草甘膦异丙胺盐水剂防除水葫芦效果及其在水中的残留

Glyphosate isopropylamine control of water hyacinth and the chemical residue in water

采用枯叶指数、枯柄指数、新根抑制、鲜重防效等指标,评价草甘膦异丙胺盐对水葫芦的防除作用,并测定其在水中的残留。盆栽毒力测定结果表明,草甘膦异丙胺盐对水葫芦新根的抑制作用最强,LC50为185.54μg.L-1,对叶、叶柄、鲜重的毒力较弱,LC50分别为385.89 g.L-1、475.82 g.L-1、790.86 g.L-1。田间水域试验结果表明,草甘膦异丙胺盐对水葫芦的新根有很好的抑制效果,药后40 d,1.91 g.L-1的抑制效果达100%。草甘膦异丙胺盐防除叶片的速效性较好,施药后20 d,1.91 g.L-1对叶片的防除效果达96.69%,优于40 d后85.42%的防效。草甘膦异丙胺盐对叶柄和鲜重的防除效果较差,1.91 mg.L-1草甘膦异丙胺盐处理40 d后,对叶柄和鲜根的防效分别为52.34%、63.18%。在室内静止水体与流水中分别施用1.37 mg.L-1、1.91 mg.L-1和2.73 mg.L-1草甘膦异丙胺盐防除不同覆盖率(0%、60%、90%)的水葫芦后,水体中残留量均未超过0.7mg.L-1最高污染物水平(美国一级饮用水标准)。

The control of Eichhornia crassipes Solms with glyphosate isopropylamine was evaluated by using leaf-withering index, petiole-withering index, inhibition of new roots, and fresh-weight. Residues of glyphosate isoprop-ylamine in water was also determined. Glyphosate isopropylamine showed a high inhibition effect on new root with an LC50 f 185.54μg·L^-1. The herbicide showed a relatively low toxicity to lamina, petiole and fresh-weight of E. crassipes in the laboratory test. The LC50 on lamina, petiole, and fresh-weight reached 385.89μg·L^-1, 475.82μg·L^-1, and 790.86μg·L^-1, respectively. The control of E. crassipes with glyphosate isopropylamine was also conducted in the field. Glyphosate isopropylamine at the dose of 1.91 mg·L^-1 inhibited the generation of all new roots. Glyphosate isopropylamine （1.91 mg·L^-1） showed 96.69% control efficiency on lamina after treatment for 20 days, while only 85.42 % control efficiency was found after 40 days. The control efficiencies of the herbicide on petiole and fresh-weight were were relatively low, i. e. , 52.34% and 63.18%, respectively, at the dose of 1.91 mg·L^-1. Glyphosate isopropylamine applications in still and running water bodies that were 0 %, 60 %, and 90 % covered with E. crassipes were 1.37 mg·L^-l , 1.91 mg· L^-l , and 2. 73 mg·L^-l , respectively. The glyphosate isopropylamine residues after the applications were all lower than 0. 7 mg·L^-1, the maximum limit for drinking-water set by EPA in the U. S.