Considerations for Nitrogen Sidedress in Corn and early Grain Sorghum

Due to frequent and excessive rainfall and subsequent prolonged saturation of the soil, the probability of nitrogen loss is very high this season.  Unfortunately, the probability of requiring additional Nitrogen inputs to reach yield goals is high.  

Sidedressing Corn and Milo is fairly uncommon here in NC Oklahoma, but considered standard practice in other production areas in the country.  Garber Coop is equipped to handle your Sidedress needs.  We have drop tubes with orifice plates to stream UAN between the rows in our custom application rigs.  First Sidedress window typically is V5-V6 (5-6 collar corn) and before Boot in Sorghum. 

However, these time frames need to be accelerated if the plants show symptoms of Nitrogen deficiencies such as yellowing on the lower leaf tissue.  Nitrogen is mobile in the plant as well as in the soil, so symptomology is noticeable in lower leaf tissue first.  Another important consideration is Sulfur.  Sulfate Sulfur is also mobile in the soil and can leach, but is relatively immobile in plants.  Symptoms of Sulfur deficiencies can be confused nitrogen, however, with Sulfur the entire plant appears pale or yellow.  

So, how do you make a determination on what to do?  There are two main ways to determine in season adjustments; soil sample at various depths and leaf tissue analysis.  Soil sample at 0-6 inch, 6-12 inch and 12+ inches to determine where your nitrogen is and at what concentration.  Leaf tissue analysis is a snap shot in time and needs to be done over a period of weeks to generate a baseline.  In conjunction with soil samples, this method can help determine the appropriate rates and identify other hidden hungers that the plant is experiencing.  

If you would like more information on this subject, please contact Kevin Brown at 580-541-9014.

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