Weed populations and pickling cucumber (Cucumis sativus) yield under summer and winter cover crop systems

Cucumber growers are increasingly interested in integrating cover crops into their cropping systems. This study was conducted to measure the effect of summer and winter cover crops on weed populations and cucumber yield. The experimental design was a factorial of cover crop and killing method. The cover crops were sorghum sudangrass [Sorghum bicolor (L) x S. sudanense (P) Stapf.], cereal rye (Secale cereale L.), hairy vetch (Vicia villosa Roth), and bare ground was used as a control. The cover crops were killed either by discing or with glyphosate application. Cover crop killing method had no effect on weed density, weed species composition, cucumber yield, and soil nutrient composition. Weed density was lower in all cover crop systems compared to bare ground. At 43 days after cover crop kill (DAK) in 2002, weed density was 40, 56, 65, and 372 plants m−2 in the sorghum sudangrass, cereal rye, hairy vetch, and bare ground treatments, respectively. Similar results were found at 40 DAK in 2003. Cucumber yield was the highest in sorghum sudangrass and rye systems, and lowest in the hairy vetch system. Sorghum sudangrass and rye showed potential for improvement of cucumber yield. However, fresh residue of rye in early summer may interfere with crop planting. In spite of the high weed suppression, the hairy vetch system was unacceptable because of the low cucumber yield.