| Abstrakt: |
Field experiments were conducted in 2022 at the University of Arkansas Pine Bluff Small Farm Outreach Center near Lonoke, Ark., to evaluate the impact of coating fertilizer with herbicides on weed control efficacy. The first study used three herbicide programs [florpyrauxifen-benzyl (Loyant), a premixture of florpyrauxifen-benzyl + penoxsulam (Novixid), and a mixture of halosulfuron (Permit) + florpyrauxifen-benzyl (Loyant)] applied either as directly coated on urea or as a foliar spray application following urea application, leading to a total of six treatments. Urea (46%), Loyant, Novixid, and Permit were applied at 68.96, 0.03, 0.06, and 0.01 lb ai/ac, respectively. A nontreated control that received an application of urea was also included for weed control evaluation purposes. In a second study, the effect of coating urea with the 4-hydroxyphenylpyruvate dioxygenase-(HPPD-) inhibiting herbicide benzobicyclon (Rogue) was evaluated for weed control. Benzobicyclon sprayed versus coated on urea was applied preflood, flood or post-flood (2 weeks after flood treatment) at 0.34 lb ai/ac. In the first study, barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.], rice flatsedge (Cyperus iria L.), and yellow nutsedge (Cyperus esculentus L.) control were affected by treatments at 7, 14, and 22 days after application (DAA), while hemp sesbania [Sesbania herbacea (Mill.) McVaugh] control was affected only at 7 DAA. In most cases, Novixid sprayed foliarly and Novixid-coated urea provided near similar levels of control of barnyardgrass, rice flatsedge, yellow nutsedge, and hemp sesbania. In the second study, hemp sesbania and sprangletop (Diplachne spp) control were numerically improved with Rogue applied at flood compared to the other application timings. Also, Rogue-coated on urea at flood provided numerically greater control of both weeds, 15 and 29 days after flood, than did the herbicide when sprayed. As a result, Novixid-coated and Rogue-coated fertilizers may be viable options to maintain high levels of weed control on some of the most problematic Arkansas rice weeds while mitigating off-target herbicide movement. [ABSTRACT FROM AUTHOR] |
