CN207516297U - A kind of device for monitoring soil ammonia volatilization loss in real time using ammonia gas sensor - Google Patents

Abstract

The utility model provides a device and method for real-time monitoring of soil ammonia volatilization loss by using an ammonia sensor. The device includes a detection cover, an ammonia sensor and a data collector; the detection cover is a hollow cylindrical structure with an opening at the bottom; The ammonia sensor is arranged in the detection cover; the ammonia sensor is connected with the data collector; the data collector is located outside the detection cover and is used for storing and outputting the ammonia concentration and providing power for the ammonia sensor at the same time. The utility model can dynamically monitor the loss of ammonia volatilization after fertilization in real time, and the detection data can be obtained in real time, which can visually display the change curve of the ammonia concentration, and can also copy the data to the computer for analysis and processing, which is convenient, fast and effective, and can be applied to soil in greenhouses or fields The real-time, effective and accurate detection of ammonia volatilization loss provides a reliable basis for improving nitrogen use efficiency in farmland, promoting agricultural energy conservation and emission reduction, and reducing ecological environment pollution.

Description

A device for real-time monitoring of soil ammonia volatilization loss using an ammonia sensor

technical field

The utility model relates to modern planting technology, in particular to a real-time monitoring device for soil ammonia volatilization loss in greenhouse or field environment.

Background technique

my country is a large agricultural country, and the main way for the farmland ecosystem to maintain high crop yields is high nitrogen fertilizer input. China's nitrogen fertilizer use accounts for about 35% of the world's total, but its nitrogen use efficiency is very low, and the loss of ammonia volatilization from farmland nitrogen fertilizer is an important reason.

However, ammonia is one of the most abundant alkaline gases in the atmosphere. Ammonia plays an important role in the deposition of acid gases and the travel of aerosols, seriously affecting regional air quality and atmospheric visibility. At the same time, ammonia volatilizes into the atmosphere and returns to land and marine ecosystems in the form of dry and wet deposition. Excessive ammonia deposition causes a series of environmental and ecological problems such as soil acidification, water eutrophication, and reduction of biodiversity, causing serious damage to natural ecosystems. It has become a serious threat to the sustainable development of agriculture in my country and the world. In addition, excessive ammonia volatilization loss increased nitrogen fertilizer input, resulting in indirect economic losses. Therefore, the establishment of a real-time monitoring device for ammonia volatilization in farmland will help improve nitrogen use efficiency in farmland, promote agricultural energy conservation and emission reduction, reduce ecological environmental pollution, and improve environmental quality.

At present, the measurement methods of ammonia volatilization loss in farmland mainly include the Draeger nitrogen tube method, intermittent airtight pumping method, optical method laser-induced fluorescence method and photoacoustic spectroscopy, etc. Such measurement methods require gas sampling of ammonia samples, calculation and analysis. The amount of ammonia is large and time-consuming, and real-time online monitoring cannot be achieved; at the same time, the influence of micro-scale turbulence characteristics has a certain impact on the accuracy of the determination data after long-term ammonia sample collection. Taking the intermittent airtight pumping method as an example, it is necessary to use a vacuum pump to pump air to make the ammonia volatilized from the soil in the airtight room pass through the washing bottle containing 2% boric acid with the air flow, so that it can be absorbed in the boric acid solution, and the solution is collected with 0.01 mol·L-1H2SO4 titration, and then calculate the amount of ammonia absorbed by boric acid. This method needs to be converted to obtain the ammonia volatilization loss after fertilization, which requires manual measurement and calculation every day 7-15 days after fertilization, and cannot dynamically monitor the ammonia volatilization loss after fertilization in real time, which is time-consuming and labor-intensive.

Therefore, it is necessary to provide a device and method capable of real-time monitoring of soil ammonia volatilization loss.

Utility model content

The purpose of the utility model is to provide a device which can monitor the volatilization loss of soil ammonia in real time by using an ammonia sensor.

A device for monitoring soil ammonia volatilization loss in real time according to the utility model includes a detection cover, an ammonia sensor and a data collector; the detection cover is a hollow cylindrical structure with an opening at the bottom, and several through holes are arranged on the detection cover; The ammonia sensor is arranged in the detection cover; the ammonia sensor is connected to the data collector; the data collector is located outside the detection cover and is used for storing and outputting the ammonia concentration and providing power for the ammonia sensor at the same time.

When in use, the detection cover is placed in the experimental plot to be tested, and it is used to fix the detection cover 1-2cm deep into the soil layer. Through detection, the ammonia volatilization amount in the area covered by the detection cover is obtained, and then the ammonia volatilization amount of the experimental plot in the fertilization area is calculated. .

Further, in order to avoid the impact of excessive humidity on the performance of the sensor after the land is watered, the drying part is screw-connected to the ammonia sensor, and the drying part is made of a stainless steel breathable mesh with a built-in desiccant. The setting of the drying part is for the purpose of satisfying moisture absorption, and a common structure in the field can be adopted. For example, the drying part is made of a stainless steel breathable mesh with a built-in desiccant.

Further, the drying part is a cylindrical structure with a diameter of 2-3 cm and a height of 5-10 cm, and the desiccant is anhydrous calcium chloride. The bottom and the middle and upper part of the cylinder are connected by threads, which is convenient for repeated reuse of anhydrous calcium chloride.

Further, the detection cover can be made of transparent materials; such as plexiglass.

The cylindrical shape of the detection cover has a diameter of 8-10cm and a height of 5-10cm.

The arrangement of the through holes facilitates the exchange of the gas inside the hood and the air outside the hood, and facilitates the real-time detection of the concentration of ammonia loss in the soil; the diameter of the through holes is 0.5-1.5 cm, and the number of through holes is more than one.

Further, the ammonia sensor includes an ammonia sensor unit and a pretreatment unit, wherein the sensor unit is used to change the resistance of the sensor unit when exposed to ammonia in the air;

The pre-processing unit includes a sub-calibration module and an analog-to-digital conversion module, which is used to perform calibration and analog-to-digital conversion on the signal output by the sensor unit.

The ammonia sensor module can be installed under the drying layer. It is a hollow cylindrical structure with a closed lower end and is made of plastic. The upper end of the ammonia sensor module and the bottom of the drying layer are connected by threads, with a diameter of 2-3cm and a height of 3-5cm.

Wherein, the ammonia sensor unit adopts a resistive sensor structure type, adopts a silicon/silicon dioxide substrate structure, adopts an interdigitated metal electrode, and adopts a polyaniline-based nanocomposite structure film as a sensitive layer.

The electrode of the ammonia sensor unit is connected to the input end of the pretreatment unit by soldering; the wire output port of the pretreatment unit is connected to the input end of the data collector; the length of the wire is 10-20cm.

Further, the data collector has a built-in WIFI module to upload and collect data wirelessly;

Furthermore, the data collector is equipped with an LED display to display the collected ammonia concentration in real time, or to further display the ammonia concentration change curve.

The utility model also provides a method for real-time monitoring of soil ammonia volatilization loss by using an ammonia sensor.

Wherein, the ammonia sensor adopts a resistive sensor structure type, adopts a silicon/silicon dioxide substrate structure, adopts an interdigitated metal electrode, and adopts a polyaniline-based nanocomposite structure film as a sensitive layer.

The basic working principle of the ammonia sensor is: after the reducing volatile ammonia is in contact with the sensitive layer of the sensing unit, the hole concentration of the sensitive material polyaniline in the sensitive layer is changed by donating electrons, and the conductivity is used to The formula δ=epμ, where δ is the conductivity of the sensitive material, e is the electronic charge, p is the electron concentration, μ is the electron mobility, the conductivity of the sensitive material is proportional to the hole concentration, for the resistive sensor, the sensitive The electrical conductivity of the material is reflected in a change in sensor resistance. Therefore, when the volatile organic compound comes into contact with the sensitive layer of the sensor unit, it changes the conductivity of the sensitive material, which is finally reflected in the change of the resistance of the sensor unit.

Further, the method further includes preprocessing the ammonia sensor, the preprocessing is performing self-calibration on the ammonia sensor, or further, includes performing analog-to-digital conversion on the data obtained by the ammonia sensor.

In the sensor unit, the substrate is made of a silicon/silicon dioxide substrate; the electrode is a metal electrode with an interdigitated electrode structure, and the metal material is any one of gold, silver or aluminum; the sensitive film layer is spin-coated or drop-coated. Painted by any method.

In addition, the power supply module uses a battery or power supply, such as a cable with a length of 3-6m and a power supply voltage of 5VDC.

Through the device of the utility model for real-time monitoring of soil ammonia volatilization loss by using an ammonia sensor, the following beneficial effects can be obtained.

First of all, a device of the present utility model that utilizes an ammonia sensor to monitor soil ammonia volatilization loss in real time uses a resistive chemical sensor to detect in real time the ammonia volatilization concentration after nitrogen fertilizer is applied to the soil in the field or in the greenhouse. Compared with the currently used physical optics and other detection methods have the advantages of high efficiency, rapidity and accuracy.

Secondly, in the device of the present invention, a drying layer is arranged on the upper end of the ammonia sensor unit to avoid the influence of excessive humidity on the performance of ammonia detection, which helps to improve the accuracy of ammonia detection. At the same time, the ammonia gas sensor of the device is located inside the detection cover, which provides a detection gas chamber for the ammonia gas sensor, does not require a gas collection device, and is easy to use.

In addition, in the device of the present invention, the data collector has the functions of collection, storage, display and output, which is convenient for subsequent data processing. At the same time, the display function is convenient and direct, and can quickly make effective judgment and analysis on the nitrogen fertilizer use efficiency after soil fertilization.

To sum up, the utility model provides a device and method for real-time monitoring of soil ammonia volatilization loss by using an ammonia sensor, which can monitor the ammonia volatilization loss after fertilization in real time, obtain the detection data in real time, and visually display the ammonia concentration change curve. The data can also be copied to the computer for analysis and processing, which is convenient, fast and effective. It can be applied to the real-time, effective and accurate detection of soil ammonia volatilization loss in greenhouses or fields, and can provide a solution for improving the nitrogen utilization rate of farmland, promoting agricultural energy saving and emission reduction, and reducing ecological pollution. Environmental pollution provides a reliable basis.

Description of drawings

Fig. 1 is a schematic structural diagram of a device for real-time monitoring of soil ammonia volatilization loss by using an ammonia sensor according to a specific embodiment of the present invention.

Fig. 2 is a structural schematic diagram of an ammonia sensor for real-time monitoring of soil ammonia volatilization loss and a drying layer provided on the ammonia sensor according to a specific embodiment of the present invention.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in detail.

Detailed exemplary embodiments are disclosed below. However, specific structural and functional details disclosed herein are merely for purposes of describing example embodiments.

It should be understood, however, that the invention is not limited to the particular exemplary embodiments disclosed, but covers all modifications, equivalents, and alternatives falling within the scope of the disclosure. Throughout the description of the figures, the same reference numerals denote the same elements.

Referring to the accompanying drawings, the structures, proportions, sizes, etc. shown in the accompanying drawings of this specification are only used to match the content disclosed in the specification, for those who are familiar with this technology to understand and read, and are not used to limit the utility model The restrictive conditions that can be implemented, so there is no technical substantive significance, any modification of structure, change of proportional relationship or adjustment of size, without affecting the effect and the purpose of the utility model, should still be Fall within the scope covered by the technical content disclosed in the utility model. At the same time, the position-limiting terms quoted in this specification are only for the convenience of description, and are not used to limit the scope of implementation of the utility model. The change or adjustment of the relative relationship, without substantive changes in the technical content, when It is also regarded as the scope that the utility model can implement.

Also, it should be understood that as used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Also it will be understood that when a component or unit is referred to as being “connected” or “coupled” to another component or unit, it can be directly connected or coupled to the other component or unit or intervening components or units may also be present. Also, other words used to describe the relationship between elements or elements should be interpreted in the same fashion (eg, "between" versus "directly between," "adjacent" versus "directly adjacent," etc.).

As shown in FIG. 1 , the specific embodiment of the present invention includes a structural schematic diagram of a device for real-time monitoring of soil ammonia volatilization loss using an ammonia sensor. The device includes a detection cover 1 , an ammonia sensor 2 and a data collector 3 .

The detection cover 1 is a cylindrical shape with a lower opening made of plexiglass, with a diameter of 10 cm and a height of 8 cm; the upper surface of the detection cover has 10 through holes 6 with a diameter of 1 cm.

The ammonia sensor 2 is arranged in the detection cover 1; the ammonia sensor 2 includes an ammonia sensor unit and a pretreatment unit, wherein the sensor unit is used to change the temperature of the sensor unit when it comes into contact with ammonia in the air. Resistor; the preprocessing unit includes a sub-calibration module and an analog-to-digital conversion module for calibrating and analog-to-digital conversion of the signal output by the sensor unit.

The ammonia sensor 2 is connected to the data collector 3; the data collector 3 is located outside the detection cover 1, and is used for storing and outputting the ammonia gas concentration and providing power for the ammonia sensor 2 at the same time.

Further, the data collector 3 has a built-in WIFI module to wirelessly upload and collect data;

Furthermore, the data collector 3 is equipped with an LED display to display the collected ammonia concentration in real time, or to further display the ammonia concentration change curve.

In addition, in order to absorb moisture in the air of the detection cover 1 , the device further includes a drying component 4 which is detachably arranged on the ammonia gas sensor 2 .

The drying part 4 is a cylindrical structure with a diameter of 2-3 cm and a height of 5-10 cm, and the desiccant is anhydrous calcium chloride. The bottom and the middle and upper part of the cylinder are connected by threads, which is convenient for repeated reuse of anhydrous calcium chloride.

As shown in Figure 2, the ammonia sensor 2 is arranged below the drying layer, and is a hollow cylindrical structure with a closed lower end, made of plastic. The upper end of the ammonia sensor 2 is connected to the bottom of the drying layer by threads, with a diameter of 2 cm and a height of 3 cm. The output port 5 of the ammonia sensor is connected to the input end of the data processor 3 .

Adopt the above-mentioned device that utilizes ammonia sensor 2 to monitor soil ammonia volatilization loss in real time to carry out the method for real-time monitoring as follows:

Connect the various components, start the power supply, and perform preprocessing on the output result of the ammonia gas sensor 2. The preprocessing is to perform self-calibration on the ammonia gas sensor, or further, include analog-to-digital conversion of the data obtained by the ammonia gas sensor.

Wherein, the ammonia sensor 2 adopts a resistive sensor structure type, adopts a silicon/silicon dioxide substrate structure, adopts an interdigitated metal electrode, and adopts a polyaniline-based nanocomposite structure film as a sensitive layer.

Then cover the detection cover 1 in the experimental area to be tested, go deep into the soil layer 1-2cm, fix the detection cover 1, use the ammonia sensor 2 to detect, and send the detection data to the data collector 3 for processing, and obtain the detection cover through detection 1 Ammonia volatilization in the coverage area and then calculate the ammonia volatilization of the experimental plot in the fertilization area.

Wherein, the ammonia gas sensor 2 adopts a resistive sensor structure type, adopts a silicon/silicon dioxide substrate structure, adopts an interdigitated metal electrode, and adopts a polyaniline-based nanocomposite structure film as a sensitive layer.

In addition, the power supply adopts a mobile power supply with a power supply voltage of 5VDC.

It should be noted that the above-mentioned embodiment is only a preferred embodiment of the utility model, and it cannot be understood as a limitation on the scope of protection of the utility model. Changes and modifications all belong to the protection scope of the present utility model.

Claims (7)

1. A device for real-time monitoring of soil ammonia volatilization loss, characterized in that it comprises a detection cover, an ammonia sensor and a data collector; the detection cover is a hollow cylindrical structure with openings below, and the detection cover is provided with some through holes; The ammonia sensor is arranged in the detection cover; the ammonia sensor is connected to the data collector; the data collector is located outside the detection cover and is used for storing and outputting the ammonia concentration and providing power for the ammonia sensor at the same time. 2. The device according to claim 1, characterized in that, the device also includes a drying part, the drying part is screw-connected on the ammonia sensor, the drying part is made of a stainless steel breathable mesh, and the built-in drying agent. 3. The device according to claim 2, wherein the drying part is a cylindrical structure with a diameter of 2-3 cm and a height of 5-10 cm, and the desiccant is anhydrous calcium chloride. 4. The device according to claim 1, wherein the ammonia sensor comprises an ammonia sensor unit and a pretreatment unit, wherein the sensor unit is used to change the resistance of the sensor unit when it comes into contact with ammonia in the air ; The pre-processing unit includes a sub-calibration module and an analog-to-digital conversion module, which is used to perform calibration and analog-to-digital conversion on the signal output by the sensor unit. 5. The device according to claim 1, wherein the data collector has a built-in WIFI module to upload and collect data wirelessly. 6. The device according to claim 1, wherein the data collector is configured with an LED display to display the collected ammonia concentration in real time, or further display the ammonia concentration change curve. 7. The device according to claim 6, wherein the ammonia sensor unit adopts a resistive sensor structure type, adopts a silicon/silicon dioxide substrate structure, adopts interdigitated metal electrodes, and adopts polyaniline-based nano The composite structure film is used as the sensitive layer.