Influence of cover crop and herbicide treatment on weed control and yield in no-till sweet corn (Zea mays L.) and Pumpkin (Cucurbita maxima Duch.)

Sweet corn and pumpkin were planted no-tillage (NT) into cover crop residue treatments of vetch, rye, crimson clover, and ladino clover controlled with glyphosate, and a bare ground conventional tillage (CT) control. Objectives included evaluation of crop growth, yield, and weed suppression in NT versus CT treatments. Herbicide application was also investigated, with a plus and minus herbicide treatment (alachlor plus cyanazine for sweet corn, or ethalfluralin for pumpkin) as the main factor in the factorial experiment, and cover crops the subfactors. Weed control 4 wk after planting was dependent upon cover crop. The fewest weed numbers and least biomass were found in the ladino clover plots, but clover regrowth and subsequent competition with the cash crop were severe. Herbicides also affected weed biomass at 4 wk after vegetable planting, with least biomass in herbicide-treated plots. Neither cover crop nor herbicide treatment significantly affected weed weight by 8 wk after planting or pumpkin fruit weight at harvest. Pumpkin yield was not influenced by herbicide application. The vetch cover, although harboring greatest weed biomass, produced the greatest total yield (car weight) in sweet corn. When averaged over cover crop, sweet corn yields were higher in herbicide-treated plots than in untreated ones. Both sweet corn and pumpkin maturity were generally delayed in the absence of herbicide treatments or in the presence of cover crop residues, especially clover and rye residues.