Response of Vegetable Crops to Nitrogen Rates in Tillage Systems With and Without Vetch and Ryegrass

Abstract

Abstract Direct-seeded bush beans, sweet corn, summer squash, and transplanted tomato and cabbage were grown under varying tillage and cropping systems in 1982 and 1983. Cultural treatments were conventional tillage (CT), no-tillage without cover crop (NT–CC), and no-tillage with a cover crop (NT + CC) of hairy vetch (Vicia villosa) in 1982 and perennial ryegrass (Lolium multiflorum) in 1983. Split applications of N were 56 and 112 kg·ha−1 in CT plots and 0, 56, and 112 kg·ha−1 in NT plots. Plant stand and yields of bush beans and sweet corn were highest in CT plots in both years. Plant stand of squash was less for CT in 1982, but greater for CT than for NT + CC in 1983. Yields of squash were similar, but plant dry weight was greater in CT than in NT + CC. Plant stand of tomato and cabbage for NT + CC was similar to CT in 1982, but cabbage stand was greatest for CT in 1983. Total tomato yields were greater for NT – CC in 1982 and similar to those for CT in 1983, but yields were greatly reduced for NT + CC in 1983. Only in 1982 were cabbage heads of certain treatments marketable and they were greatest for CT. Sidedressing bush bean, sweet corn, cabbage, and summer squash plants with N in NT – CC plots increased yields linearly in 1982. Of the crops grown by NT + CC, only yields of bush beans and cabbage in 1982 and green fruit of tomato in 1982 showed a linear increase by sidedressing with N. Sidedressing with N increased N contents of all crops linearly in 1982, but not in 1983. Weed control was excellent in CT sweet corn and satisfactory in CT and NT – CC plots of the other crops. For the other crops in NT + CC plots, most of the weed and/or cover crop growth was the regrowth of vetch in 1982 and perennial ryegrass in 1983 after weed control chemicals were applied.