In 2002, a new research and extension initiative was established to promote the evaluation and use of improved corn silage hybrids. The initiative is focused on research and extension education in southeastern and central Minnesota, two areas of extensive corn silage use. This initiative involves the Corn Silage Hybrid Testing Consortium, which includes University of Minnesota extension educators, researchers, and cooperating producers.

For a fee, hybrid corn seed companies were invited to participate in trials planted at four locations in spring 2002. Entries were submitted for testing in one or both regions, with two locations (test sites) per region. The two test sites in the central MN (Stearns County) region were cooperating farmers’ fields near Melrose and St. Martin. The two southeastern MN region test sites were cooperating farmers’ fields near La Crescent (Houston Co.) and Potsdam (Olmsted Co.). Over 30 entries were tested at each test site.

At each test site, four replications of each corn silage entry were seeded in 2-row plots at a population of 32,000 seeds per acre in 30-inch rows. The southeastern test sites were seeded in early May, and the central test sites seeded in mid May. Entry relative maturities (RM), as provided by participating companies, ranged from 95 to 114 RM in the southeast region and from 85 to 107 RM in the central region. All entries at a particular test site were harvested on the same date, targeting 65% average moisture content.

Whole-plant yield and forage quality were determined. Quality parameters included moisture content, crude protein, neutral detergent fiber (NDF, an estimate of intake potential), in vitro digestibility (IVD, a biological assay), NDF digestibility (NDFD, the digestibility of the NDF fraction expressed as % of NDF), and starch concentration. All quality parameters except NDFD were expressed as a % of dry matter (DM). Milk production per ton and per acre were estimated using the MILK2000 spreadsheet developed by the University of Wisconsin. Milk per acre represents the combined impact of yield and quality.

Results from 2002 are presented in detail in Minnesota Varietal Trials Results (MP108-2003, January 2003 or on the web at www.maes.umn.edu/pubs.html). Corn silage entries differed in silage yield and quality at all four test sites. Average moisture content at harvest was close to the 65% target at all test sites, but moisture content of individual entries varied due in part to differences in RM. Silage yields were highest at La Crescent (avg. 29.0 ton/acre), intermediate at Potsdam and St. Martin (avg. 25.3 ton/acre), and lowest at Melrose (avg. 17.0 ton/acre). Hybrid performance varied considerably in each test. For example, Table 1 shows the range in performance for several parameters among corn silage hybrids tested at Potsdam in Olmsted Co. The hybrid with the highest estimated milk per ton produced 41% more milk per ton than the lowest performer in the test. Similarly, the hybrid with the highest estimated milk per acre produced 56% more milk per acre than the lowest performer in the test. Table 2 shows the range in performance among corn silage hybrids tested at Melrose.

Table 3 provides a few specific examples of how three hybrids differed in the test at La Crescent. Hybrid A was among the highest yielding entries in the test and was thus among the highest in estimated milk production per acre. Hybrid B was among the highest quality silages, so even though it was not among the highest in silage yield, its moderately high yield placed it among the highest in milk per acre. Hybrid C was among the highest quality silages. However, because its yield was relatively low, it was not among the entries with the highest milk per acre.

In general, the best corn silage hybrids are those that produce high yields of high quality forage. Tables 4 and 5 list those hybrids tested at each test location that ranked among the highest in both yield and quality as determined by milk per acre and milk per ton. Consult the Minnesota Varietal Trials Results (MP108-2003, January 2003 or on the web at www.maes.umn.edu/pubs.html) for detailed data on the performance of these and other hybrids in the test.

Our thanks to the producers who provided test sites and the companies that participated in the trials! The call for entries for the 2003 testing program have been distributed. It can be found on the web at www.agro.agri.umn.edu/forages. Contact Doug Swanson at 612-624-7729 or swans030@umn.edu with any questions.