Choosing an irrigation system for small acreages depends on field and goalsWritten by Natasha Wheeler
Worland – “When we think about how we will irrigate our small acreage, it really should be tailored to the specific location and crop and designed in a way that is going to compliment our efforts. We want to maximize yield. We also want to think about the bottom line,” remarked University of Wyoming Extension Educator Caleb Carter at WESTI Ag Days in Worland on Feb. 20.
Efficiency is a common consideration when producers look at irrigation, but Carter suggested looking beyond the field when deciding which type of system is best for a specific location.
“I spent a couple of summers doing research in Powell, and lots of people there have really shallow, 12- or 15-foot-deep wells they use to water their lawns. Those wells are dry until the irrigation water starts running, and then they all fill up,” Carter described as an example of hydrology related to irrigation systems.
He also described examples near Laramie where an endangered Wyoming toad resides, thanks to habitat created by flood irrigation practices.
“When we talk about efficiency, people throw out numbers, but they don’t always account for where that water is going, and it may be going to some other beneficial uses,” he said.
Labor and land
Labor is another important consideration when choosing an irrigation system because there are many different options.
“Do we want a system where we can go to our computer and say, boom, irrigate? Or do we want to go out there and move dams and flood pastures? The technology exists to do either one of those,” remarked Carter.
Various systems also come with different costs and different levels of precision in water application. Finances and production goals are also important considerations when deciding how to irrigate a field.
Topography also impacts which kind of system is best suited to a specific area. For example, flood irrigation or other surface irrigation scenarios require a relatively flat field because water doesn’t flow uphill.
“It’s also important to think about our soil type when we are choosing an irrigation method. If we have a really heavy soil that can hold a lot of water but has a slow infiltration rate, a flood or surface irrigation system is going to be more effective than a sprinkler,” he commented.
In one case, Carter worked with producers who switched from a flood irrigation system to a pivot in their alfalfa field, but yields declined.
“They had really good clay-loam soil. It held a lot of water, and the flood irrigation was able to fill that soil profile. When they switched to the pivot, they weren’t able to apply enough water to fill that root zone,” Carter explained.
Good irrigation requires the soil to both absorb water and disperse it through the soil profile. If soils have a high infiltration rate, water from flood irrigation systems may flow through too quickly, moving below the root zone instead of benefiting the crop.
Producers should also be familiar with the water rights associated with their property and usage.
“We sometimes get people buying property that maybe are not familiar with Wyoming water law or their responsibilities, but if we have property and it has water rights, we are responsible for the maintenance of the ditches and the infrastructure that delivers the water to that property,” Carter stated.
This may involve burning ditches, removing weeds or clearing debris to ensure that water flow is not inhibited.
“We are also responsible for head gates and things that impact how water is delivered to our field or property,” he added. “We need to make sure we’re staying up on our responsibilities.”
Systems vary from surface irrigation systems, such as furrow, flood or gated pipe, to sprinkler systems, such as hand lines, wheel lines, K-lines and Big Guns. Drip irrigation systems can also be installed, depending on the goals of the producer.
“Hand lines are nice, but they are a lot of labor,” Carter commented. “We can drag K-lines with our four-wheeler or tractor to move them around the field.”
Big Guns are popular with producers who want precision in water application over their pastures, and wheel lines or side rolls may be more appropriate for crops such as alfalfa that shouldn’t be trampled on as they grow.
“Drip irrigation has the potential for the least amount of labor, but it is the most expensive as well,” he continued. “A lot of the cost has to do with how far away the water source is, as well as the shape of the field.”
An oddly shaped field with a lot of topography will present more challenges and costs for even water distribution over the whole crop.
Costs and maintenance
“Costs also have to do with the level of automation. We can have a drip irrigation system where we go out manually and turn the water on in each zone, or we can also have a system where we take our smartphone out of our pocket, say how much we want to irrigate in each zone and turn it on,” he explained.
No matter which type of irrigation is best for a certain field, Carter emphasized using proper management once the system is installed.
“We can have the best, most wonderful system, but if we’re not monitoring, maintaining and operating it in the best manner for that system, it’s not going to do us any good or serve us in the way we designated it,” he said.