Spring Planting Notes

Corn Hybrids Will Adjust to Late Planting
Growers are heading into fields planting corn between rain events. Typically, the majority of growers plant corn between April 20 and May 10, that is the target. Those with large acreages plant earlier and those growers whom have smaller acreages have the flexibility to wait till soil planting conditions are ideal.
In the back of many growers’ minds, if planting is delayed, should one choose shorter season hybrids? The answer is no. Hybrids adjust to delayed planting dates and we have seen this at the Graves-Chapple Farm with three years of planting date demonstrations.
As planting date is delayed, the hybrids speed up the time between planting and silking. The plant adjusts especially the longer season hybrids compared to early maturity hybrids.
Corn responds and adjusts to the growing season to compensate for later planting dates.
However, it is wise if weather delays planting, it is important to plant the longest maturity hybrids first. This allows the plants to take advantage of the longest growing season.

Inoculate Soybean Seed When Planting Into CRP
Soybean nitrogen fertilization is not recommended as it generally does not increase soybean yields. The number of nodules that form by Rhizobium on the soybean plants decrease with increasing amounts of nitrogen in the soil. Soybeans will take up a significant amount from the soil if it is available first, and then make their own nitrogen with the use of Rhizobium.
In situations that have not been in soybean production for three to five years, it is important to inoculate the seed so the Rhizobium will make the plants own nitrogen.
Fields that have been in CRP for a number of years and now being planted to soybean should soybean seed inoculated. Also, any other acres that have not been planted in soybeans for last three to five years should also be planted with inoculated seed. Another situation to apply inoculants is low pH soils that have been corrected with a liming application.
Typically in a corn soybean rotation, in Missouri, we do not see any advantage to inoculating soybean seed yearly. When soybeans are planted often, the soils will have a natural level of Rhizobium that will establish on soybeans and allow them to make their own nitrogen.
For more information, contact Wayne Flanary, Regional Agronomist, University of Missouri Extension at 660-446-3724.