Spring 2022 fertilizer applications

By John Fulton

We say every growing season is unique and 2022 is no different. Supply chain and labor challenges along with high fertilizer prices have already created a unique situation in agriculture before we get to spring work. Consequently, fertilizer decisions coupled with fertilizer applications are important for profitable production of crops and forages. Regardless of choosing fixed-rate or variable-rate applications of fertilizers, an important factor to efficient and effective use of fertilizers is proper maintenance, setup and calibration of broadcast spreaders. Calibration and maintenance checks of broadcast spreaders is recommended. For 2022, that becomes important to ensure accurate and uniform application of NPK and other granular nutrients.

To start, spreader settings need to change accordingly for the fertilizer product being applied while these settings may need to be adjusted based on application rates and field conditions. While technology on spreaders, especially VRT spreaders, has increased over the past decade, field performance remains vital for profitable production. Just because the latest technology has been adopted does not directly correlate to accurate field performance; unfavorable consequences are possible if incorrect rates or non-uniform application occur. 

Calibration should be part of a regular maintenance schedule for all application equipment. For spinner spreaders, weather conditions, fertilizer physical properties, field conditions, technology setup, spreader maintenance and calibration, and the operator can all have an impact of field performance. The following information provides recommendations from our digital at team on ensuring peak performance of spinner spreaders.

Fertilizer source and quality matters!

Fertilizer products vary in density and physical properties therefore spreader setup in accordance to product is vital. Measure fertilizer density and adjust settings accordingly. Visit http://ohioline.osu.edu/factsheet/fabe-5501 for a detailed discussion on the effect of fertilizer material properties on spreading plus density charts of common fertilizers. 

Proper maintenance of the spreader

Before operation, double check the following maintenance points: proper conveyor tension, bearings, tire inflation, conveyer wear along with vane and spinner wear. Common problems include un-level spinners, spinners operating at different RPMs, damaged discs, spinners not centered evenly under chute, fertilizer build-up on parts, bent or cracked spinners, and corroded hoppers or components.


Calibration procedures vary between manufacturers and applicator models. However, two essential aspects exist for accurate field execution; 1) metering to obtain the right rate (bin to spinners) and 2) uniformity of spread (spinners to ground).

  1. Metering mechanism — Bin to Spinners. Meter calibration will include running the conveyor over a known time or distance then measuring the amount of dispensed product and comparing to the in-cab display estimated amount. Adjustments to gate height and conveyor constant will help dial into an accurate metering. One will need to calibrate for different fertilizers since varying in density and properties. Equipment manuals outline the proper procedure and specific adjustments to make.
  • Spread Uniformity — distribution patterns can be difficult to evaluate without conducting a proper spread pattern test. Pan testing following standard protocol is necessary to evaluate spread uniformity. Consult with a spreader dealer on obtaining a spread pattern test kit. 
  • Spread Width — spread width or swath spacing needs to be maintained in order to prevent too much or too little overlap between swaths. If not already being used, guidance systems greatly reduce error and operator fatigue in spreaders/spreader trucks. 
  • Proper Setup — use the calibrated settings for a particular fertilizer including adjusting the product density within the in-cab display setup, using the correct spinner speed, and adjusting chute to proper position. Remember to operate at the specified spread width to ensure correct overlap with adjacent passes.

More details on calibration and setup for spreaders can reviewed in the following 3 documents: 

• Spinner-Disc Spreader Set Up and Calibration (Field Execution Manual — Part 1) @ https://ohioline.osu.edu/factsheet/fabe-561

• Correcting Irregular Spread Patterns (Field Execution Manual — Part 2) @ https://ohioline.osu.edu/factsheet/fabe-562

• Proper Spinner-Disc Spreader Operation, Terms and Definitions (Field Execution Manual —Part 3) @ https://ohioline.osu.edu/factsheet/fabe-563

• Find additional resources and information on fertilizer application, visit the Ohio State University Digital Ag website: https://digitalag.osu.edu/precision-ag/research-focuses/precision-crop-management

Dr. John Fulton, Professor, can be reached at fulton.20@osu.edu. This column is provided by the OSU Department of Food, Agricultural and Biological Engineering, OSU Extension, Ohio Agricultural Research and Development Center, and the College of Food, Agricultural, and Environmental Sciences.

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