Plant electroporation

Abstract

Methods for electroporating plants and electroporation systems are described. The electroporation may be based on one or more of plant species, plant size, plant density, plant health and plant growth. The electroporation may target the basal portion of the plants. The plant characteristics may be sensed by driving electrodes used for electroporation in a sensing phase, preceding the electroporation treatment stage.

Description

Plant electroporationCross reference to related application

[0001] This application is related to Australian Provisional Patent Application Number 2024901645, filed on 31 May 2024, the contents of which are incorporated herein by reference in their entirety.Field

[0002] The invention relates to the field plant electroporation, in particular electroporation to achieve plant mortality.Background

[0003] Various methods have been employed to control and manage weeds, including mechanical removal, the use of herbicides, and the application of other physical or biological techniques. The selection of the appropriate weed control method often depends on factors such as the type of crop, the specific weed species, and the environmental considerations.

[0004] Another method that has been employed to control and manage weeds is electroporation. Electroporation is a technique that involves the application of an electric field to cells. At sufficiently high dosage the electric field is effective to cause the weed to die.

[0005] Electroporation for the control of weeds has a number of advantages, including environmental advantage in not using herbicides and in avoiding potential regrowth where the root system of the plant is not mechanically removed. However, to date the adoption of electroporation has been limited and a need exists for further options for electroporation of weeds.Summary

[0006] Various methods of electroporating plants and various electroporation systems for electroporating plants are described. The electroporation may be at a dosage to achieve a high mortality rate, which is the number of plants killed divided by the numberof plants targeted. In some embodiments the high mortality rate is at least 70%, at least 80%, or at least 90%.

[0007] A method of electroporating plants includes determining one or more of plant species, plant size, plant density, plant health and plant growth, of one or more plants or groups of plants to be electroporated, setting an electroporation dosage based on the determined one or more of plant species, plant size, plant density, plant health and plant growth stage, and applying a pulsed electric field to the one or more plants at the set electroporation dosage.

[0008] In some embodiments determining the one or more of plant species, plant size, plant density and plant growth stage includes or consists of applying a first dosage electric field to the one or more plants, measuring one or more electrical characteristics of the one or more plants during application of the first electric field, and determining the one or more of plant species, plant size, plant density and plant growth stage based on the measured electrical characteristics. The measured electrical characteristics may include one or more of voltage, current, impedance, and energy consumed.

[0009] In some embodiments setting the electroporation dosage based on the plant density includes increasing the dosage as the plant density increases.

[0010] In some embodiments applying the electric field at the set electroporation dosage comprises controlling one or more of voltage, pulse length, pulse frequency, and number of pulses.

[0011] In some embodiments the method further includes controlling a speed of travel of a vehicle carrying the electroporation system based on the plant density, wherein a higher plant density results in a lower speed of travel.

[0012] In some embodiments the method further includes controlling a pulse frequency of the electroporation dosage based on the plant density, wherein a higher plant density results in a higher pulse frequency.

[0013] In some embodiments determining the one or more of plant species, plant size, plant density, plant health and plant growth stage is determined by analysing an image or video of the one or more plants or groups of plants.

[0014] In some embodiments the method further includes controlling a spacing between one or more electrodes of the electroporation system based on the plant density.

[0015] In some embodiments the method further includes determining when the electroporation treatment is complete based on measured electrical characteristics associated with electrodes that generate the pulsed electric field and ceasing application of the electric field in response.

[0016] In some embodiments the method further includes controlling positioning of one or more electrodes of the electroporation system based on the determined one or more of plant species, plant size, plant density, plant health and plant growth stage.

[0017] An electroporation system includes one or more sensors for determining one or more of plant species, plant size, plant density, plant health and plant growth stage of one or more plants or groups of plants to be electroporated, a pulse generator for generating electrical pulses, a pulse applicator for applying the electrical pulses to one or more electrodes to generate a pulsed electric field, and a controller configured to set an electroporation dosage based on the determined one or more of plant species, plant size, plant density, plant health and plant growth stage and cause the pulse generator and pulse applicator to apply an electric field to the one or more plants at the set electroporation dosage.

[0018] In some embodiments electroporation system is configured to apply a first dosage electric field to the one or more plants, measure one or more electrical characteristics during application of the first electric field, and determine the one or more of plant species, plant size, plant density, plant health and plant growth stage based on the measured electrical characteristics.

[0019] In some embodiments the measured electrical characteristics include one or more of voltage, current, impedance, and energy consumed.

[0020] In some embodiments the controller is configured to set the electroporation dosage by increasing the dosage as the plant density increases.

[0021] In some embodiments the controller is configured to control one or more of voltage, pulse length, pulse frequency, and number of pulses to apply the electric field at the set electroporation dosage.

[0022] In some embodiments the electroporation system further includes a vehicle for transporting the pulse generator, pulse applicator, and controller, wherein the controller is configured to control a speed of travel of the vehicle based on the plant density, such that a higher plant density results in a lower speed of travel.

[0023] In some embodiments, the controller is configured to control a pulse frequency of the electroporation dosage based on the plant density, wherein a higher plant density results in a higher pulse frequency.

[0024] In some embodiments the electroporation system further includes an electrode actuator for controlling a position or orientation of the one or more electrodes, wherein the controller is configured to control the electrode actuator to adjust at least one of the electrode position and orientation based on the plant density.

[0025] In some embodiments the electroporation system further includes an imaging system for producing at least one image or video of plants, wherein the controller configured to determine the one or more of plant species, plant size, plant density, plant health and plant growth stage based on the at least one image or video.

[0026] In some embodiments the controller is configured to determine when the electroporation treatment is complete based on measured electrical characteristics of the pulse generator or pulse applicator and cease application of the electric field in response.

[0027] In some embodiments the electroporation system further includes an electrode actuator for controlling positioning of the one or more electrodes, wherein the controller is configured to control the electrode actuator based on the determined one or more of plant species, plant size, plant density, plant health and plant growth stage.

[0028] A method of electroporating plants includes targeting the basal portion of one or more plants for electroporation, applying an electric field to the basal portion of the one or more plants, and controlling one or more parameters of the electric field to achieve a mortality rate for the electroporated plants.

[0029] In some embodiments targeting the basal portion of the plants comprises positioning one or more electrodes proximate to the basal portion of the plants.

[0030] In some embodiments the method further includes mechanically pushing over the plants to position the one or more electrodes proximate to the basal portion.

[0031] In some embodiments the one or more electrodes are oriented horizontally to target the basal portion of the plants.

[0032] In some embodiments the one or more electrodes are oriented vertically and positioned to be at least partially aligned with the basal portion of the plants.

[0033] In some embodiments controlling the one or more parameters of the electric field comprises controlling one or more of voltage, pulse length, pulse frequency, and number of pulses.

[0034] In some embodiments the method further includes sensing one or more environmental factors and controlling the electric field based on the sensed environmental factors. The environmental factors may include one or more of plant species, plant size, plant density, plant health and plant growth stage.

[0035] In some embodiments the method further includes providing a first, lower dosage electric field to the plants for a sensing phase, measuring one or more electrical characteristics during the sensing phase, and applying the electric field for the electroporation based on the measured electrical characteristics.

[0036] An electroporation system includes one or more electrodes configured to be positioned proximate to the basal portion of one or more plants, a pulse generator for generating electrical pulses, a pulse applicator for applying the electrical pulses to the one or more electrodes, and a controller configured to control the positioning of the one or more electrodes to target the basal portion of the plants and control one or more parameters of the electrical pulses applied by the pulse applicator to achieve a high mortality rate for the electroporated plants.

[0037] In some embodiments the electroporation system further includes an electrode actuator controlled by the controller to position the one or more electrodes proximate to the basal portion of the plants.

[0038] In some embodiments the electroporation system further includes a vehicle for transporting the electroporation system, wherein the electrode actuator is configured to mechanically push over the plants to position the electrodes proximate to the basal portion.

[0039] In some embodiments the one or more electrodes are oriented horizontally to target the basal portion of the plants.

[0040] In some embodiments the one or more electrodes are oriented vertically and positioned to be at least partially aligned with the basal portion of the plants.

[0041] In some embodiments the controller is configured to control one or more of voltage, pulse length, pulse frequency, and number of pulses to achieve the high mortality rate.

[0042] In some embodiments the electroporation system further includes one or more sensors for sensing one or more environmental factors, wherein the controller is configured to control the electrical pulses based on the sensed environmental factors.

[0043] In some embodiments the environmental factors include one or more of plant species, plant size, plant density, plant health and plant growth stage.

[0044] In some embodiments the controller is configured to apply a first, lower dosage electric field to the plants for a sensing phase, measure one or more electrical characteristics during the sensing phase, and apply the electrical pulses for the electroporation based on the measured electrical characteristics.

[0045] A method of electroporating plants includes applying a first dosage electric field to a plant, measuring one or more electrical characteristics of the plant during application of the first electric field, and applying a second dosage electric field to the plant based on the measured electrical characteristics.

[0046] In some embodiments the first electric field is applied for a sensing phase and the second electric field is applied for an electroporation treatment phase for achieving a plant mortality rate.

[0047] In some embodiments the measured electrical characteristics include one or more of voltage, current, impedance, and energy consumed.

[0048] In some embodiments the method further includes determining an environmental factor based on the measured electrical characteristics and applying the second electric field based on the determined environmental factor. The environmental factors may include one or more of plant species, plant size, plant density, plant health and plant growth stage.

[0049] In some embodiments the first dosage electric field is a lower dosage than the second dosage electric field.

[0050] Further aspects of the present disclosure and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings.Brief description of the drawings

[0051] Figure 1 shows a block diagram of an electroporation system.

[0052] Figure 2 shows a diagram of a switching circuit for an electroporation system.

[0053] Figure 3 shows a block diagram of an example computer processing system that may be used in an electroporation system.

[0054] Figure 4 shows an example arrangement and five example connections of electrodes in an electroporation system.

[0055] Figures 5A, 5B respectively show two different electrode orientations for an electroporation system.

[0056] Figures 5C, 5D respectively show two different electrode orientations for an electroporation system.

[0057] Figure 6 shows a diagrammatic plot of electric field strength against time for sensing phase and an electroporation treatment phase.

[0058] Figure 7 shows three examples of voltage pulse shape that may be applied to the electrodes of an electroporation system.

[0059] Figures 8A and 8B show the results of a series of electroporation experiments on ryegrass and gazania respectively.

[0060] Figures 9A, 9B, and 9C show a framework for determining an electroporation dosage for plants having particular environmental factors.

[0061] Figure 10 shows a flow diagram of a method performed by a controller of an electroporation system.

[0062] Figure 11 shows results of a laboratory test in which different electroporation dosages were applied to annual ryegrass plants of varying size.Detailed description of the embodiments

[0063] The present disclosure relates to methods and devices for electroporation of plants, in particular electroporation of plant cells to kill weeds. The electroporation involves applying short pulses of high voltage electric field to the cells of the plant. This disrupts the cell membrane and homeostatic processes, which may lead to cell injury and death.

[0064] In some embodiments the electric field is applied to the basal part of the plant. Targeting the basal part of the plant allows for more energy efficiency than targeting the entire plant. For example, the upper stem and leaves may have higher electrical resistance and may be less crucial for the plant's survival. In some embodiments the electroporation provides a dose of electric field effective to achieve a high mortality rate for the electroporated plants by disrupting meristematic tissue in the plant that is located in the basal part of the plant. The mortality rate may be at least 70% or at least 80% or at least 90% or close to or at 100%, or any value in between.

[0065] In some embodiments the electric field applied to the plant is controlled and is based on one or more environmental factors. The environmental factors may include any one or more of plant presence, species, growth stage, cross-sectional area of an aspect of the plant such as the area occupied by the stem or stems of the plant, plant mass, soil conditions like moisture, pH, temperature, humidity. In some embodiments the environmental factors are limited to one or more characteristics of the plants to be electroporated. The environmental factors may be sensed by one or more sensors of the electroporation system or may be received as input to the electroporation system. The environmental factors may be determined as an estimated or predicted value rather than a direct measurement and need not be an exact value.

[0066] In some embodiments an environmental factor is an identification of a plant species. The identification may be determined directly by analysis of sensor input or based on user input directly specifying the species. Alternatively the identification may be determined based on other measurements or input, for example detection of shades of green of the plant through image or video analysis.

[0067] In some embodiments an environmental factor or the environmental factor is a measure of plant size, plant density, plant health or a measure of the plant’s growth stage. The measure of plant size, density, health or growth stage may be determined directly by sensor measurement or based on input directly specifying a size or size index value. Alternatively the measure of plant size, density, health or growth stage may be determined based on other sensor measurements or input, for instance a combination of a measure or input of cross-sectional area of the plant and plant mass, or a combination of a measure or input of an estimate of one or more of the number of or density of stems, leaves, and the plant height.

[0068] Additionally, or as part of measure of the plant growth stage, a measure of plant vitality may be made or an input received indicating plant vitality. For example healthy plants may be electroporated, and unhealthy plants not, or the healthy and unhealthy plants electroporated at different doses, for instance the healthy plants electroporated at a higher dose than the unhealthy plants.

[0069] In some embodiments the control over the electric field is dependent on detection of the presence of one or more plants. For example the presence of a plant may be detected through image or video analysis, or through another sensor such as a lidar sensor, another type of optical sensor or a mechanical sensor. Taking the example of video analysis, the analysis can detect the presence of a plant by recognizing green foliage against a brown background. This may indicate a plant is present at the location. It may also indicate the vitality of the plant based on the amount of green detected. Alternatively an input may be received to indicate when to electroporate. The input may be generated responsive to a manual operation, for example a button press to indicate a plant is at the location of an electrode, or may be received from another system, for example an analysis system of an environmental sensor.

[0070] The control of the electric field may include control over one or more of electrode voltage, pulse length, pulse shape, pulse frequency, and the number ofpulses. In particular, any of these variables may have one value for one environmental condition and a different value for another environment condition.

[0071] The control over the electric field applied to the plant, for example control based on one or more environmental factors, may be achieved by controlling the signal applied to the electrode or electrodes used to generate the electric field. In some embodiments a voltage applied to an electrode is in the range 4-25kV (preferably 10-20 kV) (inclusive), the pulse width is 10-1,000 ps (inclusive), the frequency of the pulses is 100- 10,000Hz (preferably 100-1 ,000 Hz) (inclusive) and the number of pulses applied to the plant is 1-100 (inclusive) or more. Each pulse of electric field during electroporation treatment of a plant may be between 500-1,000 V / cm (inclusive). The control over the electric field may also be achieved by controlling the physical location of the electrode or electrodes providing the electric field. As stated above, in some embodiments one or more of these variables is determined based on one or more environmental factors.

[0072] In some embodiments the electrode geometry may also be controlled to affect the electric field applied to a plant, for example by controlling the distance between one or more electrodes, the vertical locations of one or more electrodes, a horizontal electrode plate, and / or a pair of spaced apart vertical electrode plates. In other embodiments the electrode geometry is fixed. The electrode geometry may also be controlled based on one or more environmental factors.

[0073] In some embodiments electrode feedback is utilised to control the electric field. The feedback may be based on based on electrical measurements, like current, impedance, and energy consumed. The feedback for example, may be utilised to optimize the electroporation treatment in real-time. In one example the electrode or electrodes are driven to produce a relatively low electric field in a pre-dosage stage and electrical measurements made. The electric field produced is then based on the electrical measurements. In another example, once a change in electrical measurements is detected the electroporation of a plant may cease. In a further example, the feedback may be used to assess its effectiveness or assess when a dosage is complete. In that case the feedback may indicate whether or not a further (e.g. second) electroporation should be applied.

[0074] Figure 1 shows a block diagram of an electroporation system 100. The system100 includes a pulse generator 101 for generating pulses for creating an electric field, acontroller 110 for controlling the operation of the system 100, a pulse applicator 120 for receiving the pulses from the pulse generator and providing them to electrodes 140 and a vehicle 130 for carriage of the electroporation system 100. Whilst Figure 1 and the following description references embodiments with a plurality of electrodes, in other embodiments there may be a single electrode. The blocks represent functionality of the electroporation system 100 and do not necessarily require physical separation when provided in different blocks, or require physical co-location when provided within the same block.

[0075] The pulse generator 101 includes a power supply 102, which is a high voltage power supply capable of creating electric potential and current sufficient to drive the electrodes 140. The power supply 102 may drive the electrodes directly or may supply energy to charge storage 103, for example a capacitor bank. In some embodiments, the capacitor bank is configurable to adjust the total capacitance. The configuration may be based on feedback or sensing, or based on user input.

[0076] The pulse generator 101 includes supply switching circuitry 104. The supply switching circuitry 104 controls the delivery of the electrical pulses to the pulse applicator 120. The supply switching circuitry 104 may include fast switching devices like MOSFETs, IGBTs, GTOs, thyristors, or silicon carbide technologies. In some embodiments, the supply switching circuitry 104 includes a step-up transformer, with the voltage on the output or secondary side being sufficient to drive the electrodes to create the required electric field, and the voltage on the input or primary side being lower. The supply switching circuitry 104 may be on the input or primary side of the transformer. Pulse shaping circuits may also be used to develop the desired pulse waveform. In some embodiments the pulses have a non-sinusoidal shape. In some embodiments the pulses have a rise time that is substantially less than the rise time of a sinusoid at the same frequency. In some embodiments the rise time is in the range of 50 to 1000 nanoseconds. For example, the pulses may be exponentially decaying pulses, truncated exponentially decaying pulses, rectangular pulses or another non-sinusoidal shape.

[0077] In some embodiments the pulse generator 101 includes electrical sensor circuitry 105. The electrical sensor circuitry 105 senses, directly or indirectly at least one of voltage and current whilst the electroporation system 100 is operating, in particular whilst the electrodes 140 are being driven to generate an electric field. As such, theoutput of the electrical sensor circuitry 105 may be processed to determine or identify an environmental condition, for example one or more characteristics of a plant, which detection may be performed one or more of before, during and after electroporation. Alternatively or additionally, the electrical sensor circuitry 105 provides feedback, utilised to control the electric field, for example as described previously herein. Data generated by the electrical sensor circuitry 105 may be provided to the controller 110 for processing.

[0078] The pulse applicator 120 drives the electrodes 140. In some embodiments the pulse applicator 120 is configured to selectively drive one or more electrodes from a plurality of electrodes. The configuration may include electrode switching circuitry 121 that can select one or more sets of the electrodes 140, for example to target specific plants or specific areas. The switching circuitry 121 may also configure the polarity of one or more of the electrodes 140. An example of switching circuitry 121 is described herein with reference to Figure 2.

[0079] In some embodiments the pulse applicator 120 includes an electrode actuator 122. The electrode actuator 122 may be a mechanical or electromechanical system that controls one or more of the positioning (which may include controlling the orientation) of the electrodes in 3D space. This control may be utilised to target plants based on their identified characteristics. The control may be used in conjunction with the control over what electrodes are driven, for example the control provided by the electrode switching circuitry 121.

[0080] In some embodiments the pulse applicator 120 includes applicator sensor circuitry 123. The applicator sensor circuitry 123 measures or detects one or more environmental factors through one or more of electrical, optical and mechanical sensors. Example environmental factors that may be measured or detected include variables related to plant species, plant size, plant density, plant health or vitality, plant growth stage, plant proximity, terrain, soil type, soil moisture, temperature, humidity, and the pulse characteristics. Data generated by the applicator sensor circuitry 123 relating to the measured or detected variables may be provided to the controller 110 for processing.

[0081] The vehicle 130 may carry the other components of the system 100. In use the vehicle can be controlled, manually (either on-vehicle or remotely) or semi- or fully-autonomously, to drive over an area for electroporation of plants in the area. The vehicle 130 has its own power supply, for example a battery, which may be used to power some components of the system 100. The vehicle may carry a generator, used to power some other components of the system 100. For example the power supply 102 may be a generator carried by the vehicle 130.

[0082] In some embodiments the vehicle 130 may carry vehicle sensor circuitry 131. The vehicle sensor circuitry 131 provides additional sensor data that may be provided to the controller 110. This data may indicate one or more of the speed or velocity of the vehicle, the location of the vehicle and the acceleration of the vehicle or a part thereof, for example the electrodes 140 or a housing of the electrodes 140. The vehicle sensor circuitry 131 may include additional sensors, such as cameras, proximity sensors and force sensors.

[0083] In some embodiments the vehicle 130 includes a user interface 132. The user interface 132 allows an operator to control the electroporation system. In some embodiments, live sensor data is displayed on a display device of the user interface 132 to inform the operator. For example camera data or processed feedback data from any of the sensors of the electroporation system may be displayed. In some embodiments, a user interface is located outside the vehicle 130, instead of or in addition to an in-vehicle user interface, allowing the operator to control the electroporation system remotely. It will be appreciated that remote control, away from the high-voltage components, may have safety advantages.

[0084] The controller 110 controls operations of the electroporation system 100. The controller 110 may be a central controller or may be formed by a plurality of control modules, which may be co-located or distributed about the electroporation system 100. The controller may be or include a computer processing system and may include one or more computer processors such as microprocessors or microcontrollers. Instructions executable by a computer processor of the controller 110 to cause the controller 110 to perform its functions may be provided in non-transitory memory 114. The controller may include configurable logic controllers or application specific integrated circuits. For some functions, for example for control over the electrode actuator 122, the controller may include or consist of analogue control circuitry.

[0085] There are several variables of the electroporation system 100 that may be controlled by the controller 110. In various embodiments any combination of one or more of the variables are controlled. Other variables may be fixed during operation of the electroporation system 100 and not controlled by the controller 110. The control by the controller 110 may be based on output from one or more of the electrical sensor circuitry 105, the applicator sensor circuitry 123 and the vehicle sensor circuitry 131. The control by the controller 110 may be based on user input received via the user interface 132 or otherwise. If the electroporation system 100 includes other sensors or input, then the control may be based on output from the other sensors or input from the other input. The controller 110 can process data from various electrical, optical and mechanical sensors to assess plant and environmental conditions for the purposes of controlling one or more aspects of the operation of the electroporation system 100.

[0086] In some embodiments the controller 110 controls the power supply 102. The controller 110 may control delivery of charge to the charge storage 103. The electrical sensor circuitry 105 may include a sensor to detect the charge stage of the charge storage 103 and the controller may control delivery of charge based on the detected charge state.

[0087] In some embodiments the controller 110 controls the charge storage 103. For example, if the charge storage 103 is a configurable capacitor bank, the total capacitance can be adjusted by the controller 110, either through user input or automated feedback control.

[0088] In some embodiments the controller 110 controls the supply switching circuitry 104. The supply switching circuitry 104 may be controlled to achieve a required switching timing, frequency and duration and may be controlled to achieve a particular waveform. When the electroporation system 100 includes controllable pulse-shaping circuitry, then the controller 110 may control the pulse-shaping circuitry. In some embodiments, the controller 110 may control the supply switching circuitry 104 to deliver the same waveform to each of the electrodes 140 or different waveforms to one or more of the electrodes 140.

[0089] In some embodiments the controller 110 controls the electrode switching circuitry 121. The controller 110 can control the selection and polarity configuration ofthe electrodes. This control may, for example, target the required plants, or optimise the electric field orientation on the targeted plants.

[0090] In some embodiments the controller 110 controls the electrode actuator 122. The mechanical positioning, location and orientation of the electrodes in 3D space may be controlled, for example to adapt based on identified plant characteristics.

[0091] In some embodiments the controller 110 causes parts of a user interface to be displayed. For example, the controller 110 may cause a display screen to display user interface information. The display screen may be a touch screen display to receive user input. User input may be provided through other mechanisms, including for example a keyboard, a point and click device, a button or any combination thereof.

[0092] In some embodiments the controller 110 provides navigation and operational control for semi-autonomous or fully autonomous operation. The controller 110 may also receive a predetermined user input and responsive to the predetermined user input cease semi-autonomous or fully autonomous operation.

[0093] Figure 2 shows a diagram of a switching circuit 200. The switching circuit 200 may be, or form a part of, the electrode switching circuitry 121 of Figure 1 and will be described in that context, with like reference numerals between Figures 1 and 2 referring to like components. The switching circuit 200 is located between and connected to the pulse generator 101 and the electrodes 140. The switching circuit 200 controls which electrode of the electrodes 140 is active or in other words which electrode or electrodes generate an electric field subject to pulses being received from the pulse generator 101. In some embodiments the switching circuit 200 also controls the polarity of electrodes 140, for example as between an electrode pair which is the cathode and which is the anode or whether all electrodes are cathodes or anodes, in which case the conduction path is through ground.

[0094] The pulse generator provides high voltage (HV) line and a return (R) line. The HV line may be positive or negative in polarity with respect to the R line. The switching circuit 200 is configured to provide control over whether an electrode of the electrodes is connected to the HV line, the R line or has no connection (n.c.). The electrode switching circuitry 121 configures at least one electrode to connect to the R line. In someembodiments every electrode of the electrodes 140 is individually controllable. In other embodiments less than all of the electrodes 140 are individually controllable.

[0095] The connection between the HV line and the R line is controlled by a bank of first switches 201. Each switch in the bank of first switches 201 connects a line to an electrode of the electrodes 140 to either the HV line or the R line, the switching state of each switch in the bank of first switches 201 controlled by the controller 110. The controller 110 may individually control each switch in the bank. Alternatively the controller 110 may control groups of electrodes together, for examples pairs of adjacent electrodes may be controlled together so as to have one connected to the HV line and the other connected to the R line and then both simultaneously switch to the other when required. In some embodiments the R line is a line to ground.

[0096] A bank of second switches 202 controls whether the electrodes 140 are in a connected state or a disconnected state. In the connected state, the electrode is either connected to the HV line or the R line, dependent on the relevant switch in the bank of first switches 201. In the disconnected state the electrode is floating, with no connection. In some embodiments the option for no connection is removed for one or more (up to all) of the electrodes 140. The switching state of each switch in the bank of first switches 201 is controlled by the controller 110. This control may be on an individual switch basis or as on a group basis. In some embodiments the bank of second switches 202 are controlled to be either all connected or all disconnected and simultaneously switch between these states.

[0097] Figure 3 shows a block diagram of an example computer processing system 300 for performing the functions of the controller 110. The computer processing system 300 may be a standalone computer processing system for performing the relevant functions. The computer processing system 300 may be carried by the vehicle 130. Figure 3 shows a selection of components of a computer processing system. It will be appreciated that the computer processing system 300 will include other hardware components that are not shown, such as a power supply.

[0098] The computer processing system 300 includes a processing unit 301. The processing unit 301 may include one or more than one processing device, such as one or more central processing units, or one or more central processing units and one or more graphics processing units. The processing unit may utilise system memory 302and transitory memory 303 when performing the method. The instructions executable by the processing unit 300 may be stored in non-transitory memory 304. The processing unit 301 communicates with other devices of the computer processing system 300 over a bus 305.

[0099] The computer processing system 300 includes an input / output (I / O) interface 306 for communication via one or more wired or wireless connections utilising suitable communication protocols. The I / O interface 306 is utilised to communicate with the pulse generator 101 and pulse applicator 120. The I / O interface 306 may also be utilised to communicate with the vehicle 130 and other components, such as the peripheral components shown in Figure 3 of a camera 308 (which might be one or more additional cameras to any camera provided in the pulse generator 101 , pulse applicator 120 or vehicle 130), a keyboard 309 for user input and a display device 310 to present information and in the case of a touch screen device, receive user input. It will be appreciated that other peripherals may be provided and that not all the peripherals shown in Figure 3 need to be provided.

[0100] The computer processing system 300 includes a communication interface 307 for communication with a network 350, via a wired or wireless connection utilising a suitable communication protocol. The network 350 may be a local area network or a wide area network or combination of two or more networks.

[0101] In alternative embodiments, the computer processing system 300 may be a server, which performs the relevant functions on request from a client carried by the vehicle 130, with the inputs and outputs provided through input / output 306 instead being provided through the communication interface(s) 307. The client may also be a computer processing system, having the same form or a similar form as the computer processing system 300 depicted in Figure 3. In further alternative embodiments, the controller 110 has a different form, for example including one or more programmable logic devices or application specific integrated circuits, in which case the hardware architecture will be different to the architecture of Figure 3.

[0102] Figure 4 shows an example arrangement and four example connections (referenced A to D) of the electrodes 140 (reference numeral shown for example connection A only). Figure 4 shows the array when viewed from the top. In other words, the terrain over which the electrodes 140 traverse is into the page.

[0103] In the embodiment shown a set of the electrodes 140 is configured in an array, in particular a four-by-four array. In other embodiments the array may be a different size (e.g. MxN where M and N are non-zero integers) and the electrodes may be spatially arranged differently, either in a uniform spacing arrangement or a non-uniform spacing arrangement. Whilst in Figure 4 the electrodes are represented as circles, this is intended to only represent the example spatial arrangement of the electrodes and is not intended to indicate that the electrodes necessarily have a circular cross-sectional shape. The electrodes 140 may have a cross section through a horizontal plane that is square, rectangular, circular, triangular or another shape. The electrodes 140 may be plate electrodes.

[0104] In the embodiment shown the electrodes 140 include two wheel electrodes 140A (reference numeral shown for example connection A only and only for one wheel). The wheel electrodes 140A form part of wheels of the vehicle 130. In other embodiments the wheel electrodes 140 are located in another part of the vehicle 130.

[0105] As indicated by the key “Electrode connection” in Figure 4, the connection state for each electrode 140 (including the wheel electrodes 140A) is indicated by its fill state. A solid black fill indicates a connection to a HV line (e.g. the HV line of Figure 2), a solid white fill indicates a connection to a return line (e.g. the return line of Figure 2) and a hatched line fill indicates an inactive state (e.g. connection to no connection (n.c.) of Figure 2). Each of the four example connections may be formed by a switching configuration of the electrode switching circuitry 121 , for example by configuring the switches in the switching circuit 200. The electroporation system 100 may be set to an example connection, or change between any two or more of the example connections, under the control of the controller 110, or by another process (e.g. a manual process) of setting the configuration of the electrode switching circuitry 121.

[0106] In the example connection A, the electrodes 140 in the array are all connected to the HV line and the wheel electrodes connected to the return line. The generated electric field is therefore applied on plants between the electrode array and any of the wheels.

[0107] In the example connection B, the wheel electrodes 140A are active, one wheel electrode 140A connected to the HV line and the other wheel electrode 140A connected to the return line. The electrodes 140 in the array are all electrically floating (i.e.inactive). The generated electric field is therefore applied on plants between the wheel electrodes 140A.

[0108] In the example connection C the wheel electrodes 140A are electrically floating, and the electrodes 140 in the array are alternately connected to the HV line and the return line, forming columns of HV line connected electrodes and return line connected electrodes. The columns are arranged parallel to a direction of travel indicated by arrow T, such that the electric field is applied on plants between each pair of adjacent columns of electrodes.

[0109] In the example connection D the wheel electrodes 140A are electrically floating, and the electrodes 140 in the array are alternately connected to the HV line and the return line, forming rows of HV line connected electrodes and return line connected electrodes. The rows are arranged perpendicular to the direction of travel T, such that the electric field is applied on plants between each pair of adjacent rows of electrodes.

[0110] In the example connection E, the wheel electrodes 140A are electrically floating, the leftmost column of electrodes 140 are connected to the HV line, the rightmost column of electrodes 140 are connected to the return line, and the two columns of electrodes 140 between the leftmost and rightmost columns of electrodes 140 are electrically floating. The rightmost and leftmost columns of electrodes 140 are arranged parallel to a direction of travel indicated by arrow T, such that the electric field is applied on plants between the rightmost and leftmost columns of electrodes 140.

[0111] Other connection arrangements may be formed. Each electrode may be individually controlled to be either active (e.g. connected to the HV line or return line) or inactive (e.g. electrically floating). Alternatively groups of two or more electrodes may be controlled together.

[0112] Control over where the generated electric field is applied may be achieved by controlling the connection state of the electrodes 140 and controlling the positioning of the electrodes. The horizontal location of the electrodes may be controlled at least in part by travel of the vehicle 130. In addition, all or one or more sets of the electrodes may be moveable, for example by being mounted on a moveable housing or platform, to provide control over one or more of the vertical location of the electrodes, the horizontal location of the electrodes (e.g. to provide relatively fine control in addition to therelatively course control that may be provided by movement of the vehicle) and the orientation of the electrodes. Further, each electrode may be independently movable with respect to the other electrodes 140, for example by being mounted on a moveable housing or platform, to provide control over one or more of the vertical location of the electrode, the horizontal location of the electrode, and the orientation of the electrode. In the case of plate electrodes the orientation may be changeable between horizontal and vertical. The movement may be controlled by the electrode actuator 122.

[0113] Particular connection states of the electrodes 140 may be used together with particular positioning and / or orientation of the electrodes. Referring to example connection A, each electrode in the array may be positioned with a horizontal orientation. Referring to example connections C and D, each electrode in the array may be positioned with a vertical orientation. Additionally the height of the electrodes in the array may change. Referring to example connection A, the electrodes may be positioned with a horizontal orientation. Referring to example connections C and D, the electrodes may be positioned with a vertical orientation. When targeting the basal part of the plant, the height may be set to achieve the targeting and the electrodes themselves or another part of the electroporation system used to contact and push over the plants to which the electric field is to be applied (or both), so that the electrodes are located to achieve that targeting.

[0114] Figure 5A diagrammatically shows an example of an electrode 140 in a horizontal orientation relative to the terrain or ground. The electrode 140 is carried by a vehicle (e.g. the vehicle 130) with wheels 502, 503. The wheels include wheel electrodes 140A. In the ground is a plant 501 to be electroporated. The vehicle may travel in the direction T, and the electrode 140 positioned at a height H that causes it to be located close to a basal portion of the plant 501. The electrode 140 itself may push the plant over as shown. The vehicle may include other structures that act to push the plants over to allow the electrode 140 to be positioned near the basal part of the plants. Whilst Figure 5A shows only a single electrode 140, there may be more than one electrode, for example an array of electrodes as described herein. The electrode 140 may be connected to the HV line and one or both of the wheel electrodes 140A connected to the return line.

[0115] Figure 5B diagrammatically shows an example of a pair of electrodes 140, each in a vertical orientation relative to the terrain or ground. The electrodes 140 are carriedby a vehicle (e.g. the vehicle 130) with wheels 502, 503. The wheels include wheel electrodes 140A. In the ground is a plant 501A to be electroporated. The vehicle may travel in a direction that is into the page, and the electrodes 140 positioned at a height H that causes it to be at least in part horizontally aligned with a basal portion of the plant 501A, whilst clearing the ground. The vehicle may travel across the page (e.g. in the direction T of Figure 5A) and the electrodes 140 raised and lowered as required to enable this travel. The raising and lowering may also be required for travel into (or out of) the page, for example to clear an obstacle or in the case of thick foliage. In the example of Figure 5B the lower portion of the electrodes are aligned with the basal portion of the plant. Where the plant is relatively larger, then the entirety of the electrodes may be aligned with the basal portion of the plant. Whilst Figure 5A shows only a single pair of electrodes 140, there may be more than one electrode pair, for example an array of electrode pairs as described herein. One electrode 140 may be connected to the HV line and the other connected to the return line. Both of the wheel electrodes 140A may be electrically floating.

[0116] Figure 5C shows an embodiment of an electroporation system 100 having an electrode 140 for electroporating a plant or group of plants 510 having plant members 510A, 510B, 510C, and 510D. As the vehicle 130 carrying the electroporation system 100 travels in the direction T, the electrode 140 contacts plant members 510A and 510B and can deliver an electroporation dosage to the plant or group of plants 510. However, plant member 510B is pressed into physical contact with plant member 510C, which in turn is pressed into physical contact with plant member 510D. The result of this is that plant member 510B shields plant members 510C and 510D from the electrode 140. Plant members 510C and 510D being shielded from the electrode 140 may reduce the efficacy of the electroporation dosage applied to the plant or group of plants 510. The likelihood of this issue arising may increase with increasing plant densities. Referring to Figure 5D, this issue may be addressed by suspending electrode tines 140a from the electrodes 140. In the embodiment of Figure 5D, the electrode tines 140a are configured to move between and / or through portions of the plant or groups of plants 510 as the electrode 140 travels in the direction T. The electrode tines 140a may therefore reduce the likelihood a plant member being pressed into physical contact and shielding another plant member from exposure to the electrode 140 as the electrode 140 travels in the direction T.

[0117] In some embodiments an electroporation dosage for a plant or group of plants is provided with a single electrode orientation or single electric field orientation. In other embodiments a plant or group of plants is provided an electroporation dosage in which the electric field is oriented in multiple directions across multiple pulses. This may be achieved by changing the electrode orientation or connectivity during treatment or by performing two or more stages of treatment at different orientations. The use of multiple directions may dependent on one or more environmental factors, for example used for plants that are large in size, have many tillers, or have low electric conductivity, or local electrical heterogeneity of the terrain.

[0118] In some embodiments, the electric field orientation is selected or controlled to not be parallel to the bulk direction of crop roots underlying the targeted weed plants, to minimise damage to crops.

[0119] Figure 6 shows a diagrammatic plot of electric field strength against time for a two-phase process that includes a sensing phase over time period T1 and an electroporation treatment phase over time period T2. The electric field may be generated by the electroporation system 100, under the control of the controller 110. In particular, one or both of the voltage and current may be controlled by the pulse generator 101 (based on control signals from the controller 110), to generate an electric field with an electric field strength approximating that shown in Figure 6. Both phases may be completed with the electrodes in the same or substantially the same position.

[0120] In the sensing phase a relatively lower dosage of electric field is applied. The lower dosage electric field may be by a reduced field strength or average field strength, a reduced field duration or reduced duty cycle, or a combination thereof. In the example of Figure 6, both a reduced intensity and a reduced duty cycle over three pulses is shown. The electric field dosage in the sensing phase may be insufficient to achieve mortality of plants, but is sufficient for a measurement to be taken, for example a measurement by the electrical sensor circuitry 105 or a measurement by the applicator sensor circuitry 123 . In the electroporation treatment phase, a relatively higher electric field dosage is applied, sufficient to achieve a high mortality rate for at least a target plant (which target plant may be a specific plant or a class of plant). In the example of Figure 6, both an increased intensity and an increased duty cycle over three pulses is shown.

[0121] The electric field dosage during the electroporation treatment phase may be determined by the controller 100, at least in part based on measurement by the electrical sensor circuitry 105, the applicator sensor circuitry 123, or both. In some embodiments the electroporation treatment phase is controlled by the controller 110 based on one or more further measurements, for example measurement by the vehicle sensor circuitry 131 or based on input from the camera 308.

[0122] The arrangement of Figure 6 is an illustrative example. There may be more or less pulses in sensing phase and more or less pulses over the electroporation treatment phase. The shape of the pulses may be different to the rectangular pulses shown and may vary between the phases. The pulses within each phase may be, but need not be of the same intensity, duration or shape.

[0123] In some embodiments, the output from one or more sensors of the electroporation system 100 is processed to form an estimate of plant density. The electroporation dosage is then determined by the controller 110 dependent on plant density, with a higher plant density resulting in a higher electroporation dosage.

[0124] In some embodiments the output of one or more sensors of the electroporation system 100 indicates a speed of travel of the vehicle 130 or another measure of the speed of travel of the electrodes 140. The electroporation dosage is then determined by the controller 110 dependent on the speed of travel, with a higher speed of travel resulting in a lower electroporation dosage, all other variables remaining the same. In some embodiments therefore, the controller 110 causes a higher dosage per unit time when travelling at higher speeds and a lower dosage per unit time when travelling at lower speeds. The electrode width (with width here used to refer to the span of the electrode in the direction of travel) may also affect the electroporation dosage, as a wider electrode will be located at the plant for a longer duration. The electrode width may be fixed or may be a settable parameter, for example if different electrode arrays or arrangements are usable with the electroporation system 100.

[0125] In some embodiments, the speed of travel of the vehicle 130 carrying the electroporation system 100 is based on the plant density. Higher plant densities may result in a lower speed of travel for the vehicle 130. Similarly, lower plant densities may result in a higher speed of travel for the vehicle 130. Accordingly, the controller 110 may increase and decrease the speed of travel of the vehicle 130 carrying theelectroporation system 100 in response to decreasing and increasing plant densities, respectively, with all other variable remaining the same.

[0126] In some embodiments the electroporation dosage is determined by the controller 110 dependent on the electrode spacing, with a higher electrode spacing resulting in a higher electroporation dosage being determined or selected.

[0127] In some embodiments the electroporation dosage is determined by the controller 110 dependent on the electrode spacing or distance from a driven electrode to a ground or a return line, with a higher electrode spacing resulting in a higher electroporation dosage. The electrode spacing may be known and may be fixed. Alternatively the spacing may be a variable of the electroporation system 100, for example at one value when the electrodes 140 are in a horizontal orientation with a connection of example A from Figure 4 and another when the electrodes 140 are in a vertical orientation and with a connection of example C or D from Figure 4.

[0128] In some embodiments, the spacing between one or more of the electrodes 140 may be varied based on the plant density. Higher plant densities may result in smaller spacing between one or more of the electrodes 140. Similarly, lower plant densities may result in larger spacing between one or more of the electrodes 140. Accordingly, the controller 110 may increase and decrease spacings between one or more of the electrodes 140 in response to decreasing and increasing plant densities, respectively, However, it will be appreciated that reducing the spacing between the electrodes 140 may make it harder to move the electrodes 140 through higher density plants.Accordingly, in some embodiments, for plant densities above a predetermined plant density threshold value, spacings between one or more of the electrodes 140 may not be further decreased but instead one or more parameters of the electroporation dosage may be varied.

[0129] Alternatively, or additionally, electrode spacing may be controlled by changing / switching which electrodes are active (e.g. connected to HV or R line in Figure 2) and which are inactive. For example, a narrow electrode spacing may be achieved by changing / switching the electrodes to have immediately adjacent electrodes being active (e.g. connections A, C, and D in Figure 4). Further, larger electrode spacings may be achieved by changing / switching the electrodes to have one or more inactive electrodes located between two active electrodes (e.g. connections B and E in Figure 4). It will beappreciated that changing / switching the electrodes to increase the number of inactive electrodes that are located between active electrodes increases the spacing between active electrodes. Similarly, it will be appreciated that changing / switching the electrodes to decrease the number of inactive electrodes between active electrodes decreases the spacing between active electrodes.

[0130] In some embodiments, the pulse frequency of the electroporation dosage may be dependent on the plant density. Higher plant densities may result in higher pulse frequencies, while lower plant densities may result in lower pulse frequencies. Accordingly, the controller 110 may increase and decrease the pulse frequency of an electroporation dosage in response to increasing and decreasing plant densities, respectively. For example, if the vehicle 130 carrying the electroporation system 100 is travelling at a constant speed, the pulse frequency of the electroporation dosage may increase and decrease in response to increasing and decreasing plant densities, respectively.

[0131] In some embodiments, the parameters of an electroporation dosage may be selected so that, when the electroporation dosage is applied to a plant, the temperature of the plant is kept below 50°C (preferably 40°C). Accordingly, the electroporation dosage applied to a plant is a non-thermal electroporation dosage. In other words, the electroporation dosage does not kill the plant by thermal damage but instead kills the plant by electroporation. For example, one or more parameters (e.g. the magnitude of the pulses and the frequency of the pulses) of an electroporation dosage may be selected and / or controlled / adjusted in order to keep the temperature of the plant below 50°C (preferably 40°C) during application of the electroporation dosage to the plant. It will be appreciated that using a thermal electroporation dosage to heat a plant to temperatures above 50°C in order to kill the plant by thermal damage may require more energy compared to a non-thermal electroporation dosage that does not heat a plant to temperatures above 50°C in order to kill the plant. Non-thermal electroporation dosages may therefore require less energy to kill a plant compared to thermal electroporation dosages. It will also be appreciated that the time required to heat a plant to temperatures above 50°C in order to kill the plant by thermal damage using a thermal electroporation dosage may be longer than the time required to kill the plant using a non-thermal electroporation dosage, which does not have to heat the plant to temperatures above 50°C in order to kill the plant. Non-thermal electroporation dosagesmay therefore require less time to kill a plant compared to thermal electroporation dosages.

[0132] In some embodiments, the applicator sensor circuitry 123 may include a temperature sensor (e.g. a thermal camera). The temperature sensor may be used to detect the temperature of a plant during or just after application of an electroporation dosage to the plant. If, during application of the electroporation dosage to the plant, the controller 110 detects, using the temperature sensor, that the temperature of the plant increases above 40°C or 50°C, the controller 110 may adjust one or more parameters of the electroporation dosage in an attempt to reduce the temperature of the plant being electroporated. Alternatively, or additionally, the controller 110 may stop and / or prevent the application of an electroporation dosage if it determines, using the temperature sensor, a temperature (e.g. of the plant or proximate the electroporation system 100) above a threshold temperature (e.g. 100°C). This may reduce the likelihood of fires starting, especially in dry areas, and may also reduce the energy consumption of the electroporation system 100.

[0133] In order to alter the dosage, the controller 110 may cause a variation in at least one of the electrical variables of the voltage supplied to the electrodes 140, the pulse length of the pulses provided to the electrodes 140 and the frequency of the pulses. In some embodiments, where the electrode actuator 122 allows, the distance between electrodes or distance from the electrodes to ground may be varied instead of or in addition to variation of the electrical variables.

[0134] In some embodiments the controller 110 is configured to effect control based on a control system according equation 1:Equation 1:Where k is a constant. In some embodiments k is fixed at 1. In other embodiments k is a variable, with the variable set according to a determination of plant species, some species getting a higher dosage and other species getting a lower dosage, all other variables being the same. In some embodiments k is instead or in addition based onother environmental factors, such soil conditions like soil temperature, soil humidity, whether the plant surfaces are dry or wet. Plant Index may be an environmental factor relating to the plant itself. For example, the plant index may refer to the plant density. As another example, the plant index may be a value calculated from a combination of different environmental factors relating to the plant itself. For this example, each environmental factor may be weighted the same or differently in order to calculate the plant index.

[0135] In other embodiments, the controller 110 is configured to effect control based on a control system according to equation 2:Equation 2:Where k is a constant, as described in relation to Equation 1. Equation 2 may be used for static systems without a speed of travel. For example the electrodes may be placed in location at one or more plants and an electroporation dosage applied while the electrodes are stationary. Equation 2 or a variation thereof may also be used during testing, to determine appropriate electroporation dosages and to determine the values for k in Equation 1 or Equation 2.

[0136] Figure 7 shows three examples of voltage pulse shape that may be applied to the electrodes 140: exponentially decaying pulses; truncated exponentially decaying pulses; and rectangular pulses.

[0137] Figures 8A and 8B show the results of a series of experiments on ryegrass and gazania respectively. Each figure plots dosage against total electrical energy supplied to electrodes (the product of voltage (V), current (A) and time (seconds)), the dosage measured based on Equation 2 with an index value entered that reflected an observation of plant density. The darker dots indicate plant mortality and the lighter dots indicate plant survival following receipt o the electroporation dosage. The horizontal line dividing the shaded and non-shaded portions of the graphs in Figures 8A and 8B is an indicative minimum dosage, which is about 3.5 for ryegrass and about 0.75 for gazania. The controller 110 may cause the electroporation system 100 to provide a dosage at or above the minimum dosage, when the electroporation system detects or receives aninput that it is to treat that species of plant. In other words and by way of example, if the value of k in Equation 1 or Equation 2 for gazania is 1 , the value of k for ryegrass may be about 4.7. As will be appreciated from Figures 8A, 8B it may be advantageous to electroporate based on plant species in order to reduce energy consumption.

[0138] In other embodiments, the controller 110 is configured to effect control by reference to an electroporation dosage database. In such embodiments, the electroporation system 100 may identify one or more environmental factors using the applicator sensor circuitry 123. The one or more environmental factors may include but not limited to plant species, plant size, plant density, plant health or vitality, plant growth stage, plant proximity, terrain, soil type, soil moisture, temperature, humidity.Subsequently, the controller 110 may determine an electroporation dosage from the electroporation dosage database based on the identified one or more environmental factors and apply the determined electroporation dosage to one or more of the electrodes 140 to electroporate an identified plant.

[0139] Figure 9A illustrates an exemplary method of building an electroporation dosage database using test data. The “Plant Input” and “Environment Input” tables represent environmental factors that may be used to determine an appropriate electroporation dosage.

[0140] The “Plant Input” table defines the initial characteristics of the plants before application of an electroporation dosage. The “Plant Input” table incudes several environmental factors relating to the plant itself. These environmental factors include:

[0141] “Species” - the plant species or family;

[0142] “Above-ground Mass” (e.g. grams) - total weight of plant material above the soil surface, including stems, leaves, and flowers; and

[0143] “Number of tiller / leaves” - the number of stems (tillers) or leaves the plant has;

[0144] “Stem diameter” (e.g. millimeters) - the thickness of the plant’s stem;

[0145] “Growth stage” - the developmental phase of the plant (e.g., seedling, vegetative, flowering);

[0146] “Plant density” (e.g. plants / m2) - a metric of how dense, e.g. the number of plants per unit area (plants / m2), or green coverage (green % per m2, pixels per m2); and

[0147] “Plant Shape” - a description of plant morphology / phenotype, e.g. tall, flat.

[0148] The “Environment Input” table captures the soil and climate conditions associated with the plant that might influence treatment effects. The environmental factors included in the “Environment Input” Table include:

[0149] “Soil Type” - the classification of soil based on texture, composition, and structure (e.g., sandy, loamy, clayey);

[0150] “Soil Moisture” (e.g. %) - the percentage of water content in the soil;

[0151] “Soil Conductivity” (S / m) - the ability of soil to conduct electricity;

[0152] “Soil Temperature” (e.g. °C) - the temperature of the soil;

[0153] “Soil pH” - the measure of soil acidity or alkalinity;

[0154] “Soil Aeration” (e.g. %) - the proportion of air spaces in the soil;

[0155] “Air Humidity” (e.g. %) - the amount of water vapor in the air; and

[0156] “Terrain” - the physical characteristics of the land surface (e.g., flat, sloped, uneven).

[0157] The environmental factors listed in the “Plant Input” and “Environment Input” tables may be obtained using any suitable methods / devices / sensors. Further, the environmental factors listed in the “Plant Input” and “Environment Input” tables are only an example of the environmental factors that may be used to build an electroporation dosage database. It will be appreciated that additional, alternative, or fewer environmental factors may be included in each of the “Plant Input” and “Environment Input” tables.

[0158] The “Electroporation Dosage” table specifies the electrical parameters of an electroporation dosage. These parameters include:

[0159] “Voltage” (e.g. kV) - the electrical potential difference applied between two or more electrodes.

[0160] “Pulse Shape” - the description of the waveform, which may be composed of one or more of square, triangular, sinusoidal, exponentially decaying, or clipped above a predetermined amplitude, or truncated at a predetermined pulse width;

[0161] “Pulse width” (e.g. ps) - the duration of a single pulse, or the time where the pulse amplitude is non-zero;

[0162] “Frequency” (e.g. Hz) - the number of electrical pulses delivered per second.

[0163] “Field Strength” (e.g. kV / cm) - the intensity of the electric field resulting from the voltage applied;

[0164] “Treatment Time” (e.g. ps) - the total duration for which the plant is exposed to the electric field;

[0165] “Speed of travel of electrode(s)” (e.g. km / h) - the speed at which the electrode(s) 140 of the electroporation system 100 travels;

[0166] “Geometry of electrode(s)” - the shape and arrangement of the electrode(s) 140 delivering the electroporation dosage;

[0167] “Electrode spacing” (e.g. cm) - the distance or distances between two electrodes; and

[0168] “Number of Passes” - the number of times the electroporation dosage is applied to the same area or plant.

[0169] The electroporation dosage parameters listed in the “Electroporation Dosage” table are only an example of the electroporation dosage parameters that may be used to build an electroporation dosage database. It will be appreciated that additional, alternative, or fewer electroporation dosage parameters may be included in the “Electroporation Dosage” table.

[0170] The “Realtime Feedback” table indicates the electrical properties during application of the electroporation dosage. The “Realtime Feedback” table includes the following data:

[0171] “Resistance” (e.g. kQ) - the electrical resistance of the plant-soil system measured over time during treatment, from the first pulse ti to the nth pulse tn, where changes may indicate the response of the plant to the electroporation dosage;

[0172] “Current” (e.g. A) - the flow of electric charge through the plant and soil system during treatment, from the first pulse ti to the nth pulse tn, where changes may indicate the response of the plant to the electroporation dosage; and

[0173] “Energy” (e.g. J) - the total energy delivered to the plant-soil system during the electroporation dosage.

[0174] The data in the “Realtime Feedback” table may be obtained using any suitable methods / devices / sensors. Further, the real time feedback data listed in the “Realtime Feedback” table are only an example of the real time feedback data that may be used to build an electroporation dosage database. It will be appreciated that additional,alternative, or fewer real time feedback data may be included in the “Realtime Feedback” table.

[0175] The “Output” table indicates the results of the application of an electroporation dosage to a plant. The “Output” table includes the following data:

[0176] “Plant Mortality” (e.g. %) - the percentage of plants exposed to the electroporation dosage that die due to exposure to the electroporation dosage.

[0177] “Cell Damage” (e.g. pS / g) - the extent of cellular disruption in plant tissues measured per unit mass.

[0178] “Temperature” (e.g. °C) - the temperature of the plant after exposure to the electroporation dosage, indicating thermal effects of the electric dose.

[0179] “Plant Health” - the qualitative score evaluating the overall condition of the plant after exposure to the electroporation dosage (e.g. 0 = dead, 5 = optimal health).

[0180] The data in the “Output” table may be obtained using any suitable methods / devices / sensors. Further, the output data listed in the “Output” table are only an example of the output data that may be used to build an electroporation dosage database. It will be appreciated that additional, alternative, or fewer output data may be included in the “Output” table.

[0181] An electroporation dosage having particular parameters is applied to a particular plant species or family and the outcome of that particular electroporation dosage is then assessed. One or more parameters of the electroporation dosage may be subsequently optimised to achieve a plant mortality of at least 70%, at least 80%, or at least 90% and a temperature below 50°C (preferably 40°C). The temperature is the maximum temperature the plant reaches in response to being exposed to the electroporation dosage. Once the parameters of the electroporation dosage have been optimised to satisfy the plant mortality and temperature requirements, those parameters may be stored in the electroporation dosage database. This process may be repeated for the same plant species or family but varying one or more of the other environmental factors in the “Plant Input” and “Environment Input” tables. Accordingly, for a given plant species or family, a database may be built that includes multiple electroporation dosages having different parameters that can be used to electroporate plants having different environmental factors (e.g. the environment factors listed in the “Plant Input” and “Environment Input” tables). It will be appreciated that the above process can berepeated for other different plant species or families. The electroporation dosage database may therefore include multiple electroporation dosages for multiple different plant species or families having different environmental factors.

[0182] After the electroporation dosage database has been built, for this embodiment, the controller 110 of the electroporation system 100 may identify a particular plant and environmental factors associated with that plant using the applicator sensor circuitry 123. Subsequently, the controller 110 may refer to the electroporation dosage database to identify an electroporation dosage in the electroporation dosage database having environmental factors that correspond to the environmental factors identified by the applicator sensor circuitry 123. After the electroporation dosage has been identified in the electroporation dosage database, the controller 110 applies an electroporation dosage having the respective parameters of the identified electroporation dosage (i.e. the parameters in the “Electroporation Dosage” table) to the electrodes 140 to electroplate the identified plant.

[0183] Figure 9B shows an example electroporation dosage that causes a 100% mortality rate and a temperature of 34°C for a gazania plant having the particular environmental factors listed in the “Plant Input” and “Environment Input” tables. Accordingly, in use, in response to detecting a gazania plant having similar environmental factors to those listed in the “Plant Input” and “Environment Input” tables of Figure 9B, the controller 110 would cause an electroporation dosage having the parameters listed in the “Electroporation Dosage” table to be applied to the electrodes 140 to electroporate the gazania plant.

[0184] Figure 9C shows an example electroporation dosage that causes a 85% mortality rate and a temperature of 39°C for an annual ryegrass plant having the particular environmental factors listed in the “Plant Input” and “Environment Input” tables. Accordingly, in use, in response to detecting an annual ryegrass plant having similar environmental factors to those listed in the “Plant Input” and “Environment Input” tables of Figure 9C, the controller 110 would cause an electroporation dosage having the parameters listed in the “Electroporation Dosage” table to be applied to the electrodes 140 to electroporate the annual ryegrass plant.

[0185] It will be appreciated that a statistical model (e.g. machine learning or any other suitable algorithm) could be used to build and / or optimise the electroporation dosage database.

[0186] It will also be appreciated that the electroporation dosage database may not include electroporation dosages that exactly match the environmental factors identified by the controller 110 using the applicator sensor circuitry 123. It is therefore envisaged that the controller 110 could use a statistical model (e.g. machine learning or any other suitable algorithm) to identify which electroporation dosage in the electroporation dosage database would be best to use based on the particular environmental factors identified by the controller 110 using the applicator sensor circuitry 123. Alternatively, the controller 110 may use a statistical model (e.g. machine learning or any other suitable algorithm) to optimise one or more parameters of an electroporation dosage of the electroporation dosage database in order to determine parameters for an electroporation dosage to use for a particular plant having particular environmental factors identified by the controller 110 using the applicator sensor circuitry 123.

[0187] In some embodiments, the electroporation system 100 uses one or more of a measured total charge, total energy or total treated time to determine when it has reached a required electroporation dosage. This is on the basis that the other variables are known or fixed. The electroporation system 100 may cease generating the electric field or may control the speed of travel of the vehicle 130 to provide the required electroporation dosage and then cease operation or move to the next area.

[0188] Figure 10 shows a flow diagram of a method 1000. The method 1000 may be performed by the controller 110. For example instructions to cause the computer processing system 300 to perform the method 1000 may be stored in the non-transitory memory 304 and executed by the processing unit 301. The method will be described in this context, but the method can also be performed by other forms of controller.

[0189] At step 1001 the computer processing system 300 receives or generates an indication of one or more environmental factors. Various environmental factors that electroporation may be based on are described herein and will not be repeated in full. For the purposes of illustration reference will be made to just two - an identification of plant species and plant density. The plant species and plant density may be input via a user input or received via an input or communication interface from another device. Theplant species and plant density may be determined by the computer processing system 300 based on data from one or more sensors. The sensors may be optical, for example a camera or lidar system, or electrical, for example based on the sensing phase described with reference to Figure 6.

[0190] At step 1002 the computer processing system 300 sets one or more electroporation parameters based on the received or generated environmental factors and causes the commencement of electroporation by the electroporation system 100. For example, the voltage applied to the electrodes or duty cycle of the pulses or the duration of the pulses may be set. Other variables that may be set are described herein.

[0191] At step 1003 the computer processing system receives or generates an indication that the electroporation treatment is completed. As described herein this may be based on a feedback measurement, such as energy consumed. Feedback may additionally or alternatively be based on physical appearance or change in electrical properties. Alternatively step 1003 may be omitted or the indication based on a timer or counter, for example when treatment is for a fixed duration or a duration determined in step 1002, or a fixed number of pulses, or a number of pulses determined in step 1002. At step 1004 the electroporation of the plants located at the electrodes 140 is ended, for example by ceasing the application of pulses or moving the electrodes to the next plant or group of plants.

[0192] Figure 11 shows a laboratory trial conducted on annual ryegrass, where a single tiller was used without soil, and electrodes were applied directly to the plant. The ryegrass tillers where at an early vegetative stage, with diameters ranging from 0.9 to 1.3 mm.

[0193] The scatter plot of Figure 11 illustrates the relationship between treatment time (in ps) and field strength (in kV / cm) on plant health. The x-axis represents the treatment time, while the y-axis represents the field strength. The datapoints marked “X” represent plants that died after being exposed to a particular electroporation dosage, while the circular datapoints represent plants that were still alive after being exposed to a particular electroporation dosage. With reference to the “Plant Index” in Figure 11 , the size of the markers representing the respective datapoints represent the physical size of the respective plants. For example, datapoints marked with a smaller “X” represent asmaller plant, while datapoints marked with a larger “X” represent a larger plant. The same is true for the circular datapoints.

[0194] As used herein, except where the context requires otherwise, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude further additives, components, integers or steps.

[0195] It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

Claims

CLAIMS1. A method of electroporating plants, the method comprising: determining one or more of plant species, plant size, plant density, plant health and plant growth, of one or more plants or groups of plants to be electroporated; setting an electroporation dosage based on the determined one or more of plant species, plant size, plant density, plant health and plant growth; and applying a pulsed electric field to the one or more plants at the set electroporation dosage.

2. The method of claim 1 , wherein determining the one or more of plant species, plant size, plant density and plant growth comprises: applying a first dosage electric field to the one or more plants; measuring one or more electrical characteristics of the one or more plants during application of the first electric field; and determining the one or more of plant species, plant size, plant density and plant growth based on the measured electrical characteristics.

3. The method of claim 2, wherein the measured electrical characteristics include one or more of voltage, current, impedance, and energy consumed.

4. The method of claim 1, wherein setting the electroporation dosage based on the plant density comprises increasing the dosage as the plant density increases.

5. The method of claim 1 , wherein applying the electric field at the set electroporation dosage comprises controlling one or more of voltage, pulse length, pulse frequency, and number of pulses.

6. The method of claim 1 , further comprising controlling a speed of travel of a vehicle carrying the electroporation system based on the plant density, wherein a higher plant density results in a lower speed of travel.

7. The method of claim 1 , wherein determining the one or more of plant species, plant size, plant density and plant growth is determined by analysing an image or video of the one or more plants or groups of plants.

8. The method of claim 1, further comprising controlling a spacing between one or more electrodes of the electroporation system based on the plant density, wherein a higher plant density results in a smaller electrode spacing.

9. The method of claim 1, further comprising determining when the electroporation treatment is complete based on measured electrical characteristics associated with electrodes that generate the pulsed electric field and ceasing application of the electric field in response.

10. The method of claim 1, further comprising controlling positioning of one or more electrodes of the electroporation system based on the determined one or more of plant species, plant size, plant density and plant growth.

11. The method of claim 1 , wherein the electroporation dosage is a non-thermal electroporation dosage.

12. An electroporation system comprising: one or more sensors for determining one or more of plant species, plant size, plant density, plant health, and plant growth of one or more plants or groups of plants to be electroporated; a pulse generator for generating electrical pulses; a pulse applicator for applying the electrical pulses to one or more electrodes to generate a pulsed electric field; and a controller configured to: set an electroporation dosage based on the determined one or more of plant species, plant size, plant density, plant health and plant growth, and cause the pulse generator and pulse applicator to apply an electric field to the one or more plants at the set electroporation dosage.

13. The electroporation system of claim 12, configured to: apply a first dosage electric field to the one or more plants, measure one or more electrical characteristics during application of the first electric field, and determine the one or more of plant species, plant size, plant density and plant growth based on the measured electrical characteristics.

14. The electroporation system of claim 13, wherein the measured electrical characteristics include one or more of voltage, current, impedance, and energy consumed.

15. The electroporation system of claim 12, wherein the controller is configured to set the electroporation dosage by increasing the dosage as the plant density increases.

16. The electroporation system of claim 12, wherein the controller is configured to control one or more of voltage, pulse length, pulse frequency, and number of pulses to apply the electric field at the set electroporation dosage.

17. The electroporation system of claim 12, further comprising a vehicle for transporting the pulse generator, pulse applicator, and controller, wherein the controller is configured to control a speed of travel of the vehicle based on the plant density, such that a higher plant density results in a lower speed of travel.

18. The electroporation system of claim 12, further comprising an electrode actuator for controlling a position or orientation of the one or more electrodes, wherein the controller is configured to control the electrode actuator to adjust at least one of the electrode position and orientation based on the plant density.

19. The electroporation system of claim 12, further comprising an imaging system for producing at least one image or video of plants, wherein the controller is configured to determine the one or more of plant species, plant size, plant density, plant health and plant growth based on the at least one image or video.

20. The electroporation system of claim 12, wherein the controller is configured to determine when the electroporation treatment is complete based on measured electrical characteristics of the pulse generator or pulse applicator and cease application of the electric field in response.

21. The electroporation system of claim 12, further comprising an electrode actuator for controlling positioning of the one or more electrodes, wherein the controller is configured to control the electrode actuator based on the determined one or more of plant species, plant size, plant density, plant health and plant growth.

22. The electroporation system of claim 12, wherein the electroporation dosage is a non-thermal electroporation dosage.

23. A method of electroporating plants, the method comprising: targeting the basal portion of one or more plants for electroporation; applying an electric field to the basal portion of the one or more plants; and controlling one or more parameters of the electric field to achieve a mortality rate for the electroporated plants.

24. The method of claim 23, wherein targeting the basal portion of the plants comprises positioning one or more electrodes proximate to the basal portion of the plants.

25. The method of claim 24, further comprising mechanically pushing over the plants to position the one or more electrodes proximate to the basal portion.

26. The method of claim 24, wherein the one or more electrodes are oriented horizontally to target the basal portion of the plants.

27. The method of claim 24, wherein the one or more electrodes are oriented vertically and positioned to be at least partially aligned with the basal portion of the plants.

28. The method of claim 23, wherein controlling the one or more parameters of the electric field comprises controlling one or more of voltage, pulse length, pulse frequency, and number of pulses.

29. The method of claim 23, wherein the mortality rate is at least 70%, at least 80%, or at least 90%.

30. The method of claim 23, further comprising sensing one or more environmental factors and controlling the electric field based on the sensed environmental factors.

31. The method of claim 30, wherein the environmental factors include one or more of plant species, plant size, plant density, plant health and plant growth stage.

32. The method of claim 23, further comprising providing a first, lower dosage electric field to the plants for a sensing phase, measuring one or more electrical characteristics during the sensing phase, and applying the electric field for the electroporation based on the measured electrical characteristics.

33. An electroporation system comprising: one or more electrodes configured to be positioned proximate to the basal portion of one or more plants; a pulse generator for generating electrical pulses; a pulse applicator for applying the electrical pulses to the one or more electrodes; and a controller configured to: control the positioning of the one or more electrodes to target the basal portion of the plants, and control one or more parameters of the electrical pulses applied by the pulse applicator to achieve a high mortality rate for the electroporated plants.

34. The electroporation system of claim 33, further comprising an electrode actuator controlled by the controller to position the one or more electrodes proximate to the basal portion of the plants.

35. The electroporation system of claim 34, further comprising a vehicle for transporting the electroporation system, wherein the electrode actuator is configured to mechanically push over the plants to position the electrodes proximate to the basal portion.

36. The electroporation system of claim 33, wherein the one or more electrodes are oriented horizontally to target the basal portion of the plants.

37. The electroporation system of claim 33, wherein the one or more electrodes are oriented vertically and positioned to be at least partially aligned with the basal portion of the plants.

38. The electroporation system of claim 33, wherein the controller is configured to control one or more of voltage, pulse length, pulse frequency, and number of pulses to achieve the high mortality rate.

39. The electroporation system of claim 33, wherein the high mortality rate is at least 70%, at least 80%, or at least 90%.

40. The electroporation system of claim 33, further comprising one or more sensors for sensing one or more environmental factors, wherein the controller is configured to control the electrical pulses based on the sensed environmental factors.

41. The electroporation system of claim 40, wherein the environmental factors include one or more of plant species, plant size, plant density, plant health and plant growth stage.

42. The electroporation system of claim 31, wherein the controller is configured to: apply a first, lower dosage electric field to the plants for a sensing phase, measure one or more electrical characteristics during the sensing phase, and apply the electrical pulses for the electroporation based on the measured electrical characteristics.

43. A method of electroporating plants, the method comprising: applying a first dosage electric field to a plant; measuring one or more electrical characteristics of the plant during application of the first electric field; and applying a second dosage electric field to the plant based on the measured electrical characteristics.

44. The method of claim 43, wherein the first electric field is applied for a sensing phase and the second electric field is applied for an electroporation treatment phase for achieving a plant mortality rate.

45. The method of claim 43, wherein the measured electrical characteristics include one or more of voltage, current, impedance, and energy consumed.

46. The method of claim 43, further comprising determining an environmental factor based on the measured electrical characteristics and applying the second electric field based on the determined environmental factor.

47. The method of claim 46, wherein the environmental factor includes one or more of plant species, plant size, plant density, plant health and plant growth stage.

48. The method of claim 43, wherein the first dosage electric field is a lower dosage than the second dosage electric field.