2019 PFR PROVEN - REPLANT
Should I replant my corn or soybeans?
REPLANT: CORN PRACTICES
SHOULD I REPLANT MY CORN?
Consider your current yield goal when facing later planting dates. Compare your current plant stand’s potential with the potential of a higher stand planted at a later date using the table below. Take uniformity into account, as a corn crop that is out of synchrony will make in-season application timing difficult and can impact pollination and harvest. Make sure to survey the health of the surviving plants as early-season diseases have season-long impacts.
FACTORS TO CONSIDER WHEN ASSESSING CORN REPLANT
- What was the target population and what is the current plant stand?
- What was the original planting date and the potential replant date?
- How uniform is the plant stand and what was the cause of stand loss?
- How healthy is the stand?
As the season progresses, replant is at higher risk of resulting in a negative ROI. This chart encompasses data from 36 independent tests over nine years. The principle risks with late-planted corn are heat during pollination, early frost, and slow dry down.
CHECK OUT THE REPLANT CALCULATOR IN FARMSERVER® TO HELP DETERMINE WHETHER CORN REPLANT IS JUSTIFIED.
9-YEAR MULTI-LOCATION REPLANT ROI
CORN GROWING DEGREE DAY (GDD) DECISION SUPPORT TOOL
Based on your county, hybrid, and planting date, when will silking, black layer, and the first freeze occur? Select your county to view a 30-year historical perspective by visiting: mrcc.isws.illinois.edu/U2U/gdd/
The GDD Decision Support Tool uses long-term data to help you determine the late-season risks with replanted corn. The long-term weather data in the model isn’t always predictive of weather for a specific location and growing season, but it is a good place to start.
Remember that in many years, later-planted hybrids require fewer GDDs to achieve black layer compared to the same hybrid when planted early. This is because the corn plant accelerates growth in the early vegetative stages. Be sure to adjust the GDD Decision Support Tool to get an accurate prediction. For every day of planting past May 1, deduct 7 GDDs from the total number required.
Day Delay x 7= GDD reduction to achieve black layer
Uniform emergence is key to a successful corn stand. Planting into consistent soil temperatures and moisture leads to synchronized emergence and higher yields.
3-YEAR MULTI-LOCATION PLANTING DEPTH YIELD AVERAGE
REPLANT: SOYBEAN PRACTICES
SHOULD I REPLANT MY SOYBEANS?
Unlike corn, soybeans have the capacity to branch and compensate for thin stands. Uniformity in emergence is less important as soybeans flower during a longer window than corn. The key yield component for soybeans is not plants per acre, but nodes per acre. Later planted soybeans will be shorter and have fewer nodes per plant, so you must compensate for later planting by increasing your seeding rate by approximately 10,000 seeds per week after May 10.
In the chart below, note that "thickening up" a stand of soybeans doesn't add yield. You are better off with a thin stand early, than a thick stand planted late assuming the original stand is somewhat uniform.
THE EFFECT OF SUPPLEMENTAL PLANTING WITH A 30 IN. PLANTER