Late Spring Nitrate Testing Optimize Nitrogen Application
To ensure your fields have adequate nitrogen levels for the best production and highest yield, utilize a late spring nitrate test from AgSource.
The following conditions make nitrogen testing a good investment:
* Due to the biological process which converts ammonium-nitrogen into nitrate-nitrogen, nitrogen levels may be uncertain. The rate of this conversion is dependent by soil temperature, as well as other factors. When the soil temperature is less than 50 degrees most of the applied ammonia will be held in this form and not converted into nitrate.
- Little or no nitrogen was applied right after harvest.
- Small amounts of nitrogen were applied (< 125 lbs).
- Nitrogen was applied at sub-optimal conditions (temp<55°F) limiting effectiveness.
- Small amounts of manure were applied or incorporated after soil temperatures drop below 55°F.
- Early spring nitrogen application (cold soil temperatures) will not affect measured nitrate.
How to Take Soil Samples
- Divide fields into small management zones of 6-10 acres.
- Take samples when corn plants are at about 6 inches tall.
- Sample cores at a depth of 0 to 12 inches.
- Collect a minimum of 15-20 cores for the best representation (more is better).
- Thoroughly mix together (laboratory needs a minimum of 1 pound of mixed soil).
- Ship as soon as possible: samples should be sent the same day as collected.
Interpreting Test Results Use the reported nitrate-N concentration to make fertilizer application decisions:
High Range: > 26 ppm - no application needed.
Adequate Range: 21 - 26 ppm - application may or may not be needed.
Lower Range: < 21 ppm - application recommended.
For more information, reference "Nitrogen Fertilizer Recommendations for Corn in Iowa," an informational piece developed Iowa State University's University Extension in Ames, Iowa. http://www.extension.iastate.edu/Publications/PM1714.pdf
Contact AgSource Laboratories today to request sampling supplies.
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