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Posted 23 October 2006. Crop Management. Modern Corn Production Makes More Efficient Use of Nitrogen Fertilizer University of Minnesota www.pmn.umn.edu St. Paul, Minnesota (October 10, 2006) –Corn is making more efficient use of nitrogen fertilizer in recent years, University of Minnesota research shows.
"This improved efficiency didn't occur in a short period of time," said George Rehm, soil scientist with the University of Minnesota Extension Service. "The changes have taken place gradually over a number of years." The improved efficiencies are reflected in a new Extension report by Rehm and co-workers titled Fertilizing Corn in Minnesota. A combination of factors is probably responsible for the improvement in nitrogen efficiency, according to Rehm. "Modern hybrids are better," Rehm said. "They have better, more extensive root systems because they're better at tolerating a drought. And the more extensive root systems in turn lead to improved nutrient uptake." Rehm says weed control is not the problem that it was 10 to 20 years ago. Weeds compete with corn for both nutrients and water. With fewer weeds for competition, more nitrogen in the soil system is available for corn, and nitrogen efficiency of the fertilizer improves. With the widespread use of Bt corn, Rehm says the negative impact of the corn borer on production has diminished. Reduced damage to the stalk and ear has a positive impact on uptake of both nutrients and water, he points out. "Therefore, the efficiency of the use of nitrogen fertilizer is improved substantially as the damage caused by the corn borer is reduced," said Rehm. And a reduction in rootworm damage adds to the list of positive changes, according to Rehm. With reduced rootworm pressure, there is a larger, more effective root system that results in improved uptake of nitrogen fertilizer. Less nitrogen helps profit potential for farmers. In addition, avoiding over-application of nitrogen fertilizer means less leaching to the groundwater and drinking wells on silt loam and sandy soils. And with tile drainage on poorly drained soils, lower rates mean less nitrate ends up in the Minnesota and Mississippi Rivers and in the Gulf of Mexico, where it contributes to hypoxia, or dead zones. For a more detailed article by Rehm, see Extension's Minnesota Crop eNews at www.extension.umn.edu/cropenews. Contact: |
