As temperatures warm up tillage, application of fertilizer and planting will begin in
earnest very soon. If you have fields that were corn in 2013 and will be corn this year
and have not applied nitrogen fertilizer for this year’s crop, you may want to soil test for
residual nitrogen. Last year’s drought conditions impacted corn yields throughout the
region and several fields had corn grain yields of 60 bushels/ac or less and many fields
were cut for silage or even baled up as forage. If you applied nitrogen fertilizer at rates
ranging from 100 to 200 pounds per acre in 2012 and had very low yields, there is a
good possibility that significant residual nitrogen is available for a 2013 corn crop. You
may even have residual soil nitrate levels as high as 50 to 100 pounds per acre. With
anhydrous ammonia rates at $800 per ton or higher, you could save on your fertilizer
costs from $25-$50 per acre in these fields with high residual nitrogen.
While there is no guarantee your residual nitrogen rates will be high in your fields, the
combination of low yields and dry weather that occurred in some fields are factors that
contribute to less nitrogen use and loss and may lead to significant residual N (nitrogen)
in your soil. Last week there were reports from one of the main soil labs in Nebraska of
high residual nitrogen levels in soil samples of several fields across Nebraska. One thing
is certain, you will not know what your residual nitrogen levels will be unless you sample
your fields. Ideally sampling down to 3 feet would be best, but with the dry weather
we have been experiencing, it will probably be difficult to sample down to this level.
Sampling down to a depth of 2 feet should provide a very good indication of residual
nitrogen in your soil profile. There may be 50 pounds of residual nitrogen in the top 12”
If you have fields you were planning on rotating to soybeans and were corn last year,
you may want to soil test these fields, especially if these fields were low yielding.
You may want to contact your ag chemical supplier to see if they can sample your
fields or else you can check out our probe here in the Nemaha County Extension
office. Here is the link to the UNL guide to soil sampling if you have questions, http://
www.ianrpubs.unl.edu/epublic/pages/publicationD.jsp?publicationId=831. If you have
questions feel free to contact me at the Nemaha County Extension office at (402) 274-
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