Department of Plant and Soil Sciences, Mississippi State University, Mississippi State, MS, USA.
Department of Agronomy & Horticulture, University of Nebraska-Lincoln, North Platte, NE, USA.
Pest Manag Sci. 2020 Feb;76(2):737-746. doi: 10.1002/ps.5573. Epub 2019 Sep 10.
Unlike post-emergence herbicides (POSTs), little is known about droplet size effect on pre-emergence herbicide (PRE) efficacy. Four nozzle types were used to apply different PRE herbicides on eight soybean fields in Missouri and Mississippi in 2017 and 2018, respectively. Pendimethalin, metribuzin, clomazone, imazethapyr and pyroxasulfone were selected based on their physicochemical characteristics (adsorption, volatility and solubility) and were sprayed using XR11002, ULD12002, TTI6011002, and TTI11002 nozzles.
The XR nozzle produced the smallest droplet size (D ), 204 μm, followed by the ULD, TTI60 and TTI with D of 468, 646, and 794 μm, respectively. Droplet size, spray coverage, nozzle type or physicochemical characteristics showed no effect on PRE herbicide efficacy, except in the Monroe County, MS, field, with pendimethalin. The TTI60 twin fan nozzle enhanced pendimethalin weed control (up to 91%) in comparison with pendimethalin sprayed with the TTI nozzle (64%), in a high organic matter (OM) soil composed of large soil clods and high weed pressure. It was hypothesized that improved herbicide penetration assisted by the TTI60 dual fan pattern increased herbicide-moisture contact and clod coverage by the herbicide. Under soils with higher OM content (>2%) pendimethalin weed control was reduced. In soils with low OM (<0.7%), low cation exchange capacity (CEC) (<13.1%) and rainfall of 12.2 mm within 3 days after application, metribuzin also resulted in reduced weed control.
The results indicate that droplet size does not affect PRE herbicide efficacy regardless of physicochemical herbicide properties including adsorption, volatility and solubility. © 2019 Society of Chemical Industry.
与芽后除草剂（POST）不同，人们对施用于芽前除草剂（PRE）的雾滴大小对药效的影响知之甚少。2017 年和 2018 年，分别在密苏里州和密西西比州的 8 个大豆田中使用了 4 种喷嘴类型来施用不同的 PRE 除草剂。根据物理化学特性（吸附、挥发性和溶解度）选择了二甲戊灵、噻吩草胺、异恶草松、唑嘧磺草胺和吡氟酰草胺，并使用 XR11002、ULD12002、TTI6011002 和 TTI11002 喷嘴进行喷洒。
XR 喷嘴产生的雾滴尺寸（D）最小，为 204 μm，其次是 ULD、TTI60 和 TTI，D 分别为 468、646 和 794 μm。雾滴尺寸、喷雾覆盖率、喷嘴类型或物理化学特性对 PRE 除草剂的药效没有影响，除了在密西西比州门罗县的田块中，二甲戊灵除外。与 TTI 喷嘴喷洒的二甲戊灵相比，TTI60 双风扇喷嘴增强了二甲戊灵对杂草的控制效果（高达 91%），在由大土块和高杂草压力组成的高有机质（OM）土壤中。据推测，TTI60 双风扇模式改善了除草剂的穿透性，增加了除草剂与水分的接触和土块的覆盖范围。在 OM 含量较高（>2%）的土壤中，二甲戊灵除草效果降低。在 OM 含量较低（<0.7%）、阳离子交换量（CEC）较低（<13.1%）且施药后 3 天内降雨量为 12.2 毫米的土壤中，噻吩草胺也导致杂草控制效果降低。
结果表明，雾滴尺寸不影响 PRE 除草剂的药效，而与包括吸附、挥发性和溶解度在内的物理化学除草剂特性无关。© 2019 化学工业协会。
