the cylinder wall, which cannot detect the room temperature in the soil cultivation device in real time during the gas collection process, and the closed chamber method for measuring ammonia volatilization cannot take into account the influence of ventilation conditions. Summary of the Invention

[0003] The purpose of the present invention is to address the problems existing in the prior art and propose a greenhouse soil culture device and method for jointly collecting soil active nitrogen loss and greenhouse gas emissions. The device and method have a simple structure, are easy to operate, can reduce sampling errors, and are suitable for greenhouse soil culture experiments with complex interactions and large sample sizes.

[0004] The technical solution adopted by the present invention is: a greenhouse soil cultivation device for jointly measuring soil active nitrogen loss and greenhouse gas emissions, including a soil cultivation column, a greenhouse gas collection cover and an ammonia volatilization collection cover. The greenhouse gas collection cover or the ammonia volatilization collection cover is sealed and installed above the soil cultivation column. The greenhouse gas collection cover is sealed and installed above the soil cultivation column to form a greenhouse gas emission soil cultivation device, and the ammonia volatilization collection cover is sealed and installed above the soil cultivation column to form an ammonia volatilization collection device.

[0005] Specifically, the soil cultivation column includes a nitrogen elution collection hole 1, leak-proof gauze 2, a soil cultivation column 3, a soil cultivation column wrapped with thermal insulation cotton 4, the bottom surface of the soil cultivation column, the top surface of the soil cultivation column 5 and a gasket 14; the soil cultivation column 3 is installed between the bottom surface of the soil cultivation column and the top surface 5 of the soil cultivation column, the nitrogen elution collection hole 1 is arranged in the middle of the bottom surface of the soil cultivation column, the leak-proof gauze 2 is arranged above the nitrogen elution collection hole 1, the soil cultivation column 3 is wrapped with thermal insulation cotton 4, and a gasket 14 is installed above the top surface 5 of the soil cultivation column.

[0006] Specifically, the greenhouse gas collection cover includes a greenhouse gas collection cover bottom surface 6, a greenhouse gas collection cover body 7, a greenhouse gas collection cover body wrapped with insulation cotton 8, a greenhouse gas collection cover top insulation cotton 9, a greenhouse gas extraction hole 10, a battery 11, a thermometer 12 and a fan 13; the greenhouse gas collection cover body wrapped with insulation cotton 8 and the greenhouse gas collection cover top insulation cotton 9 are respectively installed around the greenhouse gas collection cover body 7 and on the outside of the top, the battery 11 is fixed on the greenhouse gas top insulation cotton 9, the top surface of the greenhouse gas collection cover body 7 is provided with a greenhouse gas extraction hole 10 and a thermometer insertion hole, the greenhouse gas extraction hole 10 is externally connected to a medical syringe, the thermometer 12 is fixed on the thermometer insertion hole and its temperature measuring end extends into the interior of the greenhouse gas collection cover body 7, the fan 13 is fixed on the inner top of the greenhouse gas collection cover body 7, and the greenhouse gas collection cover bottom surface 6 is fixed above the soil cultivation column.

[0007] Specifically, the ammonia volatilization collection cover includes an ammonia volatilization collection cover bottom surface 15, an ammonia volatilization collection cover body 16, an ammonia volatilization collection cover body wrapped with heat insulation cotton 17, an ammonia volatilization collection cover top heat insulation cotton 18, an external ammonia gas filter tube 19 and an ammonia volatilization absorption tube 20; the ammonia volatilization collection cover body wrapped with heat insulation cotton 17 and the ammonia volatilization collection cover top heat insulation cotton 18 are respectively installed around the ammonia volatilization collection cover body 16 and the top outer side, and the two sides of the top of the ammonia volatilization collection cover body 16 are respectively provided with a filter tube mounting hole and an absorption tube mounting hole, and the external ammonia gas passes through the ammonia volatilization collection cover body 16. The filter tube 19 is fixed in the filter tube mounting hole and its lower end extends into the volatile collection cover 16. The upper end is connected to a rubber tube and a sponge soaked in dilute sulfuric acid in turn. The ammonia volatilization absorption tube 20 is fixed in the absorption tube mounting hole and its absorption end extends into the volatile collection cover 16. The outer end is connected to two washing bottles containing dilute sulfuric acid through rubber tubes. The pump draws the air in the volatile collection cover 16 into the washing bottle. The absorption end of the ammonia volatilization absorption tube 20 is provided with a number of small holes at intervals. The bottom surface 15 of the ammonia volatilization collection cover is fixed above the soil cultivation column.

[0008] Preferably, the concentration of dilute sulfuric acid in the sponge is 1.1%, and the concentration of dilute sulfuric acid in the washing bottle is 1.1%.

[0009] Preferably, the soil culture column is wrapped with heat-insulating cotton 4 and pasted on all sides of the soil culture column 3 with a thickness of 3.5 cm.

[0010] Preferably, the inner and outer diameters of the greenhouse gas collection cover are consistent with the size of the soil culture column, and the greenhouse gas collection cover body is wrapped with insulation cotton 8 and the top insulation cotton 9 of the greenhouse gas collection cover is respectively pasted on the four sides and the outside of the top of the greenhouse gas collection cover body 7, and the thickness of both is 1 cm.

[0011] Preferably, the inner and outer diameters of the ammonia volatilization collection cover are consistent with the size of the soil culture column, and the ammonia volatilization collection cover body is wrapped with insulation cotton 17 and the top insulation cotton 18 of the ammonia volatilization collection cover is respectively pasted on the four sides and the outside of the top of the ammonia volatilization collection cover body 16, and the thickness of both is 1 cm.

[0012] A greenhouse soil cultivation method for jointly measuring soil active nitrogen loss and greenhouse gas emissions comprises the following steps: Step 1: Prepare the soil cultivation column, greenhouse gas collection cover and ammonia volatilization collection cover; Step 2: Place leak-proof gauze 2 on the nitrogen elution collection hole 1, place experimental soil in the soil culture column 3, adjust the soil moisture and bulk density, and apply nitrogen fertilizer. After watering, collect the nitrogen elution amount from the nitrogen elution collection hole 1; Step 3: Place the greenhouse gas collection cover on the soil cultivation column 3 with the gasket 14 laid on it, and use two clips to simultaneously clamp the top surface 5 of the soil cultivation column and the bottom surface 6 of the greenhouse gas collection cover to form a sealed greenhouse gas emission soil cultivation device. Then, put in the battery 11, start the fan 13 and turn on the thermometer 12. Use a medical syringe to connect to the greenhouse gas extraction hole 10, collect gas at 0, 15, and 30 minutes respectively, record the temperature inside the greenhouse gas emission soil cultivation device at 0 and 30 minutes, and record the atmospheric pressure on that day. Use a gas chromatograph to measure the concentrations of N2O, CO2, and CH4, and calculate the greenhouse gas emission rate in the greenhouse gas emission soil cultivation device. Step 4: After the greenhouse gas collection is completed, remove the greenhouse gas collection cover and place the ammonia volatilization collection cover on the soil culture column 3 with the gasket 14 laid on it. Use two clips to clamp the top surface 5 of the soil culture column and the bottom surface 15 of the ammonia volatilization collection cover at the same time to form an ammonia volatilization collection device. Then, insert the external ammonia filter tube 19 into the filter tube installation hole. The external ammonia filter tube 19 is connected to a rubber tube and a sponge soaked in 1.1% dilute sulfuric acid in turn. At the same time, insert the ammonia volatilization absorption tube 20 into the absorption tube installation hole. The ammonia volatilization absorption tube 20 is connected to a rubber tube, two washing bottles containing 1.1% dilute sulfuric acid and a pump. Turn on the pump, and ammonia in the ammonia volatilization collection device will volatilize. The ammonia will be extracted from the ammonia volatilization absorption tube 20 and dissolved in the 1.1% dilute sulfuric acid in the two washing bottles. After 45 minutes, turn off the pump, pour the dilute sulfuric acid solution in the two washing bottles into a 250ml reagent bottle, and use indigo blue spectrophotometry to measure the ammonia volatilization flux in the soil culture device.

[0013] Specifically, Step 1 is as follows: stick the wrapped soil cultivation column insulation cotton 4 on the outside of the soil cultivation column 3; wrap the greenhouse gas collection cover body insulation cotton 8 and the greenhouse gas collection cover top insulation cotton 9 around and on the top of the greenhouse gas collection cover 7; wrap the ammonia volatilization collection cover body insulation cotton 17 and the ammonia volatilization collection cover top insulation cotton 18 around and on the top of the ammonia volatilization collection cover 16.

[0014] The beneficial effects of the present invention are: the present invention has a simple structure and is easy to operate. The sampling error is reduced by controllable experimental conditions. It is suitable for greenhouse soil culture experiments with complex interactions and large sample sizes. In addition, the device is capable of collecting hydrological nitrogen, which is beneficial for evaluating the overall nitrogen loss of the soil system. At the same time, ammonia volatilization is collected through intermittent exhaust in a closed chamber, which is beneficial for improving the ammonia recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the greenhouse soil culture device for measuring soil greenhouse gas emissions; Figure 2 Schematic diagram of the greenhouse soil culture device for collecting soil ammonia volatilization.

[0016] Numbers in the figure: 1. Nitrogen elution collection hole, 2. Leak-proof gauze, 3. Soil culture column, 4. Insulation cotton wrapped around soil culture column, 5. Top surface of soil culture column, 6. Bottom surface of greenhouse gas collection cover, 7. Greenhouse gas collection cover body, 8. Insulation cotton wrapped around greenhouse gas collection cover body, 9. Insulation cotton on top of greenhouse gas collection cover, 10. Greenhouse gas extraction hole, 11. Battery, 12. Thermometer, 13. Fan, 14. Gasket, 15. Bottom surface of ammonia volatilization collection cover, 16. Ammonia volatilization collection cover body, 17. Insulation cotton wrapped around ammonia volatilization collection cover body, 18. Insulation cotton on top of ammonia volatilization collection cover, 19. External ammonia filter tube, 20. Ammonia volatilization absorption tube. DETAILED DESCRIPTION

[0017] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Example 1: Figure 1 、 2 As shown, a greenhouse soil cultivation device for jointly measuring soil active nitrogen loss and greenhouse gas emissions includes a soil cultivation column, a greenhouse gas collection cover and an ammonia volatilization collection cover. The greenhouse gas collection cover or the ammonia volatilization collection cover is sealed and installed above the soil cultivation column. The greenhouse gas collection cover is sealed and installed above the soil cultivation column to form a greenhouse gas emission soil cultivation device, and the ammonia volatilization collection cover is sealed and installed above the soil cultivation column to form an ammonia volatilization collection device.

[0019] The soil cultivation column further comprises a nitrogen elution collection hole 1, leak-proof gauze 2, a soil cultivation column body 3, a soil cultivation column body wrapped with thermal insulation cotton 4, a soil cultivation column bottom surface, a soil cultivation column top surface 5, and a gasket 14. Before placing soil, the leak-proof gauze 2 is laid flat on the nitrogen elution collection hole 1 to prevent soil seepage after irrigation or fertilization, which could cause experimental errors. The soil cultivation column body 3 is installed between the soil cultivation column bottom surface and the soil cultivation column top surface 5. The nitrogen elution collection hole 1 is located in the middle of the soil cultivation column bottom surface and has a diameter of 1.5 cm for collecting nitrogen elution. The leak-proof gauze 2 is located above the nitrogen elution collection hole 1. The soil cultivation column body 3 is wrapped with thermal insulation cotton 4. A gasket 14 is installed above the soil cultivation column top surface 5.

[0020] Furthermore, the greenhouse gas collection cover includes a greenhouse gas collection cover bottom surface 6, a greenhouse gas collection cover body 7, a greenhouse gas collection cover body wrapped with insulation cotton 8, a greenhouse gas collection cover top insulation cotton 9, a greenhouse gas extraction hole 10, a battery 11, a thermometer 12 and a fan 13; the greenhouse gas collection cover body wrapped with insulation cotton 8 and the greenhouse gas collection cover top insulation cotton 9 are respectively installed around the greenhouse gas collection cover body 7 and on the outside of the top, the battery 11 is fixed on the greenhouse gas top insulation cotton 9, the top surface of the greenhouse gas collection cover body 7 is provided with a greenhouse gas extraction hole 10 and a thermometer insertion hole, both of which have a diameter of 1.5 cm, the greenhouse gas extraction hole 10 is externally connected to a 50 ml medical syringe for extracting soil greenhouse gases, the thermometer 12 is fixed to the thermometer insertion hole and its temperature measuring end extends into the interior of the greenhouse gas collection cover body 7, the thermometer 12 is used to monitor the temperature inside the soil cultivation device for collecting greenhouse gas emissions, the fan 13 is fixed to the inner top of the greenhouse gas collection cover body 7, and the bottom surface 6 of the greenhouse gas collection cover is fixed above the soil cultivation column.

[0021] Furthermore, the ammonia volatilization collection cover includes an ammonia volatilization collection cover bottom surface 15, an ammonia volatilization collection cover body 16, an ammonia volatilization collection cover body wrapped with insulation cotton 17, an ammonia volatilization collection cover top insulation cotton 18, an external ammonia gas filter tube 19 and an ammonia volatilization absorption tube 20; the ammonia volatilization collection cover body wrapped with insulation cotton 17 and the ammonia volatilization collection cover top insulation cotton 18 are respectively installed around the ammonia volatilization collection cover body 16 and on the outside of the top, and a filter tube mounting hole and an absorption tube mounting hole are respectively provided on both sides of the top of the ammonia volatilization collection cover body 16. The diameter of the two holes is 1.5 cm. The external ammonia gas filter tube 19 is fixed in the filter tube mounting hole and its lower end extends into the volatilization collection cover body 16. The external ammonia gas filter tube 19 is 4 cm long. The vent tube is connected to an external rubber hose. The rubber hose and a sponge soaked in dilute sulfuric acid prevent ammonia from entering the device, forming a dynamic circulation chamber. An ammonia volatilization absorption tube 20 is fixed in the absorption tube mounting hole, and its absorption end extends into the volatilization collection cover 16. The ammonia volatilization absorption tube 20 is an 18 cm long plastic tube with a single end opening. A 2 cm plastic tube outside the cover is connected to the rubber hose. The rubber hoses are connected to two washing bottles containing dilute sulfuric acid. A pump draws air from the volatilization collection cover 16 into the washing bottles to absorb ammonia volatilization from the ammonia volatilization collection device. The absorption end of the ammonia volatilization absorption tube 20 (i.e., the 16 cm long tube inside the cover) is provided with several small holes at intervals. The bottom surface 15 of the ammonia volatilization collection cover is fixed above the soil culture column. An external ammonia filter tube 19 is connected to an external rubber hose and a sponge soaked in dilute sulfuric acid to filter ammonia from the air. The ammonia volatilization absorption tube 20 is connected to the rubber hose, gas bottle, and pump to absorb ammonia.

[0022] Furthermore, the concentration of dilute sulfuric acid in the sponge is 1.1%, and the concentration of dilute sulfuric acid in the washing bottle is 1.1%.

[0023] Furthermore, the soil culture column is wrapped with heat-insulating cotton 4 and pasted on all sides of the soil culture column 3 with a thickness of 3.5 cm.

[0024] Furthermore, the inner and outer diameters of the greenhouse gas collection cover are consistent with the size of the soil culture column (specifically: the outer diameter of the bottom end of the greenhouse gas collection cover is consistent with the outer diameter of the top end of the soil culture column, and the cover body diameter of the greenhouse gas collection cover is the same as the column diameter of the soil culture column), and the greenhouse gas collection cover body is wrapped with insulation cotton 8 and the top insulation cotton 9 of the greenhouse gas collection cover are respectively pasted on the four sides and the outside of the top of the greenhouse gas collection cover body 7, and the thickness of both is 1 cm.

[0025] Furthermore, the inner and outer diameters of the ammonia volatilization collection cover 16 are consistent with the size of the soil culture column 3 (specifically: the outer diameter of the bottom end of the ammonia volatilization collection cover is consistent with the outer diameter of the top end of the soil culture column, and the cover diameter of the ammonia volatilization collection cover is the same as the column diameter of the soil culture column), and the ammonia volatilization collection cover is wrapped with insulation cotton 17 and the top insulation cotton 18 of the ammonia volatilization collection cover are respectively pasted on the four sides and the outside of the top of the ammonia volatilization collection cover 16, and the thickness of both is 1 cm.

[0026] A greenhouse soil cultivation method for jointly measuring soil active nitrogen loss and greenhouse gas emissions comprises the following steps: Step 1: Prepare the soil cultivation column, greenhouse gas collection cover and ammonia volatilization collection cover. The inner diameter of the soil cultivation column is: diameter 23cm × height 51cm, outer diameter 31cm, and the top diameter of the greenhouse gas collection cover 7 is 25cm × height 51cm. Specifically: stick a soil cultivation column wrapping insulation cotton 4 with a thickness of 3.5cm on the outside of the soil cultivation column 3; wrap the greenhouse gas collection cover body wrapping insulation cotton 8 with a thickness of 1cm and the greenhouse gas collection cover top insulation cotton 9 around and on the top of the greenhouse gas collection cover 7; wrap the ammonia volatilization collection cover body wrapping insulation cotton 17 and the ammonia volatilization collection cover top insulation cotton 18 around and on the top of the ammonia volatilization collection cover 16.

[0027] Step 2: Place a 3 cm diameter circular leak-proof gauze 2 on the 1.5 cm diameter nitrogen elution collection hole 1, place the experimental soil in the soil culture column 3, adjust the soil moisture and bulk density, and apply nitrogen fertilizer. After watering, collect the nitrogen elution amount from the nitrogen elution collection hole 1; Step 3: Figure 1 As shown, a greenhouse gas collection cover is placed on a soil cultivation column 3 with a gasket 14 laid on it. Two clamps are used to simultaneously clamp the top surface 5 of the soil cultivation column and the bottom surface 6 of the greenhouse gas collection cover to form a sealed greenhouse gas emission soil cultivation device. Then, a battery 11 is placed, the fan 13 is started, and the thermometer 12 is turned on. A 50ml medical syringe is connected to the greenhouse gas extraction hole 10. Gas is collected at 0, 15, and 30 minutes respectively. The temperature inside the greenhouse gas emission soil cultivation device is recorded at 0 and 30 minutes, and the atmospheric pressure on that day is also recorded. The concentrations of N2O, CO2, and CH4 are measured using a gas chromatograph, and the greenhouse gas emission rate in the greenhouse gas emission soil cultivation device is calculated. Step 4: After the greenhouse gas collection is completed, remove the greenhouse gas collection cover. Figure 2As shown, the ammonia volatilization collection cover is placed on the soil cultivation column 3 with the gasket 14 laid on it, and two clips are used to clamp the top surface 5 of the soil cultivation column and the bottom surface 15 of the ammonia volatilization collection cover at the same time to form an ammonia volatilization collection device. Then, the external ammonia filter tube 19 is inserted into the filter tube installation hole, and the external ammonia filter tube 19 is connected to a rubber tube and a sponge soaked in 1.1% dilute sulfuric acid in turn (for absorbing ammonia contained in the air to prevent affecting the test results). At the same time, the ammonia volatilization absorption tube 20 is inserted into the absorption tube installation hole, and the ammonia volatilization absorption tube 20 is connected to a rubber tube, Two washing bottles containing 1.1% dilute sulfuric acid (the two washing bottles are connected by a rubber tube and are used to fully absorb ammonia in the air in the device) and a pump (used to draw air in the ammonia volatilization collection cover 16 into the washing bottles). Turn on the pump, and ammonia in the ammonia volatilization collection device will volatilize and be extracted from the ammonia volatilization absorption tube 20 into the 1.1% dilute sulfuric acid dissolved in the two washing bottles. After 45 minutes, turn off the pump, pour the dilute sulfuric acid solution in the two washing bottles into a 250ml reagent bottle, and use indigo blue spectrophotometry to measure the ammonia volatilization flux in the soil culture device.

[0028] The above describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A greenhouse soil cultivation device for jointly measuring soil active nitrogen loss and greenhouse gas emissions, characterized by: It includes a soil cultivation column, a greenhouse gas collection cover and an ammonia volatilization collection cover. The greenhouse gas collection cover or the ammonia volatilization collection cover is sealed and installed above the soil cultivation column. The greenhouse gas collection cover is sealed and installed above the soil cultivation column to form a greenhouse gas emission soil cultivation device. The ammonia volatilization collection cover is sealed and installed above the soil cultivation column to form an ammonia volatilization collection device.

2. The greenhouse soil cultivation device for jointly measuring soil active nitrogen loss and greenhouse gas emissions according to claim 1, characterized in that: The soil cultivation column comprises a nitrogen leaching collection hole (1), leak-proof gauze (2), a soil cultivation column body (3), a soil cultivation column body wrapped with heat-insulating cotton (4), a soil cultivation column bottom surface, a soil cultivation column top surface (5), and a gasket (14); the soil cultivation column body (3) is installed between the soil cultivation column bottom surface and the soil cultivation column top surface (5), the nitrogen leaching collection hole (1) is arranged in the middle of the soil cultivation column bottom surface, the leak-proof gauze (2) is arranged above the nitrogen leaching collection hole (1), the soil cultivation column body (3) is wrapped with heat-insulating cotton (4), and a gasket (14) is installed above the soil cultivation column top surface (5).

3. The greenhouse soil cultivation device for jointly measuring soil active nitrogen loss and greenhouse gas emissions according to claim 1, characterized in that: The greenhouse gas collection cover comprises a greenhouse gas collection cover bottom surface (6), a greenhouse gas collection cover body (7), a greenhouse gas collection cover body wrapped with heat insulation cotton (8), a greenhouse gas collection cover top heat insulation cotton (9), a greenhouse gas extraction hole (10), a battery (11), a thermometer (12) and a fan (13); the greenhouse gas collection cover body wrapped with heat insulation cotton (8) and the greenhouse gas collection cover top heat insulation cotton (9) are respectively installed around the greenhouse gas collection cover body (7) and on the outside of the top; the battery (11) is fixed on the greenhouse gas top heat insulation cotton (9); the top surface of the greenhouse gas collection cover body (7) is provided with a greenhouse gas extraction hole (10) and a thermometer insertion hole; the greenhouse gas extraction hole (10) is externally connected to a medical syringe; the thermometer (12) is fixed on the thermometer insertion hole and its temperature measuring end extends into the interior of the greenhouse gas collection cover body (7); the fan (13) is fixed on the inner top of the greenhouse gas collection cover body (7); and the greenhouse gas collection cover bottom surface (6) is fixed above the soil cultivation column.

4. The greenhouse soil cultivation device for jointly measuring soil active nitrogen loss and greenhouse gas emissions according to claim 1, characterized in that: The ammonia volatilization collection cover comprises an ammonia volatilization collection cover bottom surface (15), an ammonia volatilization collection cover body (16), ammonia volatilization collection cover body wrapped with heat insulation cotton (17), ammonia volatilization collection cover top heat insulation cotton (18), an external ammonia gas filter tube (19) and an ammonia volatilization absorption tube (20); the ammonia volatilization collection cover body wrapped with heat insulation cotton (17) and the ammonia volatilization collection cover top heat insulation cotton (18) are respectively installed around the ammonia volatilization collection cover body (16) and the top outer side, and the two sides of the top of the ammonia volatilization collection cover body (16) are respectively provided with a filter tube mounting hole and an absorption tube mounting hole, and the external ammonia gas filter tube (19) and the absorption tube (20) are respectively installed. The filter tube (19) is fixed in the filter tube mounting hole and its lower end extends into the volatile collection cover (16). The upper end is connected to a rubber tube and a sponge soaked in dilute sulfuric acid in sequence. The ammonia volatile absorption tube (20) is fixed in the absorption tube mounting hole and its absorption end extends into the volatile collection cover (16). The outer end is connected to two washing bottles containing dilute sulfuric acid through rubber tubes. The pump draws the air in the volatile collection cover (16) into the washing bottle. The absorption end of the ammonia volatile absorption tube (20) is provided with a plurality of small holes at intervals. The bottom surface (15) of the ammonia volatile collection cover is fixed above the soil cultivation column.

5. The greenhouse soil cultivation device for jointly measuring soil active nitrogen loss and greenhouse gas emissions according to claim 4, characterized in that: The concentration of dilute sulfuric acid in the sponge is 1.1%, and the concentration of dilute sulfuric acid in the washing bottle is 1.1%.

6. The greenhouse soil cultivation device for jointly measuring soil active nitrogen loss and greenhouse gas emissions according to claim 2, characterized in that: The soil culture column is wrapped with heat-insulating cotton (4) and pasted on all sides of the soil culture column (3) with a thickness of 3.5 cm.

7. The greenhouse soil cultivation device for combined determination of soil active nitrogen loss and greenhouse gas emissions according to claim 3, characterized in that: The inner and outer diameters of the greenhouse gas collection cover are consistent with the size of the soil culture column. The greenhouse gas collection cover body is wrapped with heat-insulating cotton (8) and the top of the greenhouse gas collection cover is covered with heat-insulating cotton (9) which is respectively pasted on the four sides and the outside of the top of the greenhouse gas collection cover body (7). The thickness of both is 1 cm.

8. The greenhouse soil cultivation device for combined determination of soil active nitrogen loss and greenhouse gas emissions according to claim 4, characterized in that: The inner and outer diameters of the ammonia volatilization collection cover are consistent with the size of the soil culture column. The ammonia volatilization collection cover body is wrapped with heat-insulating cotton (17) and the top of the ammonia volatilization collection cover is pasted on the four sides and the outside of the top of the ammonia volatilization collection cover, respectively. The thickness of both is 1 cm.

9. A greenhouse soil culture method for jointly measuring soil active nitrogen loss and greenhouse gas emissions, characterized by: The steps include: Step 1: Prepare the soil cultivation column, greenhouse gas collection cover and ammonia volatilization collection cover; Step 2: Lay leak-proof gauze (2) on the nitrogen elution collection hole (1), place experimental soil in the soil culture column (3), adjust the soil moisture and bulk density, and apply nitrogen fertilizer. After watering, collect the nitrogen elution amount from the nitrogen elution collection hole (1); Step 3: Place the greenhouse gas collection cover on the soil cultivation column (3) with the gasket (14) laid on it, and use (2) clips to simultaneously clamp the top surface (5) of the soil cultivation column and the bottom surface (6) of the greenhouse gas collection cover to form a sealed greenhouse gas emission soil cultivation device, then put in the battery (11), start the fan (13) and turn on the thermometer (12), connect the medical syringe to the greenhouse gas extraction hole (10), collect gas at 0, 15, and 30 minutes respectively, record the temperature in the greenhouse gas emission soil cultivation device at 0 and 30 minutes, and record the atmospheric pressure of the day, use a gas chromatograph to measure the concentrations of N2O, CO2 and CH4, and calculate the greenhouse gas emission rate in the greenhouse gas emission soil cultivation device; Step 4: After the greenhouse gas collection is completed, remove the greenhouse gas collection cover and place the ammonia volatilization collection cover on the soil cultivation column (3) with the gasket (14) laid on it. Use two clips to clamp the top surface of the soil cultivation column (5) and the bottom surface of the ammonia volatilization collection cover (15) to form an ammonia volatilization collection device. Then insert the external ammonia filter tube (19) into the filter tube installation hole. The external ammonia filter tube (19) is connected to the rubber tube and the sponge soaked in 1.1% dilute sulfuric acid in turn, and the ammonia volatilization is absorbed by the ammonia volatilization. The tube (20) is inserted into the mounting hole of the absorption tube. The ammonia volatilization absorption tube (20) is externally connected to a rubber tube, two washing bottles containing 1.1% dilute sulfuric acid, and a pump. The pump is turned on, and ammonia in the ammonia volatilization collection device is volatilized. The ammonia is extracted from the ammonia volatilization absorption tube (20) and dissolved in the 1.1% dilute sulfuric acid in the two washing bottles. After 45 minutes, the pump is turned off, and the dilute sulfuric acid solution in the two washing bottles is poured into a 250ml reagent bottle. The ammonia volatilization flux in the soil culture device is determined by indigo blue spectrophotometry.

10. The greenhouse soil cultivation method for jointly measuring soil active nitrogen loss and greenhouse gas emissions according to claim 9, characterized in that: Step 1 is as follows: The outer side of the soil cultivation column (3) is pasted with a wrapped soil cultivation column insulation cotton (4); the greenhouse gas collection cover body insulation cotton (8) and the greenhouse gas collection cover top insulation cotton (9) are respectively wrapped around the greenhouse gas collection cover body (7) and the top; the ammonia volatilization collection cover body insulation cotton (17) and the ammonia volatilization collection cover top insulation cotton (18) are respectively wrapped around the ammonia volatilization collection cover body and the top.

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