Irrigation control method and system based on conductivity change of rhizosphere nutrient solution

Abstract

The invention provides an irrigation control method and system based on conductivity change of a rhizosphere nutrient solution. The control method comprises the following steps: calculating a single irrigation dose; calculating the time length of single irrigation; calculating a sunrise moment and a sunset moment; the EC value of the rhizosphere nutrient solution is detected in real time through a first EC sensor arranged in the substrate, the current moment is obtained, when the current moment is between the sunrise moment and the sunset moment, first irrigation is started when the difference value delta ECr between the EC value of the rhizosphere nutrient solution and the EC value of the irrigation nutrient solution is larger than a first specific value, and second irrigation is started when delta ECr is larger than a second specific value. The irrigation duration of each time is single irrigation duration, circulation is carried out according to the starting condition of second-time irrigation, and when the irrigation moment is not smaller than the irrigation stopping moment of the day, irrigation of the day is stopped. The invention provides an irrigation control method and system based on rhizosphere nutrient solution conductivity change, and aims to solve the problem that nutrient solution is difficult to accurately irrigate according to crop requirements in matrix cultivation in the prior art.

Description

Technical Field

[0001] The invention relates to the field of soilless cultivation, and in particular to a substrate cultivation irrigation control method and system based on the change of conductivity of rhizosphere nutrient solution. Background Art

[0002] At present, large-scale greenhouses have made significant progress in large-scale production. This production model mainly relies on substrate soilless cultivation technology, which has broad development potential. Its advantages include effectively avoiding continuous cropping obstacles, increasing yields, optimizing water and fertilizer utilization, and accurately controlling nutrient solution concentration. Substrate cultivation technology integrates nutrient solution irrigation systems to provide crops with necessary water and nutrients. However, due to the small size of the substrate and its limited buffering capacity for water and nutrients, the irrigation frequency also needs to be increased accordingly, and multiple irrigations are required per day, which puts higher requirements on the accuracy of irrigation management.

[0003] Reasonable determination of irrigation frequency and amount is crucial for efficient use of resources, avoiding crop stress, and improving yield and quality. In addition, the characteristics and amount of substrate used will directly affect the amount of free water, salt concentration and oxygen concentration in the rhizosphere.

[0004] At present, commonly used nutrient solution control strategies include irrigation control based on the accumulation of solar radiation and irrigation control based on the weight of the substrate. The former is an indirect method based on experience. When the accumulation of solar radiation reaches a certain threshold, irrigation is started, but factors such as crop type, growth stage and greenhouse light transmittance are not considered. Therefore, irrigation control may not fully meet the actual needs of crops. Although the latter is directly based on the change of substrate weight, it is easily disturbed by manual operations such as leaf beating and picking, resulting in control errors. These two methods also have the problem of high cost of the control system. Conventional irrigation control methods often ignore the characteristics and usage of the substrate, as well as the content of free water in the rhizosphere, which often leads to excessive or insufficient application of nutrient solution, which not only wastes resources, but may also cause stress to crops. Summary of the invention

[0005] The present invention provides an irrigation control method and system based on the change of conductivity of rhizosphere nutrient solution, which is used to solve the problems in the prior art of insufficient free water in the rhizosphere of substrate cultivation causing crop stress or excessive irrigation causing waste and inhibiting root respiration, thereby affecting water and nutrient absorption, and realize precise irrigation of nutrient solution according to crop needs.

[0006] In view of the problems existing in the prior art, the present invention provides an irrigation control method based on the change of conductivity of rhizosphere nutrient solution, comprising the following steps: Calculate the single irrigation amount based on the volume of the substrate, the water holding characteristics of the substrate, the ratio of easily available water to readily available water, and the drainage ratio. V i ; According to the single irrigation dosage V i 、Number of irrigation devices used per unit substrate n and emitter flow q Calculate the duration of a single irrigation session t ; Calculate sunrise and sunset times; The EC value of the rhizosphere nutrient solution is detected in real time by a first EC sensor arranged in the substrate; Get the current time. When the current time is between sunrise and sunset, calculate the difference between the EC value of the rhizosphere nutrient solution and the EC value of the irrigation nutrient solution, ΔEC r , when the ΔEC r When the value is greater than the first specific value, the first irrigation is started, and the irrigation duration is the duration of a single irrigation. t ; Record the time when the first irrigation starts; Calculate the time from sunrise to the time when the first irrigation starts, and subtract this time from the sunset time to get the irrigation stop time of the day T e After the first irrigation, the EC value of the rhizosphere nutrient solution is continuously detected by the first EC sensor in real time, and the difference ΔEC is calculated. r , when the ΔEC r When the value is greater than the second specific value, the second irrigation is started, and the irrigation duration is the duration of a single irrigation. t Then, the second irrigation start condition is repeated until the irrigation time is not less than the irrigation stop time of the day. T e Stop irrigation for the day.

[0007] The first specific value and the second specific value are related to the crop type, the growth stage of the crop, the volume of the substrate and the water holding property of the substrate.

[0008] According to an irrigation control method based on the change of conductivity of rhizosphere nutrient solution provided by the present invention, the first specific value ranges from 0.03 to 0.1 mS / cm.

[0009] According to an irrigation control method based on changes in the conductivity of rhizosphere nutrient solution provided by the present invention, the second specific value ranges from 0.02 to 0.05 mS / cm.

[0010] According to an irrigation control method based on changes in the electrical conductivity of the rhizosphere nutrient solution provided by the present invention, when the EC detection function of the first EC sensor fails or is limited, the first EC sensor is used to detect the volumetric moisture content of the substrate, and an alarm is activated when the ratio of the volumetric moisture content of the substrate to the water holding capacity of the substrate is less than or equal to the ratio of the quick-acting water of the substrate.

[0011] According to an irrigation control method based on the change of the conductivity of the rhizosphere nutrient solution provided by the present invention, when the alarm is activated, the crops are supplemented with irrigation.

[0012] The present invention also provides an irrigation system based on the change of conductivity of rhizosphere nutrient solution, comprising: A cultivation component, composed of a substrate, includes a first cultivation component and a second cultivation component, wherein the second cultivation component has a plurality of cultivation positions, and each cultivation position is provided with the first cultivation component; an irrigation unit, comprising an irrigation device arranged corresponding to the first cultivation component; and First EC sensor, data collector, controller; The controller uses the irrigation control method based on the change of the conductivity of the rhizosphere nutrient solution provided by the present invention to control the irrigation start time and irrigation duration.

[0013] According to an irrigation system based on the change of conductivity of rhizosphere nutrient solution provided by the present invention, the first EC sensor adopts time domain reflection technology.

[0014] According to an irrigation system based on the change of electrical conductivity of rhizosphere nutrient solution provided by the present invention, crops are planted one by one in sequence corresponding to the first cultivation components, the first EC sensor probe is horizontally inserted into the second cultivation component, and the first EC sensor is arranged at the geometric center of the second cultivation component in the horizontal direction and at a height of 2 / 3 from the upper surface of the second cultivation component.

[0015] According to an irrigation system based on changes in electrical conductivity of rhizosphere nutrient solution provided by the present invention, the first EC sensor is connected to the data collector and the controller.

[0016] According to the present invention, an irrigation system based on the change of electrical conductivity of rhizosphere nutrient solution also includes at least one fertilizer applicator, which also includes a second EC sensor for detecting the EC value of the irrigation nutrient solution. The fertilizer applicator is connected to the emitter through a pipeline and supplies nutrient solution to the emitter.

[0017] The irrigation control method based on the change of the conductivity of the rhizosphere nutrient solution provided by the present invention determines the single irrigation dosage according to the volume of the substrate, the water holding characteristics of the substrate, the proportion of quick-acting water and the drainage proportion, and determines the irrigation start time by monitoring the change of the EC value of the rhizosphere nutrient solution compared with the EC value of the irrigation nutrient solution, thereby maintaining the concentration of the crop rhizosphere nutrient solution and the content of quick-acting water within the suitable range for the crop, avoiding the influence of salt and water stress on the crop growth, or the waste caused by excessive irrigation of nutrient solution and hindering the respiration of the crop root system to affect the absorption of water and nutrients, so as to realize precise irrigation according to the needs of the crop.

[0018] The present invention provides an irrigation system based on the change of the electrical conductivity of the rhizosphere nutrient solution. A substrate cultivation piece is provided for cultivating crops; a first EC sensor is provided for detecting the change of the EC value of the rhizosphere nutrient solution compared with the EC value of the irrigation nutrient solution and the volume water content of the substrate; a data collector is provided for collecting the data detected by the first EC sensor; a controller is provided for controlling the irrigation start time and the irrigation duration according to the irrigation control method based on the change of the electrical conductivity of the rhizosphere nutrient solution of the present invention; a fertilizer spreader containing a second EC detection sensor is provided, the fertilizer spreader is connected with each sprinkler through a pipeline, and nutrient solution is supplied to the sprinkler for executing the precise irrigation action of the nutrient solution, thereby realizing precise irrigation according to the needs of the crops. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic flow chart of an irrigation control method based on the change of conductivity of rhizosphere nutrient solution provided by the present invention; Figure 2 It is a schematic diagram of the flow of an irrigation system based on the change of conductivity of rhizosphere nutrient solution provided by the present invention; Figure 3 It is a top view schematic diagram of an irrigation system based on the change of conductivity of rhizosphere nutrient solution provided by the present invention; Figure 4 A three-dimensional schematic diagram of an irrigation system based on the change of conductivity of rhizosphere nutrient solution provided by the present invention; Figure 5 It is a schematic diagram of the structure of the EC sensor (Time Domain Reflectometry, TDR) in the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are 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.

[0022] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0023] In the description of the embodiments of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "horizontal", "upper surface" and "bottom surface" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying 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 embodiments of the present invention.

[0024] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connection" 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 a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0025] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0026] Combine the following Figure 1-Figure 5 The invention describes an irrigation control method and system based on the change of the conductivity of the rhizosphere nutrient solution.

[0027] There is a problem in the traditional technology that it is impossible to irrigate accurately and in real time according to the demand of crops for nutrient solution. As crops absorb water from the substrate nutrient solution, the salt of the rhizosphere nutrient solution is concentrated, and the free water content decreases (i.e., the water potential decreases), which increases the difficulty of root absorption of water. Since the salt concentration of the nutrient solution is directly related to its conductivity value (i.e., EC value), the salt concentration of the nutrient solution can be reflected by measuring the conductivity of the nutrient solution. The conductivity value (i.e., EC value) can be measured by an EC sensor. Therefore, in the substrate soilless cultivation mode, in order to fully supply crops with water and nutrients while avoiding the accumulation of salt in the root zone to the extent that it harms the growth of crops, the present invention provides an irrigation control method based on the change of the conductivity of the rhizosphere nutrient solution: the single irrigation amount is calculated by the substrate volume, the water holding characteristics of the substrate, the proportion of quick-acting water and the drainage ratio, and the time to start irrigation is controlled by the difference between the EC value of the rhizosphere nutrient solution and the EC value of the irrigation nutrient solution being greater than the first specific value or the second specific value, thereby achieving precise irrigation according to the needs of crops. Specifically, the following steps are included: S1: Calculate single irrigation volume V i The cultivation medium used in this embodiment is a customized commercial coconut bran strip, and the coconut bran strip with the specifications of length×width×height of 100 cm×15 cm×10 cm is selected. The single irrigation amount is calculated according to formula (1): In the formula, V i It is the single irrigation dosage, unit: L / bar; V sIt is the water holding capacity of the matrix, unit: L / strip, which is related to the volume of the matrix and the water holding characteristics of the matrix. It refers to the relatively stable water content that can be maintained in the matrix after a certain period of time after sufficient irrigation, allowing water to fully infiltrate and preventing it from evaporating. This is the upper limit of the matrix water that most plants can use, and it is measured by the following steps: ① weigh the mass of the dry matrix; ② fill the matrix with water and soak it for 24 hours, drain it for 12 hours and then weigh the mass of the matrix; ③ the difference between the two matrix masses is the water holding capacity of the matrix; ④ when the crop root system grows to the maximum, re-measure the water holding capacity of the matrix after the change due to the root system. In this embodiment, it is specifically: ① weigh the mass of the dry coconut bran strips. ② Place the coconut bran strips neatly on the "J"-shaped cultivation rack, then insert the irrigation device (in an optional embodiment, the irrigation device is set as a drip arrow) above the coconut bran strips according to the determined plant spacing, and then turn on the fertilizer applicator to inject clean water into the coconut bran strips. Specifically, if the coconut bran strips have drainage holes, use a small dose of 50-75mL of water from each irrigation device to soak the coconut bran strips every 10 minutes. Once the complete soaking point is reached, water begins to drain from the coconut bran strips. At this time, stop water supply and weigh; if the coconut bran strips do not have drainage holes, irrigate the coconut bran strips with water by drip irrigation until the volume of the coconut bran strips reaches 85% of the volume after the coconut bran strips are fully soaked, stop irrigation, and soak for 24 hours. Draw two 2cm oblique cuts on the bottom of the coconut bran strips to drain excess water, and weigh after draining for 12 hours. ③ The difference between the mass of the coconut bran strips measured in step ① and step ② is its water holding capacity. ④ The root system will change the water holding capacity of the substrate. Therefore, when measuring the water holding capacity when the crop root system is at its maximum, the crop (in this embodiment, tomatoes) is planted on the coconut bran strips, and the water holding capacity of the coconut bran strips is re-measured when the tomato crop root system grows to its maximum. It is understandable that different water holding capacity values ​​are selected according to the size of the crop.

[0028] P s It is the ratio of matrix quick-acting water to matrix water holding capacity, which is measured by experiments. Matrix quick-acting water refers to the water that crops can easily absorb from the moist matrix. The ratio of quick-acting water to matrix water holding capacity of several commonly used matrixes is: perlite 24%; zeolite with particle size less than 5mm 24%; coconut bran 58%; rock wool 85%. In this embodiment, the ratio of quick-acting water in coconut bran strips to the water holding capacity of coconut bran strips is 58%.

[0029] P e The ratio of the quick-acting water consumed when irrigation begins to all the quick-acting water is generally 5%-35%, and a smaller value is taken when a nutrient solution with a higher salt content and a substrate with a lower water holding capacity is used. In this embodiment, it is 7%.

[0030] D sThe drainage ratio is the expected drainage ratio for each irrigation. The drainage ratio refers to the ratio of the volume of the liquid discharged from the substrate to the volume of the irrigation nutrient solution after each irrigation. This ratio should be proportional to the salt content in the irrigation nutrient solution, usually 10%-30% of the volume of the irrigation nutrient solution. In this embodiment, it is 20%.

[0031] In this embodiment, the single irrigation volume calculated by formula (1) is 0.51765 L / row.

[0032] S2: Calculate the duration of a single irrigation t As shown in formula (2): t It is the duration of a single irrigation, unit: min; V i is a single irrigation dose, which is 0.51765 L / bar in this embodiment; n The number of water emitters corresponding to each coconut bran strip is 4 in this embodiment; q is the flow rate of the sprinkler, which is 2 L / h in this embodiment; 60 is the conversion factor, which is used to convert h to min.

[0033] In this embodiment, the single irrigation time is calculated by formula (2) to be 3.88 minutes, which is rounded to 4 minutes.

[0034] S3: Calculate sunrise time t sunrise and sunset time t sunset Calculate the sunrise time according to formula (3): Calculate the sunset time according to formula (4): t sunrise For sunrise time; t sunset For sunset time; T The time zone of the installation location, such as Beijing's time zone is East 8. T =8; S lo is the longitude of the installation location, with east longitude being positive and west longitude being negative, rad; S lais the latitude of the installation location, with north latitude being positive and south latitude being negative, rad; D It is the date serial number, that is, the sequence of the day in the year, such as February 11 is 42.

[0035] The result of formula (3) is a value less than 24, such as 6.69, which is converted into the sexagesimal time to represent 06:41.

[0036] S4: Insert the first EC sensor (such as a time domain reflectometer, Time Domain Reflectometry, TDR) horizontally into the substrate and set it between two crops in the center of the substrate and at a height of 2 / 3 from the top surface of the substrate. The EC value of the rhizosphere nutrient solution is detected in real time by the first EC sensor; S5: Get the current time T n When the current time is between sunrise and sunset, calculate the difference between the EC value of the rhizosphere nutrient solution and the EC value of the irrigation nutrient solution, ΔEC r , when ΔEC r When the pressure is greater than the first specific value (0.1 mS / cm in this embodiment), the first irrigation is started, and the irrigation duration is the single irrigation duration. t In this embodiment, the single irrigation duration is calculated by formula (2) as 4 minutes, and the first irrigation start time is recorded at the same time. The duration from sunrise to the first irrigation start time is calculated, and the sunset time is subtracted from this duration to obtain the whole day irrigation stop time. T e After the first irrigation, as transpiration progresses, the EC value of the rhizosphere nutrient solution in the substrate increases. The EC value of the rhizosphere nutrient solution is continuously detected by the first EC sensor in real time and ΔEC is calculated. r , when ΔEC r When the pressure is greater than the second specific value (0.05 mS / cm in this embodiment), the second irrigation is started, and the irrigation duration is the single irrigation duration. t , which is 4 minutes in this embodiment. After that, the second irrigation start condition is repeated until the irrigation time is not less than the irrigation stop time of the day. T e Stop irrigation for the day.

[0037] Among them, the first and second specific values ​​ΔEC r The size of is related to the crop type, crop growth stage, substrate volume and substrate water holding properties. The first specific value is generally set at 0.03-0.1mS / cm. The second specific value is generally set at 0.02-0.05mS / cm.

[0038] According to the law of conservation of matter, the following is the formula using ΔEC r The principle of ensuring the stability of the root zone EC value: As shown in formula (5) (6).

[0039] Δ C r is the real-time change of salt concentration in the matrix, unit: mmol / L; C s is the irrigation nutrient solution concentration, unit: mmol / L; V t is the total irrigation volume, unit: L / pot; P d It is the ratio of the volume of discharged liquid to the volume of irrigation nutrient solution; C d is the discharge concentration, unit: mmol / L; C u The concentration of nutrient solution absorbed by crops, unit: mmol / L, this value depends on the crop type and growth environment; V u The volume of nutrient solution absorbed by the crop, unit: L / pot, this value depends on the crop type and greenhouse environment; V r It is the real-time water content in the substrate, unit: L / pot.

[0040] Since the EC value is proportional to the nutrient solution concentration, equation (5) can be derived as equation (6) ΔEC r is the real-time change of the conductivity of the rhizosphere nutrient solution in the substrate compared to the conductivity of the irrigation nutrient solution, unit: mS / cm; EC s is the conductivity of the irrigation nutrient solution, unit: mS / cm; EC d is the conductivity of the discharged liquid, unit: mS / cm; EC u The conductivity of the nutrient solution absorbed by the crop, unit: mS / cm Therefore, when ΔEC r After a value is determined, EC s is a fixed value, given by ΔEC r =EC d −EC s It can be seen that EC dIt is also a fixed value, which maintains the stability of the EC value of the nutrient solution in the rhizosphere environment. The amount of nutrients absorbed by the crop EC u × V u The larger the irrigation volume, the V t It also needs to be larger to maintain the EC value of the nutrient solution in the rhizosphere environment stable, so as to achieve the purpose of precise and real-time irrigation according to crop needs.

[0041] According to one embodiment of the present invention, when the EC value detection function of the first EC sensor fails or is limited, the first EC sensor is used to detect the volumetric moisture content of the substrate, and an alarm is activated when the ratio of the volumetric moisture content of the substrate to the water holding capacity of the substrate is less than or equal to the ratio of the substrate's quick-acting water. After the alarm is activated, the crops are supplementally irrigated.

[0042] On the basis of the above-mentioned irrigation control method based on the change of the conductivity of the rhizosphere nutrient solution, the present invention further provides an irrigation system based on the change of the conductivity of the rhizosphere nutrient solution, comprising: a first cultivation component 1; a second cultivation component 2, the second cultivation component 2 has a plurality of cultivation positions, each cultivation position is provided with a first cultivation component 1, and crops 4 are planted one by one in sequence corresponding to each first cultivation component; an irrigation unit 6, comprising an emitter 5 arranged corresponding to the first cultivation component 1; and a first EC sensor 3, the probe of which is horizontally inserted in the second cultivation component, and the first EC sensor 3 is arranged horizontally in the second cultivation component. The first EC sensor 3 is connected to the data collector and the controller through the line L, and is located at the geometric center upward and 2 / 3 of the height from the upper surface of the second cultivation component 2. The data collector is used to collect data from the first EC sensor 3, and transmits the collected data to the controller (not shown in the figure). The controller controls the irrigation start time and irrigation duration through the irrigation control method based on the change of the conductivity of the rhizosphere nutrient solution of the present invention, thereby realizing accurate and real-time irrigation according to the needs of the crops.

[0043] It should be noted that the cultivation components are composed of substrates. Specifically, the first cultivation component 1 and the second cultivation component 2 can be coconut bran or rock wool, and other substrates. The shapes and specifications are not limited by the present invention, and can be square or cylindrical.

[0044] Specifically, in this embodiment, the first cultivation component 1 is a coconut bran block with a volume of 10 cm×10 cm×8 cm, and the second cultivation component 2 is a coconut bran strip with a volume of 100 cm×15 cm×10 cm. The crop seedlings are transplanted into the first cultivation component 1 and grown for a period of time. After the root system is fully grown, they are planted in the second cultivation component 2. Four plants are planted in each cultivation position of each second cultivation component 2. The first EC sensor 3 uses a TDR305N time domain reflectometer (TDR), which can measure the volume moisture content of the substrate, the EC value of the rhizosphere nutrient solution and the substrate temperature in situ and online at the same time. The moisture content measurement range of the first EC sensor 3 is 0-100%, the resolution is 1%, and the measurement accuracy is ±5%; the measurement range of the substrate volume conductivity EC value is 0-6.0mS / cm, the resolution is 0.001mS / cm, the measurement accuracy is ±0.025mS / cm in the range of 0-1mS / cm, the measurement accuracy is ±2.5% in the range of 1-2.5mS / cm, and the measurement accuracy is ±5% in the range of 2.5-6mS / cm. The measurement range of the pore water EC value is 0-55mS / cm; the temperature measurement range is -40-60 °C, with a measurement accuracy of ±0.25 °C in the range of 5-35 °C and ±0.5 °C in the range of -15-55 °C; probe length 5 cm.

[0045] In a preferred embodiment, the irrigation system based on the change of conductivity of the rhizosphere nutrient solution provided by the present invention further includes at least one fertilizer applicator, which is used to prepare the irrigation nutrient solution, and the fertilizer applicator also includes a second EC sensor that can detect the EC value of the irrigation nutrient solution. The second EC sensor is arranged on the fertilizer applicator to detect the EC value of the irrigation nutrient solution in real time, and then calculate ΔEC according to the EC difference measured by the first EC sensor and the second EC sensor. r ,According to the method provided above, precise irrigation can be achieved according to crop needs.

[0046] Furthermore, it is necessary to irrigate the four crops of the second cultivation component 2. In the technical solution provided by the present invention, the irrigation unit 6 includes an emitter 5 corresponding to the cultivation component, and the fertilizer applicator is connected to each emitter 5 through a pipeline, and supplies nutrient solution to the emitter to perform the precise irrigation of nutrient solution. In an optional embodiment, the emitter 5 is set as a dripping arrow (NDJ dripping arrow: 2.3L / h gray long-angle maze flow channel, containing Netafim2 L / h anti-drip pressure compensation dripper, wall thickness 3mm, diameter 5mm white microtube), the head of which is inserted into the corresponding cultivation matrix, and the tail is connected to the fertilizer applicator through the corresponding pipeline, which is used to perform the precise irrigation of nutrient solution.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An irrigation control method based on the change of conductivity of rhizosphere nutrient solution, characterized in that: The following steps are involved: S1: Calculate the single irrigation amount based on the volume of the substrate, the water holding characteristics of the substrate, the proportion of quick-acting water and the drainage ratio V i ; S2: According to the single irrigation dosage V i 、Number of irrigation devices used per unit substrate n and emitter flow q Calculate the duration of a single irrigation session t ; S3: Calculate sunrise and sunset times; S4: detecting the EC value of the rhizosphere nutrient solution in real time by a first EC sensor arranged in the substrate; S5: Get the current time. When the current time is between sunrise and sunset, calculate the difference ΔEC between the EC value of the rhizosphere nutrient solution and the EC value of the irrigation nutrient solution. r , when the ΔEC r When the value is greater than the first specific value, the first irrigation is started, and the irrigation duration is the duration of a single irrigation. t ; Record the time when the first irrigation starts; Calculate the time from sunrise to the time when the first irrigation starts, and subtract this time from the sunset time to get the irrigation stop time of the day T e After the first irrigation, the EC value of the rhizosphere nutrient solution is continuously detected by the first EC sensor in real time, and the difference ΔEC is calculated. r , when the ΔEC r When the value is greater than the second specific value, the second irrigation is started, and the irrigation duration is the duration of a single irrigation. t Then, the second irrigation start condition is repeated until the irrigation time is not less than the irrigation stop time of the day. T e Stop irrigation for the day; The first specific value and the second specific value are related to the crop type, the growth stage of the crop, the volume of the substrate and the water holding property of the substrate.

2. The irrigation control method based on the change of conductivity of rhizosphere nutrient solution according to claim 1, characterized in that: The first specific value ranges from 0.03 to 0.1 mS / cm.

3. The irrigation control method based on the change of conductivity of rhizosphere nutrient solution according to claim 1, characterized in that: The second specific value ranges from 0.02 to 0.05 mS / cm.

4. The irrigation control method based on the change of conductivity of rhizosphere nutrient solution according to claim 1, characterized in that: When the EC detection function of the first EC sensor fails or is limited, the first EC sensor is used to detect the volumetric water content of the matrix, and an alarm is activated when the ratio of the volumetric water content of the matrix to the water holding capacity of the matrix is ​​less than or equal to the ratio of the quick-acting water.

5. The irrigation control method based on the change of conductivity of rhizosphere nutrient solution according to claim 4, characterized in that: After the alarm is activated, the crops are supplemented with irrigation.

6. An irrigation system based on the change of conductivity of rhizosphere nutrient solution, characterized in that: include: A cultivation component, composed of a substrate, includes a first cultivation component and a second cultivation component, wherein the second cultivation component is provided with a plurality of cultivation positions, and each cultivation position is provided with the first cultivation component; An irrigation unit, comprising an irrigation device arranged corresponding to the first cultivation component; as well as First EC sensor, data collector, controller; The controller controls the irrigation start time and irrigation duration using the method according to any one of claims 1 to 5.

7. The irrigation system based on the change of conductivity of rhizosphere nutrient solution according to claim 6, characterized in that: The first EC sensor is a time domain reflectometer.

8. The irrigation system based on the change of conductivity of rhizosphere nutrient solution according to claim 6, characterized in that: The crop is planted corresponding to the first cultivation component, the probe of the first EC sensor is horizontally inserted into the second cultivation component, and the first EC sensor is arranged at the geometric center of the second cultivation component in the horizontal direction and at a height of 2 / 3 from the upper surface of the second cultivation component.

9. The irrigation system based on the change of conductivity of rhizosphere nutrient solution according to claim 6, characterized in that: The first EC sensor is connected to the data collector and the controller.

10. The irrigation system based on the change of conductivity of rhizosphere nutrient solution according to claim 6, characterized in that: It also includes at least one fertilizer applicator, which includes a second EC sensor for detecting the EC value of the irrigation nutrient solution. The fertilizer applicator is connected to the emitter through a pipeline and supplies nutrient solution to the emitter.

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