Submitted to: Popular Publication
Publication Type: Popular Publication
Publication Acceptance Date: 5/1/2005
Publication Date: 5/1/2005
Citation: Grabber, J.H. 2005, Intercropping clovers with corn silage shows promise. Midwest Forage Association, Forage Focus Magazine. May, 2005:15 Interpretive Summary:
Technical Abstract: Greater use of cover crops and living mulches could reduce nitrate and soil loss and improve soil quality under annual row crops. In southern Wisconsin, we’re growing continuous corn (Roundup ready) for silage together with August-inter-seeded Italian ryegrass, September-seeded winter rye, or no cover crop. We’re also growing corn silage in a 2-year rotation with a Kura clover living mulch or August-inter-seeded red clover, followed by one year of clover production. In addition, we’re applying manure slurry on a P-basis in November or April, and additional fertilizer to supply 160 lb/acre of available N. Findings from 2003 and 2004: Ž In 2003 (normal temperatures, dry late summer), corn silage yields ranged from 8.2 to 10.3 tons DM/acre and were greatest with red clover and least with ryegrass. In 2004 (wet spring, cool summer), corn silage yields ranged from 7.4 to 8.9 tons DM/acre and were greater with clovers or no cover crop than with rye or ryegrass. Ž Growth of cover crops and living mulch by late October was greatest with ryegrass (0.5 ton/acre). Spring growth by early May was similar for rye, Kura clover, and red clover in 2003 (0.5 ton/acre) and greatest for rye in 2004 (1.6 ton/acre). Ž In fall of both years, soil nitrate levels to a 4-foot depth ranged from 28 to 48 lb/acre and were greatest with clovers and least with ryegrass. When a year of clover production followed corn, fall nitrate levels dropped to 20 lb/acre. Ž In the year following corn, yields of red clover were greater than Kura clover in 2003 (5.0 vs. 3.8 tons/acre). Yields of both clovers were similar in 2004 (3.7 tons/acre) even though red clover was reseeded in April due to August-inter-seeding failure in 2003. Ž Applying manure in fall versus spring didn’t influence yields or soil nitrate levels. The data suggest that corn silage yields within a red clover or kura clover living mulch system are as good as or better than yields without a cover crop. August-inter-seeded Italian ryegrass depressed corn silage yields and provided only modest cover and reductions in fall nitrate prior to winterkill. Fall-seeded winter rye had intermediate performance; corn yields were improved if rye was killed in early spring. We will continue to evaluate these systems until 2007.