1. Nitrogen Management Basics
Get the most from each pound of N!
Prepared by John L. Creswell, Coordinator
Nutrient Management Education Project
If you have questions about this Power Point presentation, contact John Creswell at:
10861 Douglas Avenue, Suite B
Urbandale, IA
Phone:
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2. Account for all nitrogen sources
Nitrogen in these materials contributes to the total corn N needs:
Manure
“Weed and Feed” N
N in mixed fertilizers (such as MAP and DAP)
Starter fertilizer N
Biosolids and N-containing by-products
Crop rotation effects
Rotating corn lowers N application requirements
“Weed and Feed” N: A term used by no-till producers when they mix and apply herbicides and liquid nitrogen fertilizer (28-0-0) in the spring, before planting.
MAP: monoammonium phosphate
DAP: diammonium phosphate

3. Suggested N rates for corn production
Note: A specific nitrogen rate within a crop rotation should be based on local conditions and information.

4. Nitrogen management
Use proven N management practices appropriate for your cropping system, soil resources, and available N sources.
Apply fertilizer products in a manner and timing appropriate for each material.
Measure manure N content, calculate available N, and carefully apply manure with calibrated equipment.
Avoid volatile losses by injecting or incorporating manure, urea, and urea ammonium nitrate solutions.
Split or sidedress applications may reduce N losses and improve crop use of N.

5. N management (continued)
Work with your crop adviser and fertilizer dealer to develop a main plan and contingency plans.
Be realistic about corn yields for your soil, location, climatic conditions, and crop history.
Don’t over-apply N.
Lowers profitability, and has greatest impact on potential of nitrate entering water systems.

6. Nitrogen evaluation
Use late spring soil nitrate and fall cornstalk nitrate tests to evaluate corn N needs.
Especially on corn fields with a history of manure application.
Evaluate your corn crop in-season by scouting, visual inspection, or sensor technology.
PM 1714, Nitrogen Fertilizer Recommendations for Corn in Iowa
PM 1584, Cornstalk Testing to Evaluate N Management

7. Production practices to ensure high productivity
Rotate Crops.
Adopt proven practices for effective pest management, crop management, and soil conservation.
Maintain optimal phosphorus, potassium, and soil pH levels.
Calibrate equipment and make accurate applications.
Use adapted high-yielding hybrids and varieties.

8. For more information, see the following ISU Extension resources:
PM 1688, General Guide for Crop Nutrient Recommendations in Iowa
PM 1714, Nitrogen Fertilizer Recommendations for Corn in Iowa
PM 1584, Cornstalk Testing to Evaluate N Management
PM 1811, Managing Manure Nutrients for Crop Production
Nitrogen and Phosphorus Knowledge Web Page: