Does the sequence of addition of herbicide and adjuvants to the spray solution influence sicklepod control?

ABSTRACT The use of adjuvants associated with herbicides aims at improving the performance of application and the consequent increase in the biological effect of the treatment. However, the sequence of product added to the sprayer tank can influence the phytosanitary spray solution. Thus, this study aimed to evaluate the control of Senna obtusifolia as a function of the sequence of addition of the herbicide aminopyralid + fluroxypyr and adjuvants in the preparation of spray solution. Two herbicide doses (1 and 2 L c.p. ha-1) associated with the adjuvants mineral oil (MO), silicone polyether copolymer (SIL), and a mixture of phosphatidylcholine and propionic acid (LEC), all in the proportion of 0.3% v v-1, with alternate addition to the spray solution to evaluate the effects of the preparation sequence. The spray solution volume considered was 150 L ha-1. Evaluations of spray solution stability were performed from the visual evaluation of homogeneity, electrical conductivity, and pH. The effect of treatment on S. obtusifolia control was measured using a scoring scale and dry matter. Correlation coefficients between the evaluations were also determined. No difference of the preparation sequence of spray solution was observed for stability, pH, and electrical conductivity, but an influence was observed on S. obtusifolia control, without changing dry matter accumulation. The treatment with the adjuvant LEC previously added to the herbicide provided a higher control rate at the highest dose, while the adjuvant SIL had the opposite effect.

摘要 与除草剂复配的助剂，其作用在于提升施药性能，进而增强处理措施的生物效应。然而，向喷雾罐中添加药剂的先后顺序，会对植保喷雾液的性质产生影响。为此，本研究旨在探究喷雾液制备过程中，除草剂氯氨吡啶酸+氟氯吡啶酯（aminopyralid + fluroxypyr）与助剂的添加顺序对钝叶决明（Senna obtusifolia）防除效果的影响。试验设置两种除草剂剂量：1 L·ha⁻¹和2 L·ha⁻¹（商品制剂），搭配的助剂包括矿物油（mineral oil, MO）、聚醚改性硅油（silicone polyether copolymer, SIL）以及磷脂酰胆碱与丙酸混合物（phosphatidylcholine and propionic acid, LEC），所有助剂的添加比例均为0.3%（v v⁻¹，体积比），通过交替调整各组分的添加顺序，以考察制备顺序的影响。试验设定喷雾液施用量为150 L·ha⁻¹。通过目测均一度、电导率与pH值，对喷雾液的稳定性进行评价；采用分级评分法与干物质重量法，测定各处理对钝叶决明的防除效果，同时计算各评价指标间的相关系数。研究结果表明，喷雾液制备顺序对其稳定性、pH值及电导率无显著影响，但对钝叶决明的防除效果存在显著影响，而对干物质积累量无明显改变。当使用最高剂量除草剂时，预先添加助剂LEC的处理组防效更高，而添加助剂SIL的处理组则呈现相反效果。