No-till snap bean performance and weed response following rye and vetch cover crops

Authors: Boydston, Rick; Williams, Martin

Submitted to: Renewable Agriculture and Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/9/2016
Publication Date: 12/5/2016
Citation: Boydston, R.A., Williams, M. 2016. No-till snap bean performance and weed response following rye and vetch cover crops. Renewable Agriculture and Food Systems. doi: 10.1017/S1742170516000405.

Interpretive Summary: Vegetable growers have been slow to adapt direct seeding into killed cover crop residues despite the benefits of weed suppressive residues, sequestering nutrients, improved water infiltration, and reduced soil erosion. Field studies were conducted in two years near Paterson, WA and Urbana, IL to determine the performance of snap beans direct seeded into rye and vetch cover crops that were killed with a roller-crimper. Cereal rye was killed well by a roller-crimper even without the use of herbicides while common and hairy vetch were not completely killed by roller-crimping and essentially became a weed competing with snap beans. Heavy residues of cereal rye and vetch were difficult to plant into often resulting in lower snap bean plant stands. Cereal rye and hairy vetch suppressed weeds, but nonkilled vetch became a weed. Weed control with killed cover crops alone was less than that typically obtained when including residual herbicides or repeated cultivation. Producers electing to plant no-till snap beans into fall-planted cover crops without using any herbicides would likely need to invest in specialized high residue cultivation equipment in order to control weeds season long and prevent crop losses due to weed competition. Snap bean yields were inconsistent and often lower following cover crops compared to snap beans planted with no cover crop. Being able to adequately kill cover crops and to plant, control escape weeds, and mechanically harvest in the presence of heavy residues are challenges that must be overcome to increase no-till production practices in vegetable crops.

Technical Abstract: Fall-planted cover crops offer many benefits including weed suppressive residues in spring sown crops when controlled and left on the soil surface. However, vegetable growers have been slow to adapt direct seeding (no-till) into cover crop residues. Field studies were conducted in 2009 and 2010 near Paterson, WA and Urbana, IL to evaluate mortality of rye and vetch cover crops, weed density and biomass, and snap bean growth and yield following four cover crop control methods utilizing a roller-crimper. Rye had higher mortality than common and hairy vetch by roller-crimping, and carfentrazone applied after roller-crimping only slightly improved vetch mortality. Heavy residues of rye and escaped vetch were difficult to plant into, often resulting in lower snap bean stands. Rye and hairy vetch residues suppressed final weed biomass while common vetch reduced weed biomass one of two years. Escaped plants of both vetch species became a weed. Snap bean yields were inconsistent and often lower following cover crops compared to a fallow treatment. Being able to completely control cover crops and to plant, manage escaped weeds, and mechanically harvest in the presence of heavy residues are challenges that deter vegetable growers from readily adapting these systems.