Reduction in the spray drift of 2,4-D in tomato using hydraulic nozzles with air induction and LI-700 adjuvant

ABSTRACT The drift of hormonal effect herbicides is a major problem for agriculture, because, even in small amounts, it may cause high losses in crops with plants that are sensitive to their action mechanism. This study aimed to evaluate the efficiency of hydraulic spray nozzles with air induction, as well as the use of the LI-700 adjuvant, in the reduction of the 2,4-D herbicide drift, in tomato crop. A complete randomized split-plot experimental design, with eight replications, was used. Two herbicide solutions were assigned in the plots (with or without the use of adjuvant) [2,4-D (670 g ha-1) and 2,4-D (670 g ha-1) + LI-700 (712.88 g ha-1)], and, in the subplots, five nozzle models [simple fan (JSF11003), simple fan with air induction (AD-IA11003), dual fan with air induction (AD-IA/D11003), simple hammer fan with air induction (TTI11003-VP) and empty cone with air induction (CV-IA10003). The treatments were applied in a wind tunnel, under a pressure of 300 kPa. In a laser analyzer, applying only water, the volumetric median diameter, the relative amplitude and the percentage of drops with diameter lower than 150 µm were measured for all nozzle models. The CV-IA10003 and TTI11003-VP hydraulic nozzles outstand by reducing the 2,4-D herbicide drift and decreasing the damage to tomato plants. The addition of the LI-700 adjuvant to the 2,4-D syrup, independently of the nozzle model, reduces the drift of this herbicide and its effects on the tomato plant root. However, even when adopting these technologies, the application of the 2,4-D herbicide near the tomato crop should be avoided.

摘要 激素类除草剂飘移是农业生产中的重大难题之一，即便剂量极低，也会对其作用机制敏感的作物造成高额减产损失。本研究旨在评估带空气诱导（air induction）结构的液压喷雾喷头（hydraulic spray nozzles）的防控效果，以及添加LI-700助剂（adjuvant）对番茄田2,4-D除草剂飘移的抑制作用。

本实验采用完全随机裂区试验设计，设置8次生物学重复。主区设置两组除草剂处理方案：（1）单一2,4-D药剂（670 g·ha⁻¹）；（2）2,4-D药剂（670 g·ha⁻¹）与LI-700助剂复配（712.88 g·ha⁻¹）。副区则设置5种喷头型号：简单扇形喷头（JSF11003）、带空气诱导的简单扇形喷头（AD-IA11003）、带空气诱导的双扇形喷头（AD-IA/D11003）、带空气诱导的简易锤式扇形喷头（TTI11003-VP）以及带空气诱导的空心圆锥喷头（CV-IA10003）。

所有处理均在风洞环境中施药，施药压力设定为300 kPa。仅以清水开展空白测试时，采用激光粒度分析仪（laser analyzer）测定了所有喷头的体积中径、相对跨度以及直径小于150 μm的雾滴占比。

试验结果表明，CV-IA10003与TTI11003-VP型液压喷雾喷头在降低2,4-D除草剂飘移、减轻番茄植株药害方面表现突出。向2,4-D药液中添加LI-700助剂，无论搭配何种喷头型号，均可抑制该除草剂的飘移及其对番茄植株根系的危害。但即便采用上述防控技术，仍应避免在番茄种植区附近喷施2,4-D除草剂。