Irrigation is an important topic, because Agriculture needs a lot of water—and the proof is in the numbers.
A 2012 report by the USDA, which included a U.S. Geological Survey (USGS), provides some eye-opening figures about the U.S. agriculture sector’s irrigation and water usage: According to the survey, which monitors water use by economic sector estimates, agriculture accounts for approximately 80 to 90 percent of U.S. consumptive* water use.
The USGS survey also noted that roughly 56 million acres—or 7.6 percent of all U.S. cropland and pastureland—are irrigated in some way (that year, nearly three-quarters of irrigated acres were in 17 of the Western-most states excluding Hawaii).
Irrigation usage and irrigated areas change over time, as do irrigated acreage shares by state, in response to:
- local & regional water supply/demand and agronomic conditions
- economic and domestic/export crop-market considerations
- long-term climate change.
But the fact remains—good stewardship of water resources and advancing the efficiency of irrigation techniques is critical not only to the future profitability of agriculture but also to the survival of our land, wildlife, and human population.
Dr. Wesley Porter, an Extension Precision Ag and Irrigation Specialist with the University of Georgia, is one of many experts across the country studying solutions and providing information on technologies and techniques to producers; all to help them better manage their farming operations and profitability as they amend their water management practices.
“My research is focused mainly on practical, quick-result trials that can be rapidly implemented by producers to make near immediate impacts and changes on their farms.”
Irrigation – What’s Now, What’s Next
There are a whole host of irrigation options available to producers these days and some fascinating research is being done to improve current systems and explore new ones.
Of the current irrigation types available in 2010, USGS estimated that:
- 31,600 thousand acres (51 percent) were irrigated with sprinkler systems (primarily center pivot)
- 26,200 thousand acres utilized surface (flood) irrigation
- 4,610 thousand acres employed micro-irrigation systems
The national average application rate for 2010 was 2.07 acre-feet per acre.
As for research, this year, the Kansas Water Office (KWO) embarked on a three-year study to evaluate how the new Dragon Line™ precision mobile drip irrigation system, in combination with in-ground moisture probes, can allow farmers to “visualize” water usage as deep as three feet down in order to safely cut back on daily water usage and the more common practice of blanket scheduling of water applications or plain old eyeballing.
Porter says while the concept of water sensors is exciting, recent surveys show that, currently, only about 10% of growers nationally implement some sort of soil moisture sensor.
“Cost and how to interpret and use the data continue to be roadblocks,” explains Porter. “It’s becoming simpler to collect and interpret data to be sure, but adopting new technology is a culture switch that some farmers are reluctant to make. It’s easier for them to just run their systems on a calendar schedule and consistently stick to this schedule.”
Porter believes the biggest hurdle standing in the way of broad adoption of sensors and other water-saving irrigation technologies is proof.
“Hard data such as increased yields, reductions in money spent on energy to pump the water, and similar data is what will be required to get more of this technology adopted,” says Porter. “Saving water does not mean much if there’s no additional benefit to crop yield or profitability.”
Tom Willis, owner of T&O Farms in Liberal, Kansas, one of three operations in the state’s three-year Dragon Line irrigation study, is pleased with the early results he’s seen using water sensors.
“Using Dragon Line, ‘the water never sees the sun’ is how my son describes it,” chuckles Willis. “So far, the probe sensors and the drip irrigation have done the job they promised. They have allowed us to not put water down just based on what we see at ground level. Where we’ve used Dragon Lines, there’s also better root development, the roots go farther down.”
Current Irrigation Options – What’s Best?
In choosing an irrigation system, Porter says producers need to consider several important factors, including:
- type of crop
- fuel cost and availability
- initial cost
- labor requirements
- size and shape of the field(s)
- available water source
He adds that, in some situations, there may be additional considerations such as whether the land is owned or leased, since some systems involve installation of ground or underground piping. Farmers should also explore whether some of their existing equipment, such as a well or pumping unit, could be adapted into the system to help minimize costs.
Of the irrigation options currently in use, the most popular method continues to be the Center Pivot irrigation system used in both circular and square crop fields.
Porter notes that even though it may seem that a Lateral Irrigation system would fit better into many of the “square” fields rather than a circle, he says the labor requirements, as well as the challenge of providing a mobile water and energy source, make it too cumbersome for producers to implement.
“Center Pivots have become very advanced with many types of technology that make their operation much easier for the user,” says Porter. “Some of these technologies include remote operation, both starting and stopping, as well as continuous monitoring and warnings of problems or failures. Many also feature auto-shutdown or warning if there is rainfall detected or problems at the pump. All commercially available systems also have the option (along with a few aftermarket companies) for Variable Rate Irrigation or VRI.”
Drip Irrigation, like the system being used in the Kansas water study, is considered one of the most efficient types of irrigation, as the water source can be delivered very close to the crop roots with no opportunity for evaporation.
“Drip lines used in fruit and vegetable production is usually laying either on the surface, just under the surface, or under plastic beds,” says Porter. “And thicker walled drip tubing can be installed sub-surface (known as Sub-Surface Drip Irrigation or SDI) and can be utilized in row crops.”
Porter adds that, “more producers are considering SDI on row crops in dry land corners or outside of the pivot circles, or in smaller irregular shaped fields where overhead irrigation systems don’t work very well.”
A related method, Seepage or Sub-Irrigation, is a process of artificially maintaining the water table. The water table is kept at between 18 and 24 inches deep by delivering water from pumps, or using gravity and gate systems, to irrigation furrows (shallow open ditches). It’s especially common in the “high water table/muck soil” fields of south Florida where tomatoes, peppers and sugarcane are grown.
Seepage systems are easy to build, operate, and maintain, the drawback is inefficiency—it can be challenging to maintain the water table balance to just below the crop root zone, without oversaturation, and the practice also risks not achieving proper wetting of the soil surface without rainfall to help out.
While Drip Irrigation has been gaining popularity in the last twenty years, Seepage Irrigation remains a very common production system in Florida.
Furrow or Surface Irrigation is an even more basic method of irrigating fields. One of the oldest techniques, the farmer simply creates small parallel channels along the field in the direction of a slope (either natural or created by the farmer). Then gravity delivers the water down the furrows using gated pipe, siphon and head ditch, or a bank-less system.
Micro-Drip Irrigation is also gaining popularity, and its “cousin,” Micro-Spray Irrigation, used to irrigate tree orchards, is popular because of its ability to administer more precise applications of water at lower volumes.
One other commonly-used option on many U.S. farms is the Traveling Gun. Attached to a mobile irrigation system, it uses a high-pressure big gun to send water across pastures or row crops.
“Farmers looking for cheaper solutions or options for smaller fields where larger irrigation devices won’t fit, often choose the Traveling Gun,” says Porter. “Unfortunately, it’s not efficient…about 60% of the efficiency of, say, the Center Pivot…meaning if you set it to apply one inch of water, only 0.6” will reach the crop. However, if this is the only option when compared to dry land it’s certainly a valid option.”
Word of Warning
Porter offers one critical caveat for producers choosing new or replacement irrigation systems—not hitting the target irrigation amounts or intensities for specific soil types can lead to runoff issues.
“It’s important to you know what soil types you have under your irrigation systems and how they respond to rainfall and irrigation,” advises Porter. “Research both the soil water holding capacities (SWHC) and infiltration rates of your soils, as this will help you apply the optimum amounts that your soils can handle, and also help you estimate approximately when your soil water will be depleted.”
High-Tech Control Advances
Asked whether he could offer a glimpse into what’s next in the world of irrigation, Porter pointed to the dramatic rise in remote data acquisition capability when it comes to gathering information and controlling devices like sensors and irrigation systems.
“Now a farmer can access and control virtually all of their irrigation systems remotely from anywhere they can get internet access,” says Porter. “Connected farms are no longer an idea of the future, but are up and running everywhere across the nation.”
The concurrent rise in technologies like irrigation scheduling tools such as soil moisture sensors, smartphone scheduling apps and web-based scheduling tools are already making it easier for “early adopter” producers to be more efficient with their water usage, and Porter says that, at UGA, “we are also working on some interesting advancements on automating the VRI process and hope to have some good information on that out soon.”
Keep Learning, Keep An Open Mind
Water-saving irrigation techniques, like so many other facets of agriculture are evolving in exciting and important ways. Producers owe it to their businesses and their families, as well as to their communities and neighbors, to not only stay informed, but also to proactively adopt the best irrigation practices available.
“I would encourage growers to work closely with their local Extension service to stay abreast of developments and water issues,” advises Porter. “Each state has a unique Extension structure but the purpose is the same…serving the producers of the state. Extension has tons of information for each region on how to get interested producers pointed in the correct direction, whatever their irrigation concerns or other agricultural questions may be.”
As the nation’s premier land lender, AgAmerica Lending supports the concept of stewardship of our nation’s water resources. We know that high-quality efficient irrigation systems not only pay for themselves in better performance, but, as Bryce Philpot, AgAmerica co-owner and SVP of Operations & Finance, points out, also contribute to improving a parcel’s financial value. “Effective monitoring and control of moisture levels with precision ag irrigation equipment often allows producers to cut back on fertilizer and chemical spending, while increasing yields,” says Philpot. “This can help improve your financial position, and also help you qualify for both larger and lower-interest rate loans.”