1. Is the IRRIGATION system adequately controlling pressure?
Most fruit growing sites are large enough that it is very easy for operators to run the system differently from the way it was designed to be operated. Others have large elevation changes from the pump site to different orchard blocks. It’s important that these types of systems contain components that can automatically control pressure. Such components include pressure regulating valves, pressure regulators on laterals, and VFD (variable frequency drive) pumping systems.
2. Is the system designed to be ready for new automation technologies?
In the not too distant future growers will use the automation of their irrigation system as an important tool in managing challenging issues such as optimizing first year tree growth, increasing fruit size and mitigating alternate bearing tendencies. New automation technologies will not eliminate the need for systems to be checked but they will improve precision of irrigation and thus reduce pumping and fertilizer costs. Furthermore, these new systems will data log each irrigation event. This information can be used to evaluate the performance of irrigators and the effectiveness of irrigation scheduling decisions. The important steps to take with your new irrigation system are to install hydraulic valves that can be automated — and ask your supplier to include in the design pump controls and/or pressure relief necessary for an automated system. Plan for and include water storage facilities. In 2014 Nelson Irrigation Corporation will be introducing for sale automation equipment that eliminates the need to bury wires in the field. Ask your irrigation supplier about this new technology!
3. Is my system design suited for the site conditions and potential operational changes?
One of the easiest mistakes to make is to not plan adequately for potential changes in irrigation practices. The following tips will help keep you out of trouble:
- Never buy an under tree sprinkler system with too wide of sprinkler spacing because it is intended for frost control only. These systems nearly always get used for irrigation at some point in the future. Furthermore, under tree frost systems are more effective when they have the high uniformity that is best for irrigation.
- On steep slopes, sprinkler spacings should be closer to compensate for lost throw radius caused by sloping terrain.
- Anticipate sites that may be susceptible to wind and mitigate the effect with closer than normal sprinkler spacings, and by scheduling some irrigation sets during the night and early morning when wind conditions are lighter.
4. Is the stream height of my sprinkler too high for the cropping system I am planning?
Many of the trellis systems being installed today are placing the lowest wire at 24 to 30 inches above the ground. This will result in fruit hanging near 18 inches off the ground. The fruit, leaves and limbs obstruct sprinkler streams which cause more water (than expected) to be applied on trees that are closest to sprinklers. The R5 Rotator® with the Blue Plate has a stream height of 14 inches which is the lowest stream height of all the Rotators. Stream heights of the R10 Rotator are in the 18 to 23 inch range. Sprinklers need to be mounted 8 to 12 inches above the ground. The height of the stream in the field is the sprinkler stream height plus the mounting height of the sprinkler.
5. Is the density of my sprinklers high enough for the density of my trees?
As tree density increases so should sprinkler density to counter the effects of obstruction from tree trunks, limbs, leaves and fruit. Growers with a sharp eye have recognized the value of making sure sprinkler spacings are not too wide. These growers are planting trees in the range of 1,000 trees per acre and using the R10 Rotator in the range of 150 sprinklers/acre and the R5 Rotator in the range of 200 sprinklers/acre. It’s a small investment at planting time to go with a little closer sprinkler spacing — and it pays big returns in the future!