Targeted timing of hairy vetch cover crop termination with roller crimper can eliminate glyphosate requirements in no-till sunflower

Abstract No-till cropping systems with cover crops can improve soil health, but often rely on glyphosate, which is a contentious herbicide. In this study, we investigated whether system based the direct sowing of sunflower ( Helianthus annuus ) in dead mulch roller-crimped hairy vetch Vicia villosa could be competitive where glyphosate also sprayed to terminate crop and control weeds. We hypothesized that optimum timing roller-crimping would key eliminate requirements while maintaining performance. 3-year on-farm experiment, compared three termination stages (early: pre-flowering; Intermediate: beginning flowering; late: 70% flowering) rates (Nil, half full, i.e. 1440 g active ingredient per hectare). Vetch biomass increased progressively from early late stages, ranged between 414 658 m −2 . Higher was correlated lower weed biomass. Treatments had inconsistent effects diversity composition, largely determined by interactions treatments seasonal (different years) or local factors fields). Glyphosate-based seemed select for aggressive species, no clear species filtering effect ecological functional traits detected. Shannon H’ positively grain yield below dry threshold 150 Crop stage failure without application. However, acceptable, being at par 15% higher (mean first second no-glyphosate glyphosate-based treatments. gross margins showed same trend (+33% treatments). This time, shows targeted no-till result equal agronomic economic performances as addition glyphosate.