Degradation Of Amide Herbicides In Vegetable Waste Composting And Soil

As the substantial increasing demand of crops such as vegetables and flowers, the growing use of pesticides and the promotion of greenhouse cultivation technology, the pesticide residues in vegetables and flowers surface increase gradually and soil and water environment become more severe. Amide herbicides are used widely as bactericide and pesticides respectively. The degradation of metolachlor, acetochlor and butachlor in composting and soil was studied in this paper in different soil conditions of amide herbicides had been examined in this study. The main conclusions were obtained as follows.Liquid solid extraction + Fliorisil solid phase exteaction (LSE+SPE) is the best treatment method for samples. HPLC method for the target of the recovery is 83.2%-94.2%, the detection limit is 0.035-0.072 mg/kg, and the relative standard deviation is 4.8%-10.7%. GC-MS method of recovery is 88.6%-88.6% of the target pollutants, detection limit is 0.10-0.78 mg/kg, and the relative standard deviation is 0.9%-13.6%.The degradation of the typical amide herbicide in the process of vegetable waste composting has been studied. The degradation of metolachlor, acetochlor and butachlor is relatively slow, and the rate of degradation is 90% in 30 d, the degradation process in accordance with the availability-adjusted first-order kinetics equation. The degradation of fungicide chlorothalonil was rapid in the composting process, and 4-hydroxy chlorothalonil can inhibit compost microbial, so as to suppress the degradation of amide herbicide. Chlorothalonil and three kinds of herbicides have significant inhibitory effect on vegetable waste composting process (moisture content, pH, organic matter, total nitrogen, ammonia nitrogen and nitrate).The degradation rule of typical amide herbicides in the soil had been studied. The experimental results show that the amide herbicide such as metolachlor, acetochlor and butachlor follow the availability-adjusted first-order kinetics equation; increasing the proportion of inoculum appropriately, raising the temperature can promote the degradation of amide herbicide, fungicide chlorothalonil, inhibit the degradation of amide herbicide.