Field trials were initiated near Carrington and Absaraka, N.D., on a Heimdal clay loam and a Spottswood sandy loam, respectively to evaluate onion grade and yield in response to planting configuration, spring cover crop, and reservoir tillage. Results from the Carrington and Absaraka locations during 2002 and 2003 showed that colossal-sized onion was the largest grading size obtained (Carrington, 2003) and that the greatest number of colossal onion were from the bed configuration that had a reservoir tillage treatment. The coarser soil texture at Absaraka allowed for spring and fall formed raised bed comparison (2003) in which the fall formed raised bed tended to have greater yields and more marketable onion. Planting configuration resulting in the greatest total yield varied among locations and years but generally increased with reservoir tillage. Soil moisture and temperature monitoring during the early growing season did not differ greatly. However, differences in soil water potentials at the 6“ depth were observed during the last part of the growing season. Cover crop results indicated that a row of canola planted between onion rows for wind erosion protection will reduce onion yields even when ample water is available through routine irrigation. Herbicides for broadleaf control were not applied until onion had two true-leaves due to label restrictions. This delay enabled the canola to grow beyond the recommended stage for broadleaf control and to quickly outgrow the herbicide injury.
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