BEFORE PLANTING
Make sure that fertility and soil pH match your yield expectations. Nitrogen is the key nutrient for high yielding corn. Nitrogen requirements for corn following corn are significantly higher than those for corn on rotated ground.
Over eighty percent of 2009 corn acres will be planted with a herbicide tolerant corn hybrid. Renk Seed advocates “starting clean” on these acres with a burn down herbicide treatment or tillage. Renk also advocates using alternative modes of action in a program that features Roundup® and Liberty® brand herbicides. Roundup Ready® rates of key soil applied herbicides are available for growers to complement their herbicide tolerant crops. No matter the herbicide system, weeds measuring 4” and taller reduce corn yields.
AT PLANTING
Analyze planting date data for your area. Arlington,WI data indicates that May 1 is the ideal planting date for south central Wisconsin. It will be as much as 7-10 days earlier for southern Renk Seed customers and as much as 7-10 days later for northern customers. The better the condition of the soil for tillage or no-till planting, the better the chance of a good stand and avoiding compaction problems.
Make sure that you plant into moist soil, generally more than 1-1/2” and no more than 2” deep. Planting too shallow risks poor root development. Corn planted at 1” and corn planted at 3” will emerge only a few hours apart. It has been a trend in recent years to plant earlier and shallower. It has also been a trend to plant at higher speed in more residue. Speed and soil conditions work against consistent seed placement and it is highly recommended that growers err on the deeper side in challenging planting conditions.
Set populations to match yield expectations and adjust for planting date. Ten percent stand reduction for very early plantings are typical. Corn will not “lose yield” if the density is a little high and the crop is stressed. The only cost will be for the additional seed and trait technology fees that are not fully utilized in less than optimal yield conditions. As populations increase, growers should check the late season stalk quality of their hybrids.
GROWING SEASON
Check emergence as early as practical, especially in a cool spring when seedlings may be in the ground 3-4 weeks. Excessive rainfall and soil crusting are the two biggest problems for corn emergence. Also watch for insect feeding, fungal attack, herbicide interactions and wildlife damage. These problems will be magnified for growers planting corn on corn.
Monitor pest problems during the growing season. Corn borers reduce yields by 5% for every borer cavity found in the stalk. Rootworms prune corn roots which could result in lodged corn and inhibited nutrient uptake under stress conditions, either resulting in yield loss and harvestability problems. Be aware of the variant Western Rootworm Beetle that lays eggs in soybeans and alfalfa. In addition, the extended dipause variant of the Northern Rootworm (the eggs hatch after two years) can cause damage in corn that has been rotated. Western growers should be monitoring Western Bean Cutworm which causes ear damage late in the season.