Crops Bulletin

June 12, 2013
       Issue 5             


Prepared by

Paul Kassel

Extension Field Agronomist



Serving Clay, Buena Vista, Dickinson, Emmet, Hancock, Kossuth, Palo Alto, Pocahontas, Sac and Winnebago Counties



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Soybean late Plant/Replant Information:


Planting Date  1995-96  ISU PM 1851  ISU PM 1155

                     -- bu/a --   -----% yield potential------

April 24- 28       50.7            100                       -

May 8-13           49.8             96                     100

May 21- 25        52.0             99                    90-95

June 5-10           43.0             81                    85-90

June 20-24         31.9             61                    70-80

July 1-3             17.2             33                    50-65



Soybean Late Plant Discussion:

  • Expect a 15-25 percent yield reduction with mid- June planted soybean.
  • Or expect about 0.5 bu/a or 1% yield decline each day soybean planting is delayed in June.
  • Use an early group II variety until June 15 -20.
  • Use a late group I variety from June 15 to July 1.
  • The 1995-96 data is from a date of planting study at three northern ISU research farms. The yield reductions listed are from ISU replant publications.

Seed Treatment:


Consider seed treatments that have Apron or Allegiance for pythium and phytophthora. Phytophthora can be more aggressive with June planted soybean.


Cover Crops on Prevented Planted Acres:

  • Cover crops have been a popular topic as a fall seeded crop to improve soil quality and conserve soil. However, the term cover crop takes on a new meaning when applied to prevented planted acres.
  • Cover crops are not required on prevented planted acres. However, cover crops make agronomic sense to maintain soil quality, conserve soil and reduce the chances of fallow syndrome.
  • Options for cover crops on prevented planted acres include: summer seeded small grains, millets and forage sorghums.
  • Consider winter rye or triticale seeded in mid-July. Either of these should persist through the summer, will maintain vegetative growth without seed head emergence and should persist through fall, winter and early spring.

Prepared by Paul Kassel, Extension Field Agronomist

Phone: (712) 262-2264, Email: