Late-planted soybean recommendations

Soybean producers can use this information to help adjust their management practices and make informed decisions for late-planted soybeans.

Soybean planting has been delayed by the frequent and heavy rain events occurring this spring 2014. As a result, many soybean fields will be planted in June. Producers need to implement specific management practices to maximize the yield potential of late-planted soybeans. Michigan State University Extension recommendations for late-planted soybeans are summarized in this article.

Planting date

Plant as early as soil conditions permit. Yield losses due to delayed planting increase from 0.4 bushels per acre per day until June 1 to 1 bushel per acre per day on July 1. Also, remember that soybean maturity is delayed by one day for every three to four days that planting is delayed, increasing your risk of frost or freeze injury in the fall.

Soybean variety maturity

Planting the correct maturity group is critical to maximizing soybean yields when planting in June. Most university trials have shown that adapted full-season varieties will yield better than earlier maturing varieties when planted in June as they produce a larger crop canopy before beginning to flower. However, planting full-season varieties too late in the season increases the potential for frost or freeze damage to occur in the fall. Planting early-maturing varieties too soon will result in lower yield potential and short plants. The lowest pods on these short plants will be below the sickle bar on the grain table and left in the field at harvest.

Consider planting earlier varieties after June 15. However, avoid planting varieties that are more than 0.6 of a maturity group earlier than adapted full-season varieties for your area when planting in the June.

Row spacing and planting population

When planting in June, plant in narrow rows or 15 inches or less and increase planting populations. The combination of narrow rows and higher populations will help the crop canopy cover the soil sooner and capture more of the available sunlight. These conditions produce higher yields by reducing evaporation and increasing photosynthesis. Increase planting populations by 15 percent during the first half of June and by 20 percent when planting in the last half of June.

Seed treatments

Fungicide and insecticide seed treatments may be less beneficial with late planting as the soil will be warm and germination and emergence should occur rapidly – six to seven days. If you are planting into a field with a history of Phytophthora root rot, plant a variety with specific race resistance or plant a variety possessing a high level of field tolerance and treat the seed with the highest recommended application rates for mefenoxam or metalaxyl.

Planting depth

Whenever possible, plant soybean seed into at least 0.5 inches of uniform soil moisture. You may need to plant deeper to accomplish this when planting late. However, soybeans should not be planted deeper than 2.5 inches.

Soybean aphid management

When aphids are deposited into soybean fields in the vegetative stages during mid-season flights, they will reproduce more rapidly and reach economic thresholds two weeks sooner than aphids deposited into fields in the early reproductive stages. Scout less mature fields often and thoroughly. Late-planted soybeans are also more susceptible to injury from aphid feeding as they will have less leaf area and root growth than soybeans planted earlier in the season.

Harvest and storage

Planting late increases the risk of freeze or frost damage occurring in this fall. Information regarding how to manage frost-damaged soybeans is available online at http://msue.anr.msu.edu.

Crop insurance decisions

Producers that have purchased federal crop insurance have prevented planting coverage. The “final planting date” for soybeans in Michigan is June 15. The “late planting period” is the 25 days following the final planting date. Make sure you understand these dates and the rules and ramifications of the following options:

  • Take the prevented planting payment after the final planting date has passed and do not plant another crop for the year. Soybean prevented planting acreage claims must be submitted before June 30.
  • Plant soybeans after the final planting date, but before the end of the late planting period. The production guarantee or amount of insurance will be reduced by 1 percent for each day that planting is delayed past the final planting date.
  • Take the reduced prevented planting payment on soybeans and plant another crop any time after the late planting period for soybeans has passed.

These options are explained further in a USDA Risk Management Agency Program Announcement “Prevented Planting Examples-Soybeans” available online at: www.rma.usda.gov. The information in this publication is still current and applies to the 2014 soybean crop even though it was originally released in 2008.

This article was produced by the SMaRT project (Soybean Management and Research Technology). The SMaRT project was developed to help Michigan producers increase soybean yields and farm profitability. The SMaRT project is a partnership between MSU Extension and the Michigan Soybean Checkoff program.

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