Irrigation Research in western Nebraska

By Dean Yonts, Irrigation Systems Specialist
UNL Panhandle Research and Extension Center

The Bureau of Reclamation completed construction of the Pathfinder Irrigation Dam in 1909, which opened the North Platte Valley project to irrigation. It didn’t take long for the Department of Agriculture to realize that farmers were going to need help establishing proper irrigation practices. In 1910 the Scotts Bluff Experiment Substation, now known as the Panhandle Research and Extension Center, was established. By the summer of 1912, a number of crop rotation experiments, including both dryland and irrigated crops, were established.

Irrigated crop production continued to be a significant part of the research and over the next 20 years, experiments were conducted to determine where crops obtained water in the soil and how much water crops needed. In subsequent years, weighing lysimeters were used to determine daily crop water use values. These experiments provided the basis for modern day irrigation scheduling.

When the Scotts Bluff Experiment Station celebrated its 50th anniversary in 1960, three specific projects related to irrigation were described. One of these was conducted by Orlando.W. Howe, a USDA Irrigation Engineer, who wanted to “find out how the effects of a limited amount of water applied at the proper time and at proper intervals would compare with less discriminate use of irrigation water.” It seems the concern to conserve water was as prevalent 100 years ago as it is today. Although hybrids have changed drastically over the years, current experiments are achieving similar results to Howe’s, indicating that the concept of limiting the amount of irrigation water applied can result in economically profitable crop yields.

In another study, Norris P. Swanson, an agricultural engineer with the university, used a “specially designed sprinkler system to spray artificial rain” to study the impact of rainfall on runoff and soil erosion. Part of his results indicated that on nearly level benches no soil erosion occurred as the excess water drained slowly from the field. This experiment was conducted on different crops and field slopes and it was determined that runoff and soil erosion was much greater on fields having steeper slopes. Similar studies were conducted in the early 1980s and compared runoff and soil erosion from fields established using different tillage systems.

The creative thinking that brought about these types of studies additionally contributed to developing the “big experiment” as described by then Superintendent Lionel Harris. This project involved a number of researchers, cost $150 per acre to establish and furthermore showed a net profit. It was considered to potentially have far-reaching effects on all irrigated land in western Nebraska. Harris’ design consisted of benches having level cross slope and a gentle field slope, each separated by a grass berm. The system allowed uniform application of irrigation water while keeping runoff and soil erosion to a minimum.

Lionel Harris stated that “While it is not an entirely new development to the farmers in western Nebraska, the gently sloping level benches seem almost out of place from the air, where you are accustomed to seeing square and rectangular patches of land.” The idea never caught on in this area, but the superintendent had no way of knowing at that time that an even bigger change was coming to the landscape as a result of changing irrigation practices. As people flew through the air, they wondered what these strange perfectly round circles amongst the square and rectangular fields could be. Those circles turned out to be fields irrigated with a system called a center pivot.

In 1952, Frank Zybach patented the center pivot, resulting in an enormous change in the practice of irrigation. It wasn’t until the late 1960s and early 70s that center pivots in western Nebraska really started to appear. At first, pivots were installed on the tablelands north and south of the valley and used groundwater. In the North Platte Valley, irrigators ran surface water from Pathfinder Dam down furrows, and there was no need for a sprinkling machine.

During the late 1980s work on surface irrigation systems continued, as over 60 percent of the irrigated acres in Nebraska used furrow irrigation. Experiments during that period concentrated on methods to improve furrow irrigation efficiency. The university extensively studied a new method of furrow irrigation called surge. This system used a solar powered butterfly valve to automatically turn water on and off between two irrigation sets. The short cycle times and the wetting and drying of the furrows reduced the soil infiltration rate, increased advance time, increased application uniformity and reduced runoff.

Although surge irrigation is a viable alternative for many furrow irrigators today, the biggest changes are still occurring with the pivot. Between 2000 and 2010, furrow-irrigated acres in the North Platte Valley were converted to center pivots at a rate of approximately 10,000 acres per year. The valley growers did not give up their surface water rights, but rather dug small pits from which they diverted the surface water supply and then pumped it through the irrigation system.

Since the 1960s, a number of additional researchers have contributed to advancing irrigation practices. In the late 1960s and early 1970s, David Fonken, extension irrigation specialist, worked on an experiment to determine the water- use rate of sugarbeets using a sprinkler system at the university’s Northwest Ag Lab near Alliance. Walter L. Trimmer was the extension irrigation specialist in the early 1970s. Some of Trimmer’s work dealt with setting up weather stations throughout the Panhandle to provide crop-water use information to irrigators using a phone-in irrigation hotline. During this same time, Robert Edling, the research irrigation engineer, monitored flow in the irrigation canals to determine conveyance losses to help irrigation districts improve their delivery efficiency.

In 1980, C. Dean Yonts was hired as the research/extension irrigation engineer. In addition to his earlier work on surge irrigation, he more recently has studied the impact of limited irrigation similar to Howe’s work in the late 1950s. Yonts has concentrated on trying to define the impact on yield of sugarbeets and dry beans when irrigation is withheld during different stages of growth. He has also taken advantage of a newer type of irrigation system and has conducted deficit irrigation with corn using subsurface drip irrigation.

This article is intended to illustrate the creative and extensive nature of irrigation research conducted in western Nebraska for the past 100 years. Although progression and improvements appear to have been rapid, many of the changes have occurred only when economic situations were right and when an individual was ready to make a change. As a result, center pivots can now be controlled by computers and cell phones, yet there are still fields that are irrigated using dams and siphon tubes. With the progression of any system, the challenges and rewards are great. However, it is only when we stop to look back that one truly sees the advancements that are the results of many peoples’ lifetime work.

In this photo from the UNL Panhandle Center archives, an unidentified worker irrigates a field in June 1913 using a collapsible canvas dam.

A center pivot is used to study impact of crop water stress.

A surge valve is used to improve furrow irrigation efficiency.

Research data: The effect of season-long deficit irrigation on yield of sugarbeets.