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Subject: Agricultural Chemicals × Author: Joshi, Varsha × End date: 2018 × Start date: 2010 × Type: Thesis ×
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    ThesisItemOpen Access
    Effect of some soil amendments on dissipation and leaching of pesticides used in rice and wheat crops
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2015-07) Joshi, Varsha; Srivastava, Anjana
    The effect of different soil amendments on leaching and dissipation of the insecticides fipronil and chlorpyrifos, and the herbicide sulfosulfuron was studied under laboratory as well as field conditions in rice and wheat crop. The extraction of pesticides was done using simplified QuEChERS method. Fipronil and Sulfosulfuron were extracted in acetonitrile and were analysed in HPLC with a retention time of 5.9 and 5.1 minutes respectively, whereas hexane was used for the extraction of Chlorpyrifos which was analysed in GC at a retention time of 5.2 minutes. The recovery of fipronil, sulfosulfuron and chlorpyrifos from soil, water and crop samples was 83.0 to 94.6 %, 83.7 to 93.8% and 83.5 to 95.3% respectively. Results from the soil column leaching experiment concluded that CS and FCD were effective in reducing leaching of all the pesticides under laboratory conditions. Gypsum, CS and FCD resulted in the fast dissipation of fipronil and sulfosulfuron, whereas the half life of chlorpyrifos was reduced by the application of FCD and FYM over control. All the parameters of the GW were within the permissible limit in rice and wheat crop. CS and FCD were very effective in reducing the pesticide residue in soil, ground water and crop produce in both the crops. The residue of fipronil in rice grains was below the limit of detection (<0.002), whereas a considerable amount of fipronil was detected in rice straw. The concentration of chlorpyrifos detected in rice grains and straw was below the set MRL value. The residue of sulfosulfuron detected in wheat straw was below the maximum residue limit (0.1 mg/kg) and was not detected in wheat grains.