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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #417063
Research Project: Integrated Agricultural Systems for a Resilient Circular Bioeconomy in the Central Plains

Location: Agroecosystem Management Research

Title: Crop sequence impacts horseweed (Conyza canadensis) density and productivity in oats

Author
item Schmer, Marty
item VARVEL, GARY - Retired ARS Employee
item SWANSON, STEVE - Retired ARS Employee
item Fann, Benjamin

Submitted to: Crop, Forage & Turfgrass Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2024
Publication Date: 12/1/2024
Citation: Schmer, M.R., Varvel, G.E., Swanson, S., Fann, B.T. 2024. Crop sequence impacts horseweed (Conyza canadensis) density and productivity in oats. Crop, Forage & Turfgrass Management. 10(2): Article e70014. https://doi.org/10.1002/cft2.70014.
DOI: https://doi.org/10.1002/cft2.70014

Interpretive Summary: Diverse crop rotations provide benefits that include increased yield stability, nitrogen recovery, pest and disease resistance, improved weed management, and increased agroecosystem functions. Crop rotations and tillage practice can lead to distinct weed communities and crop sequence within diverse crop rotations influence weed prevalence and management. Agronomic crops that contain allelopathic compounds can play a role in weed suppression and management when used in a crop rotation. Sorghum (Sorghum bicolor (L.) Moench) is considered an important allelopathic crop. Differences in Conzya canadensis abundance were noticed in a long-term crop rotation study within the oat (Avena sativa L.) phase from different four-year crop rotation sequences. The four-year crop rotation sequences are corn–soybean–grain sorghum–oat (Avena sativa L.)/clover (80% Melilotus officinalis Lam. + 20% Trifolium praetense L.) and corn–oat/clover– grain sorghum–soybean). Horseweed density, present in the oat sequence, was greater following corn than following sorghum. Oat yield was similar between the four-year crop rotations. Crop sequence can influence weed pressure within diverse cropping systems.

Technical Abstract: Diverse crop rotations provide increased agroecosystem functions including improved weed management. Differences in Conzya canadensis abundance were noticed in a long-term crop rotation study within the oat (Avena sativa L.) phase from different four-year crop rotation sequences. The four-year crop rotation sequences are corn–soybean–grain sorghum–oat (Avena sativa L.)/clover (80% Melilotus officinalis Lam. + 20% Trifolium praetense L.) and corn–oat/clover– grain sorghum–soybean). We quantified Conyza canadensis abundance and biomass in oats that followed corn (Zea mays L.) or sorghum (Sorghum bicolor (L.) Moench). Conyza canadensis density, present in the oat sequence, was greater (P=0.0257) following corn than following sorghum. Oat yield was similar between the four-year crop rotations. Results suggest a possible allelopathic response by Conzya canadensis to sorghum residue. Crop sequence can influence weed pressure within diverse cropping systems.