AU2003100531A4 - A system for monitoring and improving the growth of plants - Google Patents

Description

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT A SYSTEM FOR MONITORING AND IMPROVING THE GROWTH OF PLANTS The following statement is a full description of this invention, including the best method of performing it known to me: A System for Monitoring and Improving The Growth of Plants This invention relates to a sensor and control system for use in crop growing systems. In particular the sensor is an intelligent plant measurement package that is co-sited with the target plants and measures multiple environment parameters relevant to optimal plant growth it also measures an indication of relative plant health. Multiple independent sensors located throughout the growing site process information and communicate with control packages which make intelligent decisions to control the environment. The sensors also communicate with a central reference system that has knowledge of the plant type, the specific growing environment and history information to allow informed decisions to optimise plant growth.

This invention is particularly applicable to Hydroponic or greenhouse growing systems where control over the growing environment is greater than traditional field methods. Hydroponic growing systems are fast becoming a major source of food production in the world. These systems rely on growing plants in a water and nutrient solution rather than growing in soil or other growing media. There are a number of different methods including: Ebb and Flow, Drip Method, Nutrient Film Technique (NFT) and Passive Systems. However, all methods used require the delivery of nutrient solution which includes an optimal mix of elements to promote growth. In addition, there are a number of environmental parameters that can be controlled to generate the optimal growth patterns including temperature, humidity and light. At any stage of growth plants have a particular photosynthesis rate that can be measured and compared with plant type and history to determine if the environment is optimal.

Farmers in general are recognising the need for "precision farming" which focuses on specific local application of products based on plant needs. Patent W003/009669 describes one such method.

This concept has not yet spread to the hydroponic and greenhouse industry.

In contrast, the most common farming practice is to apply a nutrition mix to an entire crop/greenhouse at a constant rate of application. The rate of application is selected to generally maximize crop yield over the entire farm/greenhouse and if often based on nutrient manufacturers specification. Unfortunately, not all areas of a hydroponic farm have consistent crop conditions nor those that match the manufacturers' environment. This practice can result in over or under application of product over a portion of the crop, which wastes money and may actually reduce crop yield. Farm viability is closely related to cost control and reducing costs through the optimal use of nutrients is critical. In addition, a number of farms apply a runoff to waste system and excess nutrients remaining in waste can cause environmental damage.

A feature of this system is to control the application of nutrients and change environment controls based on demands emitted by multiple sensors, which compete for the optimal growing conditions.

An embodiment of this invention includes sensors with multiple sensor probes co-located in a single waterproof package that communicates with other systems via wire, or optionally wireless methods. Another embodiment includes power for the sensor derived from solar radiation, which allows for a cable free installation.

An embodiment of this invention is a sensor package that is cylindrical with a clear top cover, which allows light measurement and entry of light for solar power production. Preferably this package is constructed from UV PVC but other materials may be used. The sensor package also has an internal seal near the base through which sensor probes pass. The base if the package is immersed in nutrient solution and the top of the package is above the solution. These sensor probes are able to measure nutrient Ph, electrical conductivity and temperature. The package also includes an optional opening near the top, which allows air entry to probes measuring air characteristics such as temperature, CO2 content and humidity. This invention is not limited to these probes alone and other probes can be optionally added.

Preferably the sensor package contains a microprocessor chip, which can read inputs from the individual probes, analyse these and send demand commands to other systems via wire or wireless means. Preferably this microprocessor can optionally also communicate with a central information system to access data to assist in formulating demand commands. These demand commands are formulated through comparison of the central system data, which indicates the level of growth achievable with the current level of plant activity measured. If it is determined that a plant is not reaching optimal growth additional demands are generated.

A feature of this system is the use of control packages, which can receive the commands from multiple sensor probe packages, arbitrate competing demands and activate mechanical and/or electrical systems to adjust the plant environment. In an embodiment of this invention these control packages are housed in sealed DIN 43880 boxes however other packaging may be used.

Environmental parameters that may be controlled by these systems include (but are not limited to) nutrient solution mix, pumps, fans, greenhouse roof opening actuators and CO2 gas injection.

Recognised prior art utilises a variety of automated systems to control growing environments however none have been identified that "close the growing loop" by relating ideal growth for specific plants, historical information, real time environment information and current relative plant health to optimise environment control in a fully automated way. Current art systems can control nutrient application but do not cater for individual plant demands in real time based on plant health.

Other current art systems can control environmental factors such as temperature, sunlight and humidity but are often based on sensors measuring a whole greenhouse area, not at specific plant locations on an intelligent basis described above where multiple sensors compete for optimal conditions.

A feature of this system is that the distributed sensors described above are able to communicate with a central reference system which contains data on plant types, the specific growing environment and history information. Preferably this information is contained in a database operating on a standard personal computer. In a preferred embodiment a software application allows maintenance of this database as well as collection of new data from sensors. Preferably this software is capable of presenting this data to a grower in graphical or text form. Preferably the software can also initiate control demands that override the individual plant sensor demands.

Another preferred feature of this software is to monitor sensor data and initiate alerts and reports to the grower. Preferably these alerts/reports may include (but are not limited to) failure of a sensor or controller or summary performance information. Preferably these alerts/reports may be transmitted to the grower through a variety of methods including (but not limited to) audible signals, email, mobile phone voice or SMS message and wireless communication to Personal Digital Assistant devices.

Analysis of plant health can be performed manually by refractometer or by laboratory spectrographic leaf analysis. More recently methods have improved analysis ability in the field using reflectance analysis or by analysis of fluorescence after stimulation. Patent W003/009669 describes a reflectance sensor and patent WO 2002/5114 describes a method of measurement of fluorescence, which allows measurement of plant health. These prior art methods use measurement of light at near infrared wavelengths and measure light reflected from or emitted from plant leaves.

In an embodiment of this invention, commercial sensors using these (or other) methods may be used.

In another embodiment of this invention a novel procedure consisting of the measurement of the transmission of infrared light through a sample plant leaf may be used. The amount of light passing through a leaf has been determined to be an indicator of the relative health of the sample. In an embodiment of this invention the light emitted is at a peak wavelength of 940nm however other wavelengths may be used. In a preferred embodiment of this invention an infrared light emitter is positioned above a leaf and a sensor package containing an infrared reciever is placed below the leaf. In another preferred embodiment the emitter and receiver are located in handheld tongs which allow periodic manual testing.

Brief Description of the Drawings This invention may be better understood with reference to the illustrations of the embodiments of the invention, which include: Figure 1, which is a block diagram showing the components of the system. Multiple sensor packages 1 are located at plant locations. Sensor packages 1 communicate with multiple controllers 2 via communications links 4 to effect environment changes. Sensor packages also communicate with the central reference system 3 to obtain reference data.

Figure 2 showing a drawing of an embodiment of the sensor package. The package is contained in a rigid plastic case 1. The case has a clear plastic top 2 and a plastic seal 3 part way down the inside cylinder. Sensor probes 4 for measuring liquid protrude downwards through this seal. Sensor probes for measuring air 5 are located in a chamber near an opening 6 in the main case 1. Sensor probes for measuring light 7 are positioned inside the case under the clear top 2. The base of the case is open 8 to allow liquid entry. Sensor electronics 9 process sensor probe measurements and communicate to other systems.

Figure 3 showing drawings of an embodiment of the infrared leaf sensor. The sensor package 1 has a flexible but semi-rigid tube 2 with the infrared emitter at the tip 3. The infrared receiver 4 is protected inside the sensor package behind a clear plastic top 5. The tube is positioned so that the plant leaf 6 is between the emitter 3 and receiver 4. Another embodiment of this sensor is the use of fibre optic inside the tube 2 and the emitter located inside the sensor package at 7.

Figure 4 showing another embodiment of the infrared sensor in a manual tong tool. The tool has a rigid plastic handle 1 and jaws containing the infrared emitter 2 and receiver 3. An operator can position the jaws manually around a leaf. The tool handle contains a button 4, which can be pressed to indicate to the sensor package 6 electronics that a measurement is being made. The tool is connected to the sensor package 6 via flexible cable 5. An optional embodiment is the use of data encoding the measurement reading in the infrared emitter signal and another receiver 7 inside the sensor package capable of decoding the infrared signal. This removes the need for the cable

Claims (6)

1. A system for monitoring and improving the growth of plants comprising: multiple sensor packages, multiple control packages and a central reference system where the sensor packages independently measure growing plant environment parameters and performance, request relevant data from the reference system, make demand decisions based on relevant data and communicate demands to the control packages which arbitrate and activate systems to effect environment changes.

2. A sensor probe that is capable of measurement of relative plant health by the transmission of infrared light through a plant leaf comprising a controlled light source, a light receiver and microprocessor electronics and software to measure light transmission intensity and calculate relative plant health. Optionally, the light source may be modulated and include data.

3. A system for monitoring and improving the growth of plants as claimed in claim 1 where the sensor packages contain multiple sensor probes measuring Ph, electrical conductivity, temperature and plant health (and other optional probes), electronics and software to capture probe measurements, obtain reference data, make demand decisions and communicate the demands to multiple control packages.

4. A system for monitoring and improving the growth of plants as claimed in claim 1 where the control packages contain electronics and software that receives demands from sensor packages, determines if this specific controller controls particular environment systems to meet the demands, arbitrates among multiple demands and activates systems to meet the demands.

A system for monitoring and improving the growth of plants as claimed in claim 1 where all communication is via a wireless network and sensors optionally contain solar power cells to avoid the need for cables.

6. A system for monitoring and improving the growth of plants substantially as herein before described with reference to figures 1 to 4 of the accompanying drawings. NANOSYS PTY LTD 3 July 2003 Stephen French