Method and system for cultivating crops

Abstract

The present disclosure relates to a method and system (100) for cultivating a crop (10). A supply amount of a nutrient solution is supplied to the crop (10), the nutrient solution having a first electrical parameter indicative of an electrical conductivity of the supplied nutrient solution, and a supply parameter indicative of a nutrient supply of the crop (10) is determined based on the supply amount and the first electrical parameter. A discharge amount of the solution discharged from the crop (10) is acquired, a second electrical parameter indicative of a conductivity of the discharged solution is measured, and a discharge parameter indicative of nutrients discharged from the crop (10) is determined based on the discharge amount and the second electrical parameter. A nutrient absorption parameter indicative of nutrients absorbed by the crop (10) is determined based on a difference between the supply parameter and the discharge parameter.

Description

Technical Field

[0001] This invention relates to methods and systems for cultivating crops. Background Technology

[0002] Plant cultivation, such as in greenhouses or open fields, involves supplying crops with water and nutrients. Photosynthesis is the driving process of crop development. In this process, light energy is converted into the chemical energy contained in hydrocarbons (especially sugars), which the crop can use to develop. Plant development includes the regular growth of the crop as a whole, but also includes processes such as fruit production and ripening. Therefore, the process of photosynthesis involves the crop's absorption and fixation of dry matter. The growth stage of a crop largely determines its active state, and thus the process of photosynthesis. The active state can change over time, for example, over an hour, a day, a week, and a season. Summary of the Invention

[0003] The aim is to provide methods and systems for cultivating crops, particularly for controlling the cultivation of crops.

[0004] One aspect provides a method for cultivating crops, comprising: supplying a nutrient solution to the crop at a supply rate, the nutrient solution having a first electrical parameter indicating the conductivity of the supplied nutrient solution; and determining a supply parameter indicating nutrient supply to the crop based on the supply rate and the first electrical parameter. The method further includes acquiring a discharge rate of solution discharged from the crop, measuring a second electrical parameter indicating the conductivity of the discharged solution, and determining a discharge parameter indicating nutrient discharge from the crop based on the discharge rate and the second electrical parameter. The method includes determining a nutrient absorption parameter indicating nutrient absorption by the crop based on the difference between the supply parameter and the discharge parameter. Thus, it is possible to determine how much nutrient has been absorbed and fixed by the crop, for example, to determine the state of the crop. The nutrient solution supplied to the plant may be water-based, with several nutrients added. Nutrients may be soluble in the nutrient solution. For example, the concentration of nutrients in the nutrient solution may be directly related to the conductivity of the nutrient solution. Therefore, the electrical parameter may be directly correlated with the concentration of nutrients in the fluid. For example, a high conductivity of the nutrient solution may generally indicate a higher nutrient concentration, for example, due to a higher ion content. The first and second electrical parameters may be expressed in Siemens per meter.

[0005] The composition of the nutrient solution can be known and predetermined by the grower. A first electrical parameter of the nutrient solution can be measured, for example, before it is supplied to the crop. A second electrical parameter can be measured at or near the discharge line receiving the discharge from the crop. The electrical parameter indicates the conductivity of the fluid and is therefore a measure of its ability to conduct electricity. It should be understood that the electrical parameter can also be measured as resistance.

[0006] The first and second electrical parameters are directly related to the nutrient concentrations in the nutrient solution and the discharged solution, respectively. Combining the first and second parameters, a derived mass balance can be obtained. Therefore, the nutrients absorbed by the plant can be estimated based on the difference between the absolute nutrient supply and absolute nutrient discharge.

[0007] It may be necessary to keep crop nutrient uptake as stable as possible, and, if necessary, allow only gradual changes in nutrient uptake. For example, low nutrient uptake may indicate water stress in the crop, as there may not be enough water available for nutrient transport and absorption. Large variations in nutrient uptake may indicate crop stress, negatively impacting crop development. Therefore, nutrient uptake parameters can be controlled, including supply and other environmental conditions, to maintain stable and gradual changes over time.

[0008] Optionally, nutrient absorption parameters indicate the quality of nutrients absorbed by the crop.

[0009] Optionally, the method includes determining a mapping between a first set of parameters, including electrical parameters, of the nutrient solution or discharged solution and the composition of the nutrient solution, and determining the composition of the discharged solution based on the determined mapping and a second set of parameters, including second electrical parameters. The second set of parameters may also include the discharge volume. This mapping relationship can be determined from the known composition of the solution. Therefore, the first set of parameters may be known or can be determined (e.g., measured). Characteristics can be determined between known components and their associated first set of parameters. This mapping can be used to determine the nutrient composition in the discharged fluid. The second set of parameters, including the second electrical parameters, can be mapped, for example, through this mapping relationship to obtain an estimate of the composition of the discharged solution. Using the estimated composition of the discharged solution, and the composition of the nutrient solution supplied to the crop (which may be known or can be measured or determined using the mapping relationship), it is possible to determine which specific nutrients or nutrient classes have been absorbed or have not been absorbed by the crop, and in what quantities by which the crop has absorbed them.

[0010] Optionally, the first set of parameters includes acidity parameters that indicate the acidity of the solution.

[0011] Optionally, the method includes measuring a second acidity parameter indicating the acidity of the discharged solution. Optionally, the second set of parameters includes the second acidity parameter. Optionally, the second set of parameters includes one or more of a translucency parameter, a viscosity parameter, a temperature parameter, and a color parameter.

[0012] Optionally, the method includes measuring a first acidity parameter that indicates the acidity of the supplied solution.

[0013] Optionally, the method includes analyzing the discharged solution (e.g., a sample of the discharged solution) to determine its composition. The determined composition of the discharged solution can be compared with the nutrient solution supplied to the crop (e.g., known or measured) to determine which specific nutrients have been absorbed by the crop and in what amounts.

[0014] Optionally, the supply parameter is determined as the product of the supply amount and a first electrical parameter, and / or the discharge parameter is determined as the product of the discharge amount and a second electrical parameter. The supply amount and discharge amount can be expressed in units of volume or mass, such as relative to the leaf surface area of ​​the crop. The first and second electrical parameters can be expressed in Siemens units per meter, assumed to be directly related to nutrient concentration. Multiplying the supply amount by the first electrical parameter and the discharge amount by the second electrical parameter, respectively, yields parameters indicating the quantity of nutrients, which can be used to determine the nutrients absorbed by the plant.

[0015] Optionally, the method includes determining the change of a second electrical parameter of the discharged solution over a period of time, and generating a warning signal if the change of the second electrical parameter exceeds a predetermined threshold. If a sudden and sharp increase in the second electrical parameter is observed, this could be an indication of reduced nutrient absorption following a previous supply event. Therefore, unabsorbed nutrients may remain in the crop substrate. Since the crop has already absorbed water from the substrate, the nutrient concentration in the substrate increases compared to the supplied solution. During the next supply event, nutrients in the substrate may be flushed away and discharged from the crop, resulting in a sharp increase in the nutrient concentration in the discharged solution, which can be detected from the measured second electrical parameter. Therefore, a large change in the electrical parameter can indicate a large change in nutrient concentration and can be a signal that the crop is under stress, particularly when the crop has insufficient available water and / or the crop temperature is too high for optimal nutrient absorption.

[0016] Optionally, the method includes increasing the supply of a first amount of nutrient solution to the crop if the change in the second electrical parameter exceeds a predetermined threshold.

[0017] Optionally, nutrient solution can be supplied to the crop in batches. Nutrient solution can be supplied to the crop periodically, especially during the day. The volume of each batch can be adjusted from one supply event to another, for example, depending on the condition of the crop.

[0018] Optionally, for each batch of nutrient solution supplied to the crops, appropriate supply parameters are determined.

[0019] Optionally, the method includes determining a cumulative supply parameter indicating the nutrient supply to the crop over a predetermined time period by summing the supply parameters of multiple supply batches within the time period. This time period may, for example, span several hours, a day, or multiple days.

[0020] Optionally, the solution discharged from the crop can be collected in batches.

[0021] Optionally, for each batch of collected effluent solution, appropriate effluent parameters are determined.

[0022] Optionally, the method includes determining a cumulative discharge parameter indicating nutrients discharged from the crop within a predetermined time period by summing discharge parameters of multiple collected discharge batches within the time period.

[0023] Optionally, the method includes determining a water absorption parameter that indicates the amount of water absorbed by the crop based on the difference between the amount of nutrient solution supplied and the amount of solution discharged.

[0024] Optionally, the method includes measuring an irradiance parameter indicating the amount of light exposure received by the crop, and determining an evaporation parameter indicating the rate of water evaporation from the crop based on the measured irradiance parameter. Light exposure can be a measure of crop transpiration activity. The irradiance parameter can be expressed as the ratio or percentage of water absorbed by the crop through transpiration. The irradiance parameter can be related to the leaf surface area of ​​the crop. Optionally, the amount of nutrient solution supplied to the crop can be adjusted based on the measured irradiance parameter. For example, the supply can be adjusted proportionally to the irradiance parameter.

[0025] Alternatively, absorption parameters can be determined based on cumulative irradiation parameters, which indicate the total amount of light the crop has received over a period of time (e.g., throughout the day). The total amount of light energy received by the crop over a time interval can be determined based on light irradiation (e.g., photon flux per unit (leaf) surface area, light intensity, or power). This can be used to determine the crop's photosynthetic activity and thus the associated nutrient uptake. Therefore, cumulative irradiation parameters can be used to determine absorption parameters.

[0026] Optionally, the method includes determining a water fixation parameter that indicates the amount of water fixed by the crop based on the difference between the water absorption parameter and the water evaporation parameter.

[0027] Optionally, the method includes adjusting the nutrient solution supply based on one or more of water absorption parameters, evaporation parameters, and water fixation parameters.

[0028] Optionally, nutrient absorption parameters are determined only after a first non-zero discharge is obtained following the supply of nutrient solution. Initially, the nutrient solution supplied to the plant is absorbed by the substrate in which the crop grows, with no discharge. Once the substrate is saturated, fluid discharge can be obtained when more nutrient solution is supplied.

[0029] Alternatively, the nutrient solution supplied to the crop may cause the first electrical parameter to gradually stabilize over time. A constant or gradually changing second electrical parameter can indicate the stable nutrient concentration in the discharged solution, and therefore the stable water and nutrient uptake by the crop. Such conditions may be favorable for crop development.

[0030] Optionally, the supply of nutrient solution can be adjusted over time according to the determined nutrient absorption parameters.

[0031] Optionally, the composition of the nutrient solution supplied to the crop remains constant over time. Therefore, only the supply rate can be adjusted over time, while the nutrient concentration remains constant.

[0032] Optionally, the amount of nutrient solution supplied can be adjusted over time according to the crop's activity level.

[0033] Optionally, the amount of nutrient solution supplied to the crop depends on the crop type.

[0034] Alternatively, the nutrient solution supply can be zero during the night. At night, the substrate can remain dry to allow for root aeration of the crop.

[0035] On the other hand, a crop cultivation system is provided, for example, arranged to perform the method described herein. The system includes a nutrient solution reservoir fluidly connected to a nutrient solution supply line and a discharge line, the nutrient solution supply line being arranged to supply a given amount of nutrient solution to the crop, and the discharge line being arranged to discharge a given amount of discharged solution from the crop. The system includes a first sensor and a second sensor, the first sensor being arranged to measure a first electrical parameter of the nutrient solution supplied to the crop, the first electrical parameter indicating the conductivity of the nutrient solution, and the second sensor being arranged to measure a second electrical parameter of the discharged solution from the crop, the second electrical parameter indicating the conductivity of the discharged solution. The system includes a processing device configured to determine, based on the supply amount and the first electrical parameter, a supply parameter indicating the nutrient supply to the crop; a discharge parameter indicating the nutrient discharge from the crop based on the discharge amount and the second electrical parameter; and a nutrient absorption parameter indicating the nutrient absorption by the crop based on the difference between the supply parameter and the discharge parameter.

[0036] On the other hand, a processing apparatus is provided for a crop cultivation system such as those described herein. The processing apparatus is configured to receive a first sensor signal and a first electrical parameter associated with the amount of nutrient solution supplied to the crop, the first electrical parameter indicating the conductivity of the nutrient solution; receive a second sensor signal and a second electrical parameter associated with the amount of effluent discharged from the crop, the second electrical parameter indicating the conductivity of the effluent; determine a supply parameter indicating nutrient supply to the crop based on the supply amount and the first electrical parameter; determine an effluent parameter indicating nutrient discharge from the crop based on the effluent amount and the second electrical parameter; and determine a nutrient absorption parameter indicating nutrient absorption by the crop based on the difference between the supply parameter and the effluent parameter.

[0037] It should be understood that the methods described herein may include computer-implemented steps. Implementations may include computer devices, in which the processes are performed. The invention also extends to computer programs suitable for practicing the invention, particularly computer programs on or within a carrier. The program may be in the form of source code or object code, or any other form suitable for use in implementing the invention. The carrier may be any entity or device capable of carrying the program. For example, the carrier may include storage media such as ROM, e.g., semiconductor ROM or hard disk. Furthermore, the carrier may be a transmissible carrier, such as electrical or optical signals that can be transmitted via cable or optical fiber or by radio or other means (e.g., via the Internet or the cloud).

[0038] For example, some implementations can be implemented using a machine or tangible computer-readable medium or product that can store instructions or instruction sets, which, if executed by a machine, can cause the machine to perform methods and / or operations according to the implementation.

[0039] Various implementations can be achieved using hardware components, software components, or a combination of both. Examples of hardware components may include processors, microprocessors, circuits, application-specific integrated circuits (ASICs), programmable logic devices (PLDs), digital signal processors (DSPs), field-programmable gate arrays (FPGAs), logic gates, registers, semiconductor devices, microchips, chipsets, etc. Examples of software may include software components, programs, applications, computer programs, application programs, system programs, machine programs, operating system software, mobile applications, middleware, firmware, software modules, routines, subroutines, functions, computer-implemented methods, procedures, software interfaces, application programming interfaces (APIs), methods, instruction sets, computational code, computer code, etc.

[0040] It should be understood that any aspects, features, and options described herein can be combined. In particular, it should be understood that any aspects, features, and options described in this method are equally applicable to systems and apparatuses, and vice versa. Attached Figure Description

[0041] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0042] Figure 1 A schematic example of a crop cultivation system is shown.

[0043] Figure 2 A schematic example of measurement data regarding the discharged solution is shown. Detailed Implementation

[0044] Figure 1 A schematic example of a system 100 for cultivating crop 10 is shown. Crop 10 is cultivated on a substrate 11, which is supported herein by a container 12. System 100 includes a nutrient solution reservoir 13 fluidly connected to a nutrient solution supply line 14 arranged to supply nutrient solution to crop 10. A discharge line 15 is arranged to discharge the nutrient solution from the crop. System 100 includes a first sensor unit 16 arranged to measure a first electrical parameter of the nutrient solution supplied to the crop, which indicates the conductivity of the nutrient solution. In this example, the first sensor unit 16 is also configured to measure the flow rate of the nutrient solution supplied to crop 10. The first sensor unit 16 may also optionally be arranged to measure other properties of the nutrient solution, such as temperature, viscosity, color, and translucency. System 100 also includes a second sensor unit 17 arranged to measure a second electrical parameter of the discharged solution from the crop, which indicates the conductivity of the discharged solution. Here, the second sensor unit 17 is also configured to measure the flow rate of the discharged solution from the crop 10. The second sensor unit 17 may also optionally be arranged to measure other properties of the nutrient solution (such as one or more of temperature, viscosity, color, and translucency). Here, the system 100 also includes an illumination sensor 18 arranged to measure light irradiation.

[0045] The system includes a processing unit 20. The processing unit 20 is configured to receive a first sensor signal and a first electrical parameter from a first sensor unit 16, the first sensor signal being associated with the amount of nutrient solution supplied to the crop, and the first electrical parameter indicating the conductivity of the nutrient solution. The processing unit 20 is also arranged to receive a second sensor signal and a second electrical parameter from a second sensor unit 17, the second sensor signal being associated with the amount of effluent discharged from the crop, and the second electrical parameter indicating the conductivity of the effluent.

[0046] Processing unit 20 is configured to determine supply parameters indicating nutrient supply to the crop based on the supply amount and a first electrical parameter. Processing unit 20 is also configured to determine discharge parameters indicating nutrient discharge from the crop based on the discharge amount and a second electrical parameter. Based on the difference between the supply parameters and the discharge parameters, processing unit 20 is configured to determine nutrient absorption parameters indicating nutrient absorption by the crop.

[0047] Therefore, it is possible to determine how much nutrient has been absorbed and fixed by crop 10, for example, to determine the state of the crop. The nutrient solution supplied to the plant can be water-based, with several nutrients added. Nutrients can be dissolved in the nutrient solution. For example, the concentration of nutrients in the nutrient solution can be directly related to the electrical conductivity of the nutrient solution. Therefore, electrical parameters can be directly correlated with the concentration of nutrients in the fluid. For example, a high electrical conductivity of the nutrient solution can generally indicate a higher nutrient concentration, for example, due to a higher ion content. The first and second electrical parameters can be expressed in Siemens per meter.

[0048] The composition of the nutrient solution can be known and predetermined by the grower. A first electrical parameter of the nutrient solution can be measured, for example, before it is supplied to the crop. A second electrical parameter can be measured at or near the discharge line receiving the discharge from the crop. The electrical parameter indicates the conductivity of the fluid and is therefore a measure of its ability to conduct electricity. It should be understood that the electrical parameter can also therefore be measured as resistance.

[0049] The first and second electrical parameters are directly related to the nutrient concentrations in the nutrient solution and the discharged solution, respectively. Combining the first and second parameters, a derived mass balance can be obtained. Therefore, nutrient uptake by plants can be estimated based on the difference between absolute nutrient supply and absolute nutrient discharge.

[0050] It may be necessary to keep crop nutrient uptake as stable as possible, and, if necessary, allow only gradual variations in nutrient uptake. For example, low nutrient uptake may indicate water stress in the crop, as there may not be enough water available for nutrient transport and absorption. Large variations in nutrient uptake may indicate crop stress, negatively impacting crop development. Therefore, nutrient supply and other environmental conditions can be controlled to maintain stable and gradual nutrient uptake parameters over time.

[0051] In this example, the supply parameter is determined as the product of the supply amount and a first electrical parameter, and the discharge parameter is determined as the product of the discharge amount and a second electrical parameter. In one example, the supply amount to the crop is 3.7 liters. The first conductivity parameter, measured by the first sensor unit 16, is 2.8 millisiemens per meter. Discharge is detected at the discharge line 15. The discharge amount, measured by the second sensor unit 17, is 0.9 liters, and the second electrical parameter associated with the discharged solution is 3.5 millisiemens per meter. The supply parameter is determined as the product of the supply amount and the first electrical parameter, here 3.7 multiplied by 2.8, resulting in a supply parameter value of 10.4. The discharge parameter is determined as the product of the discharge amount and the second electrical parameter, here 0.9 multiplied by 3.5, resulting in a discharge parameter value of 2.6. The absorption parameter is calculated as the difference between the supply parameter and the discharge parameter, here yielding a value of 7.8. The supply parameter, discharge parameter, and absorption parameter can be considered as mass-derived parameters, directly related to the mass supply, discharge, and absorption of nutrients, respectively. The environmental conditions of crop 10 can be controlled in such a way that the absorption parameters remain essentially constant and change gradually. In particular, the nutrient solution supply can be controlled based on the absorption parameters.

[0052] Figure 2 An example of measurement data from the second sensor unit 17 is shown. The lower line shows the cumulative discharge measurement results over a day. The upper line shows the measurement data of the electrical parameters of the discharged solution over a day. Figure 2 As can be seen, the batch discharge corresponds to the batch supply of nutrient solution to the crop. It can also be observed that the discharge volume of each supply batch decreases throughout the day, indicating an increase in water absorption by the crop. A constant second electrical parameter can indicate proportional nutrient absorption. It can be seen that the electrical parameter indicating the conductivity of the discharged solution initially decreases slightly and eventually stabilizes. However, a sharp increase in the electrical parameter measurement was observed between approximately 3 PM and 4 PM. This sharp increase indicates a sudden high conductivity of the discharged solution, and therefore a sudden high concentration of nutrients in the discharged solution. This could be an indication that a relatively large amount of nutrients has been flushed away from the substrate and therefore not absorbed by the crop. It can be concluded that the crop may have experienced water stress in the past, as it appears to have absorbed a large amount of water but only a small amount of nutrients. If such a large change is observed in the measurement of the second electrical parameter, the nutrient solution supply can be adjusted accordingly. Other environmental conditions of the crop, such as light exposure, temperature, and the concentration of carbon dioxide in the ambient air, can also be adjusted.

[0053] The invention will be described herein with reference to specific examples of embodiments thereof. However, it will be apparent that various modifications and changes may be made therein without departing from the spirit of the invention. For the purpose of clarity and concise description, features will be described herein as part of the same or different embodiments; however, alternative embodiments having all or some of the features described in these different embodiments are also contemplated.

[0054] However, other modifications, changes, and substitutions are also possible. Therefore, the specifications, drawings, and examples should be considered illustrative rather than restrictive.

[0055] In the claims, any reference numerals placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of other features or steps besides those listed in the claims. Furthermore, the words "a" and "an" should not be construed as limited to "only one," but are used to mean "at least one," and do not exclude multiples. The fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used advantageously.

Claims

1. A method for cultivating crops, comprising: The amount of nutrient solution supplied to the crop, the nutrient solution having a first electrical parameter indicating the conductivity of the supplied nutrient solution, and a supply parameter indicating the supply of nutrients to the crop is determined based on the amount of supply and the first electrical parameter. The amount of solution discharged from the crop is obtained, a second electrical parameter indicating the conductivity of the discharged solution is measured, and a discharge parameter indicating the amount of nutrients discharged from the crop is determined based on the amount of solution discharged and the second electrical parameter. Nutrient absorption parameters, which indicate the nutrients absorbed by the crop, are determined based on the difference between the supply parameters and the discharge parameters.

2. The method of claim 1, wherein the nutrient absorption parameter indicates the quality of nutrients absorbed by the crop.

3. The method according to claim 1 or 2, comprising determining a mapping between a first set of parameters, including electrical parameters, of the nutrient solution and the composition of the nutrient solution, and determining the composition of the effluent based on the determined mapping and a second set of parameters, including the second electrical parameters.

4. The method according to any one of the preceding claims, wherein the supply parameter is determined as the product of the supply amount and the first electrical parameter, and / or wherein the discharge parameter is determined as the product of the discharge amount and the second electrical parameter.

5. The method according to any one of the preceding claims, wherein the change of the second electrical parameter of the discharged solution is determined over a period of time, and a warning signal is generated if the change of the second electrical parameter exceeds a predetermined threshold.

6. The method of claim 5, further comprising increasing the supply of a first amount of nutrient solution to the crop if the change in the second electrical parameter exceeds the predetermined threshold.

7. The method according to any one of the preceding claims, wherein the nutrient solution is supplied to the crop in batches.

8. The method of claim 7, wherein for each batch of nutrient solution supplied to the crop, corresponding supply parameters are determined.

9. The method of claim 8, further comprising determining a cumulative supply parameter indicating the supply of nutrients to the crop within a predetermined time period by summing the supply parameters of a plurality of supply batches within the time period.

10. The method according to any one of the preceding claims, wherein the solution discharged from the crop is collected in batches.

11. The method of claim 10, wherein for each batch of collected effluent solution, corresponding effluent parameters are determined.

12. The method of claim 11, further comprising determining a cumulative discharge parameter indicating nutrients discharged from the crop within a predetermined time period by summing the discharge parameters of a plurality of collected discharge batches within the time period.

13. The method according to any one of the preceding claims, comprising determining a water absorption parameter indicating the amount of water absorbed by the crop based on the difference between the amount of nutrient solution supplied and the amount of solution discharged.

14. The method according to any one of the preceding claims, comprising measuring an irradiance parameter indicating the amount of light exposure received by the crop, and determining an evaporation parameter indicating the rate of water evaporation of the crop based on the measured irradiance parameter.

15. The method of claims 13 and 14, further comprising determining a water fixation parameter indicating the amount of water fixed by the crop based on the difference between the water absorption parameter and the water evaporation parameter.

16. The method according to any one of claims 13 to 15, comprising adjusting the supply of the nutrient solution based on one or more of the water absorption parameter, the evaporation parameter, and the water fixation parameter.

17. The method according to any one of the preceding claims, wherein the nutrient absorption parameters are determined only after a first non-zero discharge is obtained following the supply of the nutrient solution.

18. The method according to any one of the preceding claims, wherein the nutrient solution supplied to the crop causes the first electrical parameter to gradually stabilize over time.

19. The method according to any one of the preceding claims, wherein the supply of the nutrient solution is adjusted over time according to the determined nutrient absorption parameters.

20. The method according to any one of the preceding claims, wherein the composition of the nutrient solution supplied to the crop remains constant over time.

21. The method according to any one of the preceding claims, wherein the supply of the nutrient solution is adjusted over time according to the active state of the crop.

22. The method according to any one of the preceding claims, wherein the amount of nutrient solution supplied to the crop depends on the crop type.

23. The method according to any one of the preceding claims, wherein the supply of the nutrient solution is zero during the night.

24. A crop cultivation system comprising a nutrient solution reservoir fluidly connected to a nutrient solution supply line and a discharge line, the nutrient solution supply line being arranged to supply a quantity of nutrient solution to the crop, and the discharge line being arranged to discharge a quantity of nutrient solution from the crop. The system includes a first sensor and a second sensor. The first sensor is arranged to measure a first electrical parameter of the nutrient solution supplied to the crop, the first electrical parameter indicating the conductivity of the nutrient solution. The second sensor is arranged to measure a second electrical parameter of the discharged solution from the crop, the second electrical parameter indicating the conductivity of the discharged solution. Processing device, which is configured for Based on the supply amount and the first electrical parameter, supply parameters indicating the nutrient supply to the crop are determined. Based on the discharge rate and the second electrical parameter, discharge parameters indicating the nutrients discharged from the crop are determined, and Nutrient absorption parameters, which indicate the nutrients absorbed by the crop, are determined based on the difference between the supply parameters and the discharge parameters.

25. A processing apparatus for a crop cultivation system, said crop cultivation system, for example, according to claim 24, wherein the processing apparatus is configured for... The system receives a first sensor signal and a first electrical parameter, the first sensor signal being associated with the amount of nutrient solution supplied to the crop, and the first electrical parameter indicating the conductivity of the nutrient solution. The system receives a second sensor signal and a second electrical parameter, the second sensor signal being correlated with the amount of effluent discharged from the crop, and the second electrical parameter indicating the conductivity of the effluent. Based on the supply amount and the first electrical parameter, supply parameters indicating the nutrient supply to the crop are determined. Based on the discharge rate and the second electrical parameter, discharge parameters indicating the nutrients discharged from the crop are determined, and Nutrient absorption parameters, which indicate the nutrients absorbed by the crop, are determined based on the difference between the supply parameters and the discharge parameters.

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