The history of the Knorr-Holden corn plot
and the Scottsbluff Experiment Substation

By Dr. Gary Hergert and Rex Nielsen
UNL Panhandle Research and Extension Center

The story of Agricultural Research in the North Platte River Valley and the Knorr-Holden Corn Plot began with the establishment of the Scottsbluff Experiment Substation in 1910. Soon a large series of rotation plots were laid out on the newly plowed ground.

Since it was established in 1912, the Knorr-Holden plot has been a significant part of the research conducted at the experimental substation, which has become the Panhandle Research and Extension Center, and continues to yield valuable information about the ecology, environmental impact and production principles of long-term, continuous irrigated corn.

The Knorr-Holden Plot was conceived when the first large scale irrigation projects were under construction in the North Platte Valley of western Nebraska. There was a need to determine the best methods of farming the newly developed irrigated land.

In the first half of the 19th century many historic trails followed the North Platte River Valley. Thousands of immigrants traveled through the area on the way to the west coast with few stopping to settle. With the arrival of the railroad in the late 1860s and the elimination of the threat of Indian attack, a few years later the area became a promising site for homesteaders.

The rush of homesteaders became quite large in the late 1880s and early 1890s. The settlers soon realized that rainfall in western Nebraska was generally insufficient and unreliable enough to grow most crops to maturity. With only a few small streams in the area, the waters of the North Platte River were soon called upon to make up for the rain not supplied by nature.

The first irrigation company in the area was formed in 1887 to irrigate the area now included in Farmers Irrigation District. The canal system for this irrigation district was extended from time to time and was finally completed in 1911. The second irrigation company was also formed in 1887. This company was called the Minatare Mutual Canal, and Winters Creek Canal was finished in 1888. Several other small canals were completed in the next few years. Irrigation from these canals was an immediate success. This attracted a great deal of attention from drought-stricken farmers in the area. The success of the irrigation projects proved that irrigation would be a necessity to realize the full productivity of the land. However it would take large-scale irrigation projects to realize the full agricultural potential of the North Platte River Valley.

Many more canals, large and small, were proposed, but due to the area farmers’ lack of financial resources, large-scale irrigation projects would need government support. In 1895 Nebraska enacted an irrigation district law permitting the formation of districts with the power to assess land for irrigation improvements.

The Federal Reclamation Act was passed in 1902 and studies were begun by the Reclamation Service for the North Platte Project. The project was authorized in 1903, and during the same year surveys were started to determine the location of irrigable lands and a reservoir site. In 1905, construction began on the Pathfinder Dam and the Interstate Canal. By 1915, work on the Interstate Canal and Reservoir was completed and work had started on the Fort Laramie Canal. The Northport Canal system was started in 1918. All construction was completed by 1925 and the Guernsey Dam was completed in 1927. Several other dams and irrigation projects have been constructed since 1925.

The North Platte Project extends 111 miles along the river valley from near Guernsey, Wyo., to below Bridgeport. The city of Scottsbluff is near the center of the development. The project supplies water for irrigation of approximately 390,000 acres that are divided into four irrigation districts. A supplemental supply is furnished to eight water user associations serving a combined area of 190,000 acres. Also the aquifer created by the surface irrigation provides groundwater to irrigate another 100,000 acres.

With this large acreage now open to irrigation and the majority of farmers in the area lacking experience in managing the irrigated crops grown on the sandy soils of the valley, the U.S. Department of Agriculture (USDA) soon recognized that new techniques were needed to be developed to successfully farm the newly irrigated lands. To facilitate research and disseminate information to area farmers, an agricultural experiment station was established in the area.

Shortly after construction of the Scotts Bluff Experimental Substation, the native soil is broken on the ground where the Knorr-Holden Plot would come to be located.

In 1910, the USDA, in cooperation with the Nebraska Experiment Station, created the Scottsbluff Experiment Substation on 160 acres of unclaimed land six miles east of Mitchell. The Office of Western Agriculture, USDA, managed the station until 1948, when the land and management was turned over to the University of Nebraska. The Scotts Bluff Ag Lab is currently part of the University of Nebraska Panhandle Research and Extension Center.

The native short-grass prairie was broken out in 1910, and the next spring the land was seeded to oats. Then in 1912, under the supervision of Fritz Knorr, the first superintendent of the station, an extensive series of both irrigated and dryland rotation experiments were begun.

In 1917, James A. Holden became the second station superintendent to supervise the rotation plots. Under his supervision the foundation was set for the rotation plots to become a long-term project. The rotation plots were continued until 1941, when all but the continuous corn plots were discontinued. From 1942 to the present, the corn plots have been maintained as a study by themselves.

Over the years, the data collected from this plot has been presented at national meetings and published in many bulletins and scientific journals. From the time of establishment to the present, at least three dozen scientists and graduate students have been involved in the plot.

The data collected from the plot has proven that continuous corn can be successfully grown in western Nebraska and that manuring (applying livestock manure) is a valuable practice in maintaining soil productivity. It has shown that N fertilization alone was capable of restoring most of the production capacity of the soil. The practice of manuring greatly improved the physical condition of the soil.

Initiation of N fertilization resulted in a much more rapid recovery of yield than did the initiation of manuring. In the first year of N fertilization on non-manured, non-fertilized soil, yields reached a level that required 10 years of manuring to attain. Protein levels in the corn grain have been consistently highest on manured treatments at all but the 160 lb/A nitrogen fertilizer rate. Cultivation without manuring or N fertilization decreased the soil N content to 40 percent of the native content after 30 years of continuous corn production. In the plots receiving manure treatments, the soil N content has increased to 147 percent of the level present in the soil in its native condition.

Also organic matter in the top 12 inches of soil in the manured plots was 68% higher then what the non manured plots had. The yearly manure applications from 1953 to the present have increased soil nitrogen and organic matter levels to the point that they now exceed what the native sod had when first plowed in 1912.

Valuable information has been collected from this plot over the years, and much more can be collected in the future. This type of information can only be collected from plots that are long-term in design. Continuous research plots, however, are rare because they require a commitment for generations past and future. We appreciate the efforts of Mr. Frank Anderson and others who supervised the plots for many years when the value of long-term research was not as well understood as it is today.

At the present time, more than 700,000 acres are irrigated in the Panhandle, and of that, 310,000 acres are in corn. The average corn yield in 1914 was about 60 bushels per acre; the average today is 160 bushels per acre. These statistics show the value of corn to the area and the improvement that research has made.

Local producers gather at the Knorr-Holden plot for a recent field day.

The Knorr-Holden plot is one of the five oldest continuous field crop experiments in the United States. It is also the oldest irrigated corn plot, and the third-oldest corn research plot in North America and possibly the world. Two other continuous field experiments, the Morrow Plots at the University of Illinois and Sanborn Field at the University of Missouri, received National Historic Landmark designation in the 1960s.

To date, only three long-term research plots were listed in the National Register of Historic Places: the Magruder Plots in Oklahoma (listed 1979); the Old Rotation at Auburn University (listed 1988); and the Knorr-Holden plots at Scottsbluff (1992).

The National Register of Historic Places is the federal government’s official list of historic properties worth of preservation. Properties with significant historical importance that meet certain criteria are eligible for nomination to the Federal Register. The process of including properties in the National Register of Historic Places is designed with several levels of review at both state and national levels. These reviews follow an orderly and systematic process that requires extensive research and documentation of the nominated property. This process was begun in the fall of 1991 and was successfully concluded in June of 1992.

Dr. Gary Hergert is the soil fertility specialist at the UNL Panhandle Research and Extension Center, and present scientist in charge of the plot. Rex Nielsen is the Soils Research Technologist at the Panhandle Research and Extension Center