Effects of Competitive and Allelopathic Interactions on Field Pea and Soybean under Organic Management

Experiments were conducted during 2011 and 2012 at Dickinson Research Extension Center (DREC), ND and at Carrington Research Extension Center (CREC) to understand the effects of competitive and allelopathic interactions on field pea and soybean under organic management. Another preliminary controlled environmental study was conducted with two cultivars of soybean (Viking 1832 and Viking 1706) to provide additional information on crop allelopathy. Five field pea cultivars from two distinct leaf types were chosen to determine competitive ability against weeds. Results indicated that semi-leafless cultivars (Cooper and Golden) had better plant establishment than normal leaf type (PS07100091, NDP080106 and NDP080102). Based on the results, these two semi-leafless cultivars could be considered more competitive against weeds. Results from the greenhouse study also indicated the superiority of a semi-leafless cultivar. Future studies need to be done to determine other morphological traits that make pea plants more competitive against increased weed pressure