Handling Corn in an "Emergency" Forage Season: Expected Yields

June 24, 2004  11(16):106

Joe Lauer, Corn Agronomist  

In eastern Wisconsin, many farmers are faced with an "emergency" forage situation. Forage inventories will not carry through next winter and forage is needed for their dairy operation. Last week in the Wisconsin Crop Manager (11:94), Dr. Dan Undersander summarized a research project evaluating numerous crops for an emergency season. A conclusion from that project is that corn can produce relatively high forage yields (2.48 to 9.05 T dry matter/A) even though planted late on July 1. I would like to follow up on Dr. Undersander's article and report on what can be expected for corn forage yield at various locations in Wisconsin.

In an emergency season, farmers desire to maximize forage yield. Planting date significantly affects forage yield in corn with the major effect on grain yield. Table 1 summarizes all experiments conducted at Arlington involving forage yield response to planting date. Forage yield of corn planted on May 1 in 1993 was 7.7 T dry matter/A and by July 1 had decreased to 3.9 T dry matter/A. Over all years corn planted on May 1 has yielded 8.6 T dry matter/A. Corn planted on July 1 has produced 3.2 to 6.8 T dry matter/A depending upon year with an overall average of 5.1 T dry matter/A.

At locations around Wisconsin, corn forage yield has ranged from 7.1 to 10.1 T dry matter/A when planted on May 1 (Table 2). Corn planted on July 1 has produced 3.5 to 6.7 T dry matter/A depending upon location. Most of these data were collected during 1998 and 1999.

Clearly corn is a viable alternative when the objective is to produce "emergency" forage. On July 1 planting dates, little grain is present in the forage, so forage quality is dependent upon stover traits. Management decisions that influence quality in an emergency corn forage situation include: hybrid maturity in relation to fall frost date, hybrid NDFD trait, and plant density. A future article will discuss some guidelines for maximizing quality through hybrid selection options for ultra-late planting dates and changes to plant density recommendations.

Table 1. Forage yield (T dry matter/A) response to planting date at Arlington, WI.
  Planting date Last planting date treatment
Year May 1 June 1 July 1 *
1993 7.7 6.5 3.9 July 1
1994 8.5 6.4 3.3 July 11
1995 7.3 6.7 4.7 July 10
1996 9.5 6.9 6.2 June 24
1997 7.7 5.6 3.2 July 1
1998 10.7 10.0 6.6 June 25
1999 10.0 9.0 6.6 June 25
2000 8.3 7.8 4.0 June 20
2001 9.4 8.0 3.8 June 13
2002 8.7 8.4 5.1 June 10
2003 8.5 8.5 6.8 June 13
Overall 8.6 7.8 5.1 ---
* Forage yield estimated from model when last planting date treatment for experiment was before July 1.

 

Table 2. Forage yield (T dry matter/A) response to  planting date in Wisconsin.
  Planting date Last planting date treatment
Locations May 1 June 1 July 1 *
Arlington 8.6 7.8 5.1 July 11
Ashland 7.1 6.3 3.5 June 25
Hancock 10.1 8.8 5.1 June 28
Lancaster 8.0 8.1 6.7 June 24
Marshfield 8.9 7.5 4.5 July 1
Spooner 8.5 7.6 4.4 June 25
* Forage yield estimated from model when last planting date treatment for experiment was before July 1.

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