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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Sustainable Agricultural Systems Laboratory » Research » Publications at this Location » Publication #360583
Research Project: Enhancing Sustainability of Mid-Atlantic Agricultural Systems Using Agroecological Principles and Practices

Location: Sustainable Agricultural Systems Laboratory

Title: Weed species and traits associated with organic grain crop rotations in the Mid-Atlantic region

Author
item TEASDALE, JOHN - Former ARS Employee
item Mirsky, Steven
item Cavigelli, Michel

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2019
Publication Date: 9/12/2019
Citation: Teasdale, J.R., Mirsky, S.B., Cavigelli, M.A. 2019. Weed species and traits associated with organic grain crop rotations in the Mid-Atlantic region. Weed Science. 67:595-604.

Interpretive Summary: Organic cropping systems usually involve a lot of tillage, which can foster growth of annual weed species. Analysis of weeds over the first 18 years of the long-term Farming Systems Project at Beltsville, Maryland revealed that tall, erect annual broadleaf weeds were most prominent in corn and soybeans in most years of the experiment. These species were usually most abundant in a short corn-soybean rotation and less abundant in longer crop rotations that included winter wheat and forage crops, in which tillage timing varied from year to year. These results support the idea that crop rotation length and complexity can help control weed competition in organic systems. These results will be of interest to organic farmers, crop consultants and others working to improve the sustainability of organic grain crop production systems.

Technical Abstract: Organic cropping systems are characterized by regular soil disturbance events in the form of primary tillage for seedbed preparation and cultivations for weed removal after planting. The Farming Systems Project at Beltsville, Maryland, USA, is a long-term experiment comparing three organic rotations: corn-soybean, corn-soybean-wheat, and corn-soybean-wheat-forage. Analysis of the soil cover by weeds over the first 18 years of this experiment revealed that tall, erect annual broadleaf weeds such as smooth pigweed, common lambsquarters, horseweed, jimsonweed, and velvetleaf were the most prominent weeds in corn and soybeans in most years of the experiment. These species were usually most abundant in the corn-soybean rotation and less abundant in the longer rotations that had more diverse seasonal soil disturbance regimes. Generally, these species exhibited traits adapted to the disturbance regimes, nutrient availability, crop environment and duration, and local meteorological conditions associated with the summer annual corn and soybean crops. Their relative proportion in corn and soybeans was determined primarily by the presence and timing of spring tillage, which in turn determined meteorological conditions driving emergence periodicity. Fluctuating conditions for weed emergence along with a persistent seedbank undoubtedly led to the coexistence of the dominant species found in this experiment.