除草剂2,4-D丁酯对皮燕麦安全性和产量的影响及其残留动态分析

以陇燕3号为试验材料,喷施低、中和高3个剂量(450, 750和1050 mL·hm^-2)的2,4-D丁酯,在药后1,7,14,21,28 d以及开花期、灌浆期植株和收获后籽粒中测定2,4-D丁酯残留量,探讨不同剂量2,4-D丁酯处理对杂草防效、燕麦的安全性、株高和产量的影响。结果表明,2,4-D丁酯对燕麦安全性、产量及田间杂草防效影响显著。高剂量下燕麦出现顶端下垂、叶尖发红和药斑等药害现象。杂草防效随2,4-D丁酯施用剂量的增加而提高。高剂量除草剂喷施后45 d,株防效较药后30 d仍有小幅上升,鲜重防效达到90%以上。3个剂量均使株高有一定程度的降低,高剂量下燕麦株高较对照降低了10.49%。低剂量下干草产量有所降低,但与对照差异不显著(P>0.05),籽粒增产22.64%;中剂量下燕麦干草产量呈增加趋势,籽粒增产40.57%;高剂量下,燕麦干草产量下降了8.85%(P<0.05)。2,4-D丁酯及2,4-D在皮燕麦中的残留量随除草剂施用剂量的增加而上升。施药28 d后,高浓度下燕麦中2,4-D丁酯和2,4-D残留量最高,达0.168 和0.011 mg·kg^-1,显著(P<0.05)高于低浓度处理。综上所述,本试验条件下,750 mL·hm^-2为皮燕麦田2,4-D丁酯的最佳使用剂量。

Effects and residual dynamics of 2, 4-D butyl ester on the safety and yield of covered oat under field conditions

The aim of this study was to evaluate the weed-control effects and the persistence of the herbicide 2, 4-D butyl ester in field crops of covered oat. Covered oat (cultivar Longyan No.3) at the 3-4 leaf stage was treated with 2, 4-D butyl ester at three application rates (450, 750, and 1050 mL·ha^-1). The dissipation and residue dynamics of 2, 4-D butyl ester and its decomposition products in covered oat plants were evaluated at 1, 7, 14, 21, and 28 days after application, and at the flowering, grain filling, and maturity stages. The effects of this herbicide on weeds and on the safety, yield, and plant height of oat were investigated. The results showed that 2, 4-D butyl ester significantly affected the safety and yield of oat, but was effective in controlling weeds in oat fields. High dosages caused damage to the oat crop, such as top sagging, leaf redness, and medicine spots. The efficacy of weed control improved with increasing concentrations of 2, 4-D butyl ester. The 1050 mL·ha^-1 treatment had the strongest control effect, with up to 90% weed control at 45 days after treatment. The application of 2, 4-D butyl ester decreased oat plant height by 10.49% at the 1050 mL·ha^-1 dosage. The 450 mL·ha^-1 concentration of 2, 4-D butyl ester reduced oat hay yield, but it did not differ significantly (P>0.05) from that of the control, and improved oat grain yield by 22.64%. The 750 mL·ha^-1 concentration of 2, 4-D butyl ester improved oat yield by 40.57%. The 1050 mL·ha^-1 dosage of 2, 4-D butyl ester significantly (P<0.05) reduced oat hay yield by 8.85%. The degradation dynamics of 2, 4-D butyl ester and 2, 4-D in covered oat were positively related to the dosage of 2, 4-D butyl ester. The largest amounts of 2, 4-D butyl ester and 2, 4-D residues (0.168 and 0.011 mg·kg^-1, respectively) were in covered oats at 28 days after application of 2, 4-D butyl ester at the highest dosage (1050 mL·ha^-1), and were significantly higher than the amounts of residues at 28 days after applying lower dosages. On the basis of these experimental results, we concluded that application of 2, 4-D butyl ester at 750 mL·ha^-1 is the best treatment to control weeds in covered oat fields.