Adequate Nitrogen is essential for optimum crop production.  However, applying excess nitrogen can have serious environmental consequences.  Nitrogen, in the form of nitrate, is extremely soluble in water and will be carried down through the soil profile as the water drains.  Over application of nitrogen can mean a decrease in profits and increased potential for ground water contamination.

The Pre-sidedress Nitrate Test has been developed to aid farmers in the prediction of nitrogen needs by corn at the time when sidedress applications are normally made. This test takes into consideration nitrogen that is released from organic nutrient sources (such as manure, compost, cover crops and soil organic matter) in addition to nitrogen fertilizer.

Sampling Procedure for Nitrogen Soil Test

1) Sample soil when corn is 8 to 12 inches tall.

2) Collect 15 to 20 soil cores per field to a depth of 12", if possible.  If you cannot get to 12", sample as deep as you can.  Avoid areas where starter fertilizer bands were applied, areas where manure was stacked, or areas where fertilizer/manure applications were unusually heavy or light.

3) Combine the cores for each field and mix completely.  Take a subsample of approximately 1 cup and dry it immediately.  Soil can be dried in an oven at about 200.  Samples can also be air dried if spread out thinly on a nonabsorbent material in a dry, well ventilated area.  A fan will reduce drying time.  Do not put wet samples on absorbent material because it will absorb some nitrate.  The longer the delay in drying the sample, the less accurate the results will be.

4) Put the dried soil in a bag that has your name, address, sample number and from which field the sample was taken.  Send sample along with $8.00 per sample to:
   The University of Vermont Agricultural Testing Lab
   Hills Building, Carrigan Drive
   Burlington, VT 05405-0082

Note: Please write "SWEET CORN" on top of the page with your name, mailing address and phone.
(otherwise you will receive fertilizer recommendations for field corn.)

5) Results will be mailed to you the day after being received by the Testing Lab.
Use the following table to estimate the amount of nitrogen you will want to sidedress your sweet corn.

 Soil Test results      Recommended Nitrogen Sidedressing
   (ppm NO3-N)       (lbs actual N / acre)

         0-10                 130
       11-20                 100
       21-25                   50
         25+                     0
For more information contact:
Vern Grubinger, UVM Extension Vegetable and Berry Specialist
11 University Way, Brattleboro VT 05301
(802) 257-7967
vernon.grubinger@uvm.edu