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How To Sample


StalkNitrate.jpgCorn Stalk Sampling Instructions 

When to Sample: Take samples 1 - 3 weeks after black layers have formed on 80% of the kernels of most ears. 

What to Sample: Cut stalk segments eight inches long. Take stalk segments from between 6 and 14 inches above the soil. Avoid damaged stalks and remove sheaths.

Amount of Sample: Within an area not larger than 10 acres, 15 stalk segments should be randomly collected. Together, these stalks form one 'composite' sample. Areas of differing soil types or management should be sampled separately.

Shipping: Place stalks in a paper bag. Do not use plastic bags! Ship samples as soon as possible. Refrigerate if delay in shipping is one or more days. Do not freeze.

Citation: Iowa State University Extension and Outreach, PM 1584, Cornstalk Testing to Evaluate Nitrogen Management A.M. Blackmer , A.P. Mallarino, 2000. Permission to use instructions and images was granted by ISU. For more information, visit: http://www.extension.iastate.edu/Publications/PM1584.pdf

For laboratory specific information, please contact the location nearest you. 

AgSource Laboratories - Bonduel, WI715-758-2178 bonduel@agsource.com 
AgSource Laboratories - Ellsworth, IA 515-836-4444ellsworth@agsource.com 
AgSource Laboratories - Lincoln, NE 402-476-0300 lincoln@agsource.com 
AgSource Laboratories - Umatilla, OR541-922-4894 umatilla@agsource.com