Application of Bentazon and Sethoxydim in Soybean Oil with Rotary Atomizers1

Abstract

AbstractRotary atomizers have been reported to have the capability to apply herbicides effectively in substantially reduced carrier volumes when compared to conventional application methods using flat fan nozzles. Several field studies (Typic Ochraqualfs, Argiaquic‐Argialbolls, and Aerie Ochraqualfs soils) were conducted during 1983 and 1984 to evaluate weed control in soybean [Glycine max (L.) Merr.] with bentazon {3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4(3H)‐ one 2,2‐dioxide] and sethoxydim {2‐[1‐(ethoxyimino)butyl]‐5‐[2‐ (ethylthio)propyl]‐3‐hydroxy‐2‐cyclohexene‐1‐one} applied in 2.3 to 9.4 L ha−1soybean oil concentrate (SOC) with rotary atomizers operating at two different cup rotating speeds. These treatments were compared with water carrier treatments applied with rotary atomizers at 28 L ha−1and flat fan nozzles at 187 L ha−1. Weed control attained with bentazon and sethoxydim applied with rotary atomizers was equal to that obtained with flat fan nozzles. Herbicide rate and rotary atomizer cup speed affected the .weed control realized with rotary atomizer applications in 2.3 to 9.4 L ha−1SOC, but not with 28 L ha−1water carrier. No increase in weed control was observed when bentazon or sethoxydim were applied in SOC carrier with rotary atomizers, compared with applications in water with either rotary atomizers or flat fan nozzles. Rotary atomizers offer the ability to apply herbicides effectively in carrier volumes of 28 L ha−1or less, greatly increasing the efficiency of spray operation.