香蕉秸秆堆肥对四种农药残留降解影响

通过单因子梯度试验研究了香蕉秸秆堆肥过程关键因子—C/N、温度、含水率、pH对香蕉栽培生产过程中经常施用的4种农药——百菌清、三唑酮、氯氰菊酯和溴氰菊酯残留降解的影响.结果显示,香蕉秸秆堆肥对4种农药具有明显的降解作用，在通风方式为机械翻堆条件下，百菌清的最佳降解条件为:C/N=35∶1，温度为40℃，含水率为60%，pH =9.7；三唑酮的最佳降解条件为:C/N=35∶1，温度为40℃，含水率为70%，pH=9.45；氯氰菊酯的最佳降解条件为:C/N=25∶1，温度为40℃，含水率为70%，pH=9.7；溴氰菊酯的最佳降解条件:C/N=35∶1，温度为50℃，含水率为70%，pH=9.7.根据上述单因素控制试验，利用非线性动力学模型分析可得百菌清、三唑酮、氯氰菊酯和溴氰菊酯的最小降解半衰期分别为28.8min、 4.32h、16.8h和 12h.

Degradation of four pesticides in banana straw compost

Chlorothalonil, triadimefon, cypermethrin and deltamethrin are widely used pesticides in fruit, vegetable and other crop production. In banana production, they are commonly applied for insect disease prevention. Therefore, the environmental behavior of these four pesticides and their residues need to be investigated for their roles in food production. In our research, the effects of C/N ratio, temperature, water content and pH, the key factors in banana straw composting, on the degradation of the four pesticides were studied with the aim to optimize degradation of the pesticide residues in the banana straw compost. The residues were detected with GC-ECD. The result indicated the compost greatly accelerated the degradation of the four pesticides. Under the artificial ventilation mode-turnover, the optimal degradation conditions of four pesticides were as follows: for chlorothalonil, C/N =35:1, 40℃, water content = 60% , pH = 9.7 ; for triadimefon, C/N = 35:1, 40℃, water content = 70% , pH = 9. 45 ; for cypermethrin, C/N = 25:1 , 40℃ , water content =70% , pH =9.7; for deltamethrin, C/N =35:1, 50℃ , moisture content =70% , pH =9.7. From the above individual tests and non-linear kinetic models, the minimum half lives of chlorothalonil, triadimefon, cypermethrin and deltamethrin were 28. 8 min, 4.32 h, 16.8 h, 12 h respectively.