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ARS Home » Research » Publications at this Location » Publication #211439
Title: Self-Seeded Cereal Cover Crop Effects on Interspecific Competition with Corn

Author
item MC DONALD, P - IA STATE UNIVERSITY
item Singer, Jeremy
item WIEDENHOEFT, M - IA STATE UNIVERSITY

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2007
Publication Date: 3/3/2008
Citation: Mc Donald, P.B., Singer, J.W., Wiedenhoeft, M.H. 2008. Self-Seeded Cereal Cover Crop Effects on Interspecific Competition with Corn. Agronomy Journal. 100:440-446.

Interpretive Summary: Perpetuating cereal cover crops through self-seeding may increase adoption by reducing risk and cost. Winter rye, wheat, and triticale were used to develop self-seeding cover crop systems in a soybean-corn rotation. Cereals were planted in varying configurations and managed chemically and mechanically. The objective of this study was to quantify competition of self-seeded winter cereal cover crops growing concurrently with corn. Total weed density responded more to environment than cover crop treatment, with 12.0 and 2.2 weeds per meter squared (m-2) in 2005 and 2006. Cover crop treatments lowered corn grain yield 5 to 22% compared to a no cover crop check. The most promising treatment lowered corn grain yield 7 and 11%. Cover crop regrowth did not significantly shade corn during early growth, which indicates water is probably more limiting in this system than light. Lower corn kernel number appears most responsible for the yield reduction. These results indicate that self-seeded cover crops have approximately the same yield reduction as cover crops killed at planting of the cash crop, yet with no risk or cost of establishment. These results may lead to increased cover crop use by farmers and enhanced soil and water conservation.

Technical Abstract: Perpetuating cereal cover crops through self-seeding may increase adoption by reducing risk and cost. Winter rye (Secale cereale L.), wheat (Triticum aestivum L.), and triticale (x Triticosecale Wittmack) were used to develop self-seeding cover crop systems in a soybean [Glycine max (L.) Merr.]-corn (Zea mays L.) rotation. Cereals were planted in varying configurations and managed chemically and mechanically. The objective of this study was to quantify interspecific competition of self-seeded winter cereal cover crops growing concurrently with corn. Total weed density responded more to environment than cover crop treatment, with 12.0 and 2.2 weeds m-2 in 2005 and 2006. Cover crop treatments lowered corn grain yield 5 to 22% compared to a no cover crop check. The most promising treatment lowered corn grain yield 7 and 11%, which is in the range for previously reported yield reduction using rye cover crops when rye was killed at or immediately after planting in a corn-soybean rotation. Cover crop regrowth intercepted < 9% photosynthetically active radiation (PAR) during early growth of corn, which indicates water is probably more limiting in this system than light capture. Lower kernel density appears most responsible for the yield reduction. Additional research should focus on reducing interspecific competition during vegetative growth in corn when sink size is being determined.