Historic Knorr-Holden Corn Plot
The historic Knorr-Holden experimental site near Mitchell, Nebraska, is the oldest irrigated maize plot in North America and possibly the world. It has over 100-year-old manure and urea treatment plots under furrow-irrigated continuous maize. The N fertilization alone was capable of restoring most of production capacity of the soil and the practice of manuring greatly improved the physical condition of the soil.
After a full century of the experiment, in 2014, N treatments were revised, and a few extra N treatment plots were added. Now, the experiment is randomized complete block design with four replications. The main factor is N treatment, which includes urea-N treatments of 0, 56, 112, 168, 224 and 280 kg N ha-1 in non-manured plots and urea-N treatments of 0, 56, 112, 168 kg N ha-1 and N treatments based on spring soil test and crop sensing at V6 in manured plots. Manure plots received 67 Mg ha-1 of cattle manure in 2014 and will continue at same rate every four years.
100-year Corn Yield Data from the Historic Knorr-Holden Plot in Nebraska
It takes years, if not decades, before measurable changes in crop productivity and soil properties due to management practices can be detected. The objective of this experiment was to evaluate the effects of long-term cattle manure and inorganic fertilizer applications on irrigated continuous maize grain yield, yield stability and reliability, nitrogen use efficiency (NUE), and soil properties. The experiment was conducted at the Knorr–Holden Plot in Scottsbluff, NE, from 1912–2012.
Unveiling of Historic Knorr-Holden Plot Signboard
Started in 1912, the Knorr-Holden Plot near Scottsbluff is perhaps the world’s oldest irrigated continuous corn research plot. It was recently commemorated with a sign to mark its significance to both Nebraska history and agricultural research history in Nebraska.
Unveiling of Historic Knorr-Holden Plot Signboard | IANR News (unl.edu)