Corn roots, wet soils, and nitrogen
While the need for 20 or more pounds of nitrogen per week could raise the possibility of a shortage, the production of plant-available nitrogen from soil organic matter through the process of mineralization is also at its maximum rate in mid-season, Nafziger explained. “In a productive soil with a healthy crop, mineralization at mid-season likely provides at least half the nitrogen needed by the crop on a daily basis. This means that normal amounts of fertilizer nitrogen, even if there has been some loss, should still be adequate to supply the crop,” he said.
“Though we could measure soil nitrogen present or apply urea by air on the wetter fields or parts of fields where the crop shows deficiency, it would seem prudent to wait to see if the crop recovers its green color before going to this expense. The loss of crop color in wet soils is mostly due to loss of root function and less nutrient uptake, and roots will need to recover before the canopy does. Even without adding more nitrogen, odds are good that the crop will recover and thrive in the coming weeks, providing the weather remains favorable,” Nafziger said.