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Is it still safe to apply second application of fertilizer on wheat?

The recent wave of heat really kicked the winter wheat crop into high gear. We had this question twice this week… and we get it most years. “I was planning for my second application of fertilizer, things were busy, and the wheat crop has leaped ahead, now the flag leaf is emerged… Can I still do it?” The answer is YES, but you do need to be careful.

First, remind ourselves of the reason we do split application to begin with. The crop is in a state of rapid growth and nutrients are in very high demand. You likely can see the appearance of the first application fading, or running out, and the crop likely turning mare pale shades of green. (the 2X overlaps are deep green still, while 1X application in majority of field are lighter)  The plan all along was to deliver the nutrients at a time when the crop needs them.  That fact has certainly not changed, and that time is now (or possibly last week) for wheat crop north of London and into Eastern Ontario. Please do stick with your plan.  The fertilizer you will apply will be used to support the plant during grain fill and to pack protein and test weight into the kernels.  These things will greatly impact yield.  And, if you are a Hard Red Wheat grower, the protein component is obviously a primary concern.  You want to make the grade.

Ways to make UAN+ATS application as safe as possible…

  • Avoid application in the sunny parts of the day. The leaves are sensitive.
  • Consider to dilute UAN with water, this will make more drops, but the droplets half as concentrated. Be sure to stay within proper operating pressure and rate for your streamer nozzles.  Target is still to have large droplets that reach the ground.
  • Try to apply at night, or when dew present, more dilution, UAN droplets should roll off leaves easier. Can even be effectively applied during a light rain.
  • Including ATS can increase burn, but the crop will still need the sulfur, so keep it in the mix. Just be more careful.
UAN injury 24 hours after application in the heat of the day. Double overlapped area in corner of field. Rest of the field not this severe.

Thing to consider with DRY fertilizer application…

  • Make sure equipment is calibrated to properly throw fertilizer as far as you want it too. Granular fertilizer products, and application technology that exists in countryside now give very accurate and effective placement ability, and I really like the job that was done in my own wheat crop last year.
  • Avoid using dusty fertilizer product and avoid making application when the plants are wet. The dust sticks to the dew, and is likely to increase incident of leaf burn.
Topdressing HRWW with Amidas. Photo courtesy of Calvin Brown , Manager at P&H Kerwood

If you are a DIY’er, but only have narrow application equipment, please do not make a fresh set of tracks in the field at 40 or 50 ft.  That tramping will be a definite and significant yield loss.  The small cost of custom application at a wider width will leave you with much more wheat to sell.

Split application of fertilizer is a practice that will be applied by spring wheat growers also.

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