Crops
by Dr. Paul Tracy
Give early planted soybeans good odds
Traditionally, I have been hesitant to recommend the early planting of any crop, especially soybeans. Maybe that comes from the hundreds of poor stands and replant fields that I have walked over the years. Also, the choice of soybean varieties for replanting is often limited.
Offsetting early planting concerns is recent university data that show if early planted soybeans emerge and survive, they often yield equal to or better than their mid- to late-season planted counterparts. They simply have more time to build extra nodes and the leaf area food factory required to generate excellent yields. This higher yield potential can only be achieved if conditions and management practices are optimum. In fact, while early planting may pay off under high yielding conditions, it offers few benefits in fields that have historically yielded poorly.
Risks aside, I know that if weather allows it, there will be early planted beans this year. If you plant early, consider the following.
Improved genetics have allowed soybeans to be planted earlier. Choose varieties with the best possible emergence and early seedling vigor ratings.
Traditionally, agronomists recommend moving up at least one maturity group when planting soybeans early. However, recent work by Dr. Bill Wiebold etal., at the University of Missouri has shown that traditional maturity groups for your region offer more consistency than switching to earlier maturity group varieties.
A recent guide sheet from Michigan State University lists several recommendations for early planted soybeans. The following was taken from that publication, with a few of my observations thrown in:
• Don’t plant unless the soil is dry enough for equipment to work properly. Soil and sidewall compaction problems are generally more severe when planting early into wet soils.
• Early planted soybeans must be treated with a fungicide and should be treated with an insecticide to prevent early season disease and insect problems.
• Tillage helps dry and warm early season soils. In no-till or strip till, make special effort to clear as much residue as possible immediately above the planted seed.
• Plant higher elevated fields first. They are drier and less susceptible to frost/freeze injury.
• Plant only high quality seed. Excessively dry or damaged seed imbibe water faster, increasing the likelihood of chilling injury.
• Wait until soil temperatures are 55 degrees with at least 24 hours above 50 degrees, plus a warming trend in the immediate forecast.
• Use a high quality planter to ensure optimum planting depth.
• Consider planting 10 to 15 percent higher seeding rates.
• Make sure that the early planting does not violate the terms of your crop insurance. |
A reason for planting soybeans early is to move crop maturity up in the calendar year to expedite harvest or to avoid late summer drought. Asian soybean rust avoidance is often discussed as another reason for early planting. In Dr. Wiebold’s work, early planting did lead to earlier crop maturity, but that response was not linear. Generally, for every 2 to 4 days a soybean crop is planted early, soybean maturity was moved up by 1 to 2 days. In years of early rust infection, this could be important.
The ideal soil temperature for soybean germination is around 80 degrees. At 50 degrees, germination can occur, but will be delayed by a few weeks during which only bad things can happen to the seed or seedling. For these reasons, early planted soybeans must have the best seed protection possible, including both disease and insect suppression products.
I believe in the benefits of no-till production systems, but they can be a disadvantage when planting early. If tillage is not part of your system, good residue cleaners in no-till operation will help. A high quality planter is superior to a drill when planting soybeans early.
Sudden death syndrome is a non-treatable disease that infects early planted soybeans much more often then their later planted counterparts. When planting early, select the variety with the highest SDS tolerance rating. Don’t plant soybeans early in a field with SDS history.
Dr. Paul Tracy is director of agronomy for MFA Incorporated.
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