Microcosm device suitable for carbon and nitrogen cycle research of rice-fish compound system

Abstract

The invention discloses a microcosm device suitable for carbon and nitrogen cycle research of a rice-fish compound system. The microcosm device comprises a device main body, a gas production cover and a water inlet and drainage system. The device body comprises a main box body, a water tank and a fan. The gas production cover comprises a support, a cover, a gas production pipe and a sealing ring. The water inlet and drainage system comprises a water inlet pipe, a water outlet pipe, valves and flowmeters. The device is easy to build, disassemble and reuse in a field environment, and long-term or short-term observation can be carried out on the premise that a farmland plough layer is not damaged; and a researcher can conveniently collect gas, soil, water and animal samples. According to the invention, carbon-nitrogen cycle characteristic comparison of different modes of the rice-fish compound system can be carried out on a small-area field, and the method is also suitable for regional networking monitoring research for comparing different soil and climate condition differences. The method has important significance for deeply researching the carbon-nitrogen cycle characteristics and mechanism of the rice-fish compound system, and is worthy of popularization and application.

Description

Technical Field

[0001] The invention relates to a scientific research device, in particular to a microcosm device suitable for studying carbon and nitrogen cycles in a rice-fish composite system, and belongs to the technical field of farmland material cycle analysis. Background Art

[0002] The carbon and nitrogen cycle of farmland systems is an important component of the global biogeochemical cycle. Monitoring and evaluating the carbon and nitrogen cycle process of farmland systems is the basis and prerequisite for achieving the goal of reducing agricultural emissions and pollution. In recent years, my country's rice-fish system has developed rapidly, the planting and breeding area has increased rapidly, the planting and breeding model has been continuously innovated, and the degree of intensiveness has been increasing. The rice-fish system uses the niche complementarity and mutualistic symbiosis principles of rice and aquatic animals to achieve efficient utilization of agricultural resources. However, in the specific application process of the rice-fish system, due to the lack of optimization of the new system and the unreasonable operation of focusing on fisheries and neglecting rice, problems such as soil nutrient imbalance, water eutrophication, and increased greenhouse gas emissions have become increasingly serious. At present, there are still few studies on the fate characteristics and sink-source analysis of carbon, nitrogen and other substances in the whole growth period of the rice-fish system, and there is also a lack of devices that can be used to monitor and evaluate the carbon and nitrogen cycle.

[0003] The study of carbon and nitrogen cycle in rice-fish complex system involves many links such as plants and animals, soil layer, soil leaching, surface runoff and gas flux. There are two main research approaches: field in-situ observation and microcosm model simulation. Field in-situ observation has the problems of high production and maintenance costs, large spatial heterogeneity, low experimental control accuracy and poor sampling representativeness. In the process of basic construction such as field leveling and field ridge heightening, the arable layer is often disturbed too much, resulting in abnormal results of previous research. In comparison, the microcosm model can overcome the above problems, but the premise of its application is not only to ensure the normal operation of the system, such as the normal growth of rice and aquatic animals, but also to restore the real field environment as much as possible. In addition, the microcosm device should also provide the convenience of experimental control and sample collection, and reduce the cost of construction and maintenance as much as possible. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the existing microcosm device cannot completely restore the real field environment.

[0005] In order to solve the above technical problems, the present invention provides a microcosm device suitable for the study of carbon and nitrogen cycle in a rice-fish composite system, comprising:

[0006] A main box body, the bottom and top of the main box body are open, and the main box body is configured such that: its bottom can be inserted and fixed in the cultivation layer of the rice field, the insertion depth is not less than the maximum root depth of the rice, and the top of the main box body is higher than the water surface of the rice field; the main box body is used to divide micro-areas in the rice field;

[0007] The gas collection hood is configured to be able to be sealed and buckled on the top of the main box body, or to be separated from the main box body.

[0008] In some embodiments, a circle of water troughs is provided on the inner side of the top of the main box body, and the water troughs are configured such that when the gas collection hood is connected to the main box body, the bottom of the gas collection hood is immersed in the water trough.

[0009] In some embodiments, the microcosm device further comprises:

[0010] A water inlet pipe, which is located on the first side wall of the main box body and close to the top of the main box body;

[0011] A first valve, which is arranged on the water inlet pipe;

[0012] A first flow meter, which is arranged in the water inlet pipe;

[0013] A water outlet pipe, which is located on a second side wall of the main box body, the second side wall being opposite to the first side wall;

[0014] The second flow meter is arranged on the water outlet pipe.

[0015] In some embodiments, the water inlet pipe includes a horizontal water inlet pipe, a vertical water inlet pipe, and a series pipe, and the series pipe is configured to be connected to the vertical water inlet pipe of other nearby micro universe devices.

[0016] In some embodiments, the water outlet pipe includes a horizontal water outlet pipe, a rotary joint and a water depth adjustment pipe, and the horizontal water outlet pipe and the water depth adjustment pipe are respectively connected to one of the two connecting ends of the rotary joint.

[0017] In some embodiments, the installation height of the horizontal water outlet pipe is configured such that when the bottom of the main box is fixed to the rice field tillage layer, the horizontal water outlet pipe is close to the soil surface.

[0018] In some embodiments, the water depth regulating pipe can adjust the inclination angle by rotating the swivel joint to control the highest water level of the micro area.

[0019] In some embodiments, the main box further includes a first fan and a second fan arranged diagonally:

[0020] The first fan is installed on the third side wall of the main box body, close to the top of the main box body, and has a gap between the first fan and the third side wall of the main box body;

[0021] The second fan is installed on the fourth side wall of the main box body, close to the top of the main box body, and has a gap between the second fan and the fourth side wall of the main box body.

[0022] In some embodiments, the gas collection hood is composed of a bracket and a hood, and the hood is in close contact with each edge of the bracket.

[0023] In some embodiments, an opening is provided on the top of the gas collection hood, and a gas collection pipe is inserted into the top of the gas collection hood. The gas collection pipe and the opening are sealed and connected via a sealing ring. The gas collection pipe is a silicone hose.

[0024] Beneficial effects of the present invention: The microcosm system provided by the present invention is easy to build, disassemble and reuse in a field environment, and is suitable for the study of carbon and nitrogen cycles in a rice-fish composite system. Using the above-mentioned microcosm system, research can be carried out without destroying the cultivated layer of the farmland. The internal environmental factors of the system are close to the actual situation of the field, which can achieve precise control of the system and facilitate researchers to collect samples such as gas, soil, water and animals. The present invention has few restrictions on the use conditions and is suitable for different topography, field size, climate, and soil environment, and is worthy of promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a three-dimensional exploded view of a micro-universe device provided by a preferred embodiment of the present invention.

[0026] Figure 2 It is a top view of a micro-universe device provided by a preferred embodiment of the present invention.

[0027] Figure 3 It is a front cross-sectional view of a micro-universe device provided by a preferred embodiment of the present invention.

[0028] Figure 4 This is a usage scenario diagram of a micro universe device provided by a preferred embodiment of the present invention.

[0029] The meanings of the symbols in the above drawings are as follows:

[0030] 100 Device body

[0031] 110 Main box

[0032] 111 sink

[0033] 120 Water inlet pipe

[0034] 121 Horizontal water inlet pipe

[0035] 122 Vertical water inlet pipe

[0036] 123 Series Pipeline

[0037] 124 valve

[0038] 125 Flow meter

[0039] 130 Water outlet pipe

[0040] 131 Horizontal outlet pipe

[0041] 132 Rotary Joint

[0042] 133 Water depth regulation pipeline

[0043] 134 Flow Meter

[0044] 141 Fan

[0045] 142 Fan

[0046] 200 Gas Collection Hood

[0047] 210 Bracket

[0048] 220 Cover

[0049] 230 Seal

[0050] 240 Gas Pipe DETAILED DESCRIPTION

[0051] The words "first", "second" and similar terms used in this specification and claims do not indicate any order, quantity or importance, but are only used to distinguish different components. The words "one" or "an" and similar terms do not indicate a quantity limitation, but indicate the existence of at least one. In the description of this patent, unless otherwise specified, "multiple" means two or more.

[0052] In the description of this patent, words such as "including" or "having" and the like mean that the elements or objects appearing before "including" or "having" include the elements or objects listed after "including" or "having" and their equivalent elements, and do not exclude other elements or objects.

[0053] In the description of this patent, when an element is referred to as being "fixed to / mounted on (or similar terms)" another element, it may be directly on the other element or there may be intervening elements. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be intervening elements at the same time. On the contrary, when an element is referred to as being "directly on" another element, there are no intervening elements.

[0054] In the description of this patent, the terms "front", "rear", "up", "down", "left", "right", "horizontal", "lateral", "longitudinal", "top", "bottom", "inside", "outside", "clockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this patent and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this patent.

[0055] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.

[0056] The overall structure of the micro-universe device provided by a preferred embodiment of the present invention is as follows Figure 1 As shown in FIG. 1 , this microcosm device is suitable for studying the carbon and nitrogen cycle of the rice-fish composite system. The microcosm device mainly consists of a device body 100 and a gas collection cover 200. When gas collection is not performed, the gas collection cover 200 is separated from the device body 100. Figure 1 Before gas collection, the gas collection cover 200 is sealed and fastened to the top of the device body 100, as shown in FIG. Figure 3 The status shown in .

[0057] The device body 100 is composed of a main box 110 and other functional accessories. In the present embodiment, the main box 110 is a rectangular parallelepiped without upper and lower bottom surfaces, that is, its bottom and top are open. When the microcosm device is placed in a rice field, the bottom of the main box 110 is inserted into the rice field tillage layer and fixed. The main box 110 divides the rice field into micro-areas to study the carbon and nitrogen cycle of this micro-area. The insertion depth of the main box 110 is not less than the maximum root depth of rice. At this time, the top of the main box 110 is higher than the water surface of the rice field, and the upper part of the rice is exposed as much as possible from the top of the main box 110, such as Figure 3 As shown in . Preferably, the main box 110 is welded from 4 1 cm thick PP plates, 2 meters long, 2 meters wide, and 0.8 meters high, and is buried 0.3 meters below the tillage layer during the winter idle period. A water trough is welded on the inner side of the top of the main box 110, and the water trough is 5 cm wide and 5 cm high. If the main box body is too large to be inserted, a trench can be dug in the rice field in advance, the main box body can be placed in the trench, and the gap in the trench can be filled with soil.

[0058] The device body 100 is equipped with a water inlet and outlet system, which consists of a water inlet assembly and a water outlet assembly. The water inlet assembly is installed on the first side wall of the main box body 110, close to the top of the main box body 110, and below the water tank 111. The water outlet assembly is installed on the second side wall of the main box body 110, close to the bottom of the main box body 110. The above two side walls are opposite to each other, such as Figure 1 When the bottom of the main box 110 is inserted into the paddy field cultivation layer, the water outlet assembly is close to the soil surface.

[0059] The water inlet assembly includes a water inlet pipe 120, a valve 124, and a flow meter 125. Furthermore, the water inlet pipe 120 is composed of a horizontal water inlet pipe 121, a vertical water inlet pipe 122, and a series pipe 123. The horizontal water inlet pipe 121 passes through the first side wall of the main box body 110, and its water outlet extends into the main box body 110, and the valve 124 is installed at the above-mentioned water outlet. The flow meter 125 is arranged on the horizontal water inlet pipe 121 and is located outside the first side wall of the main box body 110. The flow meter 125 on the water inlet pipe records the inflow of water during the entire growth period and counts the water demand of the system. The vertical water inlet pipe 122 is connected to the horizontal water inlet pipe 121, and the bottom end of the vertical water inlet pipe 122 is close to the soil surface. The series pipe 123 can connect the vertical water inlet pipes of multiple micro universe devices, such as Figure 4 shown.

[0060] The drainage assembly includes a water outlet pipe 130 and a flow meter 134. Further, the water outlet pipe 130 is composed of a horizontal water outlet pipe 131, a rotary joint 132 and a water depth adjustment pipe 133. The horizontal water outlet pipe 131 and the water depth adjustment pipe 133 are respectively connected to one of the two connection ends of the rotary joint 132, such as Figure 1 As shown. The installation position of the horizontal outlet pipe 131 on the side wall of the main box 110 depends on the placement depth of the bottom of the main box 110 in the paddy field cultivation layer: when the main box 110 is fixed in the paddy field cultivation layer, the horizontal outlet pipe 131 should be close to the soil surface. The swivel joint 132 can rotate to adjust the angle, drive the adjustment of the inclination angle between the water depth adjustment pipe 133 and the water surface of the paddy field, thereby adjusting the height of the outlet of the water depth adjustment pipe 133 to control the highest water level inside the micro universe. The principle of communicating vessels is used here. The flow meter 134 is arranged on the horizontal outlet pipe 131 and is located outside the side wall of the main box 110. The amount of water flowing out of the system is recorded by the flow meter 134 on the outlet pipe to simulate surface runoff and calculate the carbon and nitrogen loss of surface runoff.

[0061] The device body 100 is equipped with an air circulation system, including two fans: fan 141 and fan 142. Figure 1As shown. Fan 141 is installed on the third side wall of the main box body 110 and close to the top of the main box body 110, below the water tank 111. In order to enhance air circulation, a gap is left between fan 141 and the third side wall of the main box body 110. Similarly, fan 142 is installed on the fourth side wall of the main box body 110 and close to the top of the main box body 110, below the water tank 111. The fourth side wall is opposite to the third side wall. In order to enhance air circulation, a gap is also left between fan 142 and the fourth side wall of the main box body 110. When the above two fans are working, the air in the micro-area can flow well. In order to enhance the disturbing effect of the fan on the air, fan 141 and fan 142 are staggered, that is, fan 141 is closer to the connecting edge of the third side wall and the first side wall, and fan 142 is closer to the connecting edge of the fourth side wall and the second side wall, as shown Figure 1 shown.

[0062] The gas collection hood 200 is composed of a bracket 210 and a hood 220. The bracket 210 is connected by light pipes, and plastic connectors are used at the corner tops. The light pipes can be plastic pipes, aluminum alloy pipes, etc. Figure 1 As shown in , the pipe is cut into suitable lengths, which are used for each side of the rectangular support 210, and a cross-shaped support is added to the top of the support. The size of the cover 220 is customized according to the support 210. When the cover 220 covers the support 210, the cover 220 should fit the sides of the support 210. The cover 220 should be made of a flexible thin material with good air tightness, such as canvas, plastic cloth, etc. Preferably, the support 210 of the gas collection hood is welded by a 2 cm diameter metal pipe, with a bottom of 1.95 meters × 1.95 meters and a height of 0.6 meters. The cover 220 is sewn from airtight canvas.

[0063] A circular hole is dug out on the top surface of the cover 220, and a gas collection pipe 240 is inserted into the circular hole. Furthermore, an annular sealing ring 230 is first placed in the circular hole, and the gas collection pipe 240 is inserted into the hole of the sealing ring 230 and fixed, so that the gas collection pipe 240 and the circular hole on the top surface of the cover 220 are sealed and connected by the sealing ring 230, and the air tightness is better. Preferably, the sealing ring 230 adopts a rubber plug, and the gas collection pipe 240 can adopt a silicone hose. The silicone hose passes through the rubber plug, and the length of the silicone hose inside the cover 220 is 0.4 meters, and the length outside the cover 220 is 1 meter.

[0064] When gas is collected, the device body 100 is sealed and connected with the gas collection hood 200. This embodiment adopts a liquid seal method: a circle of water tanks 111 are arranged around the inner side of the top of the main box body 110. Before the gas collection hood 200 is buckled into the device body 100, water is pre-filled into the water tank 111. The length and width of the bottom of the bracket 210 depend on the internal size of the water tank 111. When the gas collection hood 200 is buckled into the device body 100, the bottom edge of the bracket 210 and the bottom edge of the cover 220 are immersed in the water storage of the water tank 111, so that the airtightness of the connection between the device body 100 and the gas collection hood 200 is very good.

[0065] In this embodiment, 12 micro-regions are arranged in a 3×4 square matrix, such as Figure 4 As shown. Four micro-plots in the same row form a group, and their respective water inlet pipes are connected together using serial pipes. In each group, four areas are set up: rice monoculture without chemical fertilizers, rice monoculture with fertilizers, fish farming with conventional feed, and fish farming with optimized feed, and they are arranged randomly. Thirty-six rice holes are transplanted in each micro-plot. Seven days after rice transplanting, three carps are released, each weighing about 30 grams.

[0066] During the rice growing season, the maximum water depth of the micro-area is controlled by using a vertical water inlet pipe 122, which is gradually increased from 5 cm to 25 cm. Fans 141 and 142 are turned on regularly to improve the ventilation inside the micro-area. Greenhouse gases are collected in the micro-area every 2 weeks. Before gas collection, the gas collection hood 200 is installed in the water tank 111 on the top of the device body 100, the water tank 111 is filled with water, and fans 141 and 142 are turned on to allow the gas in the main box 110 to circulate. Every 20 minutes, the gas is extracted and stored in an air bag, and then the gas is analyzed. The data collected by the flow meter 125 records the water demand of the system, and the data collected by the flow meter 134 simulates the surface runoff. After statistical calculations, the carbon and nitrogen cycle of the rice-fish complex system can be obtained.

[0067] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A microcosm device suitable for the study of carbon and nitrogen cycles in a rice-fish complex system, characterized in that: include: A main box, the bottom and top of which are open, the main box being configured such that: its bottom can be inserted into and fixed in the rice field cultivation layer, the insertion depth is not less than the maximum root depth of rice, and the top of the main box is higher than the water surface of the rice field; the main box is used to divide micro-areas in the rice field; The gas collection hood is configured to be able to be sealed and buckled on the top of the main box body, or to be separated from the main box body.

2. A microcosm device suitable for the study of carbon and nitrogen cycle in rice-fish complex system according to claim 1, characterized in that: A circle of water trough is provided on the inner side of the top of the main box body, and the water trough is configured so that when the gas collection hood is connected to the main box body, the bottom of the gas collection hood is immersed in the water trough.

3. A microcosm device suitable for the study of carbon and nitrogen cycle in rice-fish complex system according to claim 1, characterized in that: Also includes: A water inlet pipe, which is located on the first side wall of the main box and close to the top of the main box; A first valve, which is arranged on the water inlet pipe; A first flow meter, which is arranged on the water inlet pipe; a water outlet pipe, which is located on a second side wall of the main box body, the second side wall being opposite to the first side wall; A second flow meter is arranged on the water outlet pipe.

4. A microcosm device suitable for the study of carbon and nitrogen cycle in rice-fish complex system according to claim 3, characterized in that: The water inlet pipe includes a horizontal water inlet pipe, a vertical water inlet pipe and a series pipe, and the series pipe is configured to be connected to the vertical water inlet pipes of other nearby micro-universe devices.

5. The microcosm device suitable for the study of carbon and nitrogen cycle in rice-fish complex system according to claim 3, characterized in that: The water outlet pipe comprises a horizontal water outlet pipe, a rotating joint and a water depth regulating pipe. The horizontal water outlet pipe and the water depth regulating pipe are respectively connected to one of the two connecting ends of the rotating joint.

6. A microcosm device suitable for the study of carbon and nitrogen cycle in rice-fish complex system according to claim 5, characterized in that: The installation height of the horizontal water outlet pipe is configured such that when the bottom of the main box is fixed to the rice field cultivation layer, the horizontal water outlet pipe is close to the soil surface.

7. The microcosm device suitable for the study of carbon and nitrogen cycle in rice-fish complex system according to claim 5, characterized in that: The water depth regulating pipe can adjust the inclination angle by rotating the rotary joint to control the highest water level of the micro area.

8. The microcosm device suitable for the study of carbon and nitrogen cycle in rice-fish complex system according to claim 1, characterized in that: Also included are a first fan and a second fan arranged diagonally: The first fan is installed on the third side wall of the main box body, close to the top of the main box body, and has a gap between the first fan and the third side wall of the main box body; The second fan is installed on the fourth side wall of the main box body, close to the top of the main box body, and has a gap between the second fan and the fourth side wall of the main box body.

9. The microcosm device suitable for the study of carbon and nitrogen cycle in rice-fish complex system according to claim 1, characterized in that: The gas collection hood is composed of a support and a hood, and the hood is fitted with each edge of the support.

10. A microcosm device suitable for the study of carbon and nitrogen cycle in rice-fish complex system according to claim 9, characterized in that: An opening is provided on the top of the gas collection hood, into which a gas collection pipe is inserted. The gas collection pipe is sealed and connected to the opening via a sealing ring; the gas collection pipe is a silicone hose.

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