Date: May 01, 2014
Magazine:
May 2014 Irrigation Advances

Despite receiving some much needed rain as this was being written in early spring, California is still in a drought situation and water is top of mind for virtually every grower in the state.

Craig Stafford, regional manager for Nelson Irrigation, who is stationed in the Salinas Valley area, said the conversation today very much revolves around water efficiency.  Growers want to know, he said, what they can do to more efficiently use the water they have been allocated.

One knee jerk response that seems to get a lot of attention in the consumer press is drip irrigation.  But Nelson Irrigation specializes in sprinkler systems, which are the best irrigation option for many different growers and crops.  “It makes no more sense for us to tell you that everyone should use high efficiency sprinkler systems than for a drip guy to tell you everyone should use drip,” he said.

Each application has its uses and one of the goals of Nelson Irrigation is to make sure that anyone using their systems are operating as efficiently as possible.  Stafford estimated that 60-70 percent — maybe even more — of sprinkler irrigation users have done something to improve their systems and make them more water efficient.  However, he said very few would have no room for improvement.  Improvements in technology continue to march on, so even systems that are only several years old very likely can be updated to yield better water savings.  And any system 10 or 15 years old that is relying on brass impact sprinklers and aluminum piping has a great opportunity for water savings.

In an interview on water efficiency, Stafford focused on piping and automation with a few comments on sprinkler heads as well.

He indicated that a switch from aluminum pipe to plastic might offer the best opportunity for water savings.  That switch also allows for increased automation, which can reduce labor costs as well as water use.  Stafford explained that a typical older sprinkler irrigation system will use aluminum pipes and brass impact sprinkler heads.  The aluminum pipe could have two to dozens of valves per field that typically require an irrigator to turn each of those valves off and on by hand.

On its face, that requires water inefficiencies because they cannot all be turned on at the same time.  So to make sure each area gets sufficient water, some areas will be overwatered.  Aluminum pipe also drains down at the conclusion of each watering, which again means using more water that wouldn’t have to be used if they all turned off at the same time.  And there is also a certain amount of corrosion in metal piping that is going to occur over time, which also leads to water loss.

Stafford said the trend is clearly toward plastic piping with automated valves.  When the system is turned off, everything shuts down at once keeping the pipes full of water.  So when the system starts up automatically again, it is ready to go immediately and each section gets the same amount of water.  An irrigator can be much more precise in his water allocation for each field.

Stafford said state-of-the-art systems are also equipped with wireless systems that allow for their operation remotely.  This tends to be even more efficient as the system can be started and stopped exactly when it needs to be as opposed to when the irrigator makes it over to the field.  “It also allows one irrigator to handle more fields,” Stafford said.

Ultimately, automation gives the grower more control of his irrigation system, which is the point any time, but especially when water is scarce.

With regard to the sprinkler heads themselves, Stafford said brass impact sprinkler heads were the sprinkler of choice for generations of farmers.  But they do wear down, become less efficient and are very expensive to replace.  While a grower might have a huge brass sprinkler inventory that he is reluctant to replace, Stafford said any brass sprinkler head that is a decade old or older is almost surely not operating at peak efficiency.  The cost of replacing or repairing those sprinkler heads is expensive.

Stafford said there are replacement heads made out of durable high tech plastic that work better, are much easier to maintain, easier to update and are more efficient.  “Uniformity is key and very important,” said the Nelson Irrigation representative, adding that often a grower discovers he can use a smaller nozzle that is more efficient and uses less water when swapping out his traditional brass sprinkler heads for high-tech, more efficient modern versions.

Nelson Irrigation’s version of high tech sprinklers are marketed under the R2000 WF moniker.

He said it is difficult to determine an exact ROI (return on investment) for the updating or replacing of an irrigation system “because it depends on the crop and the current system being used.  Each grower’s situation is different.”

But he said it can be worked out with pencil and paper and the payback is typically faster than expected.  He said many of his customers of high value vegetable crops have found the switch to be very palatable.  As mentioned the payback comes in three different ways: potentially better yields, less water use and less labor.  Additionally, given the current water situation when every drop counts, a grower needs to weigh his ROI with efficiency.  He added that there are several irrigation companies out there that have specialized in buying these systems and renting them or leasing them out to growers to minimize the capital outlay if that’s an issue.  Stafford said the cost of course, is always important and especially in these times when some growers might have had to fallow land because of their reduced water allocation, leading to less income than expected.

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