Adoption of conservation tillage practices has been slow in organic vegetable production, partially due to producers' concerns regarding weed management. Integrating cover crops into a conservation tillage program may provide organic producers a viable weed management option enabling growers to practice conservation tillage. A four-year study was conducted to evaluate the influence of different tillage methods (two conventional and two conservation practices) jointly with a mixed winter cover crop for weed suppression, time required for hand weeding, and crop yield in organically managed eggplant (2012 and 2014) and sweet corn (2013 and 2015) production systems. Tillage treatments were conventional tillage without surface mulch (CT-BG) and with black polyethylene (plastic) mulch (CT-BP), strip-tillage (ST), and no-tillage (NT) with cover crop residue. At 2 and 7 WAT/P (weeks after transplanting/planting), intra-row weed density was higher in CT-BG and ST, and inter-row weed density was higher in CT-BG and CT-BP treatments. Time required for hand-weeding was greatest in CT-BG and least in CT-BP and NT treatments. Eggplant yield was lowest in NT treatment in 2012 but similar among treatments in 2014. Sweet corn yield was similar among treatments in 2013 but highest in ST in 2015. Though both CT-BP and NT treatments showed greater potential for weed suppression, production input was highest in CT-BP but least in NT. Implications of these findings suggest that there is a potential to use strip tillage integrating with stale seedbed tactic for weed management in organic vegetables, which reduces herbicide use, hand-labor, and overall weed management cost while maintaining high yield potential.
Nomenclature: Broadleaf plantain, Plantago major L. PLAMA; carpetweed, Mollugo verticillata L. MOLVE; goosegrass, Eleusine indica (L.) Gaertn. ELEIN; large crabgrass, Digitaria sanguinalis (L.) Scop. DIGSA; smooth crabgrass, Digitaria ischaemum (Schreb.) Schreb. ex Muhl. DIGIS.