Many fields across the area experienced hail damage from this week’s storms that has led to concerns with corn and soybean stands, survival and their impact on final grain yield.

Questions arise as to:

• What is and will be the final stand of the soybean field?
• How healthy is the soybean plant?
• Given the current stand and defoliation, how much yield impact will the reduced stand have?
• Should the crop be replanted?
• What are the replant options for soybeans

1. Check the number of live plants per foot of row. Lay a tape in the row and dig up all plants in a 3-foot or more length. For drilled beans, two rows could be dug. Repeat several times over the field, keeping track of the live plants per foot of row.
2. Examine plants carefully and separate into three piles.

Table 2 shows the yields that may be expected when populations are thinned at various stages of development. Table 3 shows approximate yield loss due to late planting, beans start to lose yield potential when planted after mid-May in northern Iowa.

Generally, full season adapted varieties can be planted in northern Iowa up until late-June. That would be Late Group II through the end of June and then an Early Group II in July.

A small amount of leaf area loss, especially at early stages of growth does not usually result in much yield loss. Hail loss estimates on beans are complicated by bruising, and the effect of lower stem bruises is hard to evaluate. Deep bruises can result in lodging of the soybeans later in the season.

Todd Vagts
Iowa State University Extension
Field Crops Specialist
1240 D. Heires Avenue 
Carroll, IA 51401 
Office: 712-792-2364; Cell: 712-249-6025;  Fax: 712-792-2366
Email: vagts@iastate.edu