Dordt field tests produce surprising results
Posted: Sunday, November 30, 2008
SIOUX CENTER, Iowa -- The Dordt College Agriculture Department recently released crop yield results from its fall field trials.
The trials were conducted by agriculture majors in Dordt's Field Crop Production and Management class, under the supervision of Dr. Ron Vos, professor of agriculture at Dordt College.
Students who participated in the field sized-comparison study were Brett Heidema, Manhattan, Mont; Josh Koch, Earlham, Iowa; Johnathon J. Nagel, Three Rivers, Mich.; Benjamin Witte, Wauconda, Ill.; and Maria Verburg, Vergennes, V.T. They were assisted by Mike Schouten of the Dordt Agriculture Stewardship Center.
Vos said his crop production class was surprised this year by the lack of corn rootworm pressure. The Agriculture Department had trapped adult corn rootworms for the past three years, and this year's test plots found a marked decrease in rootworms.
Twenty-one crop varieties from nine companies were included in the yield trials. Participating companies were Asgrow, Dekalb, Croplan, Pioneer, Prairie Brand, Mycogen, Northrup King, Stine and Viking.
Six different trials were conducted on Dordt's fields located just north of Sioux Center. In the trials, seed varieties were planted in strips of one or two equipment-widths completely across the field. Because these narrow strips lie close to one another, field variability between treatment strips is minimized. The treatments are replicated at least four times in the field to overcome chance field differences. In addition, the order of the varieties in each block is chosen at random, avoiding a source of unconscious bias.
"To ensure accuracy and credibility of our data, we used on-farm sized comparison analysis," Vos said.
Replication, randomization and field sized strips ensure the results will be valid and applicable to farmers' field situations. The students also used a measurement called the "least significant difference" (LSD). If the difference between two varieties is greater than the LSD, then the difference is considered significant.
Vos said results are published at an LSD of .05, "which means we are certain these results are statistically valid 19 out of 20 times." An LSD of .25, for example, would be valid three out of four times.
"We hope that by providing our data to farmers, they will have a valuable tool in deciding their seed choices for next year," said Dr. Vos. He added his thanks to all those who in one way or another participated in the field trial.
To view results from this year's trials, log on to the college's Agriculture Department's Web site at :http://www.dordt.edu/academics/programs/aagriculture/
The trials were conducted by agriculture majors in Dordt's Field Crop Production and Management class, under the supervision of Dr. Ron Vos, professor of agriculture at Dordt College.
Students who participated in the field sized-comparison study were Brett Heidema, Manhattan, Mont; Josh Koch, Earlham, Iowa; Johnathon J. Nagel, Three Rivers, Mich.; Benjamin Witte, Wauconda, Ill.; and Maria Verburg, Vergennes, V.T. They were assisted by Mike Schouten of the Dordt Agriculture Stewardship Center.
Vos said his crop production class was surprised this year by the lack of corn rootworm pressure. The Agriculture Department had trapped adult corn rootworms for the past three years, and this year's test plots found a marked decrease in rootworms.
Twenty-one crop varieties from nine companies were included in the yield trials. Participating companies were Asgrow, Dekalb, Croplan, Pioneer, Prairie Brand, Mycogen, Northrup King, Stine and Viking.
Six different trials were conducted on Dordt's fields located just north of Sioux Center. In the trials, seed varieties were planted in strips of one or two equipment-widths completely across the field. Because these narrow strips lie close to one another, field variability between treatment strips is minimized. The treatments are replicated at least four times in the field to overcome chance field differences. In addition, the order of the varieties in each block is chosen at random, avoiding a source of unconscious bias.
"To ensure accuracy and credibility of our data, we used on-farm sized comparison analysis," Vos said.
Replication, randomization and field sized strips ensure the results will be valid and applicable to farmers' field situations. The students also used a measurement called the "least significant difference" (LSD). If the difference between two varieties is greater than the LSD, then the difference is considered significant.
Vos said results are published at an LSD of .05, "which means we are certain these results are statistically valid 19 out of 20 times." An LSD of .25, for example, would be valid three out of four times.
"We hope that by providing our data to farmers, they will have a valuable tool in deciding their seed choices for next year," said Dr. Vos. He added his thanks to all those who in one way or another participated in the field trial.
To view results from this year's trials, log on to the college's Agriculture Department's Web site at :http://www.dordt.edu/academics/programs/aagriculture/
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