Dynamic monitoring system for transpiration of greenhouse crops

Abstract

The invention provides a greenhouse crop transpiration dynamic monitoring system, which belongs to the technical field of irrigation and comprises a weighing module, a data acquisition and transmission module and a data processing module. The weighing module comprises a matrix weight variation weighing module, a crop weight variation weighing module, a liquid inlet weighing module and a liquid outlet weighing module and is used for acquiring corresponding parameter data. The weighing module acquires information and then transmits the information to the data acquisition and transmission module, and the data acquisition and transmission module receives the data and then performs communication configuration to realize remote data transmission. And the data processing module performs difference calculation on the received data information, and obtains the weight variation of each weighing module and the predicted value of the environment correction model to obtain the transpiration of the greenhouse crops. The crop transpiration can be continuously and accurately monitored, a planter can timely and quantitatively evaluate the water management condition of facility crop cultivation, and the method has important significance in formulating a reasonable irrigation strategy and improving the water utilization efficiency of greenhouse crops.

Description

Technical Field

[0001] The invention belongs to the technical field of irrigation, and in particular relates to a dynamic monitoring system for greenhouse crop transpiration. Background Art

[0002] Understanding the changing patterns of crop transpiration is of great significance for greenhouse irrigation management decisions. Due to the complex and changeable greenhouse environment, transpiration is difficult to measure accurately. Among the commonly used measurement methods for greenhouse irrigation decisions, the weighing method is simpler and more practical than other moisture sensor measurement methods. However, there are many problems with existing greenhouse weighing systems: some systems require a large number of weighing nodes and take up a lot of space; some can only calculate the moisture content of the substrate and cannot accurately determine the crop transpiration. For example, Chinese patent applications with publication numbers CN112673948A and CN115997667A disclose an irrigation system based on substrate moisture content weighing. The system can obtain substrate moisture content, but cannot obtain crop transpiration information; Chinese patent application with publication number CN109657730A discloses a method and system for predicting greenhouse crop transpiration, which uses parameters such as greenhouse environment and crop images to predict crop transpiration. The transpiration obtained by this method is not an actual measured value, and its accuracy is difficult to grasp; some are complex in structure and costly; Chinese patent application with publication number CN105699244A discloses an automatic crop transpiration metering system, which requires all plants and substrates to be placed on a main bracket. The system architecture is complex and is only suitable for measuring small potted plants. Summary of the invention

[0003] In order to solve the problems of inaccurate measurement of greenhouse crop transpiration and complex structure, the present invention provides a greenhouse crop transpiration dynamic monitoring system.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A greenhouse crop transpiration dynamic monitoring system, comprising:

[0006] The weighing module includes a substrate weight change weighing module, a crop weight change weighing module, a liquid inlet weighing module and a liquid discharge weighing module, which are respectively used to measure the substrate weight change, crop weight change, liquid inlet and liquid discharge of greenhouse crops. The substrate weight change weighing module includes a cultivation rack and second weighing sensors arranged at the four corners of the cultivation rack; the crop weight change weighing module includes a hanging truss, a vine rack and an S-shaped weighing sensor symmetrically hung between the truss and the vine rack;

[0007] Data acquisition and transmission module, used to receive the signal transmitted by the weighing module and perform communication configuration to realize remote data transmission;

[0008] The data processing module is used to receive the information from the data acquisition and transmission display module, calculate the difference between the acquired weighing data value and the historical weighing data value one minute ago, obtain the weight change of each weighing module, and obtain the greenhouse crop transpiration amount according to the net value subtracted from the weight change of each weighing module and the predicted value of the environmental correction model.

[0009] Preferably, the liquid inlet weighing module includes a liquid inlet pipe, a liquid inlet weighing basin and a first weighing sensor, and the liquid discharge weighing module includes a liquid discharge pipe, a liquid discharge weighing basin and a third weighing sensor. A plurality of drip arrows are arranged on the liquid inlet pipe, one drip arrow is fixedly placed in the liquid inlet weighing basin, and the remaining drip arrows are used to supply water to crops. The first weighing sensor and the third weighing sensor are respectively placed under the liquid inlet weighing basin and the liquid discharge weighing basin.

[0010] Preferably, the data acquisition and transmission module further comprises a display module, which converts the transmitted signals of the sensor and the weighing module into digital signals for display.

[0011] Preferably, the data acquisition and transmission module includes a junction box and a PLC. The junction box is connected to the weighing module and the display module. The PLC is connected to the display module for data acquisition and storage. The PLC realizes remote data transmission after communication configuration with the configuration software. The junction box is used to aggregate the signals of the sensor and the weighing module and send them to the display module.

[0012] Preferably, the weight changes of the weighing modules are subtracted to obtain the crop transpiration, which specifically includes:

[0013]

[0014] In the formula, Represents crop transpiration; W Irrigation represents irrigation volume; W Slab represents the matrix weight; W Drain Represents the liquid displacement; W Crop represents the crop weight; dt is the time interval for calculation.

[0015] Preferably, it also includes an environmental sensor module for obtaining greenhouse environmental parameters, wherein the greenhouse environmental parameters include measuring the temperature, relative humidity, water vapor saturation pressure difference VPD and photosynthetically active photon flux density PPFD in the greenhouse, and the PLC is connected to the environmental sensor via an RS485 communication port.

[0016] Preferably, the environmental correction model obtains the leaf area index of the crop by an image method, inputs the greenhouse environmental parameters and the leaf area index into a pre-trained random forest model, and obtains a predicted value of the crop transpiration.

[0017] The greenhouse crop transpiration dynamic monitoring system provided by the present invention has the following beneficial effects:

[0018] The greenhouse crop transpiration monitoring system includes a weighing module, a data acquisition and transmission module, and a data processing module. The weighing module includes a substrate weight change weighing module, a crop weight change weighing module, a liquid inlet weighing module, and a liquid discharge weighing module, which are used to obtain corresponding parameter data. After the weighing module collects information, it passes it to the data acquisition and transmission module. After receiving the data, the data acquisition and transmission module performs communication configuration to realize remote data transmission. The data processing module performs difference calculation on the received data information, obtains the weight change of each weighing module and the predicted value of the environmental correction model to obtain the greenhouse crop transpiration. The ability to continuously and accurately monitor crop transpiration facilitates growers to timely and quantitatively evaluate the water management status of facility crop cultivation, which is of great significance for formulating reasonable irrigation strategies and improving the water utilization efficiency of greenhouse crops. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiment of the present invention and its design scheme, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 It is a structural schematic diagram of a greenhouse crop transpiration dynamic monitoring system of the present invention;

[0021] Figure 2 It is a flow chart of a greenhouse crop transpiration dynamic monitoring system of the present invention;

[0022] Figure 3 This is a display interface diagram of a greenhouse crop transpiration dynamic monitoring system of the present invention;

[0023] Figure 4 The figure is the monitoring result of the transpiration of 9 tomato plants per hour on a typical sunny day in one embodiment;

[0024] Figure 5 The following is an example of monitoring the transpiration of 9 tomato plants every ten minutes on a typical sunny day.

[0025] Figure 6 The figure is the monitoring result of the transpiration of 9 tomato plants per hour on a typical cloudy day in one embodiment;

[0026] Figure 7 The following is an example of monitoring the transpiration of 9 tomato plants every ten minutes on a typical cloudy day.

[0027] Figure 8The figure is a schematic diagram of the results of using the random forest algorithm to predict crop transpiration in an embodiment.

[0028] Description of reference numerals:

[0029] 1-S-type weighing sensor, 2-cultivation rack as a whole, 21-tomato plant, 22-substrate cultivation pot, 23-cultivation trough, 3-liquid inlet weighing module, 31-liquid inlet pipe, 32-drip arrow, 33-liquid inlet weighing basin, 34-first weighing sensor, 4-second weighing sensor, 5-drainage weighing module, 51-drainage pipe, 52-drainage weighing basin, 53-third weighing sensor. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0031] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the technical solutions of the present invention 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 cannot be understood as a limitation on the present invention.

[0032] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0033] Example

[0034] The present invention provides a greenhouse crop transpiration dynamic monitoring system, specifically a cultivation weighing system with simple structure, accurate measurement and low cost. Figure 1 and Figure 2 As shown, the system includes: a weighing module, a data acquisition and transmission module and a data processing module.

[0035] The weighing module includes a substrate weight change weighing module, a crop weight change weighing module, a liquid inlet weighing module 3 and a liquid discharge weighing module 5. The substrate weight change weighing module is composed of a cultivation frame and a single-point weighing sensor. Four second weighing sensors 4 are arranged at the four corners of the cultivation frame. Each second weighing sensor 4 is connected to two parallelogram iron plates at the upper and lower parts. The two are connected by bolts. The iron plates and the support frame are also connected by bolts to measure the substrate weight change above the cultivation frame. The crop weight change weighing module is composed of a hanging vine frame and an S-type weighing sensor 1. Two S-type weighing sensors 1 are symmetrically hung on the truss of the greenhouse. The hanging vine frame is hung with a hook below. After the hanging vine rope is hung on the hanging vine frame, the weight change of the hanging vine crop below can be measured. The inlet weighing module 3 and the discharge weighing module 5 include an inlet weighing basin 33, a discharge weighing basin 52, a first weighing sensor 34, a third weighing sensor 53 and an inlet pipe 31. One dropper 32 is fixedly placed in the inlet weighing basin 33, and the remaining dropper 32 is used to supply water to the crops. After the performance data of the dropper 32 is determined by actual testing, the weight change of the inlet weighing basin 33 within a period of time is multiplied by the number of dropper 32 used for irrigation to obtain the inlet amount within the period of time, and the discharge flows into the discharge weighing basin 52 through the discharge trough on the cultivation rack and the discharge pipe 51, thereby obtaining the discharge weight.

[0036] The data acquisition and transmission module includes a junction box, an instrument, a power supply and a programmable logic controller (PLC). The weighing sensor converts the mass signal into an electrical signal, which is then aggregated through the junction box and sent to the instrument. The instrument converts the electrical signal into a digital signal and displays it. At the same time, it is wired to the PLC and wirelessly transmits data after communication configuration is performed through the configuration software. The junction box is connected to multiple weighing sensors to balance the measured angle difference and signal aggregation of multiple sensors. The instrument is connected to the junction box to display the digital quantity of the weighing module. The instrument supports ModBus communication protocol for remote data transmission. The power supply is a 24VDC / AC transformer, which is connected to the instrument to power the instrument. The PLC is connected to the instrument of the above-mentioned weighing module and the environmental sensor through the RS485 communication port for data acquisition and storage. The PLC realizes remote data transmission after communication configuration with the configuration software. In a greenhouse environment, temperature, relative humidity, solar radiation, and VPD are important indicators affecting the transpiration of greenhouse crops. Therefore, the system also includes an environmental sensor module, which is composed of sensors corresponding to measuring temperature, relative humidity, VPD and PPFD data. It is connected to the PLC through an RS485 interface and is used to measure the temperature, relative humidity, water vapor saturation pressure difference VPD and photosynthetic active light quantum flux density PPFD in the greenhouse.

[0037] The data processing module, including the supporting configuration software platform, can collect the data of the above-mentioned weighing module and environmental module in real time, and calculate and analyze the collected real-time data and historical data to obtain the current transpiration of the crop community. The transpiration of greenhouse crops is calculated by using the difference between the current data value and the historical data one minute ago to obtain the weight change of each weighing module. The calculation is performed according to the following formula to obtain the net value of the weight change of each weighing module:

[0038]

[0039] In the formula, Represents crop transpiration; W Irrigation represents irrigation volume; W Slab represents the matrix weight; W Drain Represents the liquid displacement; W Crop represents the crop weight; dt is the time interval for calculation.

[0040] Crops mainly carry out photosynthesis through leaves. The size of leaves is positively correlated with crop transpiration or transpiration rate. Therefore, crop leaf area is also the main influencing factor for predicting transpiration. The environmental correction model is based on greenhouse environmental parameters and samples of the target crop leaf area index (LAI) and is trained using the random forest algorithm. It has a corrective significance for the transpiration monitoring of the greenhouse crop transpiration dynamic monitoring system. The relevant parameters of the greenhouse environment obtained by the environmental sensor module, the LAI of the crop obtained by the image method, and the transpiration obtained by the cultivation weighing device are input into the pre-trained random forest model to output the predicted value of the target crop transpiration. According to the net value of the weight change of each weighing module, the predicted value of transpiration output by the random forest algorithm model is corrected to obtain the greenhouse crop transpiration. Through the above continuous process, the dynamic and continuous measurement of greenhouse crop transpiration is realized.

[0041] The following is a specific embodiment of the present invention:

[0042] Nine mature tomato plants with consistent growth were selected as test subjects, and the transpiration of greenhouse crops was monitored using the above system.

[0043] Cultivation rack overall 2 Figure 1The crop weight change weighing module uses two S-shaped weighing sensors 1 to measure the weight change of the tomato plant 21 below the hanging vine rack, and the substrate weight change weighing module uses the four second weighing sensors 4 at the bottom to measure the weight change of the substrate cultivation pot 22 above the cultivation rack. The substrate cultivation pot 22 is placed on the cultivation trough 23. Ten drop arrows 32 are arranged on the liquid inlet pipe 31, one of which is placed in the liquid inlet weighing basin 33, and the other nine drop arrows 32 are inserted into the substrate cultivation pot 22. Since the water output of the drop arrows 32 is uniform, 9 times the weight change of the liquid inlet weighing basin 33 is measured as the liquid inlet amount, which is measured by the electronic scale 34 below. The drainage after irrigation flows into the drainage weighing basin 52 through the drainage trough in the cultivation rack through the drainage port 51, and the drainage amount is measured by the third weighing sensor 53. The software algorithm is used to calculate the weight difference of the weighing module in one minute in real time, and the crop transpiration of 1 minute (3 minutes, 5 minutes, 10 minutes, 30 minutes and 60 minutes can be selected) is displayed in real time. The calculation results and the temperature and humidity, VPD and photosynthetic active light quantum flux density in the greenhouse are displayed on the interface in the form of values ​​and charts, which is convenient for growers to timely evaluate the quantitative moisture status of greenhouse crops.

[0044] The greenhouse crop transpiration dynamic monitoring system is used to continuously collect tomato transpiration data for 24 hours, with a data collection step of 1 minute. The main interface of the monitoring system software platform is as follows Figure 3 The monitoring results of transpiration of 9 tomato plants per hour and every 10 minutes on a typical sunny day are as follows: Figure 4 and Figure 5 As shown in the figure, the monitoring results of transpiration of 9 tomato plants per hour and every 10 minutes on a typical cloudy day are as follows: Figure 6 and Figure 7 The monitoring results are consistent with the actual transpiration law of crops, that is, transpiration increases with time in the morning and decreases with time in the afternoon. The transpiration rate generally reaches a peak at 12 o'clock, and there is only a small amount of transpiration at night. On sunny days, the total daily transpiration of 9 tomato plants is 11,500g, and the average transpiration per plant is 1,278g; on cloudy days, the total daily transpiration is 8,280g, and the average transpiration per plant is 920g.

[0045] The transpiration of 9 tomato plants and the environmental parameters in the greenhouse were collected in real time for 10 consecutive days. The leaf images of the tomato plants were collected once a day, and the leaf area index was calculated by counting all the leaf areas. In this embodiment, the indoor VPD mean value, the indoor PPFD mean value, and the LAI value calculated on the day were used as input, and the actual transpiration obtained by the transpiration dynamic monitoring system within the hour was used as output, totaling 240 groups of data, to construct a sample set, and then use the sample set to train to obtain a random forest model. The original sample set is divided into a training sample set and a test sample set according to a preset ratio. A part of the samples are randomly selected from the original sample set as training samples, and another part of the samples are used as test samples. In this embodiment, the ratio of the number of groups of the original sample training sample set and the test sample set is 8:2. The original data of the embodiment of the present invention totals 240 groups, of which 192 groups are divided into training data sets and 48 groups are used as test data sets according to the ratio of 8:2. The greenhouse environmental parameters, the target crop LAI parameters, and the transpiration obtained by the cultivation weighing system are input into the trained random forest model to obtain the predicted value of the transpiration of the target crop. Figure 8 The results of using the random forest algorithm to predict crop transpiration are shown in the test phase R 2 =0.937, RMSE=27.581, the prediction effect is good.

[0046] It should be pointed out that the specific implementation methods described above can enable those skilled in the art to understand the invention more comprehensively, but do not limit the invention in any way. Therefore, although the invention has been described in detail in this specification and embodiments, those skilled in the art should understand that the invention can still be modified or replaced by equivalents; and all technical solutions and improvements that do not deviate from the spirit and scope of the invention are included in the protection scope of the patent for the invention. Any figure mark in the claims should not be regarded as limiting the claims involved. Any simple change or equivalent replacement of the technical solution that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention belongs to the protection scope of the present invention.

Claims

1. A greenhouse crop transpiration dynamic monitoring system, characterized in that: include: The weighing module comprises a substrate weight variation weighing module, a crop weight variation weighing module, a liquid inlet weighing module and a liquid discharge weighing module, which are respectively used to measure the substrate weight variation, crop weight variation, liquid inlet and liquid discharge of greenhouse crops. The substrate weight variation weighing module comprises a cultivation frame and second weighing sensors (4) arranged at the four corners of the cultivation frame; the crop weight variation weighing module comprises a hanging truss, a vine frame and an S-shaped weighing sensor (1) symmetrically hung between the truss and the vine frame; Data acquisition and transmission module, used to receive the signal transmitted by the weighing module and perform communication configuration to realize remote data transmission; The data processing module is used to receive the information from the data acquisition and transmission display module, calculate the difference between the acquired weighing data value and the historical weighing data value one minute ago, obtain the weight change of each weighing module, and obtain the greenhouse crop transpiration amount according to the net value subtracted from the weight change of each weighing module and the predicted value of the environmental correction model.

2. A greenhouse crop transpiration dynamic monitoring system according to claim 1, characterized in that: The liquid inlet weighing module (3) comprises a liquid inlet pipe (31), a liquid inlet weighing basin (33) and a first weighing sensor (34); the liquid discharge weighing module (5) comprises a liquid discharge pipe (51), a liquid discharge weighing basin (52) and a third weighing sensor (53); a plurality of drop arrows (32) are arranged on the liquid inlet pipe (31); one drop arrow (32) is fixedly placed in the liquid inlet weighing basin (33); the remaining drop arrows (32) are used to supply water to crops; the first weighing sensor (34) and the third weighing sensor (53) are respectively placed under the liquid inlet weighing basin (33) and the liquid discharge weighing basin (52).

3. A greenhouse crop transpiration dynamic monitoring system according to claim 1, characterized in that: The data acquisition and transmission module also includes a display module, which converts the transmitted signals of the sensor and the weighing module into digital signals for display.

4. A greenhouse crop transpiration dynamic monitoring system according to claim 3, characterized in that: The data acquisition and transmission module includes a junction box and a programmable logic controller PLC. The junction box is connected to the weighing module and the display module. The PLC is connected to the display module for data acquisition and storage. The PLC realizes remote data transmission after communication configuration with the configuration software. The junction box is used to summarize the signals of the sensor and the weighing module and send them to the display module.

5. A greenhouse crop transpiration dynamic monitoring system according to claim 1, characterized in that: The weight changes of each weighing module are subtracted to obtain the crop transpiration, which is: In the formula, φ transp Represents crop transpiration; W Irrigation represents irrigation volume; W Slab represents the matrix weight; W Drain Represents the liquid displacement; W Crop represents the crop weight; dt is the time interval for calculation.

6. A greenhouse crop transpiration dynamic monitoring system according to claim 4, characterized in that: It also includes an environmental sensor module for obtaining greenhouse environmental parameters, wherein the greenhouse environmental parameters include measuring the temperature, relative humidity, water vapor saturation pressure difference VPD and photosynthetically active photon flux density PPFD in the greenhouse. The PLC is connected to the environmental sensor via an RS485 communication port.

7. A greenhouse crop transpiration dynamic monitoring system according to claim 6, characterized in that: The environmental correction model obtains the leaf area index of the crop by an image method, inputs the greenhouse environmental parameters and the leaf area index into a pre-trained random forest model, and obtains the predicted value of the crop transpiration.

Images