Automatic Irrigation and Fertilizer Injection Systems
What is automatic irrigation?
Automatic irrigation is the use of a control system to operate irrigation structures to control the flow of water from one zone, or set of zones, and occurs in the absence of the irrigator.
Automation can be used in a number of ways:
(1) To start and stop irrigation through supply outlets, wireless valves, and gates.
(2) To start and stop electric or engine driven pumps and fertilizer equipment.
(3) To control flow of water from one irrigation zone or a section of a zone. Allowing multiple zone to be added to your irrigation schedule.
These changes occur automatically without any direct manual effort of the irrigation staff.
What are the benefits of automatic irrigation?
As the irrigator is not required to constantly monitor the progress of an irrigation, the irrigator is available to perform other tasks – uninterrupted.
The irrigator is not required to constantly check the progress of zones being irrigated. The irrigator is able to be away from the property, relax with the family, and sleep through the night.
More timely irrigation:
Irrigators with automation are more inclined to irrigate when the plants need water, not when it suits the irrigator.
Assists in the management of higher flow rates:
Many irrigators are looking to increase the irrigation flow rates they receive through installing bigger channels and piping. Such flow rates generally require an increase in labor as the time taken to irrigate a zone is reduced, thus requiring more frequent change over. Automation allows for these higher flows to be managed without an increase in the amount of labor and operated by a smart device.
More accurate cut-off:
Automation of the irrigation system allows sensors to control the water at the appropriate point in the zones. This is usually more accurate than manual checking because mistakes can occur if the operator is too late or too early in making a change of water flow.
Reduced runoff of water and nutrients:
Automation can help keep fertilizer in the root zone, effectively reducing run off from the property. Retaining fertilizer on farm has both economic and environmental benefits.
Reduced costs for vehicles used for irrigation:
As the irrigator is not required to constantly check progress of an irrigation, trucks, motor bikes, four wheelers, and other vehicles are used less. This reduces the running costs of these vehicles as they require less frequent replacement.
What are the disadvantages of automatic irrigation?
There are costs in purchasing, installing, and maintaining automatic equipment. Also the cost and commitment to hire, train, and support the irrigating staff. Once the system is up and operational, the benefits and cost savings are immediate.
Today's irrigations systems are build on rugged industrial control platforms used in other exacting operations. Some example of systems are power generation, water/waste water management, and hospitals.
Can the irrigator trust an automatic system to work correctly every time?
Sometimes failures will occur. Often these failures are because of human error in settings, accidents (tractor runs over field equipment), and maintaining the systems. A well maintained system will work tirelessly day and night.
There is a need to maintain the field and irrigation equipment to ensure the system works correctly. Maintenance scheduling of valves, sensors, and pumps should implemented by the irrigating staff. Equipment should be installed properly protected to avoid damage from farm equipment and field personnel
What automatic irrigation systems are available?
Timer/ Sensor Hybrid:
As the name suggests, this system is a hybrid of portable timer and sensor systems. Like a portable timer, it uses an electronic device to activate the opening and closing of the irrigation structures. However, this system has an additional feature of the irrigator being able to place a moveable sensor in the field or substrate. When the system comes in contact with water, it transmits radio signals to the timer devices at the outlets to open or close the valve or structures and sends a radio message to a receiver to let the landowner know water has reached the cut-off points or user selected set points.
Automation systems that use Supervisory Control and Data Acquisition (SCADA) consist of a personal computer and software package to schedule and control irrigation via a radio or cellular links. Signals are sent from the computer to control modules in the field to start pumps, open and close irrigation valves or structures with linear actuators. Valves and gates are opened and closed on a sensors reading or time basis, some systems have the capacity to automatically alter the time to the valve or gate if the water supply is inconsistent.
SCADA based systems have the additional benefit of being able to start and stop pumps and motors, open valve and gates, trend system dynamics, and inform the user of events and alarms.
How can an irrigation layout be automated?
An irrigation layout can be automated at one of two places; in sections of the fields or at individual areas. Placement of valves and sensors is important to the accuracy of the irrigation. Most of the time the existing piping and valve location can be used.
Automation of fields or substrate
This system uses remote wireless control valves in lieu manual field valves. Field sensors monitor field and environmental condition, that data is sent to the main controller to control the irrigation and fertigation.
Automation of channels sections
This method of automation requires a larger amount of fall to be available in the channel system to allow for a change in water level between different areas. This change in water level is required to prevent water flowing onto bays previously irrigated, when another section is to be irrigated. On many farms this fall is not available, so this method of automation in many cases is not suitable.
Which system is best?
All systems of automation have advantages and disadvantages that need to be considered when deciding which system will suit the irrigation layout for a particular property. There is no system that will be the "best" system for all properties.
The methods of irrigation used by the irrigator need to be considered. If a system that can be moved around the property and perhaps used on other properties is required, then the irrigator needs to consider those systems that are portable. If the irrigator wants a system where the components are fixed and can follow the same irrigation sequence each irrigation, then a fixed system would be more appropriate.
In determining the best system for a property, the irrigator will need to consider the cost of the system, back up servicing of the system, and which system will best suit the property and irrigation layout.
Where do I start?
Development of a whole farm plan for the property is a good way to start preparing for automation. During the development of a whole farm plan, landholders should consider automatic irrigation in the planning process so they can incorporate some of the features required for automation from the start. This might involve design of the valving or gate automation if that is possible or structures that will suit automation at a later stage.
When it comes to starting to install automation there are a number of ways of getting started. One way is to start by automating those areas irrigated at night, so appropriate irrigation flow rates can be achieved, without disrupting the irrigator's sleep. Another is to automate those areas that are difficult to irrigate – areas of short and steep areas that require the irrigator to be present more often or require frequent changes.
Automation is not only suited to areas of the farm that have been laser graded. Non-lasered areas can also be automated.
With the information from a whole farm plan, irrigation devices that will be used when the automation is implemented, can be purchased and used manually, until full automation is completed.
Automation and Control review
AgRite automation team