Melissa Wilson, Nutrient Management Specialist, University of Maryland
Thinking about sidedressing nitrogen on your corn grain or corn silage this spring? With the wet season we’ve had, it might be a good idea. Consider using the Pre-sidedress Soil Nitrate Test (PSNT) to help with your decision. The PSNT should be run when the corn is between 6 and 12 inches tall. If the soil nitrate levels are high enough, you do not need to add additional nitrogen. If the test shows low levels, you should think about sidedressing additional N to avoid potential yield losses. Your UME county Nutrient Management Advisor can run the test if you take the sample. There are some conditions to the test though:
PSNT is applicable on fields where:
- Corn for silage or grain is being grown
- Manure/biosolids have been applied within the past two (2) years OR a forage legume was grown last year
- Less than 50 pounds of commercial fertilizer nitrogen per acre were applied prior to sidedress
PSNT is not applicable on fields where:
- More than 50 pounds of commercial fertilizer nitrogen per acre have been applied prior to sidedress
- Commercial fertilizer has historically been the only nutrient source
- Irrigation is used
For more information about how to collect the sample, visit: https://extension.umd.edu/sites/extension.umd.edu/files/_images/programs/anmp/SFM-2.pdf.
You may also read Doug Beegles article from Penn State in 2015:http://extension.psu.edu/plants/crops/news/2015/06/nitrogen-loss-concerns-with-heavy-rains
