Integrating fall-planted cereal cover crops with herbicides for weed control in dry edible beans

Abstract

Field experiments were conducted in Parma and Kimberly, ID, in 2023 and 2024 to determine weed suppression by fall-planted small grain cover crops in dry beans (Phaseolus vulgaris L.). Cover crops included barley (Hordeum vulgare L.), triticale (Triticosecale wittmack L.), and winter wheat (Triticum aestivum L.), and these treatments were compared to a no-cover crop control. Cereal cover crops were either terminated chemically with glyphosate or harvested for forage. Herbicide treatments included pre-emergence and post-emergence herbicides and a nontreated check. Based on cover crops, termination, and herbicide treatments, there were 35 treatments that were replicated four times. Haying treatments reduced dry bean population by 38% in Parma but had no significant impact on dry bean seed yield. Chemically terminated cover crop treatments reduced dry bean population in Kimberly by 37% and seed yield by up to 49%. Cover crops reduced weed biomass in dry beans by 65%–80% in Parma and 14%–54% in Kimberly at 8 weeks after dry bean planting. All herbicide treatments, except dimethenamid-p + S-ethyl-N,N-dipropylthiocarbamate, reduced weed biomass by 25%–75% in Parma and 33%–76% in Kimberly. The dry bean seed yield was reduced by 31% in Parma and 67%–72% in Kimberly in the nontreated check. Economic analysis indicated that all cover crop treatments were profitable, except for wheat in Parma and chemically terminated barley in Kimberly. There is promising potential for integrating cover crops and herbicides for effective weed management in dry beans.