Cover crop mixtures for suppression of herbicide-resistant Brassica rapa and Raphanus sativus weeds

Overview

This research investigates the use of cover crop mixtures as a sustainable weed management tool for herbicide-resistant (HR) Brassica rapa and Raphanus sativus in no-till cropping systems in Argentina's Pampas region. The study tests whether cover crop mixtures produce higher biomass and residue cover than monocrops, and whether this translates into stronger suppression of HR weed establishment and growth. By integrating cover crops into cropping systems, the research aims to reduce dependence on herbicides, mitigate the evolution of HR weeds, and support long-term agroecosystem sustainability. Outcomes will inform decision support systems for managing HR B. rapa and R. sativus.

Technical specifications

Research approach:

• Field experiments will be conducted in areas heavily infested with HR B. rapa and R. sativus
• Winter cover crops including rye, triticale, oat, and hairy vetch will be evaluated as monocrops and as grass-legume mixtures
• A control treatment without cover crops will be included for comparison
• Cover crops will be assessed at varying densities and sowing dates
• Biomass production in spring and residue cover at the V4 maize stage (early summer) will be measured
• Suppressive effects on HR weed establishment and growth will be quantified
• Cover crop species closely related to the target weeds will be excluded to prevent gene flow risks

Key hypotheses being tested:

• Cover crop mixtures produce higher total biomass and residue cover than monocrops
• Cover crop mixtures provide greater suppression of HR B. rapa and R. sativus compared with monocrops
• HR weed presence is negatively correlated with cover crop biomass and residue production

Technology readiness level

This research is at the field validation stage. Previous studies at the institution have documented the benefits of cover crops for soil health, subsequent crop yields, and water use in the Pampas region. Current work is focused on generating empirical data on weed suppression effects, which will be used to develop decision support systems for HR B. rapa and R. sativus management. The research is ongoing, with planned field experiments to validate cover crop performance under real-world conditions.