Interest in micro irrigation systems and micro sprinkler irrigation for orchards continues to increase with improvements in tree production, crop quality and water application uniformity, along with decreases in water use, fertilizer use and labor. As improvements in system efficiency continue to grow, growers and users are adapting to the purposes and the benefits that micro sprinkler systems can provide. The Drip Store’s wide range of micro sprinklers and micro sprayers for orchard irrigation are available in a range of flow rates from a low of 5 GPH to a high of 70 GPH and with diameters from 3' up to 40'.
Micro sprinklers with moving parts and micro sprayers, jets without moving parts have small droplets and low flow application rates that help maintain low water tension in the soil, preventing tree stress. Micro sprinklers and micro sprayers are suited for irrigation under tree canopies, for seedlings, young saplings and mature trees in all types of spacing configurations. Micro sprinklers or micro sprayers under tree canopies can be installed with one micro sprinkler or sprayer per tree, one between two trees, one on each side of the tree or with spacing that can cover the whole orchard, with additional crops between the tree rows. Like drip emitters, micro sprinklers and micro sprayers operate at low flow rates and pressures, and are available in a wide range of flow rates and coverage diameters to meet the demands of any application.
One of the main advantages of micro sprinkler or micro sprayer irrigation in orchards is the ability to apply an even amount of water to a large area of ground around each tree. For a micro sprinkler or micro sprayer irrigation system installations to operate efficiently, it needs to have the capability to replenish the amount of water the trees use, seamlessly. With micro sprinklers or micro sprayers it is possible to avoid over watering by adjusting the water duration to compensate for the amount of water applied, and by changing the micro sprinkler or micro sprayer nozzles or heads, so that the soil is never over-saturated.
One of the main features of micro sprinkler systems is the range of the application rates, from 0.05 inches/hour and up. Because there is a direct relation between application rate and irrigation duration, there can also be a range in the duration needed to complete an irrigation cycle. For example, 8 minutes is required to apply 0.4 inch of water with an application rate of 3 inches/hour, while 8 hours is needed to apply the same amount at a rate of 0.05 inch/hour. This range of rates is readily available using micro-sprinklers or micro sprayers. For example, when low volume, under canopy, overhead irrigation is desired for an orchard, a mini sprinkler (one type of micro sprinkler) can cover the small area under the tree canopy and can be used to water young saplings. The mini sprinkler operates at low pressure and has a wide range of flow rates and diameters.
Most installations in orchard irrigation use the micro sprinklers or micro sprayers underneath the trees, while in some areas of the world they are installed on top of the trees for frost protection. The micro sprinkler or micro sprayer soaks the ground under the tree canopy within the shaded soil and evaporation is substantially reduced.
Micro sprinklers or micro sprayers are more efficient than flood irrigation, and they can help produce healthier trees by eliminating or reducing root diseases and providing some advantage when needed for frost control.
Like drip irrigation, micro sprinkler or micro sprayer irrigation requires the following to complete a system. The system includes a pump if needed, an 80 to 120 mesh filter, a flow meter to read the flow applied, pressure gauges on the inlet and outlet sides of the system, a fertilizer injector to feed the trees or to clean the system with appropriate chemicals, a pressure regulator to lower the pressure to the optimal pressure required by the system, a manual or solenoid valve per each section and an automatic controller if solenoid valves are used. The flow meter and the fertilizer injector are optional and are highly recommended because they help to increase productivity by helping in measuring flow and feeding the trees automatically. The distribution network’s main line, valves and laterals should be sized to the maximum flow rates of water application each section or valve requires in gallon per minute (GPM). The distribution network consists of the main line from the pump or filter, sub laterals controlled by a solenoid or manual valve, air vents, tree laterals with one lateral per each row, micro sprinklers or micro sprayers with one or two per each tree, and any fittings and accessories needed to complete the system.
Stage of installation:
1. Install the pump, filter, flow meter, fertilizer injector, main lateral, sub laterals and valves.
a. Test the system.
b. Pressurizes the system.
2. Install to the valves the sub laterals and tree laterals, leaving the end line open.
a. Test and flush the system and close the end of the line.
3. Install micro sprinklers or micro sprayers.
4. Turn the system on and check each valve, making sure all micro sprinklers and micro sprayers are operating correctly and with uniformity between the first sprinklers on the line and the last.
5. Review, and adjust the system as needed, and schedule regular maintenance.