A device and method for dynamic monitoring of evapotranspiration processes in a multifunctional complex planting system

Abstract

The application discloses a kind of multifunctional compound planting system evapotranspiration process dynamic monitoring device and method, lysimeter measuring cylinder is arranged in the upper portion of lysimeter filter layer, soil evaporation barrel and intercropping crop lysimeter barrel are buried in the soil of lysimeter measuring cylinder top portion, soil moisture sensor is connected to the outer wall of one side of lysimeter measuring cylinder, automatic water supply device is connected to the bottom of the outer wall of the other side, with automatic water supply device is located in the same side, groundwater supply device and water level gauge are equipped in the bottom of lysimeter filter layer, the other side is equipped with drain pipe, drain pipe is connected with leakage device, lysimeter filter layer bottom is connected with weighing sensor, drip irrigation belt is arranged in crop row;Based on lysimeter weight, soil moisture, irrigation data, automatic water supply data, groundwater recharge data, drainage data, leakage data and meteorological data, the change of soil storage water quantity is calculated.The application can accurately characterize the evapotranspiration process of compound system.

Description

Technical Field

[0001] This invention belongs to the field of crop and soil moisture data measurement technology, specifically relating to a device and method for dynamic monitoring of evapotranspiration in a multifunctional intercropping system. Background Technology

[0002] In agricultural research, the study of evapotranspiration in intercropping is essential. Crop transpiration is the process by which water is lost from the plant surface to the atmosphere in the form of water vapor. It is influenced by both external environmental conditions and the regulation and control of the plant itself. Soil evaporation is the process by which water in the soil rises and vaporizes from the soil surface into the atmosphere, affecting changes in soil moisture content. Crop lysimeter systems are of great significance in studying the dynamic distribution characteristics of soil moisture, evaporation and transpiration patterns, and interspecific water relationships. However, current research treats plant transpiration and soil evaporation as independent entities, requiring separate measurements. Soil evaporation is relatively easy to observe, as it can be measured using soil evaporation buckets; while plant transpiration is commonly measured using wrap-around stem flow meters. Due to the significant changes in stem size throughout the growth period, the size of the wrap-around probe needs adjustment, and most studies have only observed a portion of the growth period, resulting in a relative lack of research on the entire growth period. In particular, current intercropping models cannot accurately study the evapotranspiration processes of two or more intercropping systems. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a device and method for dynamic monitoring of the evapotranspiration process in a multifunctional composite planting system, which can accurately characterize the evapotranspiration process of the composite system.

[0004] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0005] A device for dynamic monitoring of evapotranspiration process in a multifunctional composite planting system includes a lysimeter and a drip irrigation tape. The lysimeter includes a lysimeter filter layer and a lysimeter measuring cylinder disposed on the upper part of the lysimeter filter layer.

[0006] Soil evaporation tank and intercropping crop evaporation tank are buried in the soil at the top of the lysimeter measuring cylinder;

[0007] A soil moisture sensor is connected to one side of the outer wall of the lyometer cylinder, and an automatic water replenishment device is connected to the bottom of the other side of the outer wall.

[0008] Located on the same side as the automatic water replenishment device, the bottom of the lyopermeameter filter layer is equipped with a groundwater replenishment device and a water level gauge, and a drain pipe is provided on the other side, which is connected to the seepage device;

[0009] The bottom of the filter layer of the lysostat is connected to a weighing sensor;

[0010] The drip irrigation tape is placed between the crop rows.

[0011] In the above technical solution, the automatic water replenishment device includes a water supply tank. The lower end of the water supply tank is connected to a water pressure sensor. One side of the water pressure sensor is connected to a water supply pipe, and the other side is connected to a gas pressure pipe. The middle part of the water supply pipe is connected to the measuring cylinder of the lysimeter through a water inlet, and an inlet valve is provided in the upper part of the pipe. The inlet valve contains a flow sensor. The lower part of the water supply pipe is connected to the groundwater replenishment pipe of the groundwater replenishment device, and a control valve is provided between the two.

[0012] In the above technical solution, the leakage device includes a leakage water volume tank, a seepage pipe and a leakage valve. The seepage pipe is connected to the drain pipe and a leakage valve is provided between the two. The leakage water volume tank is located at the outlet of the seepage pipe.

[0013] In the above technical solution, the drain pipe is equipped with a drain valve and a flow sensor.

[0014] In the above technical solution, the groundwater recharge device includes a recharge valve, a recharge port, and a groundwater recharge pipe. One end of the groundwater recharge pipe is connected to the lyopermeameter filter layer, and the other end is connected to the recharge port. A recharge valve is provided at the recharge port.

[0015] In the above technical solution, a water level gauge is also connected to the groundwater recharge pipe near the recharge valve. The top of the water level gauge is connected to the ground, and the bottom is controlled by the water level valve.

[0016] The above technical solution also includes a data acquisition box, which is used to acquire data on lysimeter weight, soil moisture, irrigation data, automatic water replenishment data, groundwater replenishment data, drainage data, leakage data, and meteorological data, in order to calculate changes in soil water storage.

[0017] A method for dynamic monitoring of evapotranspiration in a multifunctional integrated planting system:

[0018] The local groundwater depth is greater than the lysimeter height. Drip irrigation is used to replenish the groundwater during time period t, with the irrigation volume controlled at I. The groundwater recharge device, automatic water supply device, and drainage pipe are shut off, while the water level gauge and seepage device are opened to stabilize the water level to the required level for the experiment. The changes in intercropped crop transpiration ET1, soil evapotranspiration ET2, and soil water storage ΔW during time period t are calculated.

[0019]

[0020]

[0021] ΔW=P+I-W3-ET1-ET2-ΔS3

[0022] Where: ΔS1 is the weight change of the intercropped crop evaporation tank after watering and the end of the experiment within time period t; ΔS2 is the weight change of the soil evaporation tank after watering and the end of the experiment within time period t; r1 is the radius of the intercropped crop evaporation tank; r2 is the radius of the soil evaporation tank; ρ is the density of water; P is the rainfall within time period t; ΔS3 is the leakage within time period t; W3 is the transpiration of the main crop within time period t, and W3 = W2 - ET1 - ET2, where W2 is the weight of the evaporation meter after time period t.

[0023] A method for dynamic monitoring of evapotranspiration in a multifunctional integrated planting system:

[0024] The local groundwater depth is less than the height of the lyometer. The groundwater recharge is denoted as CR. Drip irrigation is applied during time period t', with the recharge amount controlled at I'. The drainage pipe and automatic water supply device are closed, while the groundwater recharge device, water level gauge, and seepage device are opened to stabilize the water level to the required experimental level. The changes in crop transpiration ET'1, soil evapotranspiration ET'2, and soil water storage ΔW' during time period t' are calculated.

[0025]

[0026]

[0027] ΔW′=P′+I′+CR-W′3-ET′1-ET′2-ΔS′3

[0028] Where: ΔS′1 is the weight change of the intercropped crop evaporation tank after watering and the end of the experiment within time period t', ΔS′2 is the weight change of the soil evaporation tank after watering and the end of the experiment within time period t', r1 is the radius of the intercropped crop evaporation tank, r2 is the radius of the soil evaporation tank, ρ is the density of water, P' is the rainfall within time period t', ΔS′3 is the leakage within time period t', W'3 is the transpiration of the main crop within time period t', and W′3=W′2-ET′1-ET′2, W'2 is the weight of the evaporation meter after time period t';

[0029] Groundwater recharge (CR) is obtained through the following methods:

[0030]

[0031]

[0032]

[0033]

[0034] a1=θ FC ×Z×1000

[0035]

[0036]

[0037]

[0038] Among them: CR max For potential groundwater recharge, D w To observe the depth of groundwater, D wc Where is the critical groundwater depth, k is a factor related to evapotranspiration, ET′=ET′1+ET′2, W a θ represents the actual water storage in the root zone, a1 represents the water storage corresponding to the field capacity at the maximum root zone depth, a2 represents the water requirement above the average between the field capacity and the wilting point, and a3, a4, b1, b2, b3, and b4 are all empirical parameters. FC Z represents the field water holding capacity of the soil, Z represents the maximum root zone depth of the crop, LAI represents the leaf area index, and W represents the maximum root zone depth of the crop. c For key soil moisture content, W c To stabilize soil water storage, θ WP This refers to the water content of wilted plants.

[0039] A method for dynamic monitoring of evapotranspiration in a multifunctional integrated planting system:

[0040] The local groundwater depth is less than the height of the lyometer. Drip irrigation is used to replenish water during the time period t”, with the drip irrigation water volume controlled at I”. The drainage pipe, groundwater recharge device, and seepage device are closed, while the automatic water replenishment device and water level gauge are turned on. The water volume U is controlled by the automatic water replenishment device to stabilize the water level to the required level for the experiment. The changes in intercropped crop transpiration ET”1, soil evapotranspiration ET”2, and soil water storage ΔW” during the time period t” are calculated.

[0041]

[0042]

[0043] ΔW″=P″+I″+UW″3-ET″1-ET″2

[0044] Where: ΔS″1 is the weight change of the intercropped crop evaporation tank after watering and the end of the experiment within the time period t”; ΔS″2 is the weight change of the soil evaporation tank after watering and the end of the experiment within the time period t”; r1 is the radius of the intercropped crop evaporation tank; r2 is the radius of the soil evaporation tank; ρ is the density of water; P” is the rainfall within the time period t”; W”3 is the transpiration of the main crop within the time period t”; and W″3 = W″2 - ET″1 - ET″2, where W″2 is the weight of the evaporation meter after the time period t”.

[0045] The beneficial effects of the present invention are as follows: The device for dynamic monitoring of the evapotranspiration process of the multifunctional intercropping system of the present invention can acquire lysimeter weight, soil moisture, irrigation data, automatic water replenishment data, groundwater replenishment data, drainage data, leakage data and meteorological data, which are used to calculate the changes in the transpiration of intercropped crops, soil evapotranspiration and soil water storage, and accurately characterize the evapotranspiration process of the intercropping system. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of the device for dynamic monitoring of the evapotranspiration process of the multifunctional composite planting system described in this invention;

[0047] Figure 2 This is a schematic diagram of the automatic water supply device, the groundwater supply device, and the water level gauge in this invention;

[0048] Figure 3 This is a schematic diagram of the leakage device in this invention;

[0049] Figure 4 This is a schematic diagram of the structure of the weighing sensor in this invention;

[0050] Figure 5(a) is a top view of the soil evaporation tank in this invention;

[0051] Figure 5(b) is a top view of the intermediate crop evaporation tank of the present invention;

[0052] In the diagram: 1. Weather station; 2. Drip irrigation tape; 3. Soil moisture sensor; 4. Lysimeter measuring cylinder; 5. Lysimeter filter layer; 6. Drainage pipe; 7. Leakage device; 8. Soil evaporation tank; 9. Intercropping crop evaporation tank; 10. Water level gauge; 11. Automatic water replenishment device; 12. Groundwater recharge device; 13. Weighing sensor; 14. Base; 15. Data acquisition box; 601. Drainage valve; 701. Leakage valve; 702. Infiltration pipe; 703. Leakage water volume tank; 801. Outer cylinder of soil evaporation tank; 802. Inner cylinder of soil evaporation tank; 803. Sand mesh of soil evaporation tank; 804. 901. Curved handle of soil evaporation tank; 902. Outer cylinder of intercropped crop evaporation tank; 903. Inner cylinder of intercropped crop evaporation tank; 904. Sand mesh of intercropped crop evaporation tank; 1005. Curved handle of intercropped crop evaporation tank; 1106. Water level valve; 1107. Water supply tank; 1108. Air pressure pipe; 1109. Water pressure sensor; 11000. Water supply pipe; 1101. Inlet valve; 1102. Inlet; 1103. Control valve; 1201. Replenishment valve; 1202. Replenishment port; 1203. Groundwater replenishment pipe; 1301. Cement base; 1302. Weight sensor. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are merely illustrative of the invention and are not intended to limit the invention.

[0054] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0055] like Figure 1 As shown, a device for dynamic monitoring of evapotranspiration in a multifunctional intercropping system includes a weather station 1, a drip irrigation tape 2, a soil moisture sensor 3, a lysimeter cylinder 4, a lysimeter filter layer 5, a drainage pipe 6, a seepage device 7, a soil evaporation bucket 8, an intercropping crop lysimeter bucket 9, a water level gauge 10, an automatic water replenishment device 11, a groundwater replenishment device 12, a weighing sensor 13, a base 14, and a data acquisition box 15.

[0056] The weather station 1 is located near the lysimeter measuring cylinder 4, within a 5-meter range.

[0057] The drip irrigation tape 2 is set on the ground, with one pipe for two rows of main crops and one pipe for four rows of intercropped crops. The drip irrigation tape 2 is connected to the water source and is used to replenish the ground water.

[0058] The lysimeter cylinder 4 is a cylindrical transparent tube with a diameter of 1m and a height of 1.7m, installed underground. Its top is open and connected to the outside, and the top is flush with the ground. Crops are planted in the soil at the top. The soil evaporation tank 8 and the intercropping lysimeter tank 9 are located inside the lysimeter cylinder 4. Before planting, the soil evaporation tank 8 and the intercropping lysimeter tank 9 are buried in the soil at the top of the lysimeter cylinder 4. A soil moisture sensor 3 is connected to one side of the outer wall of the lysimeter cylinder 4, and an automatic water replenishment device 11 is connected to the bottom of the other side. The bottom of the lysimeter cylinder 4 is open and connected to the lysimeter filter layer 5. The lysimeter filter layer 5 is filled with fine sand as a filter layer for water replenishment or drainage. The lysimeter cylinder 4 and the lysimeter filter layer 5 constitute the lysimeter.

[0059] Referring to Figure 5(a), the soil evaporation bucket 8 is divided into two layers. The outer cylinder 801 of the soil evaporation bucket is a cylindrical PVC hollow cylinder with a diameter of 10cm and a height of 15cm. The inner cylinder 802 of the soil evaporation bucket is a cylindrical PVC hollow cylinder with a diameter of 8cm and a height of 15cm. The inner cylinder 802 is set inside the outer cylinder 801 of the soil evaporation bucket. The top and bottom of both the inner and outer cylinders are open. The bottom of the inner cylinder 802 is provided with a soil evaporation bucket sand mesh 803 and the top is connected to an arc-shaped handle 804, which makes it easy to lift the inner cylinder 802 out of the soil.

[0060] Referring to Figure 5(b), the intercropping evaporation tank 9 is divided into two layers. The outer cylinder 901 of the intercropping evaporation tank is a cylindrical PVC hollow cylinder with a diameter of 20cm and a height of 30cm. The inner cylinder 902 of the intercropping evaporation tank is a cylindrical PVC hollow cylinder with a diameter of 18cm and a height of 30cm. The inner cylinder 902 is set inside the outer cylinder 901 of the intercropping evaporation tank, and the top and bottom of both the inner and outer cylinders are open. The bottom of the inner cylinder 902 of the intercropping evaporation tank is provided with an intercropping evaporation tank sand mesh 903, and the top is connected to an arc-shaped handle 904 of the intercropping evaporation tank, which makes it easy to lift the inner cylinder 902 of the intercropping evaporation tank out of the soil.

[0061] When in use, the soil evaporation tank 8 and the intercrop transpiration tank 9 are driven vertically into the soil, and the inner tank is filled with soil. The soil evaporation and intercrop transpiration are indirectly obtained by weighing the soil in the inner tank.

[0062] In this embodiment, the dimensions of the soil evaporation tank 8 and the intercropping crop transpiration tank 9 are those used in the research group's experiment; other dimensions can be selected for actual use.

[0063] The number of soil moisture sensors 3 is selected according to actual needs. In this embodiment, 7 sensors are set. Specifically, they are installed at intervals of 10, 20, 30, 50, 70, 120 and 170 cm from the ground downwards. The data recording interval of the sensors is 10 minutes, which is used to monitor the soil moisture of different soil layers.

[0064] See Figure 2The automatic water replenishment device 11 includes a water supply tank 1101. The lower end of the water supply tank 1101 is connected to a water pressure sensor 1103. One side of the water pressure sensor 1103 is connected to a water supply pipe 1104, and the other side is connected to a pressure pipe 1102. Water enters through the water supply pipe 1104, and pressure is released through the pressure pipe 1102. The middle part of the water supply pipe 1104 is connected to the lysimeter cylinder 4 through a water inlet 1106, and a water inlet valve 1105 is provided in the upper part of the pipe to control the amount of water entering the lysimeter cylinder 4. The water inlet valve 1105 contains a flow sensor to monitor the water flow in real time. The lower part of the water supply pipe 1104 is connected to a groundwater recharge pipe 1203, and a control valve 1107 is provided between the two. During the water intake period, the control valve 1107 needs to be closed in the lysimeter cylinder 4.

[0065] The bottom of the lyofiltration filter layer 5 is provided with a drainage pipe 6 and a seepage device 7 on one side, and a groundwater replenishment device 12 and a water level gauge 10 (located on the same side as the automatic water replenishment device 11) on the other side. The bottom is connected to a weighing sensor 13.

[0066] See Figure 3 The leakage device 7 includes a leakage volume tank 703, a seepage pipe 702, and a leakage valve 701. The seepage pipe 702 is connected to the drain pipe 6, and a leakage valve 701 is provided between the two. The seepage valve 701 is used to control the seepage of water. Water flows into the leakage volume tank 703 through the seepage pipe 702. The leakage volume tank 703 is provided with scale lines to measure the amount of water seepage (leakage data). The drain pipe 6 is provided with a drain valve 601 to control drainage. In addition, the drain pipe 6 is provided with a water flow sensor.

[0067] like Figure 2 As shown, the groundwater recharge device 12 includes a recharge valve 1201, a recharge port 1202, and a groundwater recharge pipe 1203. One end of the groundwater recharge pipe 1203 is connected to the lyostat filter layer 5, and the other end is connected to the recharge port 1202. A recharge valve 1201 is installed at the recharge port 1202, which is connected to a groundwater source via a pipe. Groundwater enters through the recharge port 1202 and opens the recharge valve 1201, allowing groundwater to be replenished. A water level gauge 10 is also connected to the groundwater recharge pipe 1203 near the recharge valve 1201. The top of the water level gauge 10 is connected to the ground, and the bottom is controlled by a water level valve 1001. The water level gauge 10 is used to monitor the water level changes inside the lyostat measuring cylinder 4, facilitating indirect control of the drip irrigation recharge and groundwater recharge. A flow sensor is also installed at the recharge port 1202.

[0068] See Figure 4The weighing sensor 13 includes a cement base 1301 and three weight sensors 1302. The three weight sensors 1302 are horizontally and evenly arranged on the top of the cement base 1301 in an equilateral triangle manner. The weight sensors 1302 are used to measure the weight change of the lysimeter.

[0069] The lower end of the weighing sensor 13 is a base 14, and a data acquisition box 15 is installed inside the base 14. The data acquisition box 15 is used to acquire the weight of the lysimeter, soil moisture, irrigation data (drip irrigation water replenishment of drip irrigation tape 2), automatic water replenishment data, groundwater replenishment data, drainage data, leakage data, and data from the weather station 1 (including rainfall, evapotranspiration, light intensity, temperature, and humidity). The data is used to calculate the change in soil water storage.

[0070] A device for dynamically monitoring the evapotranspiration process of a multifunctional integrated planting system, with different application scenarios as follows:

[0071] (1) The local groundwater depth is greater than the height of the lysimeter (the sum of the heights of the lysimeter measuring cylinder 4 and the lysimeter filter layer 5). Without considering the influence of groundwater, under water-saving conditions, the amount of drip irrigation water on the ground is controlled to study the water use of crops and soil. The specific steps are as follows: Drip irrigation is carried out within a certain time period t, and the amount of drip irrigation water is controlled to I. The groundwater supply device 12, the automatic water supply device 11 and the drainage pipe 6 are closed. The water level gauge 10 and the seepage device 7 are opened to stabilize the water level to the required level for the experiment. The weight difference △S1 and △S2 of the intercrop lysimeter tank 9 and the soil evaporation tank 8 after drip irrigation are measured manually during this period. After the experiment, the weight W2 of the lysimeter is recorded. The radius of the intercrop lysimeter tank 9 is recorded as r1 and the radius of the soil evaporation tank 8 is recorded as r2. The changes in the transpiration of the intercrop ET1, the evapotranspiration of the soil ET2 and the soil water storage △W during the time period t are determined.

[0072]

[0073]

[0074] ΔW=P+I-W3-ET1-ET2-ΔS3 (3)

[0075] W3 = W2 - ET1 - ET2 (4)

[0076] In the formula, ET1 is the transpiration of the intercropped crop within time period t (mm), ΔS1 is the weight change of the intercropped crop transpiration tank 9 between irrigation and the end of the experiment within time period t (g), ΔS2 is the weight change of the soil evaporation tank 8 between irrigation and the end of the experiment within time period t (g), ET2 is the soil evapotranspiration within time period t (mm), r1 is the radius of the intercropped crop transpiration tank 9 (cm), r2 is the radius of the soil evaporation tank 8 (cm), and ρ is the density of water (g / cm³).3 ), △W is the change in soil water storage (g) during time period t, P is the rainfall (mm) during time period t, I is the drip irrigation water replenishment (mm) during time period t, △S3 is the seepage (mm) during time period t (seepage data obtained from seepage water tank 703), and W3 is the transpiration of the main crop (mm) during time period t.

[0077] (2) The local groundwater depth is less than the height of the lysimeter. Considering the influence of groundwater, there are two situations.

[0078] ① First case

[0079] The groundwater recharge is denoted as CR. The surface drip irrigation volume is controlled to study crop and soil water use. The specific steps are as follows: Drip irrigation is performed within a certain time period t', with the recharge volume controlled as I'. The drain pipe 6 and automatic water supply device 11 are closed, while the groundwater recharge device 12, water level gauge 10, and seepage device 7 are opened to stabilize the water level to the required experimental level. The weight differences ΔS'1 and ΔS'2 of the intercropping evaporation tank 9 and the soil evaporation tank 8 after drip irrigation are manually measured within this time period. After the experiment, the weight of the evaporation meter W'2 is recorded. The radius of the intercropping evaporation tank 9 is denoted as r1, and the radius of the soil evaporation tank 8 is denoted as r2. The changes in crop transpiration ET'1, soil evapotranspiration ET'2, and soil water storage ΔW' within the time period t' are determined.

[0080]

[0081]

[0082] ΔW′=P′+I′+CR-W′3-ET′1-ET′2-ΔS′3 (7)

[0083] W′3=W′2-ET′1-ET′2 (8)

[0084] In the formula, ET′1 is the transpiration of the intercropped crop during time period t' (mm), ΔS′1 is the weight change of the intercropped crop between the irrigation tank 9 and the end of the experiment during time period t' (g), ΔS′2 is the weight change of the soil evaporation tank 8 between the irrigation tank 8 and the end of the experiment during time period t' (g), ET′2 is the soil evapotranspiration during time period t' (mm), ΔW′ is the change in soil water storage during time period t' (g), P′ is the rainfall during time period t' (mm), I′ is the drip irrigation replenishment during time period t' (mm), ΔS′3 is the seepage during time period t' (mm), and W′3 is the transpiration of the main crop during time period t' (mm).

[0085] The groundwater recharge CR was obtained through the following methods:

[0086]

[0087]

[0088]

[0089]

[0090] a1=θ FC ×Z×1000 (13)

[0091]

[0092]

[0093]

[0094] Among them: CR max For potential groundwater recharge, D w To observe the groundwater depth (m), D wc Let be the critical groundwater depth (m), k be a dimensionless factor related to evapotranspiration, ET′=ET′1+ET′2 (mm), W a a1 represents the actual water storage capacity in the root zone (mm), a2 represents the water storage capacity (mm) corresponding to the field capacity at the maximum root zone depth (measured by soil moisture sensor 3), a3 represents the water requirement (mm) above the average between the field capacity and the wilting point (empirical value), a3 and a4 are empirical parameters, b1, b2, b3, and b4 are all empirical parameters, and θ represents the actual water storage capacity in the root zone (mm), a1 represents the water storage capacity (mm) corresponding to the field capacity at the maximum root zone depth (measured by soil moisture sensor 3), a2 represents the water requirement (mm) between the field capacity and the wilting point (empirical value), a3 and a4 are empirical parameters, and b1, b2, b3, and b4 are all empirical parameters. FC Z represents the field water holding capacity of the soil, Z represents the maximum root zone depth of the crop (observed by lysimeter tube 4), LAI represents the leaf area index, and W represents the maximum root zone depth of the crop. c For key soil moisture content (mm), W c To stabilize soil water storage (mm), θ WP The moisture content (mm) is the amount of water absorbed during wilting.

[0095] ②The second case

[0096] The study investigated the impact of fixed groundwater volume on crop moisture. The specific steps were as follows: Drip irrigation was performed within a certain time period t”, with the drip irrigation volume controlled at I”. The drainage pipe 6, groundwater recharge device 12, and seepage device 7 were closed. The automatic water supply device 11 and water level gauge 10 were turned on. The water volume U was controlled by the automatic water supply device 11 to stabilize the water level to the required experimental level. The weight differences ΔS”1 and ΔS”2 of the intercrop evaporation tank 9 and the soil evaporation tank 8 were manually measured during this time period after drip irrigation. The weight W”2 of the evaporation meter was recorded after the experiment. The radius of the intercrop evaporation tank 9 was recorded as r1, and the radius of the soil evaporation tank 8 as r2. The changes in intercrop transpiration ET”1, soil evapotranspiration ET”2, and soil water storage ΔW” within the certain time period t” were determined.

[0097] ΔW″=P″+I″+UW″3-ET″1-ET″2 (17)

[0098] W″3=W″2-ET″1-ET″2 (18)

[0099]

[0100]

[0101] In the formula, ET″1 is the transpiration of the intercropped crop during the time period t” (mm), ΔS″1 is the weight change of the intercropped crop in the evapotranspiration tank 9 between the time period t” and the end of the experiment (g), ΔS″2 is the weight change of the soil in the evaporation tank 8 between the time period t” and the end of the experiment (g), ET″2 is the soil evapotranspiration during the time period t” (mm), ΔW” is the change in soil water storage during the time period t” (g), P” is the rainfall during the time period t” (mm), I” is the drip irrigation replenishment during the time period t” (mm), and W”3 is the transpiration of the main crop during the time period t” (mm).

[0102] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for dynamic monitoring of evapotranspiration in a multifunctional composite planting system, characterized in that, Includes a lysimeter and drip irrigation tape (2), wherein the lysimeter includes a lysimeter filter layer (5) and a lysimeter measuring cylinder (4) disposed on the upper part of the lysimeter filter layer (5); Soil evaporation tank (8) and intercropping crop evaporation tank (9) are buried in the soil at the top of the lysimeter measuring cylinder (4). The soil moisture sensor (3) is connected to one side of the outer wall of the lyometer cylinder (4), and the automatic water replenishment device (11) is connected to the bottom of the other side of the outer wall. Located on the same side as the automatic water replenishment device (11), the bottom of the lyostat filter layer (5) is provided with a groundwater replenishment device (12) and a water level gauge (10), and a drain pipe (6) is provided on the other side, which is connected to the leakage device (7); The bottom of the lyophilizer filter layer (5) is connected to the weighing sensor (13); The drip irrigation tape (2) is placed between the crop rows; The local groundwater depth is less than the height of the lysimeter. The groundwater recharge is denoted as CR. Drip irrigation is carried out during the time period t', and the drip irrigation recharge is controlled as I'. The drainage pipe (6) and the automatic water replenishment device (11) are closed. The groundwater recharge device (12), water level gauge (10) and seepage device (7) are opened to stabilize the water level to the required level for the experiment. The changes in crop transpiration ET'1, soil evapotranspiration ET'2, and soil water storage ΔW' during the time period t' are calculated. in: The weight change of the intercropped crop in the evapotranspiration tank (9) between the time period t' and the end of the experiment is the value of the weight change of the intercropped crop in the evapotranspiration tank (9). R1 represents the weight change of the soil evaporation tank (8) between the time period t' and the end of the experiment after watering, and R2 represents the radius of the intercropped crop evaporation tank (9). Let P' be the density of water, ΔS'3 be the rainfall during time period t', ΔS'3 be the infiltration during time period t', and W'3 be the transpiration of the main crop during time period t'. W'2 is the weight of the lysimeter after time period t'; Groundwater recharge (CR) is obtained through the following methods: in: For potential groundwater recharge, To observe the depth of groundwater, Where k is the critical groundwater depth, and k is a factor related to transpiration during evapotranspiration. , This represents the actual water storage in the root zone. The water storage capacity corresponding to the field holding capacity at the maximum root zone depth. The water requirement above average between field capacity and the wilting point. , , , , , These are all empirical parameters. Z represents the field water holding capacity of the soil, Z represents the maximum root zone depth of the crop, and LAI represents the leaf area index. The key soil moisture content, To stabilize soil water storage, This refers to the water content of wilted plants.

2. The device for dynamic monitoring of evapotranspiration process in a multifunctional composite planting system according to claim 1, characterized in that, The automatic water replenishment device (11) includes a water supply tank (1101), the lower end of which is connected to a water pressure sensor (1103). One side of the water pressure sensor (1103) is connected to a water supply pipe (1104), and the other side is connected to a gas pressure pipe (1102). The middle part of the water supply pipe (1104) is connected to the lysimeter measuring cylinder (4) through the water inlet (1106), and the upper part is provided with a water inlet valve (1105). A flow sensor is provided inside the water inlet valve (1105). The lower part of the water supply pipe (1104) is connected to the groundwater replenishment pipe (1203) of the groundwater replenishment device (12), and a control valve (1107) is provided between the two.

3. The device for dynamic monitoring of evapotranspiration process in a multifunctional composite planting system according to claim 1, characterized in that, The leakage device (7) includes a leakage water tank (703), a seepage pipe (702) and a leakage valve (701). The seepage pipe (702) is connected to the drain pipe (6), and a leakage valve (701) is provided between the two. The leakage water tank (703) is located at the outlet of the seepage pipe (702).

4. The device for dynamic monitoring of evapotranspiration process in a multifunctional composite planting system according to claim 3, characterized in that, The drain pipe (6) is equipped with a drain valve (601) and a flow sensor.

5. The device for dynamic monitoring of evapotranspiration process in a multifunctional composite planting system according to claim 1, characterized in that, The groundwater recharge device (12) includes a recharge valve (1201), a recharge port (1202) and a groundwater recharge pipe (1203). One end of the groundwater recharge pipe (1203) is connected to the lyostat filter layer (5), and the other end is connected to the recharge port (1202). A recharge valve (1201) is provided at the recharge port (1202).

6. The device for dynamic monitoring of evapotranspiration process in a multifunctional composite planting system according to claim 5, characterized in that, The groundwater supply pipe (1203) is also connected to a water level gauge (10) near the supply valve (1201). The top of the water level gauge (10) is connected to the ground, and the bottom is controlled by the water level valve (1001).

7. The device for dynamic monitoring of evapotranspiration process in a multifunctional composite planting system according to claim 1, characterized in that, It also includes a data acquisition box (15) for acquiring data on lysimeter weight, soil moisture, irrigation data, automatic water replenishment data, groundwater replenishment data, drainage data, leakage data and meteorological data, which are used to calculate changes in soil water storage.

8. The device for dynamic monitoring of evapotranspiration process in a multifunctional composite planting system according to claim 1, characterized in that: The local groundwater depth is greater than the height of the lysimeter. Drip irrigation is carried out during time period t, and the drip irrigation water supply is controlled at I. The groundwater supply device (12), automatic water supply device (11) and drainage pipe (6) are closed, and the water level gauge (10) and seepage device (7) are opened to stabilize the water level to the required level for the experiment. The changes in transpiration of intercropped crops ET1, soil evapotranspiration ET2 and soil water storage ΔW during time period t are calculated. in: The weight change of the intercropped crop evapotranspiration tank (9) between the time period t and the end of the experiment is the value of the weight change of the intercropped crop evapotranspiration tank (9) after irrigation and the end of the experiment. R1 represents the weight change of the soil evaporation tank (8) between the time period t and the end of the experiment, where r1 is the radius of the intercropped crop evaporation tank (9) and r2 is the radius of the soil evaporation tank (8). Let P be the density of water, ΔS3 be the rainfall during time period t, ΔS3 be the infiltration during time period t, and W3 be the transpiration of the main crop during time period t. W2 represents the weight of the lysimeter after time period t.

9. The device for dynamic monitoring of evapotranspiration process in a multifunctional composite planting system according to claim 1, characterized in that: The local groundwater depth is less than the height of the lysimeter. Drip irrigation is carried out during the time period t'', and the drip irrigation water supply is controlled at I''. The drainage pipe (6), groundwater supply device (12) and seepage device (7) are closed. The automatic water supply device (11) and water level gauge (10) are turned on. The water supply U is controlled by the automatic water supply device (11) to stabilize the water level to the required level for the experiment. The changes in the transpiration of the intercropped crop ET''1, the soil evapotranspiration ET''2 and the soil water storage ΔW'' during the time period t'' are calculated: in: The weight change of the intercropped crop in the evapotranspiration tank (9) between the time period t'' and the end of the experiment is the value of the weight change of the intercropped crop in the evapotranspiration tank (9) between the time of watering and the end of the experiment. R1 represents the weight change of the soil evaporation tank (8) between the time period t'' and the end of the experiment, where r1 is the radius of the intercropped crop evaporation tank (9) and r2 is the radius of the soil evaporation tank (8). Let P'' be the density of water, P'' be the rainfall during time period t'', and W''3 be the transpiration of the main crop during time period t''. , The weight of the lysimeter after time period t''.

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