A century of science at UNL experimental range in southern Sioux County
October 10, 2018
University of Nebraska-Lincoln scientists conduct agricultural research at many locations in western Nebraska — the Panhandle Research and Extension Center plots; the Panhandle Research Feedlot; the High Plains Ag Lab near Sidney; and in fields belonging to cooperating farmers.
One of UNL's lesser-known research laboratories attained a landmark this year. It was 100 years ago, in 1918, that the federal government gave the university an 800-acre piece of rangeland in southern Sioux County to conduct regionally relevant research.
A document signed by President Woodrow Wilson on May 3, 1918, formally granted a patent to "certain lands adjacent to the agricultural experimental station at Scottsbluff, Neb., to the Regents of the University of the State of Nebraska, for dryland agricultural experimental purposes." It had been approved by act of Congress passed on March 3, 1917.
Over the past century, the experimental range, located 10 miles north and 2 miles west of Scottsbluff, has contributed to the body of knowledge about rangeland ecology, grazing systems, animal nutrition, weed science, and even hydrology.
Mitch Stephenson, range and forage specialist at the Panhandle Center, is currently using the range site for research. Stephenson, who joined the faculty in 2015, is also familiar with previous research that was conducted at the range over the past 60 to 70 years.
"A number of UNL researchers have used the experimental range to conduct research on subjects such as distribution and variety of plants; the nutritive value of the forage at different times of the year; grazing rotation systems for cattle; the effect of grazing on vegetation; pasture response to fertilization; and groundwater and surface water hydrology."
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In the late 1950s and early 1960s, Donald F. Burzlaff, a UNL professor of agronomy specializing in range management, studied the effects of stocking rates of cattle at the experimental range. Burzlaff's work produced insight into weight gains of steers and changes in pasture vegetation under heavy, moderate and light stocking rates over multiple years.
A study conducted in 1964 and 1965 by Don Clanton, C.L. Streeter and O.E. Hoehne focused on the change in nutritive value of range forage consumed by grazing cattle over the course of the growing season. This study provided information on the types of species that cattle selected during the growing season in the Panhandle and how that influenced their nutrition status. Clanton was a professor of animal science at the North Platte Station. Streeter and Hoehne, then graduate students, were housed at what is now the Mitchell Ag Lab, where they had a nutrition lab and esophageal fistulae cattle to collect samples of grazed forages during the winter.
WEANING TO HARVEST
Professor Emeritus Ivan Rush, who was beef cattle specialist at the Panhandle Center from 1979-2008, used the site as part of his study of total systems of beef production, from weaning to harvest. Cattle would spend summers grazing at the Sioux County site. Different winter production systems were compared to see how the animals performed. Rush listed several UNL faculty who conducted foundational research over the decades.
Louis Daigger, former soils specialist, studied pasture fertilization using varying levels of nitrogen and phosphorous to try to increase production of range vegetation. He found that fertilizing too early encouraged growth of cool-season weeds that used moisture, to the detriment of native range.
James Stubbendieck, now a UNL emeritus professor of grassland ecology and emeritus director of the Center for Great Plains Studies, has authored articles and books on plants of the Great Plains. Stubbendieck was based in the panhandle from 1972-76, and studied plant distribution, variety, and physiology, according to Stephenson and Rush. Specific examples include blue grama tiller development related to temperature, and managing wind erosion in blowouts. Rush said Stubbendieck later taught a course at UNL based on research he performed at the experimental range.
Pat Reece, emeritus professor who joined the Panhandle Center faculty in 1978 and worked for 30 years as a range ecologist, studied intensive livestock-pasture rotations and their effects on key rangeland plant species, Stephenson said. A 1986 study looked at the influence of short-duration grazing on needle-and-thread, a cool-season grass, and blue grama, a warm-season grass. Reece also studied rhizome development of prairie sandreed, another warm-season grass.
"Both Pat and James conducted research that explored the physical and morphological characteristics of important rangeland plants," Stephenson said.
Some of the science performed at the experimental range had little to do with native plant communities or livestock grazing systems. The relationship between groundwater and surface water was the focus of a project in the 1990s, when the Conservation and Survey Division of UNL, in cooperation with local landowners and the North Platte Natural Resources District, studied the impact of leakage of water from unlined irrigation canals.
Steve Sibray, UNL Conservation and Survey Division Groundwater Hydrogeologist who was one of the researchers, said monitoring wells were installed in the shallow alluvial aquifer and Brule Formation in the University Lake wetlands area on the experimental range and on private property near the Interstate Canal in Sioux County.
Groundwater levels were monitored and water samples were collected to study the chemistry, environmental isotopes and age dating of the surface water and groundwater in the area.
Results from the groundwater level monitoring showed a rise in groundwater levels occurring seasonally when the Interstate Canal was filled. Surface water had a distinct chemistry and isotopic signature and was the source of most of the water in the shallow alluvial and shallow weathered Brule Formation. The monitoring wells installed at deeper depths in the Brule Formation had a different water chemistry and much older age dates and are not considered part of the shallow groundwater system.
This study laid the groundwork for additional studies that confirmed the importance of canal leakage as the primary source of recharge for the shallow aquifer of the North Platte Valley. Lining the irrigation canals to increase the efficiency of the surface water irrigation system would have a negative impact on the shallow aquifer and the wetlands of the valley.
Research at the range site also helped shed light on effective means of controlling weeds. Robert Wilson, emeritus professor and retired weed specialist from 1975-2014, working with the late Charlie Fenster, dryland cropping specialist for many years, evaluated several herbicides for control of downy brome and selectivity to native grasses. The areas around the old pond at the experimental range were infested with Canada thistle, according to Wilson.
Wilson evaluated the potential for different perennial grasses to compete (surpress) with Canada thistle. Grasses such as intermediate wheatgrass could surpress thistle growth and development. He also evaluated Milestone herbicide for thistle control, grass and tree selectivity.
"We found we could spray Milestone by air in the fall after the cottonwoods had dropped their leaves and not harm the trees. The best technique for thistle control was to spray thistle with Milestone and the following year reseed the area with intermediate wheatgrass. We also evaluated several techniques for Russian olive control."
Stephenson said current research at the experimental range revolves mostly around grazing distribution and changes in how cattle select which plants to eat as a growing season progresses.
He also is studying using targeted grazing to control cheatgrass, a weed that affects pasture productivity. Currently, this project focuses on the timing of grazing, but in the future, intensity and frequency of grazing will be studied as well: "When will cattle select cheatgrass over perennial cool-season grasses, and when will they not? And how do year-to-year variations in climate and plant growth influence this?"
"New challenges mean new research, and trying to build on what others have done."
As far as future directions, Stephenson said technology will be employed more. He is currently using Geographical Position Systems to track cattle movements and fecal DNA analysis to identify what plants cattle are eating as part of his research. Other tools, such as drones and remote sensing, might help us better understand changes in plant species composition in the future, he said. Technological advances will help collect more data and answer more questions in the future. ❖