| In this paper,7 kinds of methylated vegetable oil were synthesized by using alkali catalyzed transesterification synthesis,and then 20 kinds of tank-mix adjuvants for foliar herbicides were obtained through further compound processing of those methylated vegetable oil.Laboratory bioassay and field efficacy trial showed that tank-mix adjuvant JZ-12 had a significant synergistic effect on the control of Echinochloa oryzicola Vasing and Monochoria korsakowii by metamifop,quinclorac and penoxsulam,and preliminarily clarified its synergism mechanism.The tank-mix adjuvant JZ-12 could improve the control effect of foliar herbicides and was safe for paddy.The results of this study could provide technical support for reducing and enhancing the use of foliar herbicides in paddle fields.In this test,the optimal synthetic process conditions for 7 kinds of methylated vegetable oils were determined.Under these conditions,the yields of methylated vegetable oils were all above 92%,the saponification reaction was avoided,and the rapid separation of glycerol and methyl esters was achieved.The contents of methyl oleate,methyl linoleate,methyl stearate and methyl palmitate in 7 kinds of methylated vegetable oils were determined by using HPLC.7 kinds of methylated vegetable oils were compounded with a certain proportion,and different kinds and proportions of emulsifiers were added to make 20 kinds of tank-mix adjuvants for foliar herbicides.The greenhouse pot test was used to screen out the volume fraction of the tank-mix adjuvants for foliar herbicides that were 0.5% of the spraying amount.At this time,the herbicides had the best control effect on weeds and were safe for paddy.At this amount,compared with the metamifop 120 g a.i./hm2,the adjuvants JZ-9,JZ-12 and JZ-14 had better synergistic effects on controlling Echinochloa oryzicola Vasing,which fresh weight inhibition rates were 92.18%,95.41% and 95.33%,respectively.Compared with the quinclorac 93.75 g a.i./hm2,the adjuvants JZ-9,JZ-12 and JZ-35 had better synergistic effects on controlling Echinochloa oryzicola Vasing,fresh weight inhibition rates were 80.63%,88.13% and 86.41%,respectively.Compared with the penoxsulam 22.5 g a.i./hm2,the adjuvants JZ-12 and JZ-29 had better synergistic effects on controlling Monochoria korsakowii,fresh weight inhibition rates were 93.76% and 91.16%,respectively.In all,the addition of the tank-mix adjuvant JZ-12 had a synergistic effect on the control of three herbicides against Echinochloa oryzicola Vasing and Monochoria korsakowii.Twenty tank-mix adjuvants for foliar herbicides had good emulsification dispersibility and stability under low temperature.When the volume fraction of 20 adjuvants were 0.5% of the spray volume,adding JZ-12 and JZ-20 could reduce the surface tension of metamifop solutions with reduction rates were 23.82% and 27.34%,and contact angle with reduction rates were 39.36% and 39.51 %,respectively.Adding JZ-12 and JZ-35 could reduce the surface tension of quinclorac solutions with reduction rates were 26.25% and 28.97%,and contact angle with reduction rates were 36.54% and 44.67 %,respectively.Adding JZ-12 could reduce the surface tension and contact angle of penoxsulam,reduction rates were 27.47% and 52.38%,respectively.Meanwhile,the addition of JZ-12,JZ-14,JZ-15 and JZ-35 could increase the retention of ponceau-2R on the Echinochloa oryzicola Vasing and Monochoria korsakowii leaves,the increase rates of the retention of Echinochloa oryzicola Vasing were 143.60%,102.26%,87.96% and 75.22%,respectively,the increase rates of the retention of Monochoria korsakowii were 145.89%,72.79%,103.43% and 64.04%,respectively.That was,the tank-mix adjuvant JZ-12 for foliar herbicides had the greatest influence on the surface tension,contact angle,and the retention of the three solutions.Tank-mix adjuvants for foliar herbicides application technology test results showed that when the mixture of quinclorac and penoxsulam was used at the lowest recommended dosage with an added volume fraction of 0.5% the adjuvant JZ-12,the control effects of Echinochloa oryzicola Vasing and Monochoria korsakowii were increased by 6.66% and 5.00%,respectively.However,adding the adjuvant JZ-12 with reducing the recommended dosage of those herbicides by 20% or 40%,could not improve the control effect.That was,when the two herbicides were mixed with JZ-12 at the recommended dosage,the control effect on Echinochloa oryzicola Vasing and Monochoria korsakowii could be effectively improved.The safety test results showed that the combination of the two herbicides with the tank-mix adjuvant JZ-12 had no effect on paddy growth and no phytotoxicity.Therefore,this paper screened out tank-mix adjuvant JZ-12 [m(methylated peanut oil):m(methylated maize oil)= 2 : 1,emulsifier m(OP-7): m(PEG-400): m(ZR-5)= 1 : 1 : 0.5,the content was 20% of the quality of methylated vegetable oil] as the best tank-mix adjuvant for foliar herbicides,which had good synergistic effect for three herbicides on the control of Echinochloa oryzicola Vasing and Monochoria korsakowii. |
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