5/10/2024
Delayed Soybean Planting Considerations
Crop Focus
Written by Mark Jeschke, Ph.D., Pioneer Agronomy Manager
Key Points
- Switching to an earlier maturity variety is generally not necessary unless planting is delayed past mid-June.
- Soybean agronomists often recommend narrower rows (15 inches or less) with later planting to allow quicker canopy closure.
- Increasing seeding rate by around 10% is commonly recommended with late planting. Growers should target a final stand of 130,000 to 150,000 plants/acre.
Delayed Soybean Planting
- In wet springs, it is not unusual for soybean planting in the U.S. Corn Belt to extend into June.
- Drastic management changes are generally not required with later planting; however, some adjustments may be helpful in maximizing yield when soybean planting is delayed.
Variety Relative Maturity
- Switching to an earlier maturity variety is generally not necessary unless planting is delayed past mid-June.
- Compared to corn, soybean has a greater ability to adjust to later planting.
- A 5-year Iowa State University field study comparing yield of 1.7 and 3.0 MG varieties across a range of planting dates found that the later maturity variety had greater yield, even with planting in early June (Figure 1).
- Later planted soybean will take longer to reach physiological maturity, but not by a lot – Generally, a 3-week delay in planting equates to a 1-week delay in physiological maturity.
- A South Dakota State University study found that switching from a 2.8 to a 1.8 MG variety with mid-June planting only reduced the time to maturity by 5 days (Nygren et al., 2019).
Figure 1. Influence of planting date on soybean yield of 1.7 and 3.0 MG varieties. (Pecinovsky and Mueller, 2009).
- If planting is delayed past mid-June, it is generally recommended to switch to a variety 0.5 to 1.0 MG shorter than normal for your area, as frost prior to maturity becomes more of a concern with very late-planted soybean. Consult your Pioneer sales professional for specific variety recommendations.
Row Spacing
- Soybean agronomists often recommend narrower rows (15 inches or less) with later planting to allow quicker canopy closure.
- Earlier canopy closure is generally advantageous for maximizing yield potential and suppressing weeds.
- Narrower rows are generally advantageous in soybean regardless of planting date though, yielding 3-4 bu/acre more than 30-inch rows on average, and some studies have not shown this advantage to increase with later planting.
Seeding Rate
- It is commonly recommended to increase soybean seeding rate by around 10% above normal with June planting, althoughrate by around 10% above normal with June planting, although research results have been somewhat mixed on this point.
- Seeding rate practices can vary widely, so the need for a bump up in seeding rate will depend somewhat on individual circumstances and what is “normal” practice for the operation.
- Ohio State University recommends targeting a final stand of 130,000 to 150,000 plants/acre for soybean planted in June (Lindsey, 2019).
Lindsey, L. 2019. Recommendations for Late Planted Soybeans C.O.R.N. Newsletter 2019-12. Ohio State Univ. Extension.; Nygren, A., et al. 2019. Strategies with Delayed Soybean Planting. CropWatch June 13, 2019. Univ. of Nebraska-Lincoln. Pecinovsky, K. and D. Mueller. 2009. Soybean Planting Date in Northeast Iowa. Iowa State Univ. ISRF09-13
The foregoing is provided for informational use only. Please contact your Pioneer sales professional for information and suggestions specific to your operation. Product performance is variable and depends on many factors such as moisture and heat stress, soil type, management practices and environmental stress as well as disease and pest pressures. Individual results may vary. Pioneer® brand products are provided subject to the terms and conditions of purchase which are part of the labeling and purchase documents. All products are trademarks of their manufacturers.
