Monday, November 2, 2009
Convention Center, Exhibit Hall BC, Second Floor
While growing companion crops with corn can reduce soil and nutrient loss from cropland, they also can affect corn silage yields. In a four-year study in southern Wisconsin, no-till corn was grown with herbicide-suppressed kura clover or with June-interseeded red clover followed by one year of clover production. These rotations were compared to continuous corn grown with June-interseeded Italian ryegrass, September-seeded winter rye, or no cover crop. Each year, manure slurry was applied on a phosphorus basis and continuous corn plots received additional fertilizer at planting to supply 180 kg/ha of available nitrogen. In 2003 (dry summer), dry matter yields of corn silage were greatest with red clover (23.0 Mg/ha) and lowest with Italian ryegrass (18.4 Mg/ha). In 2004 (wet spring and cool summer), corn silage yields with kura clover (20.0 Mg/ha) exceeded other systems (16.1 to 17.8 Mg/ha). In 2005 (dry spring and early summer), corn silage yields with red clover (22.1 Mg/ha) surpassed other systems (14.1 to 16.3 Mg/ha). In 2006 (wet spring, uneven stands), corn silage yields were greatest with kura and red clovers (16.0 Mg/ha, respectively) and lowest with Italian ryegrass (12.2 Mg/ha). Spring vs. fall manure application did not influence corn yields. By late October, growth of companion crops was greatest for Italian ryegrass (0.9 to 2.0 Mg/ha), while growth of winter rye (2.9 to 5.7 Mg/ha) exceeded other companion crops by late April. Overall, corn silage yields were usually enhanced by clovers, depressed by Italian ryegrass, and not influenced by winter rye.