Irrigation innovations conserve water, but need infrastructure, delivery systems to evolve
In this podcast, Professor Styles, a member of the CSU’s Water Resources and Policy Initiatives, talks about drip irrigation and what transformations are needed to broaden its use – and conserve more water.
Styles, with more than 25 years’ of field experience in irrigation as a consultant and engineer, was honored in 2004 as the Irrigation Association’s Person of the Year.
- The ITRC at Cal Poly San Luis Obispo has published a training manual that amounts to a best seller in the niche market of moisture literature: “Drip and micro-irrigation design and management for trees, vines and row crops.”
- The manual, adopted by the Irrigation Association, is now in its fourth edition (2011), on which Styles worked with senior author Charles M. Burt. It has been published in three languages—with two more to come. Details here: http://www.itrc.org/publications.htm
- Drip irrigation, Styles says, is pressurized. Water is pushed through pipelines that branch into small irrigation hoses that transport the water directly to the plants, where individual emitters deliver water drip by drip. “We try to put the water on only as it is required, not in a large amount,” he says.
- The ITRC tests various methods at its 3-acre Merriam Irrigation Practices Field.
For more irrigation education, visit these CSU centers:
Science & the CSU podcast transcript from an interview with Stuart Styles about irrigation:
Sean Kearns (SK): This is Sean Kearns with the California State University on Science & the CSU. I’m here with Stuart Styles today to talk about drips – specifically, drip irrigation.
Dr. Styles directs the Irrigation Training and Research Center at California Polytechnic State University in San Luis Obispo. He is also a professor in the Cal Poly Bioresource and Agricultural Engineering Department. And currently his research interests include emerging electronic flow-measurement technologies, salinity management, and drip irrigation.
Dr. Styles, it’s wonderful to have you join us and share some of your insights and experiences with us. Thanks for coming.
Stuart Styles (SS): Thank you for having me.
SK: First, I’d like to get a sense of the big picture of water use in California. What percentage of water use in the state goes to the irrigation of landscapes and crops?
SS: The total amount of water use in California is about 70 million acre-feet. Agricultural uses about 35 million, so it uses about 50 percent of the total water, the developed water in the state. Landscape water use on the urban side uses about 2 million acre-feet, so it’s quite a bit lower value compared to the agricultural water use.
SK: In the big picture in California, what role do enhanced irrigation technologies and practices play in conserving water?
SS: What we have is we have a lot of new technologies that give us the opportunity to precisely put water on exactly when it’s needed and at the right location. Unless we have the right infrastructure in place, the right things in place, we can’t use these new developing technologies.
SK: And these would be things like G.I.S., remote sensing, or…
ST: …Smart controllers, remote sensing out in the field, going out and taking a moisture measurement, and doing thinks like sending that through a satellite signal and being able to remotely sense that from a field – and then some of the things we we’re going to talk about today, like drip irrigation.
SK: What kind of challenges have existed in updating the infrastructure and the management systems that were already in place for surface water, but now you have to try and develop them for drip irrigation?
ST: Drip irrigation really got started in the 1960s and 1970s; and it really took off in California for specific crops. It took off for things like trees and vines and other crops, such as strawberries. But the one characteristic that a lot of those crops had that the guys were using drip irrigation on is that they were being supplied by groundwater wells.
And the characteristic that matched up really well with groundwater wells and drip irrigation is that groundwater wells were very flexible: The wells could be turned on whenever water was required, and they could be turned off when they were done irrigating. They could vary the flow rate. They could change the amount of water that they took. And they didn’t have to order the water from anyone. Groundwater is very flexible in that respect.
But in California only about 25 percent of irrigation water is provided by groundwater sources. The majority of it — 75 percent — is provided by surface-irrigation sources. And the surface irrigation sources are from water projects. These are dams and reservoirs canal-delivery systems that bring the water in. And it has to be, typically, scheduled. A lot of those systems were designed based on historical irrigation methods, which were these old techniques – these surface, or flood-irrigation, techniques.
Now those were not very flexible. It was an arranged schedule. They could take the water from one field to another field. Typically, they would take a high flow rate for a long duration, and they could come back 10 days later. That was very much suited for surface irrigation, things like furrow irrigation or border strip or flood irrigation.
But, for drip irrigation, those farmers – those users of drip irrigation – wanted to take the water in small amounts; and they wanted it every day. It was a much different regime.
SK: In your training efforts, what’s the key factor that farmers and others need to measure and understand as they use drip irrigation?
SS: How you deal with plugging issues. As I mentioned, drip irrigation implies the flow rates coming out of the emitters are very low, so what that means is that the path sizes used for drip irrigation are very small. So it’s very easy to plug it with debris, with water that has a poor water source. Maybe it has some algae or something else that’s floating in the debris. Sometimes it’s PVC parts or things like that. A key component is to have proper filtration for our drip irrigation systems.
SK: As far as the general public, I know that many homeowners and backyard gardeners have been using drip irrigation. What can they do to try and make sure their systems flow effectively?
SS: For the landscape users, probably one of the biggest problems we run into is that landscape users would like to try and convert their turf systems over to drip irrigation. Unfortunately, we haven’t been very successful in converting turf systems over to drip irrigation.
So those landscape users that would like to utilize drip, we encourage them to go to a change in practices usually: To go to more of a shrub-based yard, where they can utilize the drip irrigation and use a lot less water than a turf application.
SK: And, finally, what would be your number one water-conservation tip regarding irrigation that you would like to leave in people’s minds.
SS: The number one tip is to measure the flow rate on the systems. For the landscape users, that means possibly getting a small kit and you can measure the pressure and the flow rate.
For the growers, we really emphasize that flow measurement is a very critical aspect, and the saying that we usually use is that, “If you can’t measure it, you can’t manage it.”
SK: I think that’s a very apt approach for a lot of things. Well, Dr. Styles, thank you for joining us here for a talk today on Science & the CSU. I appreciate it.
SS: Thank you very much for having me.
SK: For more stories about science, technology, engineering and mathematics in the California State University, check Science & the CSU, a blog site of the California State University.
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