A control method and device for integrated water and fertilizer of a center pivot sprinkler

Abstract

The present invention discloses a method and device for integrated water and fertilizer control of a center pivot sprinkler. According to the relevant parameters of the center pivot sprinkler and the fertilizer injection pump, given the irrigation quota, the amount of fertilizer applied per mu, and the fertilizer type for a certain time, the running duration of the sprinkler during the spraying of fertilizer solution, the working frequency of the fertilizer injection pump, the running duration of the fertilizer injection pump during the backwashing process, the working frequency of the fertilizer injection pump, and the running duration of the sprinkler during the spraying of clean water can be calculated. A strategy of first spraying the fertilizer solution, then synchronously carrying out the backwashing process and spraying clean water is formed, and the walking speed of the sprinkler and the frequency of the fertilizer injection pump are accurately regulated through the control system to achieve fully automatic precise operation of integrated water and fertilizer. The present invention is based on E C Or pH feedback regulation can achieve precise control of the fertilizer injection amount without using metering devices such as flow meters, avoiding problems such as large fluctuations in water pressure of large sprinklers leading to large changes in fertilization concentration, and achieving coordinated and precise application of water and fertilizer while reducing costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated water and fertilizer management, and particularly relates to a control method and device for integrated water and fertilizer management of a center pivot sprinkler. Background Art

[0002] The integrated water and fertilizer management technology has significant effects such as water saving, fertilizer reduction, and yield increase. Currently, it has become a key measure in China to increase grain production capacity, improve the utilization efficiency of water and fertilizer, and alleviate the shortage of water resources. The center pivot sprinkler has the characteristics of high automation, large single-machine control area, strong adaptability, etc., and can significantly reduce water resource consumption and labor costs. Relevant research shows that applying large-scale sprinklers for integrated water and fertilizer spraying can reduce labor input, avoid damage to crops during the operation of conventional agricultural machinery, and improve the yield and quality of crops while increasing the utilization efficiency of water and fertilizer.

[0003] However, the integrated water and fertilizer management of large-scale sprinklers in China is still in its initial stage, and there is a large gap compared with developed countries such as the United States. A small number of users who use large-scale sprinklers for irrigation and fertilization mostly use products in other fields as fertilizer injection equipment. The compatibility and performance of the equipment cannot meet the requirements, and there is a lack of appropriate irrigation and fertilization strategies, resulting in problems such as poor accuracy of water and fertilizer ratio in the system and extensive management of water and fertilizer mixing.

[0004] Therefore, carrying out research on special devices for integrated water and fertilizer management of center pivot sprinklers suitable for intensive agricultural production and the supporting irrigation and fertilization strategies conforms to national policies and the actual requirements of domestic applications, and is of great significance for improving the utilization efficiency of water resources and fertilizers in China, increasing crop yields, and protecting soil and groundwater. Summary of the Invention

[0005] In view of the above problems, the purpose of the present invention is to provide an integrated water and fertilizer device for a center pivot sprinkler with stable fertilizer injection flow, which can accurately control the fertilization concentration and fertilization amount through an irrigation and fertilization strategy, and realize fully automatic precise operation of integrated water and fertilizer management based on E C or pH regulation.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A control method for integrated water and fertilizer management of a center pivot sprinkler provided in the first aspect of the present invention is used to control the integrated water and fertilizer equipment of the center pivot sprinkler. The integrated water and fertilizer equipment of the center pivot sprinkler includes a center pivot sprinkler, a fertilizer injection pump, and a fertilizer storage unit connected to each other. The control method includes:

[0008] Obtain the inherent parameters of the sprinkler, and set the amount of fertilizer applied per mu, irrigation quota, and fertilizer type for this irrigation and fertilization;

[0009] Collect the inlet flow rate of the sprinkler before the start of this fertilizing irrigation, and the E c value or pH value of the clear water in the main pipeline of the sprinkler;

[0010] According to the inherent parameters of the sprinkler, the fertilizer application rate per mu, irrigation quota and fertilizer type of this irrigation fertilization, and the inlet flow rate, calculate the working parameters of the sprinkler and fertilizer injection pump to form the irrigation fertilization strategy for this time, specifically in the strategy of first spraying fertilizer solution and then synchronously carrying out the backwashing process and spraying clear water;

[0011] Control the center pivot type sprinkler integrated water and fertilizer equipment to execute the irrigation fertilization strategy for this time;

[0012] During the process of controlling the center pivot type sprinkler integrated water and fertilizer equipment to execute the irrigation fertilization strategy for this time, monitor and feedback regulate the concentration of the sprayed fertilizer solution: select the corresponding fertilizer solution concentration inversion prediction model according to the fertilizer type, and obtain the E c predicted value or pH predicted value of the sprayed fertilizer solution for this irrigation fertilization according to the sprayed fertilizer solution concentration and the selected fertilizer solution concentration inversion prediction model, and compare this predicted value with the E c value or pH value of the sprayed fertilizer solution collected after the start of fertilizer injection, and form a control instruction for the center pivot type sprinkler integrated water and fertilizer equipment based on the comparison result.

[0013] In some embodiments, the inherent parameters of the sprinkler include the overall length of the sprinkler, the range of the nozzles installed at the end of the sprinkler, the field sprinkler water utilization coefficient, the field surface slip coefficient, the rated speed of the drive motor, the effective radius of the supporting tires, the transmission ratio of the drive motor reducer, the transmission ratio of the wheel reducer, the distance between the center support center point of the sprinkler and the end tower truck, the rated frequency of the fertilizer injection pump, and the actual flow rate of the fertilizer injection pump after calibration.

[0014] In some embodiments, the E c value and the pH value are respectively collected by an E c sensor and a pH sensor installed downstream of the confluence of the fertilizer injection pipeline and the main pipeline of the sprinkler, and the inlet flow rate is collected by a flow meter installed at the water inlet of the main pipeline of the sprinkler.

[0015] In some embodiments, the irrigation fertilization strategy for this time includes:

[0016] Preset program: Determine the coverage area A 0 of the sprinkler and the shortest time t min for the sprinkler to run one week according to the inherent parameters of the sprinkler;

[0017] Spraying fertilizer solution: According to the maximum solubility S of the given fertilizer at room temperature, the set fertilizer application rate M per mu and the coverage area A0 Determine the total fertilizer injection volume V of the current sprinkler irrigation fertilizer solution f , and determine the actual fertilizer injection volume V of the current sprinkler irrigation fertilizer solution according to the total fertilizer injection volume V of the current sprinkler irrigation fertilizer solution f and the volume V of the fertilizer storage container in the fertilizer storage unit t ; Determine the set value x of the percentage timer of the sprinkler during the sprinkler irrigation fertilizer solution process according to the inlet flow Q of the sprinkler 0 , the fertilizer solution depth h set for the sprinkler irrigation fertilizer solution process f , the coverage area A of the sprinkler 0 and the shortest time t for the sprinkler to run one week min ; Calculate the running duration t of the sprinkler during the sprinkler irrigation fertilizer solution process according to the shortest time t for the sprinkler to run one week f and the set value x of the percentage timer of the sprinkler during the sprinkler irrigation fertilizer solution process min ; Determine the working frequency f of the fertilizer injection pump according to the actual fertilizer injection volume V of the current sprinkler irrigation fertilizer solution, the rated frequency f of the fertilizer injection pump f , the actual flow q of the fertilizer injection pump after calibration f and the running duration t of the sprinkler during the sprinkler irrigation fertilizer solution process d ; d ; f Determine the working frequency f of the fertilizer injection pump;

[0018] Backwashing process: Set the running duration t c and the working frequency f of the fertilizer injection pump during the backwashing process c ;

[0019] Sprinkling clear water: Calculate the irrigation depth h of the sprinkling clear water according to the current irrigation quota h and the fertilizer solution depth h during the sprinkler irrigation fertilizer solution process f ; Determine the set value x of the percentage timer of the sprinkler during the sprinkling clear water process according to the inlet flow Q of the sprinkler w , the coverage area A of the sprinkler 0 , the shortest time t for the sprinkler to run one week 0 and the irrigation depth h of the sprinkling clear water min ; Calculate the running duration t of the sprinkler during the sprinkling clear water process according to the shortest time t for the sprinkler to run one week w and the set value x of the percentage timer of the sprinkler during the sprinkling clear water process w ; Calculate the running duration t of the sprinkler during the sprinkling clear water process according to the shortest time t for the sprinkler to run one week min and the set value x of the percentage timer of the sprinkler during the sprinkling clear water process w , and t w >t w >t c ;

[0020] According to the running duration t of the sprinkler during the sprinkler irrigation fertilizer solution process f and the working frequency f of the fertilizer injection pump, the running duration t of the fertilizer injection pump during the backwashing processc and the operating frequency f of the fertilizer injection pump c , the operating duration t of the sprinkler during the process of spraying clear water w , and the total duration t = t of the integrated water and fertilizer operation of the sprinkler f +t w to form the current irrigation and fertilization strategy

[0021] In some embodiments, the coverage area A of the sprinkler 0 is calculated according to the following formula

[0022]

[0023] In the formula, L s is the overall length of the sprinkler; R is the range of the nozzle installed at the end of the sprinkler

[0024] The shortest time t for the sprinkler to run one week min is calculated according to the following formula

[0025]

[0026] In the formula, L f is the distance between the center point of the central support of the sprinkler and the end tower truck; i 1 is the transmission ratio of the drive motor reducer; i 2 is the transmission ratio of the wheel reducer; n is the rated speed of the drive motor; r is the effective radius of the supporting tire; η is the field surface slip coefficient, which depends on the tire pattern, tire pressure and soil compactness, and is taken as 0.92 - 0.97

[0027] The total fertilizer injection volume V of the current sprinkler spraying fertilizer solution f is calculated according to the following formula

[0028]

[0029] In the formula, k is a coefficient set to ensure the full dissolution of the fertilizer, and is taken as 1.3 - 1.6

[0030] The actual fertilizer injection volume V of the current sprinkler spraying fertilizer solution is calculated according to the following formula

[0031] V = NV t

[0032]

[0033] In the formula, N is the number of times of fertilizer mixing for the current sprinkler spraying fertilizer solution, and the rounded-up value of the N value obtained by the above formula is taken as the number of times of fertilizer mixing for the current sprinkler spraying fertilizer solution

[0034] The set value x of the percentage timer of the sprinkler during the process of spraying fertilizer solution f, it is calculated according to the following formula and rounded down to obtain:

[0035]

[0036] In the formula, η p is the utilization coefficient of the water sprayed in the field, which is related to the wind speed. When the wind speed is lower than 3.4 m / s, η p takes a value of 0.8 - 0.9. When the wind speed is between 3.4 - 5.4 m / s, η p takes a value of 0.7 - 0.8; the depth h f of the fertilizer solution during the process of spraying the fertilizer solution shall not be less than 5 mm;

[0037] The operation duration t f of the sprinkler during the process of spraying the fertilizer solution is calculated according to the following formula:

[0038]

[0039] The working frequency f of the fertilizer injection pump is calculated according to the following formula:

[0040]

[0041] The irrigation depth h w of the clear water sprayed is calculated according to the following formula:

[0042] h w = h - h f

[0043] The set value x w of the percentage timer of the sprinkler during the process of spraying clear water is calculated according to the following formula and rounded down to obtain:

[0044]

[0045] The operation duration t w of the sprinkler during the process of spraying clear water is calculated according to the following formula:

[0046]

[0047] In the formula, t min is the shortest time for the sprinkler to run one week.

[0048] In some embodiments, during the process of controlling the center pivot type sprinkler integrated water and fertilizer equipment to execute the current irrigation and fertilization strategy, the concentration of the fertilizer solution is monitored and feedback adjusted, specifically including:

[0049] Calculate the concentration of the original fertilizer solution configured in the fertilizer solution container of the fertilizer storage unit during the process of the center pivot type sprinkler spraying the fertilizer solution according to the following formula:

[0050]

[0051] In the formula, C is the concentration of the original fertilizer solution; M is the fertilizer application rate per mu; A 0 is the coverage area of the sprinkler irrigation machine; V is the actual fertilizer injection amount of the sprinkler irrigation fertilizer solution this time;

[0052] According to the inlet flow rate Q of the sprinkler irrigation machine 0 , the actual flow rate q of the calibrated fertilizer injection pump d and the configured concentration of the original fertilizer solution, calculate the concentration of the sprinkler irrigation fertilizer solution. The calculation formula is as follows:

[0053]

[0054] In the formula, C s is the concentration of the sprinkler irrigation fertilizer solution;

[0055] Select the corresponding fertilizer solution concentration inversion prediction model according to the fertilizer type. This fertilizer solution concentration inversion prediction model is used to reflect the function relationship between the concentration of the sprinkler irrigation fertilizer solution and the E c value or pH value of the sprinkler irrigation fertilizer solution;

[0056] Substitute the concentration C of the sprayed fertilizer solution s into the fertilizer solution concentration inversion prediction model to obtain the E c predicted value and pH predicted value of the sprinkler irrigation fertilizer solution for this irrigation and fertilization, and compare them with the E c value or pH value of the sprayed fertilizer solution after the start of fertilizer injection. If the comparison result exceeds the set threshold, send a shutdown signal and generate a shutdown report. If the comparison result does not exceed the set threshold, continue to execute the irrigation and fertilization strategy for this time until the running time of the sprinkler irrigation machine reaches the total running time of the integrated water and fertilizer operation of the sprinkler irrigation machine, and this irrigation and fertilization ends.

[0057] In some embodiments, when the fertilizer is a strong electrolyte, the fertilizer solution concentration inversion prediction model is:

[0058] E c = aC s + b

[0059] In the formula, E c is the conductivity; a is the first coefficient, which needs to be calibrated through experiments; b is the E of the irrigation clear water before the start of fertilizer injection c value;

[0060] When the fertilizer is an acidic or alkaline fertilizer, the fertilizer solution concentration inversion prediction model is:

[0061] pH = yC s + z

[0062] In the formula, pH is the acidity and alkalinity; y is the second coefficient, which needs to be calibrated through experiments; z is the pH value of the irrigation clear water before the start of fertilizer injection.

[0063] A central pivot type sprinkler machine integrated water and fertilizer device provided by the second aspect of the present invention includes a fertilization device, a central support, a control system and a plurality of pipelines. The fertilization device includes a fertilizer injection pump and a fertilizer storage unit. The central support includes a central support bracket and a main sprinkler pipeline located in the middle thereof;

[0064] The fertilizer injection pump is connected between the main sprinkler pipeline and the fertilizer storage unit through a pipeline, and injects the fertilizer solution in the fertilizer storage unit into the main sprinkler pipeline according to the control instruction of the control system. Among them, the inlet of the fertilizer injection pump is connected to the fertilizer outlet at the bottom of the fertilizer storage container in the fertilizer storage unit through a fertilizer suction pipeline; the outlet of the fertilizer injection pump is connected to the main sprinkler pipeline through a fertilizer injection pipeline; the main sprinkler pipeline is connected to the inlet of the fertilizer storage container through a water replenishing pipeline, and an anti-flushing pipeline is connected between the water replenishing pipeline and the fertilizer suction pipeline, and the fertilizer injection pump is flushed through the anti-flushing pipeline after each spraying of the fertilizer solution ends;

[0065] The fertilizer storage unit is used to prepare a fertilizer solution with a corresponding concentration according to the control instruction of the control system. The fertilizer storage unit includes the connected fertilizer storage container and a stirrer;

[0066] The control system includes a sensing unit, a valve group, and a first control cabinet and a second control cabinet which are arranged on one side of the central support bracket and communicate with each other. Among them,

[0067] The sensing unit includes a liquid level sensor installed on the top of the fertilizer storage container, a pressure switch installed on the fertilizer injection pipeline, and a flow meter, an E c sensor and a pH sensor installed in sequence on the main sprinkler pipeline;

[0068] The valve group includes a water replenishing electric valve, a fertilizer suction electric valve, a fertilizer injection electric valve, and an anti-flushing electric valve, which are respectively installed on the corresponding pipelines;

[0069] The second control cabinet is used to calculate the working parameters of the sprinkler machine and the fertilizer injection pump according to the parameters set by the user and the inlet flow rate of the sprinkler machine collected by the flow meter before the start of fertilizer injection, form the irrigation and fertilization strategy for this time and display it to the user; control the operation of the fertilization device, the sensing unit and the valve group according to the irrigation and fertilization strategy for this time, and monitor and feedback regulate the concentration of the sprayed fertilizer solution during the control process;

[0070] The first control cabinet is used to control the start and stop, walking speed and running time of the sprinkler machine according to the irrigation and fertilization strategy for this time, and the opening and closing of the main water supply pump of the sprinkler machine.

[0071] In some embodiments, a fertilizer suction filter and a fertilizer suction manual valve are further installed on the fertilizer suction pipeline, a water replenishment filter and a water replenishment manual valve are further installed on the water replenishment pipeline, a check valve and a fertilizer injection manual valve are further installed on the fertilizer injection pipeline, and a manual drain valve is installed at the bottom of the fertilizer storage container.

[0072] In some embodiments, the second control cabinet includes a frequency converter and a second controller disposed inside the second cabinet, and a human-machine interaction unit disposed outside the second cabinet. An irrigation and fertilization strategy generation module and an irrigation fertilizer solution concentration regulation module are integrated in the second controller. The second controller controls the operating frequency of the fertilizer injection pump through the frequency converter, and the second controller is connected to the sensing unit, the valve group and the agitator; the first control cabinet includes a percentage timer and a first controller respectively disposed outside and inside the first cabinet. Communication is carried out between the first controller and the second controller, and the first controller controls the traveling speed of the sprinkler through the percentage timer. Features and beneficial effects of the present invention:

[0073] 1) The present invention discloses a method for integrated control of water and fertilizer for a center pivot sprinkler. According to the relevant parameters of the center pivot sprinkler and the fertilizer injection device, by specifying the irrigation quota and fertilizer application amount for a certain time, working parameters such as the number of rotations of the sprinkler, the set value of the percentage counter, and the operating frequency of the piston-type fertilizer injection pump can be calculated, forming an irrigation and fertilization strategy, and accurately regulating the traveling speed of the sprinkler and the frequency of the fertilizer injection pump through the control system to achieve fully automatic precise operation of integrated water and fertilizer; in addition, this method adopts an irrigation and fertilization strategy of first performing sprinkler irrigation of the fertilizer solution and then synchronously performing the backwashing process and sprinkler irrigation of clean water. The advantages of this method compared with the simultaneous application of water and fertilizer, first performing water and fertilizer irrigation and then performing clean water irrigation are as follows: after water and fertilizer irrigation, immediately wash the fertilizer solution remaining on the leaves by irrigating clean water, improving the fertilizer utilization rate while preventing damage to the crop leaves caused by fertilizer residues.

[0074] 2) The present invention discloses a water and fertilizer integration device for a center pivot sprinkler. The device uses a plunger type fertilizer injection pump as the core fertilization equipment. Compared with other fertilization equipment, the present invention can achieve precise adjustment of the fertilizer injection amount without using metering equipment such as flow meters, avoiding problems such as large fluctuations in the water pressure of large sprinklers resulting in large changes in the fertilization concentration, and realizing precise application of water and fertilizer synergistically while reducing costs. A water and fertilizer integration device for a center pivot sprinkler disclosed by the present invention is equipped with an anti-flushing function. After the irrigation and fertilization process, the residual fertilizer liquid inside the fertilization device and pipeline can be cleaned through the anti-flushing pipeline to prevent the damage to the water and fertilizer integration system caused by the residual fertilizer liquid. A water and fertilizer integration device for a center pivot sprinkler disclosed by the present invention is equipped with a manual valve. When the system is powered off or the electric valve cannot work properly, the system can be controlled through the manual valve. A water and fertilizer integration device for a center pivot sprinkler disclosed by the present invention is equipped with a safety protection device. A pressure switch is installed in the fertilizer injection pipeline. When a fault occurs in the fertilizer injection pipeline or the fertilizer injection device, and the pressure in the fertilizer injection pipeline is greater than the working pressure of the fertilizer injection pump, the control system will automatically stop the sprinkler fertilizer liquid process and feedback a prompt to the human-computer interaction unit to prevent damage to the system caused by excessive pressure and improve the operating safety of the system.

[0075] 3) During the water and fertilizer integration process of the present invention, the water and fertilizer concentration of the main pipeline of the center pivot sprinkler can be monitored in real time and feedback regulated. First, before the fertilizer injection process, the incoming flow rate of the main pipeline of the center pivot sprinkler and the E c and pH value of the irrigation clear water are measured respectively through a flow meter, an E c sensor and a pH sensor. Then, based on the water and fertilizer integration strategy given by the irrigation and fertilization control system, the spraying fertilizer liquid concentration of the center pivot sprinkler is calculated by the above formula, and the function relationship between the spraying fertilizer liquid concentration and the conductivity and acidity / alkalinity corresponding to the preset fertilizer type is selected, and the E c or pH value of the spraying fertilizer liquid for this water and fertilizer integration strategy is calculated. Finally, the calculated E c or pH value is compared with the E c or pH value actually measured during the fertilizer injection process. If the difference between the two is greater than the set difference upper limit, the system will automatically stop the sprinkler fertilizer liquid process and feedback a prompt to the human-computer interaction unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 is the overall flowchart of a water and fertilizer integration control method for a center pivot sprinkler provided by the first aspect embodiment of the present invention;

[0077] Figure 2 is Figure 1 the flowchart for generating the irrigation and fertilization strategy for the shown control method;

[0078] Figure 3 For the Figure 1 method flowchart for monitoring and feedback regulation of fertilizer solution concentration during irrigation and fertilization based on the described control method;

[0079] Figure 4 Schematic diagram of the overall structure of a center pivot sprinkler machine for integrated water and fertilizer management provided in the second aspect embodiment of the present invention;

[0080] Figure 5 For Figure 4 schematic diagram of the structure of the piston type fertilizer injection pump and its pipeline in the shown device;

[0081] Figure 6 For Figure 4 schematic diagram of the structure of the fertilizer storage unit and its supporting pipeline in the shown device;

[0082] Figure 7 For Figure 4 schematic diagram of the structure of the center pivot and control system in the shown device;

[0083] Figure 8 For Figure 4 internal structure block diagram of the control system in the shown device. Detailed implementation manners

[0084] In order to make the objectives, technical solutions and advantages of this application clearer, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0085] On the contrary, this application covers any substitutions, modifications, equivalent methods and solutions made within the essence and scope of this application as defined by the claims. Further, in order to enable the public to have a better understanding of this application, in the following detailed description of this application, some specific details are described in detail. Those skilled in the art can also fully understand this application without the description of these detail parts.

[0086] The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions under which this application can be implemented. Therefore, they do not have a technical essence meaning. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that this application can produce and the objectives that can be achieved, should still fall within the scope covered by the technical content disclosed in this application. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of clear narration and are not used to limit the scope under which this application can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope under which this application can be implemented.

[0087] See Figure 1 For a center pivot type sprinkler integrated water and fertilizer control method provided in an embodiment of the first aspect of the present invention, which is used to control the integrated water and fertilizer equipment of a center pivot type sprinkler. The integrated water and fertilizer equipment of the center pivot type sprinkler includes a center pivot type sprinkler (hereinafter simply referred to as "sprinkler"), a fertilizer injection pump, and a fertilizer storage unit that are connected to each other. The control method of this embodiment includes the following steps:

[0088] Obtain the inherent parameters of the sprinkler, and set the fertilizer application rate per mu, irrigation quota, and fertilizer type for this irrigation and fertilization;

[0089] Collect the inlet flow rate of the sprinkler before the start of this fertilizer injection irrigation, and the E c value or pH value of the clear water in the main pipeline of the sprinkler;

[0090] According to the inherent parameters of the sprinkler, the fertilizer application rate per mu M, irrigation quota h, and fertilizer type set for this irrigation and fertilization, and the inlet flow rate of the sprinkler before the start of fertilizer injection, calculate the working parameters of the sprinkler and the fertilizer injection pump to form the irrigation and fertilization strategy for this time, specifically in the strategy of first performing sprinkler irrigation with fertilizer solution, and then synchronously performing the backwashing process and sprinkler irrigation with clear water;

[0091] Control the integrated water and fertilizer equipment of the center pivot type sprinkler to execute the irrigation and fertilization strategy for this time;

[0092] During the process of controlling the integrated water and fertilizer equipment of the center pivot type sprinkler to execute the irrigation and fertilization strategy for this time, monitor and feedback regulate the concentration of the sprinkler fertilizer solution: select the corresponding fertilizer solution concentration inversion prediction model according to the fertilizer type, and obtain the E c predicted value or pH predicted value of the sprinkler fertilizer solution for this irrigation and fertilization according to the sprayed fertilizer solution concentration and the selected fertilizer solution concentration inversion prediction model, and compare this predicted value with the E c value or pH value of the sprayed fertilizer solution collected after the start of fertilizer injection, and form a regulation instruction for the integrated water and fertilizer equipment of the center pivot type sprinkler based on the comparison result.

[0093] In some embodiments, the inherent parameters of the sprinkler include the overall length L of the sprinkler s (unit: m), the range R (unit: m) of the sprinkler head installed at the end of the sprinkler, the field sprinkler water utilization coefficient η p , the field surface slip coefficient η, the rated speed n (unit: r / min) of the drive motor, the effective radius r (unit: m) of the supporting tires, the transmission ratio i of the drive motor reducer 1 , the transmission ratio i of the wheel reducer 2 , the distance L between the center support center point of the sprinkler and the end tower truck f (unit: m), the rated frequency f of the fertilizer injection pumpd (Unit: Hz) and the actual flow rate q of the fertilizer injection pump after calibration d (Unit: L / h), q d can be obtained from the decrease value of the liquid level sensor in the fertilizer storage unit within a certain period of time.

[0094] In some embodiments, a flow meter, an E c sensor and a pH sensor are sequentially arranged on the main pipeline of the sprinkler irrigation machine; among them, the flow meter is located at the water inlet of the main pipeline of the sprinkler irrigation machine and is used to collect the clear water flow rate injected into the main pipeline of the sprinkler irrigation machine before the start of fertilizer injection, that is, the incoming machine flow rate Q 0 (Unit: m 3 / h); the E c sensor and the pH sensor are installed downstream of the confluence of the fertilizer injection pipeline and the main pipeline of the sprinkler irrigation machine and are used to collect the E c value and the pH value of the irrigation clear water before the start of fertilizer injection, as well as the E c value and the pH value of the sprayed fertilizer solution during the fertilizer injection process.

[0095] In some embodiments, referring to Figure 2 , it is the specific flowchart for generating the irrigation and fertilization strategy for this time. In the embodiments of the present invention, a strategy of first spraying fertilizer solution and then synchronously performing the backwashing process and spraying clear water is adopted, and there is no time interval between the water and fertilizer irrigation and the clear water irrigation. Considering that in the water and fertilizer integration operation of the sprinkler irrigation machine, fertilization and irrigation need to be considered jointly, after each fertilization, a certain depth of clear water must be sprayed to meet the irrigation quota required by the crops and clean the leaf surface. Compared with the synchronous application of water and fertilizer, the advantage of this embodiment of first spraying fertilizer solution and then synchronously performing the backwashing process and spraying clear water is that: after the spraying of fertilizer solution is completed, the residual fertilizer solution inside the fertilizer injection pump and its connecting pipelines is immediately cleaned to prevent the damage of the fertilizer solution residue to the water and fertilizer integration equipment of the center pivot sprinkler irrigation machine. At the same time, the residual fertilizer solution on the leaves is rinsed by irrigating clear water, improving the fertilizer utilization rate while preventing the damage of fertilizer residue to the crop leaves. The specific steps for generating the irrigation and fertilization strategy for this time in this embodiment include:

[0096] Preset program: Determine the coverage area A 0 (Unit: mu) of the sprinkler irrigation machine and the shortest time t min (Unit: h) for the sprinkler irrigation machine to run one week according to the inherent parameters of the sprinkler irrigation machine;

[0097] Spray fertilizer solution: According to the maximum solubility S (Unit: kg / L) of the given fertilizer at normal temperature, as well as the set fertilizer application rate M (Unit: kg) per mu and the coverage area A 0 of the sprinkler irrigation machine, determine the total fertilizer injection volume V f (Unit: L) of the spray fertilizer solution for this time, and according to the total fertilizer injection volume V fand the volume V of the fertilizer storage container in the fertilizer storage unit t (unit: L) to determine the actual fertilizer injection volume V (unit: L) of the irrigation fertilizer solution this time; according to the inlet flow rate Q of the sprinkler 0 (unit: m 3 / h), the fertilizer solution depth h during the irrigation fertilizer solution process f (unit: mm), the coverage area A of the sprinkler 0 and the shortest time t for the sprinkler to operate for one week min , to determine the set value x of the percentage timer of the sprinkler during the irrigation fertilizer solution process f (unit: %); according to the shortest time t for the sprinkler to operate for one week min and the set value x of the percentage timer of the sprinkler during the irrigation fertilizer solution process f , calculate the operation duration t of the sprinkler during the irrigation fertilizer solution process f (unit: h); according to the actual fertilizer injection volume V of the irrigation fertilizer solution this time, the rated frequency f of the fertilizer injection pump d , the actual flow rate q of the fertilizer injection pump after verification d and the operation duration t of the sprinkler during the irrigation fertilizer solution process f to determine the working frequency f of the fertilizer injection pump (unit: Hz);

[0098] Backwashing process: Set the operation duration t of the fertilizer injection pump during the backwashing process c (unit: m in) and the working frequency f c (unit: Hz); among them, the operation duration t of the fertilizer injection pump during the backwashing process c is set to a fixed duration, generally taken as 10 min; the working frequency f of the fertilizer injection pump during the backwashing process c is taken as the rated frequency f of the fertilizer injection pump d ;

[0099] Irrigation with clear water: According to the irrigation quota h (unit: mm) this time and the fertilizer solution depth h during the irrigation fertilizer solution process f calculate the irrigation depth h of the clear water for irrigation w (unit: mm); according to the inlet flow rate Q of the sprinkler 0 , the coverage area A of the sprinkler 0 , the shortest time t for the sprinkler to operate for one week min and the irrigation depth h of the clear water for irrigation w , to determine the set value x of the percentage timer of the sprinkler during the irrigation with clear water process w (unit: %); according to the shortest time t for the sprinkler to operate for one week min and the set value x of the percentage timer of the sprinkler during the irrigation with clear water process w , calculate the operation duration t of the sprinkler during the irrigation with clear water process w (unit: h), tw >t c ;

[0100] Finally, according to the calculated operation duration t of the sprinkler fertilizer liquid process of the sprinkler irrigation machine f and the working frequency f of the fertilizer injection pump, the operation duration t of the fertilizer injection pump during the backwashing process c and the working frequency f of the fertilizer injection pump c , the operation duration t of the sprinkler irrigation machine during the clear water sprinkler irrigation process w , and the total duration t = t f +t w (unit: h) to form the current irrigation and fertilization strategy. It should be noted that since the operation duration t of the sprinkler irrigation machine during the clear water sprinkler irrigation process w is generally much greater than the operation duration t of the fertilizer injection pump during the backwashing process c , and the clear water sprinkler irrigation process is carried out synchronously during the backwashing process, therefore, the operation duration t of the fertilizer injection pump during the flushing process is not considered when calculating the total duration t of the integrated water and fertilizer operation of the sprinkler irrigation machine c , but only determined by the sum of the operation duration t of the sprinkler irrigation machine during the sprinkler fertilizer liquid process f and the operation duration t of the sprinkler irrigation machine during the clear water sprinkler irrigation process w .

[0101] Furthermore, the coverage area A of the sprinkler irrigation machine 0 is the total irrigation area controlled by it rotating one circle around the central support shaft, and is also the fertilization area. The calculation formula is as follows:

[0102]

[0103] The shortest time t for the sprinkler irrigation machine to run one week min depends on the maximum walking speed v of the end tower truck e (unit: m / min) and the distance L between the center support point of the sprinkler irrigation machine and the end tower truck f , and the calculation formula is as follows:

[0104]

[0105] In the formula, η is the field surface slip coefficient, which depends on tire tread, tire pressure and soil compactness, etc., and generally takes 0.92 - 0.97;

[0106] The total fertilizer injection volume V of the sprinkler irrigation machine for this sprinkler fertilizer liquid f can be expressed as:

[0107]

[0108] Wherein, S is the maximum solubility of the fertilizer at normal temperature (generally taken as 20 °C), kg / L; k is a coefficient, and to ensure the full dissolution of the fertilizer, it is taken as 1.3 - 1.6;

[0109] The actual fertilizer injection volume V of the sprinkler irrigation fertilizer solution this time can be expressed as:

[0110] V = NV t

[0111]

[0112] Wherein, N is the number of fertilizer mixing times of the sprinkler irrigation fertilizer solution this time (unit: times), which depends on the volume V of the fertilizer storage container in the fertilizer storage unit t , since the number of fertilizer mixing times is an integer, for the sake of conservatism, the obtained value of N is rounded up as the number of fertilizer mixing times of the sprinkler irrigation fertilizer solution this time;

[0113] The set value x of the percentage timer of the sprinkler during the sprinkler irrigation fertilizer solution process f determines the traveling speed of the sprinkler during the sprinkler irrigation fertilizer solution process, x f can be expressed as:

[0114]

[0115] Wherein, since the percentage set value of the sprinkler is usually an integer, for the sake of conservatism, the obtained value of x f is rounded down as the set value of the percentage timer of the sprinkler during the sprinkler irrigation fertilizer solution process; η p is the field sprinkling water utilization coefficient, which is related to the wind speed. When the wind speed is lower than 3.4 m / s, η p takes 0.8 - 0.9. When the wind speed is between 3.4 - 5.4 m / s, η p takes 0.7 - 0.8; According to relevant research, when the single irrigation depth of the sprinkler is less than 5 mm, it is considered ineffective irrigation. To prevent excessive volatilization after fertilizer application, a 10 mm irrigation amount can be set as the fertilizer solution depth during the sprinkler irrigation fertilizer solution process, that is, h f = 10 mm;

[0116] The operating duration t of the sprinkler during the sprinkler irrigation fertilizer solution process f can be expressed as:

[0117]

[0118] The working frequency f of the fertilizer injection pump can be calculated by the following formula:

[0119]

[0120] Wherein, the rated frequency f of the fertilizer injection pump is taken d = 50 Hz;

[0121] The irrigation depth h of the sprinkler irrigation with clear water w can be expressed as:

[0122] h w = h - h f

[0123] In the formula, h is the irrigation quota of the sprinkler irrigation machine for the integrated operation of water and fertilizer, in mm;

[0124] The set value x of the percentage timer of the sprinkler irrigation machine during the sprinkler irrigation with clear water w determines the walking speed of the sprinkler irrigation machine during the sprinkler irrigation with clear water, x w can be expressed as:

[0125]

[0126] In the formula, the obtained x w value is rounded down to be used as the set value of the percentage timer of the sprinkler irrigation machine during the sprinkler irrigation with clear water;

[0127] The running duration t of the sprinkler irrigation machine during the sprinkler irrigation with clear water w can be expressed as:

[0128]

[0129] In some embodiments, referring to Figure 1 , the specific steps for the control center pivot sprinkler irrigation machine for the integrated operation of water and fertilizer to execute this irrigation and fertilization strategy are as follows:

[0130] First, add an appropriate amount of fertilizer into the fertilizer storage container of the fertilizer storage unit according to this irrigation and fertilization strategy, and at the same time inject clear water. When the set water level is reached, fully stir the water and fertilizer mixture in the fertilizer storage container of the fertilizer storage unit; after the fertilizer solution is fully dissolved, the control system accurately regulates the sprinkler irrigation machine and the fertilizer injection pump based on this irrigation and fertilization strategy, and the sprinkler irrigation machine starts to spray the fertilizer solution; when the injection of the fertilizer solution in the fertilizer storage unit is completed, judge whether the fertilization process is over according to this irrigation and fertilization strategy. If it is not over, repeat the above fertilizer injection process. If it is over, start the backwashing process to clean the residual fertilizer solution in the fertilizer injection pump and the fertilization pipeline; at the same time, control the sprinkler irrigation machine based on this irrigation and fertilization strategy, and the sprinkler irrigation machine continues to walk and spray clear water. After meeting this irrigation quota, this irrigation and fertilization process ends. In addition, by collecting data such as the inlet flow rate of the sprinkler irrigation machine, E c value, pH value, etc. in real time, based on the preset fertilizer solution type selection corresponding fertilizer solution concentration inversion prediction model, inversely predict the water and fertilizer application amount information in the irrigation and fertilization process in real time, that is, obtain the E c predicted value or pH predicted value of the fertilizer solution sprayed in this irrigation and fertilization, and feedback on the irrigation and fertilization process.

[0131] In some embodiments, referring to Figure 3, during the process of the center pivot sprinkler irrigation machine with integrated water and fertilizer equipment executing this irrigation and fertilization strategy, the specific steps for monitoring and feedback adjustment of the fertilizer solution concentration include:

[0132] The concentration of the original fertilizer solution configured in the fertilizer storage container during the spraying of the fertilizer solution by the above center pivot sprinkler irrigation machine can be calculated by the following formula:

[0133]

[0134] In the formula, C is the concentration of the original fertilizer solution, kg / L; M is the amount of fertilizer applied per mu, kg; A 0 is the coverage area of the sprinkler irrigation machine, mu; V is the actual fertilizer injection amount of the fertilizer solution for this sprinkler irrigation, L;

[0135] According to the inlet flow rate Q of the sprinkler irrigation machine 0 , the actual flow rate q of the calibrated fertilizer injection pump d and the concentration of the configured original fertilizer solution, calculate the concentration of the sprayed fertilizer solution. The calculation formula is as follows:

[0136]

[0137] In the formula, C s is the concentration of the sprayed fertilizer solution, kg / L, which refers to the concentration of the fertilizer solution sprayed by the sprinkler nozzle of the sprinkler irrigation machine, that is, the concentration of the fertilizer solution in the main pipeline of the sprinkler irrigation machine;

[0138] Select the corresponding fertilizer solution concentration inversion prediction model according to the fertilizer type. This fertilizer solution concentration inversion prediction model is used to reflect the functional relationship between the concentration of the sprayed fertilizer solution and the E c value or pH value of the sprayed fertilizer solution. Among them,

[0139] For strong electrolytes such as potassium chloride, ammonium dihydrogen phosphate, potassium nitrate, and potassium sulfate, the conductivity of their solutions is very strong, and there is the following functional relationship between the concentration of the sprayed fertilizer solution and the conductivity:

[0140] E c = aC s + b

[0141] In the formula, E c is the conductivity, μS / cm; a is the first coefficient, which is calibrated through experiments (taking potassium chloride as an example, using a conductivity tester to measure the conductivity values of potassium chloride solutions with concentrations of 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6% respectively, and fitting the above formula through the experimental results to calibrate the coefficient a); b is the measured conductivity of clear water, that is, the E c value of the irrigation clear water collected by the E c sensor before the start of fertilizer injection, μS / cm;

[0142] For acidic or alkaline solutions such as urea and compound fertilizer solutions, there is a functional relationship between the spraying fertilizer solution concentration and the pH value:

[0143] pH = yC s + z

[0144] Where: pH is the pH value; y is a coefficient calibrated through experiments (the calibration process can refer to the calibration process of the above coefficient a); z is the pH value of the measured clear water, that is, the pH value of the irrigation clear water collected by the pH sensor before the start of fertilizer injection.

[0145] Based on the above functional relationship, the relationship between the spraying fertilizer solution concentration of different types of fertilizers in the main pipeline of the sprinkler and the conductivity or pH value can be constructed;

[0146] Substitute the spraying fertilizer solution concentration into the fertilizer solution concentration inversion prediction model to obtain the E c predicted value and pH predicted value of the sprinkler fertilizer solution for this irrigation and fertilization, and compare them with the E c value or pH value of the sprinkler fertilizer solution after the start of fertilizer injection. If the comparison result exceeds the set threshold, a shutdown signal is sent and a shutdown report is generated. If the comparison result does not exceed the set threshold, the current irrigation and fertilization strategy is continued until the operating duration of the sprinkler reaches the total duration t of the integrated water and fertilizer operation of the sprinkler, and this irrigation and fertilization ends.

[0147] See Figures 4 to 8 , an integrated water and fertilizer device for a center pivot sprinkler provided in the second aspect embodiment of the present invention mainly includes a fertilization device, a center support 3, a control system, and several pipelines. The fertilization device includes a fertilizer injection pump 1 and a fertilizer storage unit 2. The center support 3 includes a center support bracket 51 and a main pipeline 52 of the sprinkler located in the middle thereof.

[0148] As Figures 4 to 6 shown, the fertilizer injection pump 1 adopts a plunger type fertilizer injection pump, which is connected to the main pipeline 52 of the sprinkler and the fertilizer storage unit 2 through pipelines, and injects the fertilizer solution in the fertilizer storage unit 2 into the main pipeline 52 of the sprinkler according to the control instructions of the control system. Specifically, the inlet d1 of the fertilizer injection pump 1 is connected to the fertilizer outlet at the bottom of the fertilizer storage container 31 in the fertilizer storage unit 2 through a fertilizer suction pipeline 11, and a fertilizer suction filter 22 is installed on the fertilizer suction pipeline 11; the outlet d2 of the fertilizer injection pump 1 is connected to the main pipeline 52 of the sprinkler through a fertilizer injection pipeline 12; the main pipeline 52 of the sprinkler is connected to the inlet at the top of the fertilizer storage container 31 through a water replenishment pipeline 14, and a water replenishment filter 26 is installed on the water replenishment pipeline 14. An anti-flushing pipeline 13 is connected between the water replenishment pipeline 14 and the fertilizer suction pipeline 11. After each sprinkler fertilizer solution injection ends, the fertilizer injection pump 1 is flushed through the anti-flushing pipeline 13 to prevent damage to the fertilizer injection pump 1 caused by fertilizer solution residue.

[0149] AsFigure 6 As shown, the fertilizer storage unit 2 of this embodiment is used to prepare fertilizer solution with corresponding concentration according to the control instructions of the control system, and mainly includes a fertilizer storage container 31, a stirrer, a top cover 34 of the fertilizer storage container, and a fixed chassis 35. The fertilizer storage container 31 is specifically a fertilizer barrel, placed on the fixed chassis 35. The stirrer is composed of a stirring motor 32 and a stirring impeller. The stirring motor 32 is installed on the top of the fertilizer storage container 31, and the stirring impeller is located inside the fertilizer storage container 31 and driven by the stirring motor 32. The stirring motor 32 drives the stirring impeller to fully stir the water-fertilizer mixture in the fertilizer storage container 31 according to the control instructions of the control system. The top cover 34 of the fertilizer storage container is connected to the fertilizer storage container 31 by threads.

[0150] As Figures 4 to 8 shown, the control system includes a sensing unit, a valve group, and a first control cabinet 53 and a second control cabinet 54 that are suspended on one side of the central support bracket 51 and connected. Among them:

[0151] The sensing unit includes a liquid level sensor 33 installed on the top of the fertilizer storage container 31, a pressure switch 29 installed on the fertilizer injection pipeline 12, and a flow meter 61, an E c sensor 62, and a pH sensor 63 that are sequentially installed on the main pipeline 52 of the sprinkler irrigation machine; the liquid level information inside the fertilizer storage container 31 is collected in real time through the liquid level sensor 33; the internal pressure of the fertilizer injection pipeline 12 is collected in real time through the pressure switch 29; the flow meter 61 is located at the water inlet of the main pipeline 52 of the sprinkler irrigation machine and is used to collect the incoming machine flow; the E c sensor 62 and the pH sensor 63 installed downstream of the confluence of the fertilizer injection pipeline 12 and the main pipeline 52 of the sprinkler irrigation machine are used to collect the E c value and pH value of the irrigation clear water before fertilizer injection and the E c value and pH value of the sprayed fertilizer solution during the fertilizer injection process.

[0152] The valve group includes a manual water replenishing valve 28 and an electric water replenishing valve 27 installed on the water replenishing pipeline 14, a manual drain valve 36 installed at the bottom of the fertilizer storage container 31, a manual fertilizer suction valve 37 and an electric fertilizer suction valve 23 installed on the fertilizer suction pipeline 11, and the manual fertilizer suction valve 37 is arranged close to the manual drain valve 36, a fertilizer injection electric valve 24, a check valve 67, and a manual fertilizer injection valve 68 installed on the fertilizer injection pipeline 12, and the check valve 67 and the manual fertilizer injection valve 68 are arranged close to the main pipeline 52 of the sprinkler irrigation machine, and an anti-flushing electric valve 25 installed on the anti-flushing pipeline 13;

[0153] See Figure 8, the first control cabinet 53 includes a percentage timer 66 and a first controller respectively disposed outside and inside the first cabinet; the second control cabinet 54 includes a frequency converter 64 and a second controller disposed inside the second cabinet, and a human-machine interaction unit 65 disposed outside the second cabinet. The second controller integrates an irrigation and fertilization strategy generation module and an irrigation fertilizer solution concentration regulation module (the irrigation and fertilization strategy generation module and the irrigation fertilizer solution concentration regulation module are not shown in Figure 8 ), and the first controller communicates with the second controller wirelessly or wiredly;

[0154] The human-machine interaction unit 65 includes a liquid crystal screen for the user to set the fertilizer application rate per mu, the irrigation quota, and the fertilizer type for this irrigation and fertilization, and to display the real-time working status of the water and fertilizer integration device of the center pivot sprinkler to the user;

[0155] The irrigation and fertilization strategy generation module can calculate the working parameters of the sprinkler and the fertilizer injection pump according to the parameters set by the user and the inlet flow rate of the sprinkler collected by the flow meter 61 before the start of fertilizer injection, form the irrigation and fertilization strategy for this time, and transmit it to the human-machine interaction unit 65 for display;

[0156] The irrigation fertilizer solution concentration regulation module is used to monitor and adjust the concentration of the irrigation fertilizer solution during the irrigation fertilizer solution process: select the corresponding fertilizer solution concentration inversion prediction model according to the fertilizer type, and use the E of the irrigation water before the start of fertilizer injection c value and pH value to inversely calculate the water and fertilizer application amount information during the irrigation and fertilization process in real time, compare the water and fertilizer application amount information with the E of the sprayed fertilizer solution after the start of fertilizer injection c value and pH value, and form a regulation instruction based on the comparison result. Specifically, if the comparison result exceeds the set threshold, the second controller communicates with the first controller, sends a shutdown signal to stop this irrigation and fertilization, and sends a report to the human-machine interaction unit. If the comparison result does not exceed the set threshold, continue to execute the irrigation and fertilization strategy for this time until the end of this irrigation and fertilization;

[0157] The first controller is directly connected to the percentage timer 66 and is connected to the main water supply pump of the sprinkler locally or remotely, and is used to control the start and stop, operation time of the sprinkler and the opening and closing of the main water supply pump of the sprinkler according to the irrigation and fertilization strategy generated by the irrigation and fertilization strategy generation module, and control the walking speed of the sprinkler through the percentage timer 66;

[0158] The frequency converter 64 is controlled by the second controller and is directly connected to the fertilizer injection pump, and is used to change the speed of the fertilizer injection pump motor to realize the control of the flow rate of the fertilizer injection pump 1;

[0159] The second controller is directly connected to the valve group, the stirring motor in the fertilization equipment, and the liquid crystal display screen in the human-machine interaction unit 65, and is linked to the sensing unit through the RS-485 serial bus standard. The second controller controls the operation of the fertilization equipment, the sensing unit, and the valve group according to the current irrigation and fertilization strategy generated by the irrigation and fertilization strategy generation module and the control instruction generated by the irrigation fertilizer solution concentration regulation module.

[0160] The following describes the specific working process of a center pivot sprinkler integrated water and fertilizer device provided in the second aspect embodiment of the present invention:

[0161] 1) When starting the integrated water and fertilizer device of this embodiment and before injecting fertilizer into the main pipeline 52 of the sprinkler, first input the amount of fertilizer applied per mu M and the irrigation quota h for the current irrigation and fertilization in the human-machine interaction unit 65, and set the fertilizer type. Then, the irrigation and fertilization strategy generation unit in the second control cabinet 54 can calculate working parameters such as the set value of the percentage timer of the sprinkler, the working frequency of the piston type fertilizer injection pump, and the total irrigation and fertilization time, form the current irrigation and fertilization strategy, and output it through the human-machine interaction unit 65.

[0162] 2) Open the top cover 34 of the fertilizer storage container and pour an appropriate amount of fertilizer according to the current irrigation and fertilization strategy. Start the main water supply pump of the center pivot sprinkler through the first controller in the first control cabinet 53 to fill water into the main pipeline 52 of the center pivot sprinkler. Then, the second controller opens the makeup water electric valve 27, and injects clear water into the fertilizer storage container 31 through the makeup water pipeline 14. When the liquid level in the fertilizer storage container 31 reaches the set water level detected by the liquid level sensor 33, the second controller issues a control instruction to close the makeup water electric valve 27, and the first controller issues a control instruction to close the main water supply pump of the sprinkler. At the same time, the second controller turns on the stirring motor 32 to fully dissolve the fertilizer in the fertilizer storage container 31.

[0163] 3) After the fertilizer is fully dissolved, the first controller starts the main water supply pump of the center pivot sprinkler to supply water to the main pipeline 52 of the center pivot sprinkler. When the sprinkler starts to spray water, the center pivot sprinkler starts to move according to the set value of the percentage timer 66. At the same time, the piston type fertilizer injection pump 1 and the fertilizer suction electric valve 23 are turned on through the second controller. The fully dissolved fertilizer solution enters the inlet d1 of the piston type fertilizer injection pump 1 from the fertilizer storage container 31 through the fertilizer suction pipeline 11 and is filtered by the fertilizer suction filter 23, and then the fertilizer solution at the outlet d2 of the piston type fertilizer injection pump 1 is injected into the main pipeline 52 of the sprinkler through the fertilizer injection pipeline 12. The center pivot sprinkler starts to spray the fertilizer solution. During this period, the second controller controls the flow rate of the piston type fertilizer injection pump 1 through the frequency converter 64.

[0164] 4) When the liquid level sensor 33 detects that the liquid level in the fertilizer storage container 31 reaches the lower limit, it automatically sends a signal to the second controller through the liquid level sensor 33. The second controller closes the plunger type fertilizer injection pump 1 and the fertilizer suction electric valve 23. After the plunger type fertilizer injection pump 1 stops running, it is judged whether the running duration of the fertilizer spraying process has reached t f to determine whether the current water and fertilizer process is over. If it is not over, repeat step 2) until the fertilizer spraying process ends. If the fertilizer spraying process ends, execute step 5).

[0165] 5) Start the backwashing and clean water irrigation processes. For the backwashing process, the second controller opens the backwashing electric valve 25 and the plunger type fertilizer injection pump 1. The clean water is filtered by the water replenishment filter 26 from the main pipeline 52 of the center pivot sprinkler, and then enters the inlet d1 of the plunger type fertilizer injection pump 1 through the water replenishment pipeline 14, the backwashing pipeline 13 and the fertilizer suction pipeline 11. Then, the residual fertilizer liquid at the outlet d2 of the plunger type fertilizer injection pump 1 is injected into the main pipeline 52 of the sprinkler by the fertilizer injection pipeline 12. When the set backwashing time is reached, that is, the running duration t of the injection pump during the backwashing process c has passed, the second controller closes the backwashing electric valve 25 and the plunger type fertilizer injection pump 1, and the backwashing process ends. For the clean water irrigation process, the first controller controls the center pivot sprinkler to continue walking at the running speed set according to the irrigation and fertilization strategy. The sprinkler starts to spray clean water until the irrigation process ends. The first controller controls the water supply main pump of the center pivot sprinkler to stop, and makes the center pivot sprinkler stop walking.

[0166] In addition, during the irrigation and fertilization process of the present invention, the fertilizer liquid concentration in the main pipeline 52 of the center pivot sprinkler can be monitored in real time and feedback regulation can be carried out. First, before the fertilizer injection process, the inlet flow rate of the main pipeline 52 of the center pivot sprinkler and the E c of the irrigation clean water and the pH value are measured by the flowmeter 61, the E c sensor 62 and the pH sensor 63 respectively. Then, based on the irrigation and fertilization strategy generated by the irrigation and fertilization strategy generation unit, the spraying fertilizer liquid concentration of the center pivot sprinkler is calculated by the above formula, and the function relationship between the spraying fertilizer liquid concentration corresponding to the preset fertilizer type and the conductivity and acidity is selected, and the E c or pH value of the spraying fertilizer liquid of the current water and fertilizer integration strategy is calculated. Finally, the calculated E c or pH value is compared with the E c or pH value measured during the fertilizer injection process. If the difference between the two is greater than the set difference upper limit, the first controller and the second controller send a closing instruction to the devices they control to stop the irrigation and fertilization process, and feedback and prompt to the human-computer interaction unit 65.

[0167] In the above embodiments, the pressure switch 29 is used to monitor the internal pressure of the fertilizer injection pipeline 12 in real time and transmit it to the second controller. When a fault occurs in the fertilizer injection pipeline 12 or the fertilizer injection pump 1, resulting in the internal pressure being greater than the maximum working pressure of the plunger fertilizer injection pump 1, the second controller sends a shutdown instruction to the plunger fertilizer injection pump 1 to prevent excessive outlet water pressure from damaging the plunger fertilizer injection pump 1 and the fertilizer injection pipeline 12, and at the same time avoid the occurrence of safety accidents.

[0168] In the above embodiments, when a fault occurs in the electric valve of the equipment, the integration of water and fertilizer can be achieved through the manual water injection valve 28 and manual control.

[0169] Embodiment 1

[0170] Taking the integration of water and fertilizer topdressing during the greening-jointing stage of winter wheat as an example in the embodiments of the present application:

[0171] The fertilizer applied is potassium chloride, the application rate M per mu is 4 kg, and the irrigation quota h for this time is 30 mm; the inlet flow rate of the sprinkler irrigation machine measured by the sensor is 80 m 3 / h, and the EC value of the irrigated clear water is 771.48 μS / cm; at normal temperature, 0.342 kg of potassium chloride can be dissolved in each liter of water, then:

[0172] S = 0.342 kg / L

[0173] The overall length of the center pivot sprinkler irrigation machine is 208 m, and the range of the sprinkler at the end of the sprinkler irrigation machine is 25 m. Then the coverage area of the center pivot sprinkler irrigation machine is:

[0174]

[0175] The total fertilizer injection amount for this fertilization of the center pivot sprinkler irrigation machine can be expressed as:

[0176]

[0177] The volume of the fertilizer storage container in the fertilization equipment for this sprinkler irrigation fertilizer solution is 2000 L. Then the number of fertilizer mixing times N is:

[0178]

[0179] Rounding up, the number of fertilizer mixing times N = 3 barrels. Then the actual fertilizer injection amount V is:

[0180] V = NV t = 3 × 2000 = 6000 L

[0181] The distance between the center point of the central support of the sprinkler and the end tower truck is 194 m, the rated speed of the drive motor is 1425 r / min, the effective radius of the supporting tire is 0.6325 m, the transmission ratio of the drive motor reducer is 40:1, the transmission ratio of the wheel reducer is 50:1, and the field surface slip coefficient is taken as 0.95. Then the shortest time for the center pivot sprinkler to operate one week is:

[0182]

[0183] At this time, the measured wind speed is 2.5 m / s, and the utilization coefficient of sprinkler water in the field is taken as 0.85. Then the setting value of the percentage timer of the center pivot sprinkler during the sprinkler irrigation of fertilizer solution is:

[0184]

[0185] Rounding down, the setting value x of the percentage timer of the center pivot sprinkler during the sprinkler irrigation of fertilizer solution f = 31%.

[0186] The operating duration of the sprinkler during the sprinkler irrigation of fertilizer solution is:

[0187]

[0188] Note: After the fertilizer injection pump is checked, the actual flow rate of the fertilizer injection pump is 305.2 L / h. Then the working frequency of the plunger fertilizer injection pump is:

[0189]

[0190] Rounding up, the working frequency f of the plunger fertilizer injection pump during the sprinkler irrigation of fertilizer solution = 41 Hz.

[0191] In the integrated water and fertilizer operation of the sprinkler, the sprinkler irrigation of fertilizer solution and the sprinkler irrigation of clear water should be considered together. After each sprinkler irrigation of fertilizer solution, a certain depth of clear water must be sprayed to meet the irrigation quota required by the crops and clean the leaf surface. Then the depth of the clear water sprayed this time:

[0192] h w = h - h f = 30 - 10 = 20 mm

[0193] The setting value of the percentage timer of the center pivot sprinkler during the sprinkler irrigation of clear water is:

[0194]

[0195] Rounding down, the setting value x of the percentage timer of the center pivot sprinkler during the sprinkler irrigation of fertilizer solution w = 15%.

[0196] The operating duration of the sprinkler during the sprinkler irrigation of clear water is:

[0197]

[0198] Then the total duration of the integrated operation of water and fertilizer by the sprinkler is:

[0199] t = t f + t w = 24.35 + 50.33 = 74.68 h

[0200] During the process of the sprinkler spraying the fertilizer solution, the concentration c of the original fertilizer solution prepared in the fertilizer solution container is:

[0201]

[0202] When the fertilization process starts, the concentration of potassium chloride fertilizer solution in the water-fertilizer mixture in the main pipeline at this time can be calculated as:

[0203]

[0204] According to the functional relationship between the potassium chloride fertilizer solution concentration and the conductivity built in the control system, we get:

[0205] E c = aC s + b = 2.2441×10 6 ×5.02×10 -4 + 771.48 = 1898.02 μS / cm

[0206] The upper limit of the difference between the calculated value and the measured value set this time is 10%. At this time, the conductivity E' of the water-fertilizer mixture in the irrigation main pipeline of the center pivot sprinkler measured by the EC sensor C is 1983.39 μS / cm, and we can get:

[0207]

[0208] Then the integrated water and fertilizer device of the center pivot sprinkler is in a normal working state at this time.

[0209] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0210] Although embodiments of the present disclosure have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present disclosure. The scope of the present disclosure is defined by the claims and their equivalents.

Claims

1. A method for integrated water and fertilizer control of a center pivot sprinkler, characterized in that: Used to control the water-fertilizer integrated equipment of the central pivot sprinkler, the water-fertilizer integrated equipment of the central pivot sprinkler includes a central pivot sprinkler, a fertilizer injection pump and a fertilizer storage unit connected to each other, the control method includes: Obtain the inherent parameters of the sprinkler, and set the fertilizer application amount per mu, irrigation quota and fertilizer type for this irrigation and fertilization; Collect the inflow flow of the sprinkler and the E of the clean water in the sprinkler main line before the start of this fertilizer injection irrigation. c value or pH value; According to the inherent parameters of the sprinkler, the fertilizer application amount per mu, the irrigation quota and the fertilizer type of the current irrigation and fertilization, and the inflow flow rate, the working parameters of the sprinkler and the fertilizer injection pump are calculated to form the current irrigation and fertilization strategy, specifically, the strategy of first spraying fertilizer solution, then synchronously performing the backwashing process and spraying clean water; Control the central pivot sprinkler irrigation machine water and fertilizer integration equipment to execute the current irrigation and fertilization strategy; In the process of controlling the central pivot sprinkler irrigation machine water-fertilizer integrated equipment to execute the current irrigation and fertilization strategy, the sprinkler irrigation fertilizer solution concentration is monitored and feedback-adjusted: the corresponding fertilizer solution concentration inversion prediction model is selected according to the fertilizer type, and the E of the sprinkler irrigation fertilizer solution for this irrigation and fertilization is obtained according to the sprinkler irrigation fertilizer solution concentration and the selected fertilizer solution concentration inversion prediction model. c The predicted value or pH predicted value is compared with the E of the sprinkler fertilizer solution collected after the start of fertilization. c The value or pH value is compared, and the control instructions of the water-fertilizer integrated equipment of the center pivot sprinkler are formed based on the comparison results; The fertigation strategy includes: Preset program: Determine the coverage area A0 of the sprinkler and the shortest operation time t of the sprinkler in one week according to the inherent parameters of the sprinkler min ; Sprinkler irrigation fertilizer solution: Determine the total fertilizer injection volume V of this sprinkler irrigation fertilizer solution based on the maximum solubility S of the given fertilizer at room temperature, the set fertilizer application rate M per mu, and the coverage area A0 of the sprinkler irrigation machine. f , and according to the total amount of fertilizer injected V f and the volume V of the fertilizer storage container in the fertilizer storage unit t Determine the actual amount of fertilizer V injected in this sprinkler irrigation; according to the sprinkler irrigation machine flow Q0, the set fertilizer depth h of the sprinkler irrigation process f , the coverage area A0 of the sprinkler and the shortest operation time t of the sprinkler in one week min , determine the setting value x of the percentage timer of the sprinkler during the fertilizer irrigation process f ; According to the shortest operation time of the sprinkler in a week t min and the setting value x of the percentage timer of the sprinkler during the fertilizer liquid irrigation process f , calculate the operating time t of the sprinkler irrigation process f According to the actual amount of fertilizer V injected by the sprinkler irrigation and the rated frequency f of the fertilizer injection pump d , the actual flow rate of the fertilizer injection pump after verification q d and the operating time t of the sprinkler irrigation machine during the fertilizer liquid irrigation process f Determine the operating frequency f of the fertilizer injection pump; Backwash process: Set the running time of the fertilizer injection pump during the backwash process t c And the operating frequency f c ; Sprinkler irrigation water: according to the current irrigation quota h and the fertilizer liquid depth h during the sprinkler irrigation process f Calculate the irrigation depth h of sprinkler irrigation water w According to the inflow flow Q0 of the sprinkler, the coverage area A0 of the sprinkler, and the shortest operation time t of the sprinkler in one week min and the irrigation depth h of the sprinkler irrigation water w , determine the setting value x of the percentage timer of the sprinkler during the sprinkler irrigation process w ; According to the shortest operation time of the sprinkler in a week t min and the setting value x of the percentage timer of the sprinkler during the sprinkler irrigation process w , calculate the running time t of the sprinkler irrigation process w , and t w >t c ; According to the operation time t of the sprinkler irrigation process f and the operating frequency f of the fertilizer injection pump, the operating time t of the fertilizer injection pump during the backwashing process c And the working frequency f of the fertilizer injection pump c The running time of the sprinkler irrigation machine during the sprinkler irrigation water cleaning process is t w , and the total duration of the sprinkler irrigation and fertilization integration operation t=t f +t w The irrigation and fertilization strategy is formed.

2. The control method according to claim 1, characterized in that: The inherent parameters of the sprinkler include the overall length of the sprinkler, the range of the nozzle installed at the end of the sprinkler, the field spraying water utilization coefficient, the field surface slip coefficient, the rated speed of the drive motor, the effective radius of the matching tire, the drive motor reducer transmission ratio, the wheel reducer transmission ratio, the distance between the center point of the center support of the sprinkler and the end tower vehicle, the rated frequency of the fertilizer injection pump and the actual flow of the fertilizer injection pump after calibration.

3. The control method according to claim 1, characterized in that: The E c The pH value and the pH value are measured by an E installed downstream of the junction of the fertilizer injection pipeline and the sprinkler main pipeline. c The flow rate is collected by the sensor and the pH sensor, and the inflow flow is collected by the flow meter installed at the water inlet of the main pipeline of the sprinkler irrigation machine.

4. The control method according to claim 1, characterized in that: The coverage area A0 of the sprinkler is calculated according to the following formula: Where, L s is the length of the sprinkler; R is the range of the sprinkler installed at the end of the sprinkler; The shortest operation time of the sprinkler in a week is t min , calculated according to the following formula: Where, L f is the distance between the center point of the central support of the sprinkler and the terminal tower vehicle; i1 is the transmission ratio of the drive motor reducer; i2 is the transmission ratio of the wheel reducer; n is the rated speed of the drive motor; r is the effective radius of the matching tire; η is the field surface slip coefficient, which depends on the tire pattern, tire pressure and soil compactness, and is taken as 0.92~0.97; The total amount of fertilizer injected by the sprinkler this time is V f , calculated according to the following formula: In the formula, k is the coefficient set to ensure that the fertilizer is fully dissolved, which is set to 1.3-1.6; The actual injection amount V of the fertilizer solution for this sprinkler irrigation is calculated according to the following formula: V=NV t In the formula, N is the number of times the fertilizer solution is dispensed for this irrigation. The N value obtained by the above formula is rounded up as the number of times the fertilizer solution is dispensed for this irrigation. The setting value x of the percentage timer of the sprinkler during the fertilizer liquid irrigation process f , calculated according to the following formula and rounded down to get: Where η p is the field spraying water utilization coefficient, which is related to the wind speed. When the wind speed is lower than 3.4 m / s, η p Take 0.8~0.9, when the wind speed is 3.4~5.4m / s, η p Take 0.7~0.8; the fertilizer liquid depth h in the process of sprinkler irrigation f The value shall not be less than 5mm; The operating time of the sprinkler during the fertilizer liquid irrigation process is t f , calculated according to the following formula: The operating frequency f of the fertilizer injection pump is calculated according to the following formula: The irrigation depth of the sprinkler irrigation water is h w , calculated according to the following formula: h w =h-h f The setting value x of the percentage timer of the sprinkler during the sprinkler irrigation process w , calculated according to the following formula and rounded down to get: The running time of the sprinkler irrigation machine during the sprinkler irrigation water cleaning process is t w , calculated according to the following formula: Where, t min The minimum time the pivot machine runs in a week.

5. The control method according to claim 1, characterized in that: In the process of controlling the central pivot sprinkler irrigation machine water-fertilizer integrated equipment to execute the current irrigation and fertilization strategy, the fertilizer solution concentration is monitored and feedback-regulated, specifically including: The concentration of the fertilizer stock solution configured in the fertilizer liquid container of the fertilizer storage unit during the process of the central pivot sprinkler irrigation is calculated according to the following formula: In the formula, C is the concentration of the original fertilizer solution; M is the amount of fertilizer applied per mu; A0 is the coverage area of ​​the sprinkler; V is the actual amount of fertilizer injected in this sprinkler irrigation; According to the sprinkler machine inlet flow Q0, the actual flow of the fertilizer pump after verification q d The concentration of the sprinkler fertilizer solution is calculated based on the concentration of the configured fertilizer stock solution, and the calculation formula is as follows: In the formula, C s is the concentration of fertilizer solution for sprinkler irrigation; According to the fertilizer type, the corresponding fertilizer solution concentration inversion prediction model is selected. The fertilizer solution concentration inversion prediction model is used to reflect the sprinkler irrigation fertilizer solution concentration and the E c The functional relationship between the value or pH value; The concentration of the sprinkler fertilizer solution C s Substitute the fertilizer solution concentration inversion prediction model to obtain the E of the fertilizer solution for this irrigation and fertilization sprinkler irrigation. c The predicted value and pH value are compared with the E of the fertilizer solution after the start of fertilization. c The value or pH value is compared. If the comparison result exceeds the set threshold, a shutdown signal is issued and a shutdown report is generated. If the comparison result does not exceed the set threshold, the current fertigation strategy will continue to be executed until the operating time of the sprinkler reaches the total time of the sprinkler water-fertilizer integration operation, and this fertigation ends.

6. The control method according to claim 5, characterized in that: When strong electrolytes are used as fertilizers, the inversion prediction model for fertilizer solution concentration is: E c =aC s + b In the formula, E c is the conductivity; a is the first coefficient, which needs to be calibrated through experiments; b is the E of the irrigation water before the start of fertilizer injection c value; When acidic or alkaline fertilizer is used as fertilizer, the inversion prediction model of fertilizer solution concentration is: pH=yC s +z In the formula, pH is acidity and alkalinity; y is the second coefficient, which needs to be calibrated through experiments; z is the pH value of irrigation water before fertilization begins.

7. A central pivot sprinkler irrigation machine water and fertilizer integration device based on the control method according to any one of claims 1 to 6, characterized in that: It includes a fertilizing device, a central support, a control system and several pipelines. The fertilizing device includes a fertilizer injection pump and a fertilizer storage unit. The central support includes a central support bracket and a sprinkler main pipeline located in the middle. The fertilizer injection pump is connected between the sprinkler main line and the fertilizer storage unit through a pipeline, and injects the fertilizer liquid in the fertilizer storage unit into the sprinkler main line according to the control instruction of the control system; wherein the inlet of the fertilizer injection pump is connected to the fertilizer outlet at the bottom of the fertilizer storage container in the fertilizer storage unit through a fertilizer suction pipeline; the outlet of the fertilizer injection pump is connected to the sprinkler main line through the fertilizer injection pipeline; the sprinkler main line is connected to the inlet of the fertilizer storage container through a water supply pipeline, and a backwash pipeline is connected between the water supply pipeline and the fertilizer suction pipeline, and the fertilizer injection pump is flushed through the backwash pipeline after each spraying of fertilizer liquid. The fertilizer storage unit is used to prepare fertilizer solution of corresponding concentration according to the control instruction of the control system, and the fertilizer storage unit includes a fertilizer storage container and a stirrer connected to each other; The control system includes a sensor unit, a valve group, and a first control cabinet and a second control cabinet which are arranged on one side of the central support bracket and communicate with each other; wherein, The sensing unit includes a liquid level sensor installed on the top of the fertilizer storage container, a pressure switch installed on the fertilizer injection pipeline, and a flow meter, an E c Sensors and pH sensors; The valve group includes a water replenishment electric valve, a fertilizer suction electric valve, a fertilizer injection electric valve, and a backwashing electric valve, which are respectively installed on corresponding pipelines; The second control cabinet is used to calculate the working parameters of the sprinkler and the fertilizer injection pump according to the parameters set by the user and the inflow flow of the sprinkler collected by the flow meter before the start of fertilizer injection, form the current irrigation and fertilization strategy and display it to the user; control the operation of the fertilization equipment, the sensor unit and the valve group according to the current irrigation and fertilization strategy, and monitor and feedback-adjust the concentration of the sprinkler fertilizer solution during the control process; The first control cabinet is used to control the start and stop, travel speed and running time of the sprinkler, and the start and stop of the main water supply pump of the sprinkler according to the current irrigation and fertilization strategy.

8. The device according to claim 7, characterized in that The fertilizer suction pipeline is also equipped with a fertilizer suction filter and a fertilizer suction manual valve, the water replenishment pipeline is also equipped with a water replenishment filter and a water replenishment manual valve, the fertilizer injection pipeline is also equipped with a check valve and a fertilizer injection manual valve, and a manual drain valve is installed at the bottom of the fertilizer storage container.

9. The device according to claim 7, characterized in that The second control cabinet includes a frequency converter and a second controller arranged inside the second cabinet, and a human-computer interaction unit arranged outside the second cabinet. The second controller integrates an irrigation and fertilization strategy generation module and an irrigation fertilizer liquid concentration control module. The second controller controls the working frequency of the fertilizer injection pump through the frequency converter. The second controller is connected to the sensor unit, the valve group and the agitator. The first control cabinet includes a percentage timer and a first controller respectively arranged outside and inside the first cabinet. The first controller communicates with the second controller, and the first controller controls the travel speed of the sprinkler through the percentage timer.

Images