A total of 2400 to 2900 Growing Degree Units (GDUs) accumulate during a growing season in southern Wisconsin. About 1500 GDUs accumulate by August 1 leaving 1200 GDUs for the rest of the season (Mitchell and Larsen, 1981). Much depends upon the date of the first killing frost in the fall.
A comprehensive study on emergency forages was conducted between 2002 and 2004 by Petersen et al. (2003; 2004a; 2004b) and Undersander (2008). Factors included planting date (early May, Early June and Early July), crop species (n= 18 treatments), and location (Pelican Rapids, MN, St. Paul, MN, Arlington, WI, Marshfield, WI and Spooner, WI). Table 1 describes the results of various crop species planted July 1 during 2003 and 2004 at Arlington, WI.
Dry matter (DM) production ranged from 1.0 to 13.0 Tons DM/A depending upon the growing season and species (Table 1). Corn for silage was usually among the highest yielding options for all planting dates and environments. One-cut bmr forage sorghum at times produced the highest DM yields (especially in southern Wisconsin), but performance was inconsistent and often failed to reach the target harvest maturity and moisture.
Small grains with or without pea produced low yields when planted July 1. Other studies also confirm this observation. Maloney et al. (1999) planted various small grain species August 18, 1992 and August 12, 1993 and measured yields of 0.3 to 1.8 T DM/A. However, Contreras-Govea and Albrecht (2006) measure average oat yields of 3.0 T DM/A when planted August 7and 9, 2001 at Arlington and Lancaster, WI.
Table 1. Dry matter yield (T DM/A) of various crops planted on July 1 at Arlington during 2003 and 2004. Data derived from Peterson et al. (2004b) and Undersander (2008).
|Sorghum x Sudangrass||4.6||---|
|Hybrid Pearl Millet||4.4||3.0|
|Siberian Foxtail Millet||2.9||1.8|
|Golden German Millet||2.6||2.1|
In another study, Lauer et al., (2005, 2006) produced yields of 5.3-8.6 T DM/A on July 1 planting dates (Table 2). Yield decreased as planting dates were delayed to August 1, however, yields were still greater than many species planted July 1 in the Peterson et al. (2004b) and Undersander (2008) studies (Table 1). In 2005, the August 1 planting date produced 2.1-3.4 T DM/A. Full-season hybrids produced the greatest dry matter yield and Milk per acre when planted during July (data not shown). No significant interaction among corn hybrid types was measured for Milk per Ton, although brown midrib hybrids tended to produce the best quality.
Table 2. Dry matter yield (Tons DM/A) of corn planted near July 1, July 15 and August 1 at Arlington during 2005 and 2006. Data derived from Lauer (2005; 2006).
|July 1||6.5 - 8.6||5.3 - 6.4|
|July 15||4.3 - 6.8||3.4 - 3.7|
|August 1||2.1- 3.4||0.6 - 0.8|
Corn can produce significant dry matter yield when planted during July, but the amount produced depends upon when a fall killing frost occurs. Forage quality will be similar to other grass species. Maturities should be long enough so that flowering occurs when a killing frost occurs to take advantage of the first forage quality peak (see Figure 1 in another blog article).
A negative for double-cropping corn is seed expense. There may be options for obtaining inexpensive seed from seed companies. There is no guarantee that drought will be relieved enough to germinate and allow for production.
Growers need to check on options available from their insurance companies before taking action and planting corn in late June and July for emergency forage. Herbicide labels must be adhered to before switching to other crops. A small amount of fertilizer may be justified in late-planted areas.
Contreras-Govea, F.E., and K.A. Albrecht. 2006. Forage Production And Nutritive Value Of Oat In Autumn And Early Summer. Crop Sci. 46:2382-2386.
Lauer, J., K. Kohn, and P. Flannery. 2005. Date of Planting and Hybrid Influence on Corn Forage. In Studies on cultural practices and management systems for corn. Wisconsin Research Report, Department of Agronomy, p. 110-111.
Lauer, J., K. Kohn, and P. Flannery. 2006. Date of Planting and Hybrid Influence on Corn Forage. In Studies on cultural practices and management systems for corn. Wisconsin Research Report, Department of Agronomy, p. 90-91.
Maloney, T.S., E.S. Oplinger, and K.A. Albrecht. 1999. Small grains for fall and spring forage. J. Prod. Agric. 12:488-494.
Mitchell, V.L., and R.W. Larsen. 1981. Growing degree days for corn in Wisconsin. UWEX Geological and Natural History Survey. 22 pp.
Peterson, P., M. Endres, D. Holen, C. Sheaffer, V. Crary, D. Swanson, J. Larson, and J. Halgerson. 2003. Emergency forage plantings. Research progress report.
Peterson, P., D. Undersander, M. Endres, D. Holen, K. Silveira, M. Bertram, P. Holman, D. Swanson, J. Halgerson, J. Larson, V. Crary, and C. Sheaffer. 2004a. How emergency forage crops grew in 2003. Research progress report.
Peterson, P., D. Undersander, M. Bertram, P. Holman, D. Holen, V. Crary, M. Endres, and C. Sheaffer. 2004b. Emergency forage options for July planting. Research progress report.
Undersander, D. 2008. Emergency forages. UWEX Research Summary. 3 pp.
Coblentz, W.K., M.G. Bertram, and N.P. Martin. 2011. Planting Date Effects On Fall Forage Production Of Oat Cultivars In Wisconsin. Agron. J. 103:145-155.
Coblentz, W.K., M.G. Bertram, N.P. Martin, and P. Berzaghi. 2012. Planting Date Effects On The Nutritive Value Of Fall-grown Oat Cultivars. Agron. J. 104:312-323.
Coblentz, W., and M. Bertram. 2012. Fall-Grown Oat Forages: Cultivars, Planting Dates, and Expected Yields. Focus on Forage 14(3): 3 pp.
Lauer, J. 2008. Planting corn in June and July! - What can you expect? Agronomy Advice. June 2008 Field Crops 28.421-57.
Vander Velde, K. , Craig Saxe, and Ken Barnett. 2005. Emergency Forage Plantings in Central Wisconsin.