Focus on planting tips, emergence issues and scouting for early season pests.
Planting Tips
A successful planting season means focusing on the details, including evaluating soil temperature, proper seed spacing and seed depth.
Instead of looking at temperatures at the start of planting, look at the weather forecast for 10 days following planting as this period can have the most impact. A cold rain following planting can be bad. Water temperature during initial contact with the seed is crucial. Hydration at or below 50 F likely will damage emergence and reduce stand. A cold spell after emergence is less likely to hurt stands. In addition, the growing point of corn will stay below ground for two to three weeks after emergence with normal planting temperatures.
In terms of proper seed spacing, research has shown that even plant spacing can increase yields. Poorly spaced and missing plants were found to decrease yields by 7 to 19 bushels per acre. Non-uniformity in corn stands places your sizable investment in a planter, seed and other inputs at risk of lower returns. Another way to improve in-row plant spacing is simply by slowing down the planter speed.
For seed depth, experts recommend planting corn at a depth of 1½ to 2 inches for optimal nodal root development, with 2 inches best under normal conditions and 1½ inches possibly more favorable when planting early into cool soils. Growers should never plant shallower than 1½ inches. Symptoms of irregular planting depth can include uneven emergence, non-uniform mesocotyl length and varying plant height.
Emergence Issues
Weather can have a huge impact on corn development and stand establishment.
A cold rain immediately after planting can be damaging to the crop. When the first water imbibed by a seed is too cold, imbibitional chilling injury can result. This is because cell membranes inside the seed lack elasticity, causing membranes to rupture and allow leakage of cell contents, providing a food source for invading pathogens. Large swings in soil temperature can have a similar effect on seedlings.
A spring frost also can decrease corn plant populations or force replant. Freezing temperatures can kill the growing point even if it is under the soil surface. While it can be difficult to wait after a frost, it is best to wait at least three days before attempting to assess the survival and health of the corn's growing point. Evaluating corn stands before three days can be very difficult, if not impossible.
As temperatures increase, the process needed for germination to proceed occurs at a faster rate, leading to more rapid emergence. Under ideal conditions, corn will emerge in 10 days or less. That said, these conditions can be influenced and slowed down by factors such as cooler soil conditions and heavy residue, which also can create cooler soils.
Scouting Your Fields
Once plants emerge in the field, it's never too soon for growers to start scouting their fields for pests. Following is a corn scouting calendar that provides an overview of the typical time periods specific pests emerge. Please note, this calendar may vary by region as well as by when planting occurred, especially with this year's early spring conditions in many areas.
4.02.2012