Spring is here and most of you are likely thinking about
planting dates. Deciding when to plant is all about weighing the pros and cons
Though planting corn early often results in higher yields,
choosing the wrong planting date can have adverse effects on crop establishment.
The earlier the seeds go into the ground, the more likely
they will face stresses. Cold, wet conditions can make corn emergence difficult,
causing yield loss.
In fields with non-uniform stands, the smaller,
late-emerging plants are unable to capture enough sunlight and unlikely to reach
optimal potential by harvest. Delayed emergence also lengthens the time that
seeds and seedlings are most vulnerable to early-season insects and diseases.
The likelihood of reduced stand establishment is also
greatest when planting into unfit seedbeds, when soils are excessively cold and
wet, or when planting is quickly followed by a cold spell. Here are some tips to
help you weigh your early planting options:
* Choose a planting date based on soil conditions and
weather outlook. Plant when soil temperature is close to 50 degrees and the
near-term forecast shows a warming trend;
* Delay planting for a few days, if a cold spell is
expected, to allow emergence to begin at moderate temperatures;
* Be aware of the potential for large temperature swings to
affect emergence in lighter soils planted early, especially if nighttime
temperatures dip into the 40s;
* Consider strip-tillage and residue cleaners to improve
seed to soil contact and warm the soils up faster in fields with high amounts of
* Select hybrids with higher stress-emergence scores to help
reduce the risks associated with planting in cold-stress conditions.
Planting depth also affects yield in corn production. DuPont
Pioneer has conducted planting depth trials for several years to determine just
how much yield is impacted by different planting depths.
In the trials, emergence often was quicker with shallower
planting depths, but root growth was more vigorous and tassel emergence was a
day or two earlier when corn was planted at adequate depths versus shallow
depths. Planting corn to a depth of 1.75 to 2 inches is optimum for nodal root
* 2 inches — best under normal conditions;
* 1.75 inches — may be favorable when planting early into
cool soils; and
* Never plant shallower than 1.5 inches.
Corn planted too shallow results in:
* Decreased ability to absorb water and nutrients through
* Potential to develop a condition called “rootless corn
syndrome” — this causes plants to fall over due to the lack of nodal root
development in dry soil; and
* Possible exposure of corn seedlings to herbicide residue,
increasing the potential for herbicide injury.