Alternating streaks of dark green and pale green are not uncommon in wheat in the spring and often follow the path of the nitrogen fertilizer application made earlier in the season.

While very noticeable in wheat, non-uniform application of fertilizer is a common problem in many crops where granular fertilizer applications have been made with spinner spreaders.

Many of these problems can be traced back to three sources: operator error, poor quality fertilizer, and, occasionally, a mis-adjusted spreader.

The first step to diagnosing potential spreader problems is to obtain a copy of the operator’s manual for the spreader being used. In the operators manual there will be a wealth of information such as width of spread, proper hitch height, and operating speed as well as important safety information.

Common operator errors

After reviewing the operator’s manual, observe the operator making an application. Give particular attention to the operating speed of the spinners.

Many drawn spreaders have mechanically driven spinners operating from the PTO of a tractor. The engine RPMs must be maintained at PTO operating speed.

For hydraulic-driven units, adequate pressure must be maintained in the hydraulic system to drive the spinners at rated speed.

Check to see if the width of application is being maintained by the operator. Light bars, auto steer and other navigation aids can assist the operator in maintaining application width.

Confirm that the selected width is appropriate for the spreader and the material being spread.