Progress of corn planting and corn emergence
The replant decision rarely comes easy. Numerous factors determine a field’s yield potential. Consider data like that presented in Table 1 as a tool to use in approximating what may result — based on our best available research data. Please realize though that actual yield losses may be greater or less than what is shown.
Corn not yet planted: is the window closing?
Optimum Iowa corn planting dates range from mid-April to the end of April in north central and northeast Iowa and to the first or second week in May in other parts of Iowa. The table in my March 27 article, Best planting dates for Iowa, summarizes the recommendations for various regions of Iowa. So, what is there to say the first week of May when only half of Iowa’s corn is planted? Here it is in a nutshell:
Be patient if corn is not yet planted. It is far better to wait for good soil conditions than to ‘mud in’ corn.
R. Elmore Figure 2. Corn planted on April 11 on schedule with about 80 GDD accumulated and 12 days in the soil. There is little question based on our research trials that, on average, yield potentials begin to drop after May 2 in north central and northeast Iowa; after May 13 in southwest, south central and southwest Iowa, and after May 18 in northwest, west central, central and east central Iowa. Those are average responses and we don’t know what 2012 will offer. If 2012 provides ‘average’ growing conditions, Table 1 contains some ideas on potential yield reductions associated with delayed planting. For example, if you target 35,000 plants per acre and you are able to plant between May 5 and May 15, you may experience 96 percent of the original yield potential.
Certainly it is time to plant if soil conditions allow. ‘Mudding in’ corn could be trouble the entire growing season. Soil temperatures are back to normal for this time of year across most of the state; normals are about 50 F. Soil temperatures point in our favor for planting corn. The calendar clearly shows we should not think too hard about planting, but the call for more rain this week will – and should – slow planting progress.
When soil conditions are favorable, it is time to plant corn. Is the window for planting corn closing? Not yet!