MU agronomist: Plant now, add nitrogen later
“We found almost zero nitrate in the top foot, but about 20 pounds of nitrogen per acre as nitrate in the second foot and another 20 in the third foot,” Scharf said. “In short, the nitrate has moved down, and it seems likely that a good bit has moved below 3 feet deep. I wouldn’t take a credit for last year’s nitrogen unless it was backed up by a deep soil test.”
Soil tests to measure residual nitrogen are available through the MU Soil and Plant Testing Laboratory, through local extension centers or through commercial vendors.
For information on how to interpret soil test results, MU Extension guide G9177, “Preplant Nitrogen Test for Adjusting Corn Nitrogen Recommendations,” is available for free download at extension.missouri.edu/p/G9177.
Nitrogen application also is discussed in “Best Management Practices for Nitrogen Fertilizer in Missouri” (IPM1027), available at extension.missouri.edu/p/IPM1027.
Information also is available from Scharf at plantsci.missouri.edu/nutrientmanagement. Precipitation maps are available at the link for “N Watch 2013,” a tracking tool begun in 2009 to help producers make assessments about nitrogen loss in certain regions of the state.