Corn Late-Planting
Originally written February 1, 2006 | Last updated
May 22, 2019
|
The optimum date to plant corn in Wisconsin is around May 1 in southern and May
7 in northern Wisconsin. Early planting dates are preferred to later planting dates
due to the impact on grain yield and increased drying cost of higher grain moisture
in the fall.
As planting date gets later during a growing season, there comes a time
when
- hybrid maturities must be switched,
- the use of the corn must be reconsidered (i.e. high moisture corn,
silage, forage, etc.),
- the question of whether or not corn should even be grown at all and
another crop be grown in its place, and finally
- corn is a worthy "emergency forage" and should be considered if
planting a field is delayed to July.
If the decision is to continue planting corn, then consider the
following:
- Try to achieve the same target population, but possibly reduce the
seeding rate because of possible increased corn emergence and survival
- Reduce or eliminate tillage trips
- If switching to earlier hybrid maturities then emphasize disease
resistance, Bt-corn borer traits and yield potential.
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Tillage operations when planting is delayed
Choose tillage systems that limit soil damage and improve
root-restricting soil layers. It is essential to leave the soil
condition with the maximum opportunity for unimpeded corn root
development. Potential corn yields can often be compromised more by poor soil
structure following poor tillage choices more than by lost planting days.
Poor tillage choices can include:
- wrong tool selection,
- operation timing,
- tillage depth and frequency.
While corn farmers cannot control the rain on their fields they do
have control over tillage and planting systems.
- Tillage operations in specific fields depend on the amounts needed
for satisfactory weed control. As air temperatures warm, weed growth
continues on fields that did not receive recent residual herbicide
applications. Generally, herbicide sprayers should precede tillage and
planting operations in fields that are not going to receive intensive,
full-width spring tillage.
- Surface roughness left after fall tillage operations constrain tillage options in May. Effectively, soil conditions need to
be fit down to, and at least an inch below, the intended tillage
depth, before secondary tillage is advised. Farmers will need to be more
patient in delaying secondary tillage operations if they have fields
with rough soil surfaces.
- Stale seedbed planting often reduces seedbed compaction damage and
enables earlier planting. In situations where the soil surface is smooth
enough to permit planting corn seed at
uniform depths and where timely weed control can be achieved, stale
seedbed planting should be considered. Prime candidate fields for stale
seedbed planting might be those fields where
secondary tillage, but not planting, was completed in the first half of
April this year.
- A single, shallow and well-timed tillage operation is preferred if
pre-plant tillage is deemed necessary. As long as the first tillage
operation following weeks of rain delays is done at a soil
moisture condition when tillage can make a suitable seedbed, and when
emerged weeds can be killed, no further secondary tillage operations
should be required.
- No-till corn planting remains a viable option. The probability of
successful yields with no-till does not decline with later planting
dates; if anything, the relative yield potential of no-till corn
increases versus corn yields likely to be achieved after more intensive
tillage operations.
- Vertical tillage systems may speed surface soil drying. Typically,
shallow and high-speed vertical tillage operations may help to speed up
the rate of surface soil drying when there is non-uniform
residue cover or rain-matted residue cover.
- Spring strip-tillage operations should be shallow. If farmers can wait
until soil conditions are fit down to a 4- or 5-inch depth and have the
equipment options to do shallow strip-till in spring,
there can be corn yield advantages associated with doing so.
- Precise automatic guidance tools provide new opportunities to limit
soil compaction in the actual corn rows. Use of the real-time kinetic,
or RTK, steering systems enable corn farmers to
precisely control where the wheel tracks will occur before planting.
Relative Maturity Switch Dates
There is an yield and
moisture trade-off between
full- and shorter-season relative maturity (RM) hybrids. In southern
Wisconsin the yield trade-off is 1.9 bushels per RM unit. For example, a
100 d ay RM would typically yield 19 bu/A more than a 90 day RM hybrid.
The highest yielding hybrids are those that utilize entire growing
season and are typically full-season for maturity. Eventually
full-season hybrids run out of growing season and are impacted more for
grain yield than shorter-season hybrids (Figure 1). Relative maturity
must be balanced against harvest grain moisture and the ensuing drying
costs required to dry grain down to 15.5% moisture. Full-season hybrids
are often wetter than shorter-season hybrids at grain harvest.
The date to switch hybrids depends upon corn grain price and eventual use of the
crop due to drying costs (Table 1, also click
here). As grain price increases, switch dates become later by 1-12 days.
As drying costs increase, switch dates become earlier by 4-17 days.
| Table 1. Price ratio of Energy:Corn price (i.e. $/point bu÷ $/bu
corn). Partial budget subtracting harvest costs from corn price.
Data source: Arlington, 2003 to 2010. |
| Price of Energy (LP Gas) |
Price of corn ($/bu) |
| $/gal |
$/point bu |
$3.50 |
$4.00 |
$4.50 |
$5.00 |
$5.50 |
$6.00 |
$6.50 |
| $0.00 |
$0.00 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
| $0.40 |
$0.01 |
0.002 |
0.002 |
0.002 |
0.002 |
0.001 |
0.001 |
0.001 |
| $0.80 |
$0.02 |
0.005 |
0.004 |
0.004 |
0.003 |
0.003 |
0.003 |
0.002 |
| $1.20 |
$0.02 |
0.007 |
0.006 |
0.005 |
0.005 |
0.004 |
0.004 |
0.004 |
| $1.60 |
$0.03 |
0.009 |
0.008 |
0.007 |
0.006 |
0.006 |
0.005 |
0.005 |
| $2.00 |
$0.04 |
0.011 |
0.010 |
0.009 |
0.008 |
0.007 |
0.007 |
0.006 |
| $2.40 |
$0.05 |
0.014 |
0.012 |
0.011 |
0.010 |
0.009 |
0.008 |
0.007 |
| $2.80 |
$0.06 |
0.016 |
0.014 |
0.012 |
0.011 |
0.010 |
0.009 |
0.009 |
| $3.20 |
$0.06 |
0.018 |
0.016 |
0.014 |
0.013 |
0.012 |
0.011 |
0.010 |
| Switch date: |
|
|
|
|
|
|
|
| $0.00 |
$0.00 |
May 23 |
May 23 |
May 23 |
May 23 |
May 23 |
May 23 |
May 23 |
| $0.40 |
$0.01 |
May 22 |
May 22 |
May 22 |
May 22 |
May 22 |
May 22 |
May 22 |
| $0.80 |
$0.02 |
May 20 |
May 20 |
May 21 |
May 21 |
May 21 |
May 21 |
May 21 |
| $1.20 |
$0.02 |
May 18 |
May 19 |
May 19 |
May 20 |
May 20 |
May 20 |
May 21 |
| $1.60 |
$0.03 |
May 16 |
May 17 |
May 18 |
May 18 |
May 19 |
May 19 |
May 20 |
| $2.00 |
$0.04 |
May 14 |
May 16 |
May 16 |
May 17 |
May 18 |
May 18 |
May 19 |
| $2.40 |
$0.05 |
May 12 |
May 14 |
May 15 |
May 16 |
May 17 |
May 17 |
May 18 |
| $2.80 |
$0.06 |
May 10 |
May 12 |
May 13 |
May 15 |
May 15 |
May 16 |
May 17 |
| $3.20 |
$0.06 |
May 8 |
May 10 |
May 12 |
May 13 |
May 14 |
May 15 |
May 16 |
| Partial Budget subtracting harvest costs: |
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
Rate |
|
| |
Grain yield (bu/A) |
180 |
handling |
($/bu) |
|
$0.02 |
$0.02 |
| |
Grain moisture (%) |
25.0 |
hauling |
($/bu) |
|
$0.04 |
$0.04 |
| |
Input trade-off ($/A) |
$25.00 |
trucking |
($/bu 100 miles) |
$0.11 |
$0.11 |
| |
|
|
|
storage |
($/bu month) |
$0.02 |
$0.06 |
| |
|
|
|
drying |
($/bu point) |
|
$0.06 |
$0.57 |
| |
|
|
|
Total |
($/bu) |
|
|
$0.80 |
| |
|
|
|
|
$0.80 |
/bu |
|
|
| $0.00 |
$0.00 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
| $0.40 |
$0.01 |
0.003 |
0.003 |
0.002 |
0.002 |
0.002 |
0.002 |
0.001 |
| $0.80 |
$0.02 |
0.006 |
0.005 |
0.004 |
0.004 |
0.003 |
0.003 |
0.003 |
| $1.20 |
$0.02 |
0.009 |
0.008 |
0.006 |
0.006 |
0.005 |
0.005 |
0.004 |
| $1.60 |
$0.03 |
0.012 |
0.010 |
0.009 |
0.008 |
0.007 |
0.006 |
0.006 |
| $2.00 |
$0.04 |
0.015 |
0.013 |
0.011 |
0.010 |
0.009 |
0.008 |
0.007 |
| $2.40 |
$0.05 |
0.018 |
0.015 |
0.013 |
0.011 |
0.010 |
0.009 |
0.008 |
| $2.80 |
$0.06 |
0.021 |
0.018 |
0.015 |
0.013 |
0.012 |
0.011 |
0.010 |
| $3.20 |
$0.06 |
0.024 |
0.020 |
0.017 |
0.015 |
0.014 |
0.012 |
0.011 |
| Switch date: |
|
|
|
|
|
|
|
| $0.00 |
$0.00 |
May 23 |
May 23 |
May 23 |
May 23 |
May 23 |
May 23 |
May 23 |
| $0.40 |
$0.01 |
May 21 |
May 21 |
May 22 |
May 22 |
May 22 |
May 22 |
May 22 |
| $0.80 |
$0.02 |
May 19 |
May 20 |
May 20 |
May 20 |
May 21 |
May 21 |
May 21 |
| $1.20 |
$0.02 |
May 16 |
May 18 |
May 18 |
May 19 |
May 19 |
May 20 |
May 20 |
| $1.60 |
$0.03 |
May 14 |
May 16 |
May 17 |
May 18 |
May 18 |
May 19 |
May 19 |
| $2.00 |
$0.04 |
May 11 |
May 13 |
May 15 |
May 16 |
May 17 |
May 17 |
May 18 |
| $2.40 |
$0.05 |
May 9 |
May 11 |
May 13 |
May 14 |
May 15 |
May 16 |
May 17 |
| $2.80 |
$0.06 |
May 6 |
May 9 |
May 11 |
May 13 |
May 14 |
May 15 |
May 16 |
| $3.20 |
$0.06 |
May 2 |
May 6 |
May 9 |
May 11 |
May 12 |
May 14 |
May 15 |
Harvesting costs: handling = $0.02/bu,
hauling = $0.04/bu, trucking = $0.11/bu for 100 miles, storage =
$0.02/bu of 25% for 4 monthes and 25% for 8 monthes, drying =
$0.04/point moisture above 15.5% (assume 22.5%).
Source for drying efficiency:
Hoeft et al., 2000 p.328 T15.6; also Hellevang and Morey NCH-14
Table 4. |
Switch dates usually occur around May 20 for most locations in Wisconsin. In southern
Wisconsin, two switch dates can occur for grain (May 20 and June 1), while in northern
Wisconsin only one switch date is available (May 20). The planting window is much
shorter in northern Wisconsin.
Figure 1. Shorter-season hybrids (7 to 10 days M) become more
economical (yield and moisture) than full-season hybrids after about May
23. Source: Lauer (Arlington, WI, 2002-2010).
The switch date decision is also influenced by
the eventual use of the corn (Table 1). If the
field to be planted is intended for corn silage
or high moisture grain, then switch dates can be
later because there is less concern about drying
costs. The crop needs to achieve between 25%
kernel milk for silage and black layer for high
moisture corn grain yield to optimize yield.
In addition, switch dates are influenced by geographical
location. There is more flexibility for
southern Wisconsin than northern Wisconsin. In
southern Wisconsin, we have two or more possible
switch dates for grain, May 20-25 and June 1-5
(Table 2). While in northern Wisconsin, we have
only one switch date May 20-25.
Table 2. Relative maturity of adapted corn hybrids for different planting dates
and relative maturity zones in Wisconsin.
|
|
|
Relative maturities for late planting on
|
Full-season relative maturity zone
(planting before May 15)
|
May 20
|
June 1
|
June 10
|
June 20
|
|
|
|
|
|
|
| 80 and earlier
|
75- 80
|
75- 80 (silage)
|
--
|
--
|
| 85- 90
|
80- 85
|
75- 80 (silage)
|
--
|
--
|
| 90- 95
|
85- 90
|
75- 80
|
75- 80 (silage)
|
--
|
| 95-100
|
90- 95
|
80- 85
|
75- 80 (silage)
|
--
|
| 100-105
|
95-100
|
85- 90
|
75- 80
|
75- 80 (silage)
|
| 105-110
|
100-105
|
90- 95
|
80- 85
|
75- 80 (silage)
|
| 110-115
|
105-110
|
95-100
|
85- 90
|
75- 80 (silage)
|
Another factor influencing switch date is, what
shorter-season hybrids do you switch to? During
the winter, a lot of research often goes into
selecting good high performing full-season
hybrids. But as the decision to switch to
shorter-season hybrids draws near, do you have
enough time to adequately research and find a
good performing shorter-season hybrid? Is
a good high-performing hybrid available from the
seed company? Remember
the basics (see http://corn.agronomy.wisc.edu/AA/A082.aspx)
as you select new hybrids and don't be pressured
into switching into just any hybrid - make sure
it is a good performer.
One last point is that late-planted corn often has increased pest pressure, especially from European corn borer (ECB). Planting a transgenic Bt-CB might be appropriate.
Should Corn be Planted?
If corn planting is delayed until June 1 in northern Wisconsin and June
10 in southern Wisconsin, then growers should consider putting corn
planters away and planting soybean. The low corn yields seen in June
will not recover the input costs required to produce the crop. This
decision is influenced by corn price, price of the alternative crop
(usually soybean) and the proportion of farm acres of each crop left to
be planted. If the production objective is dry grain and you have been
delayed, then you may want to begin pricing fuel for next fall.
Other crops that might be grown can
be found here.
Corn as an "emergency forage"
Corn planters could be brought back out after July 1. By this time, if
fields are not planted, the production objective becomes "emergency
forage" for dry matter production. We have produced up to 6.8 T/A dry
matter with July planting dates for corn (see have produced up to 6.8 T/A dry
matter with July planting dates for corn (see http://corn.agronomy.wisc.edu/Research/03DOP/Late2005.pdf
and
http://corn.agronomy.wisc.edu/Research/03DOP/Late2006.pdf).
Key Questions
- What is the yield penalty for late-planted corn and soybean?
- What are the latest recommended planting dates for corn?
- What corn and soybean maturities should be used when planting late?
- Should corn and soybean seeding rates change when planting is
delayed?
- Should corn and soybean planting depth change when planting is
delayed?
Further Reading
Corn Replanting or
Late-Planting Decisions (UWEX Bulletin A3353) for guidelines on switch dates for corn hybrid
maturity.
Corn Planting Options for June June, 1996 Field
Crops 28.421-7
Planting Corn in June and July! - What can you expect?
June 2008 Field Crops 28.421-57 PDF