To facilitate speedy planting between rain showers many growers are skipping starter fertilizer. What might be the consequences?
Our recent research has shown in continuous corn (CC) that 25 lb/acre each of N and P2O5 in 2×2 placement increased yield at ⅓ of the site-years by an average of 8 bushels per acre. In corn rotated with soybean (CS) increased yield occurred at ½ the site years and averaged 7 bushels per acre. Pop-up, 3 gallons 10-34-0 per acre, had little benefit in CC and was not tested in CS. Most of the yield responses to 2×2 in CC were in no-till fields, but yield increases occurred with different tillage practices in RC. Averaged over both non-responsive and responsive site-years, yield increases were less than 3.5 bushels per acre for either crop rotation. Early planting and cool soils were not related to whether or not a site responded to starter fertilizer. We found yield response to vary considerably from year to year for the same field. For example, at the most responsive field, yield increases ranged from 0 to 17 bushels per acre. In contrast to yield, starter consistently increased the rate of crop development so maturity was reached sooner. Grain moisture was less with starter than without starter – 1.2 and 0.6% for CC and CS, respectively.
If the rain stopped today and all the corn could be planted before the next rain, the earlier maturity and potential for a small increase in yield might be more beneficial than the slightly lengthier time it takes to plant. If planting continues to progress in fits and starts between rain events (which is likely given the forecast), then planting without starter may be the better decision.
