University of Illinois at Urbana-Champaign

Using Soybeans as an Alternate Forage

• Dr. Mike HutjensDairy Extension Specialist

University of Illinois at Urbana-Champaign

Jim BaltzInstructional Design Specialist

University of Illinois at Urbana-Champaign

Learning Objectives• After viewing this module you should be able to:

– Identify the stages of soybean growth

– Describe the key factors in harvesting soybeans as a silage

– Evaluate the economics of using soybeans as a forage

University of Illinois at Urbana-Champaign

Stages of Soybean Growth• Growth staging: A growth stage for a field

begins when at least 50% of the plants have reached or are beyond a certain stage and stages may overlap.– Vegetative stages– Reproductive stages

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Soybean Parts

Unifoliate Leaf

Trifoliate Leaf

Cotyledons

Growing Point

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Reproductive Stages (WI and NC)• R1: Beginning bloom• R2: Full bloom• R3: Beginning pod development• R4: Full pod• R5: Beginning seed• R6: Full seed• R7: Beginning maturity• R8: Full Maturity

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Stage Abbreviation Stage Title

Average Number of Days

R1-R2 to R3 Begin bloom to begin pod 10

R3 to R4 Begin pod to full pod 9

R4 to R5 Full pod to begin seed 9

R5 to R6 Begin seed to full seed 15

R6 to R7 Full seed to begin maturity 18

R7 to R8 Begin maturity to full maturity 9

Average number of days for each reproductive stage

adapted from Soybean Loss Instructions , National Crop Insurance Services (NCIS) #6302 Soybeans,91

University of Illinois at Urbana-Champaign

Harvesting Soybean Silage• Harvest soybeans at R3 stage, when one of the four top nodes

with a fully-developed leaf has a 3/16-inch-long pod.

• Wilt forage to 35% to 45% dry matter before ensiling depending on storage unit.

• Chop at 3/8-inch theoretical length of cut (TLC).

• Add an inoculant (similar to an effective alfalfa/legume inoculant)

• Yields in drought year 1 to 2 tons/acre

Soybean Silage by Dan Undersander, Kevin Jarvik, Tom Anderson, Nick Schneider, and Lee Milligan

University of Illinois at Urbana-Champaign

Yield and quality of soybean forage as affected by harvest maturity

Modified from Soybeans for Hay or Silage by Dr. Dan Undersander

University of Illinois at Urbana-Champaign

Forage quality of soybean silage not mixed with other crops

Soybean Silage by Dan Undersander, Kevin Jarvik, Tom Anderson, Nick Schneider, and Lee Milligan

University of Illinois at Urbana-Champaign

Soybean Hay• Harvested at R3 - when one of the top four nodes

with a fully developed leaf has a 3/16-inch long pod.

• Limit leaf loss by limiting number of times it’s mechanically handled

• Dries slow (may require 2 to 3 days)

• Raking can lead to significant leaf loss

University of Illinois at Urbana-Champaign

Cautions before using soybeans as a forage• Check what herbicides and insecticides were

used to ensure no restrictions

• Contact a crop insurance agent before harvesting for forage

University of Illinois at Urbana-Champaign

Economics of harvesting soybeans• As forage, assume 1 ½ tons of dry matter

per acre valued at $200 a ton or $300 per acre.

• As seed, $300 per acre / $15 per bushel, less than 20 bushels may be the break point

• No harvesting charges were included with the soybean seed

University of Illinois at Urbana-Champaign

In Summary• Soybean forage may an alternative forage for

dairy and beef cattle

• Consider economics of each alternative

• Be aware of residue risks and treatments

• Soybean forage will be similar to other legume forages, but not as palatable

University of Illinois at Urbana-Champaign

Check out our online dairy courses at http://online.ansci.illinois.edu/and Illini DairyNET at http://www.livestocktrail.illinois.edu/dairynet/

University of Illinois at Urbana-Champaign

Dr. Mike HutjensDairy Extension Specialist Jim Baltz

Instructional Design Specialist