The document outlines the procedure for conducting a stalk nitrate test to evaluate nitrogen management in corn fields, specifically recommending sampling 1-3 weeks after black layer formation. It details how to collect samples, the importance of testing, especially for manured fields, and categorizes nitrate-n concentrations into low, optimal, and excess ranges. Contact information for questions and a reminder to use paper bags for samples are also provided.

1. Stalk Nitrate Test
13611 B Street Omaha, NE 68144
(402) 334-7770 Fax: (402) 334-9121
www.midwestlabs.com
6 inches off
the ground
Sample 8
inches of
the stalk
Sampling
When to Sample:
Best time to sample is between 1
and 3 weeks after black layers have
formed on 80% of the kernels.
What part to sample:
Sample the 8-inch segment, 6 inches
off the ground. Remove leaf sheaths
from the segment.
How much sample:
Collect fifteen 8-inch segments at
random* within an area not larger
than 10 acres to form a single sample
to send for analysis.
Place samples in paper (not plastic)
bags to enable some drying and to
minimize growth of mold.
*Do not sample stalks that have been
damaged by disease or insects.
Questions?
Craig Ebel(402) 590-2962
cebel@midwestlabs.com
John Torpy
(402) 829-9880
torpy@midwestlabs.com
The end-of-season cornstalk
test is a good tool for
evaluating nitrogen (N)
management practices used
in any corn field in any year.
The test is most valuable
when used on field that show
no visual signs of N
deficiency. Its use is
strongly recommended for
manured corn fields.

2. Name
Address
City State Zip Code
Account Number
Telephone
Fax
email
Account Number
Grower Identification
Stalk Nitrate Test
Submittal Form Stalk nitrate-N concentrations can be
divided into three categories:
low, optimal, and excess.
Low: less than 700 ppm N
This indicated high probability that
greater availability of N would have
resulted in higher yield. Concentrations
in this range, however, give little
indication of the magnitude of yield
increase that might be expected from
more available N.
Optimal:700 to 2000 ppm N
This indicated high probability that N
availability was within the range needed
to maximize profits for the producer.
Excess: greater than 2000 ppm N
This indicates high probability that N
availability was greater than when
fertilizer N was applied at rates that
maximize profits for producers.
Sample ID Stalk Nitrate Test Comments/Other analysis
Results
$15 per
sample
Remarks