By Dr. Mark Licht and Dr. Sotirios Archontoulis
Corn planting progress began over the last several days, especially in the central and southern tiers of Iowa. That is good news, unfortunately, in north central and northwest Iowa field conditions remain wet putting farmers in those areas further behind and with Monday’s rain will not be making progress for several more days.
Recent work by Baum et al. (2019)
on yield response to planting date indicates a couple things;
- Optimal corn planting date window is from April 15 to May 13 to achieve 95% yield potential. The optimal planting date falls on April 28. This suggests that despite the challenging conditions in 2019 there is still time.
- The optimum planting date has not changed over the last 2 decades, despite the changes in genetics or weather variability.
- There is less risk in planting before April 15 compared to planting after May 13. Yield potential drops off sharply after May 20.
Bottom line, even with recent rains, there is still time to get the corn crop planted and still achieve high yield potential.
Tips to minimize yield penalties associated with planting
- Wait for soil moisture conditions to dry enough to avoid sidewall compaction. Less yield potential is lost by planting 1 day later than causing a sidewall compaction and slowing root growth.
- Use enough row unit down pressure to achieve a 2-inch planting depth but not too much causing additional compaction concerns
- Make sure the closing wheels are closing the seed furrow and providing seed-to-soil contact