Herbicide Spray Deposition in Wheat Stubble as Affected by Nozzle Type and Application Direction

Abstract

Tall wheat (Triticum aestivum L.) stubble can enhance soil water conservation during the fallow-period by trapping snow and decreasing evaporation. However, standing wheat stubble can intercept herbicide spray droplets before they reach their intended targets. This experiment aimed to evaluate the effects of three wheat stubble heights (>70 cm, 35 cm, and no-stubble), four nozzle types (XR, TTJ, AIXR, and TTI), and three application directions (angular (45°), perpendicular (90°), and parallel (0°) to the wheat row) on a spray deposition of glyphosate and a dicamba tank mixture. The ranking of droplet size from smallest to largest based on volume median diameter (VMD) was XR, TTJ, AIXR, and TTI. Wheat stubble greater than 70 cm decreased spray deposition 37%, while 35 cm stubble caused a 23% decrease. Sprayer application directions and nozzle type had significant interaction on spray deposition. Perpendicular application direction decreased spray deposition relative to the angular application direction for TTJ and TTI. Parallel application direction had lower spray deposition than angular application direction for TTJ and XR. Similarly, relatively-high-spray deposition (~75%) was provided by angular application direction regardless of the nozzle type. Applicators should consider traveling in an angular direction to the wheat rows for improved droplet deposition across spray nozzle types.

Planting into a living cover crop alters preemergence herbicide dynamics and can reduce soybean yield

“…However, cereal rye resulted in up to 44% reduction in coverage when cards were placed adjacent to cereal rye rows. Despite allowing the spray droplets to travel between rows, spraying PRE herbicides over standing cereal rye requires the sprayer boom to operate at a higher height than over rolled cereal rye because of its canopy height, which can also affect spray deposition (Simão et al 2020). When comparing the experimental years, it is likely that the higher cereal rye height at PRE application in 2021 (148 cm) and 2022 (132 cm) compared to 2020 (78 cm) also impacted the spray deposition by requiring an elevated boom height during PRE application, thus justifying the nonsignificant difference observed between roller and glyphosate on the density of droplets and spray coverage in 2021 and 2022 (Table 4).…”

Droplet Deposition and Efficacy of Real-Time Variable-Rate Application of Herbicides at Reduced Dose in Winter Wheat Fields

“…The type or size of the nozzle largely affects the droplet size and deposition of the sprayers [25,36], but its impact on herbicide efficacy is not significant in most cases [37]. The SV usually influences herbicide efficacy greatly; sometimes, a relatively low level is favorable [20,38], but sometimes, a relatively higher level is necessary for some weed species [19,39].…”