Correlation of Corn Yield to Planting Date - Mississippi
 Early planting generally sets the stage for maximum yield potential.
 Corn seed requires soil temperature of 50° F to support and promote germination and seedling growth.
 Research from several universities suggest that planting corn “early” in a region can help maximize yield potential.
Adjusting seeding rate and selecting the appropriate product maturity are also important decisions as planting date
may be timely or delayed.
Early Planting and Yield
Soils warm to an adequate temperature for corn planting at
different times depending on the geography, soil type, crop
residue, and environmental conditions. Once soil temperatures
warm they will still fluctuate throughout the day, but as warming
continues there is a greater portion of the day when the seed
zone temperature is above 50° F. Early-planted corn generally
requires more time to emerge than later-planted corn. At a soil
temperature of 50° F, it could take 20 days for 50% corn
emergence from a 2-inch soil depth. It could take 10 days at
60° F and only 4 to 5 days at 70° to 80° F soil temperatures. Be
aware of the soil temperature to give your crop the best chance
of emerging properly and getting a good start. At temperatures
below 50° F, seeds will sit dormant and become more
vulnerable to diseases, insects, and animal predators.
In Southern regions it is recommended to wait until soil
temperatures are at least 55° F at the depth that the corn seed
will be planted.1 This will encourage faster emergence and
reduce the chances for stand failure.
Planting Depth is Important
The optimal depth for corn seed placement in most cases
ranges from 1.5 to 2 inches as poor root development,
increased root lodging, and stunted growth can occur with
shallower plantings. Planting depths less than 1.5 inches may
not allow proper crown root formation. When the planter depth
is set at 1.75 inches, some seed may be at 1.5 inches and
some at 2 inches. Fields will vary in actual planting depths
depending on localized soil compaction zones and residue
levels. Early corn planted deeper than 2 inches can result in
delayed emergence and lower populations.
Seeding Rates and Plant Population
Corn planting populations to maximize profitability will vary by
corn products, soil type, and geography. Corn seeding rates
should be increased 15% above target harvest populations
when planting in cold soils (for example, to harvest 32,000
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Figure 1. A young corn plant emerging from the soil.
plants per acre – plant 36,800 seeds per acre).2 For normal
planting dates, seeding rates 10% higher than the target are
recommended.3
Corn Product Maturities
If planting corn products with relative maturities 5 to 7 days
earlier than recommended, as a full-season product for your
area, do not switch corn maturity before the date
recommended by local University Extension specialists.
Prematurely changing to an earlier maturing product may result
in reduced yield potential.
Planting into a suitable seedbed can require patience, especially
if the goal is to plant early. The potential yield benefits of early
planting can be realized by managing early-season risks.
Correlation of Corn Yield to Planting Date - MS
In Mississippi, it is not recommended to plant corn until soil
temperatures reach 55°F at a 2-inch depth or 50° F at a 6-inch
depth.4 Planting at lower temperatures can put the corn seedlings at a
higher risk for diseases and frost damage, and can increase the
potential for stand failure. Corn will produce highest yields when
planted within 4 to 5 weeks after the soil temperature is warm enough
for germination. The length of time the seedling takes to emerge is
dependent on planting depth, soil moisture, and soil temperature.
When the seed is planted prior to soil temperatures of 55° F, more
time may be required for emergence.
Mississippi Recommendations:
Optimal Planting Dates. According to Mississippi State University,
corn planting begins from February 23rd in the extreme Coastal
regions to March 20th
Table 1. Historical planting dates of different
in Northern regions
geographical regions in Mississippi.
(Table 1). Corn
planting typically
Mississippi Region Planting Date Range
wraps up from mid
Coastal
February 23—March 15
March in the Coastal
region to late April in
Southern
March 5—April 10
the Northern region.
Central
March 15—April 20
In Mississippi, early
Northern
March 20—April 25
planting can help to
lower irrigation costs, reduced insect and foliar disease pressure, and
mature the crop for an earlier harvest. However, planting corn
extremely early, even if soil temperatures are warm, may provide little
agronomic benefit and can increase the risk of stand failure. Planting
extremely early can increase the risk of frost damage and soil freezing
after planting can kill the seedlings. Poor stands may require a replant
or final yield may be reduced at harvest.
Seeding Rate. Optimal seeding rates can vary depending on the field,
environmental conditions, and corn product being planted. Contact
you local DEKALB® agronomist for recommendations on planting
population based on selected corn products. Seeding rate can be
determined by increasing the expected final stand by 5 to 15 percent
to account for seedling mortality germination failures.
Corn crops can be evaluated during the season to determine if the
planting population is correct. If populations are too low, the corn plant
may become prolific and produce more than one ear. If populations
are too high ear barrenness can occur or ear tip kernel abortion can
increase due to a lack of nutrients or moisture stress from increased
competition.
Corn Product Selection. In Mississippi, it is recommended to plant
112 to 120 day maturity corn products. Other important product
characteristics to consider are stay green potential, standability, shuck
cover, ear placement, and insect and disease resistance. When
planting corn toward the end of the planting window, it may help to
select a corn product with lower ear placement to reduce the lodging
potential.
Research studies were conducted by Mississippi State University
Extension from 2009 to 2011 at the MSU Delta and Extension Center
at Stoneville, MS and the RR Foil Research Center. Results from the
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three-year planting
study showed that
corn produced
optimal yields until
May 1 and yield
potential began to
decline when
planted after May
1 (Figure 2).5 Corn
yield declined
quickly when
planted in June.
Study findings
concluded that
when planted
Figure 2. Effect of planting date to corn yield on irribeyond the May 1
gated acres. Mississippi State University. 2009-2011.
timeframe,
irrigated corn yield
was reduced by
1.3 bu per acre
per day or 0.76%
per day in May
and by 2.1 bu per
acre per day or
1.59% per day for
June planting
dates. Results
from this study
showed that late
planting yield
reduction was
Figure 3. Effect of planting date to corn yield on drygradual for
land acres. Mississippi State University. 2010-2012.
irrigated corn acres;
therefore, when late planting is unavoidable, decent yields can still be
attained for irrigated corn acres when planting is slightly delayed past
the optimum dates.
A similar study was conducted on dryland corn acres at Mississippi
State University from 2010 to 2012 (Figure 3). Dryland corn planted
after the optimal planting dates suffered a greater loss of yield than
compared to the irrigated corn trial. For the dryland trial, yield was
reduced by 1.3 bu per acre per day or 0.83% per day for planting after
mid April.
Sources:1 When is the optimum time to plant corn? Mississippi State University Extension.
http://msucares.com (verified 3/18/14).
2
Thomison, P. and Lentz, E. Tips for cutting corn production costs. Ohio State University
Extension Fact Sheet, AGF-147-01.
3
Nielsen, R.L. and Thomison, P. 2002. Late-planted corn & seeding rates. Corny News
Network. May 2002. http://www.kingcorn.org (verified 3/18/14)
4
Corn in Mississippi: When is the optimum time to plant corn? Mississippi State University
Extension Service. http://msucares.com/crops/corn/corn1.html (verified 3/24/14).
5
Larson, E. J. 2013. What is the cut-off date for planting corn? Mississippi Crop Situation.
Mississippi State University Extension Service. http://www.mississippi-crops.com/(verified
3/24/14).
Individual results may vary, and performance may vary from location to location and from
year to year. This result may not be an indicator of results you may obtain as local growing,
soil and weather conditions may vary. Growers should evaluate data from multiple locations
and years whenever possible.
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