Corn Gluten Meal as an Alternative Weed Control Option for Spring-Transplanted Onions

Abstract

Successful screening of suitable onion (Allium cepa L.) varieties, viable production areas, and potential marketing options suggest that onions are a potential alternative crop for Oklahoma and northeast Texas. Unfortunately, onion's slow growth rate, short height, non-branching plant structure, low leaf area, and shallow root system can result in a total loss of marketable yields as a result of weed competition. Field research was conducted in 2002 and 2003 in southeast Oklahoma (Lane, OK) to determine the weed control efficacy of selected preemergent synthetic herbicides and corn gluten meal (CGM) for use in spring-transplanted onion cv. Hybrid Yellow Granex PRR, production. There were 21 treatments [12 synthetic herbicide treatments, 5 CGM application rates, a full-season weed-free (hand-weeded) treatment, a full-season weedy-check, a partial-season weed-free (weed-free for the first half of the growing season), and a weedy-check without onions]. Weed cover and weed control ratings were collected at 46 days after planting (DAP) and at harvest. The synthetic herbicide treatments resulted in significantly greater weed control at 46 DAP and harvest compared to all CGM application rates. The highest CGM rate (4,000 kg·ha−1) did maintain fair, 72.1%, total weed control and good, 82.7%, broadleaf weed control until 46 DAP. Among the synthetic herbicides, pendimethalin provided the best early and full season weed control.