"Toto, we're not in Kansas anymore!" No, Dorothy, you're not, and we're no longer in the month of April. That means the next time soils are right for planting, there may be more of a push to plant among those who thought it was too early in the April 15 to April 25 window.
Not that everyone waited. Reports indicate a large amount of both corn and soybeans in the ground in southwest Indiana, central Indiana, and even north-central Indiana. Some held off when rain was in the forecast. The point now is do you still hold off as the calendar works into May and rain is in the forecast?
Any day can be the wrong day to plant. For two years in a row before last season, May 7 and 8 turned out to be bad times to plant, because two to three weeks of cool, wet weather followed, and stands were affected on fields planted just before the cool down. Ken Scheeringa, associate climatologist at Purdue University, suggests May will be normal. A normal May includes rainy spells.
In the Purdue University Corn & Soybean Field Guide, the last date where the chart of planting date and population vs. optimum yield for corn lists 100% possible yield potential is April 30. Traditionally, agronomists have said yield potential begins to decline after May 10. For May 10, the chart, originally prepared by Emerson Nafziger at the University of Illinois and modified by Bob Nielsen, Purdue Extension corn specialist, says that at 32,000 plants per acre, you can still expect 97% of optimum yield potential.
By May 15, it's 95%, and by May 20, it's 91%. Based on averages, represented in the chart, planting May 20 vs. May 3 could mean a 6% difference in yield, or about 12 bushels per acre on 200 bushel-per-acre corn land. At $3 per bushel, that $36 less potential income per acre.
The trade-off, of course, comes if you must plant on the wet side and create sidewall compaction or general soil compaction to get corn planted on May 3 instead of May 20. Soil compaction tends to affect corn more severely than soybeans. It also affects corn more in dry summers than when moisture is plentiful.
So it's May 3- not time to panic by any means. But it appears it is prime time to get corn planted when conditions allow.