While driving around the community this week, I noticed that many of the wheat fields in the area are a much paler green color than we normally see in mid-June. I also saw many lawns, which appear to be in good condition, but were turning a pale green color. It’s clear that much of the nitrogen that was applied to wheat and turf has been washed out of the soil from all the recent rains.
Nitrogen, also abbreviated as N, is the plant nutrient most associated with green, healthy, lush growth. It is N that makes our lawns green, our crops green and trees green. Too much N, and flowering plants may grow wildly at the expense of flowers. Too little N often leads to pale green foliage and stunted development.
One form of N that is taken up by plants is nitrate. Nitrates are a water soluble form of N, meaning the nutrient can dissolve in water and wash out of soil. Once the N is washed out of reach of the roots, the plants can exhibit the pale green symptoms of nitrogen deficiency.
For those with lawns that are pale, the solution would be to fertilize the lawn. It is preferable to use a slow release fertilizer, which can help to provide even growth rate on the turf and reduce the chance that water will wash away the N. More information is available from the Purdue lawn fertilizer publication at https://www.agry.purdue.edu/turfnew/pubs/ay-22.pdf.
In wheat, there is little chance that an application this late will make a big difference in yield. However, if you applied N preplant to soils where you were going to plant corn, there is a very real possibility that much of that N was lost if no nitrogen stabilizer was applied with the N. This might be a good year to use the pre-sidedress nitrogen tests that are offered by many soil testing companies to determine just how much N is left in the field. For more information about pre-sidedress N tests, check out https://www.agry.purdue.edu/ext/pubs/AY-314-W.pdf.
Jeff Burbrink is Extension Educator-Agriculture/Natural Resources at Purdue Extension Service Elkhart County. He can be reached at 574-533-0554 or firstname.lastname@example.org.