Don't underestimate the value of starter fertilizer
But this year corn will be planted late and in wet, cold soil, mainly in central and northern Iowa, where the season is shorter. Unfortunately, we have not had research under these conditions in Iowa. Wisconsin research from a few years ago by Larry Bundy, Ph.D., and collaborators demonstrated, however, that starter application was as likely to increase corn yield with early planting dates as with late planting dates and full-season hybrids. We should not blindly extrapolate these results to Iowa because most of the research sites were north of most Iowa fields, but they should apply well to the northern tiers of Iowa counties.
- Do not underestimate the value of starter for corn planted late, mainly in northern Iowa cold soils and with a shorter season.
- Starter P will provide the most benefit with low or optimum soil test P levels and low pre-plant broadcast application rates. But do not expect much yield response if the two-year P rate for the corn-soybean rotation was applied last fall or this spring.
- Starter N may also be beneficial, mainly without high N rates applied pre-plant or near planting in the spring and with corn on corn.