Residue And Field Decline Study Of Acetochlor 50% EW In Peanut And Rape Field

Acetochlor is a selective chloroacetamid herbicide, which is used to control a wide spectrum of graminaceous weeds and grasses in peanut and several other crops. The residue dynamics of acetochlor were studied in peanut, rape and soil.The residue dynamics and final residues of acetochlor in peanut plant, peanut shell, peanut kernel, rape plant, rape seed, rape shell and soil samples were studied by gas chromatography equipped with an electron-capture detector (GC-ECD). Soil samples were extracted with methanol and other samples were extracted with methylene chloride. The extracts were cleaned up by florisil SPE. Peanut samples were fortified with acetochlor at levels between 0.005 and 1.0 mg/kg. The recovery ranged from 85.3 to 96.5% for soil, 81.5 to 89.0% for peanut plant,85.4 to 91.6% for kernel,78.5 to 85.3% for shell with the relative standard deviations of 3.9 to 5.0%,2.9 to 8.9%,4.9 to 12.1% and 4.6 to 5.7% respectively. The recovery ranged from 86.9 to 90.3% for rape plant,83.3 to 89.7% for rape seed,87.9 to 90.4% for shell with the relative standard deviations of 3.9-9.5%, 6.6-14.3% and 6.4-11.1%, respectively. The limit of detection (LOD) of the method was 0.5×10-11 g. The limit of quantifi cation (LOQ) was 0.005 mg/kg for soil,0.01 mg/kg for other sample. In 2008-2009, three areas experiments showed the dynamic equation was C = 1.9727e-0.1047T, R2=0.9292, C= 2.0684e-0.2055T, R2=0.9590 and C= 1.8325e-0.1749T, R2=0.9585 and half-life of acetochlor was 3.9,3.3 and 4.3 days in peanut soil of Zhengzhou, Putian and Changsha. In 2009-2010, two areas experiments showed the dynamic equation was C=2.3443e-0.1716T and C=1.9721e-0.1312T and the half-life of acetochlor was 3.5, and 5.2 days in rape soil of Putian and Changsha. the dynamic equation was C= 34.124e-0.3841T and C=18.826e-0.2941t and the half-life of acetochlor was 1.7, and 2.3 days in rape plant of Putian and Changsha.