Certain agricultural practices, such as the repeated application of herbicides or organic amendments to soil, can influence herbicide dissipation. This research has studied the effects of two repeated applications of mesotrione, pethoxamid, and triasulfuron on their dissipation rates in unamended soil (S) and soil amended with green compost (S+GC) or sewage sludge (S+SS). The dissipation experiment has also included an evaluation of the adsorption of the three herbicides by soils and of changes in soil dehydrogenase activity (DHA). The adsorption of the three herbicides by amended soils (Kf range 0.83-2.98) was higher than by unamended soil (Kf range 0.20-0.64). The adsorption coefficients (Kd) of mesotrione and triasulfuron were higher for S+SS, while that of pethoxamid was higher for S+GC, but no relationship between values for the time to 50% degradation (DT₅₀) and adsorption coefficients could be determined. The repeated application of mesotrione decreased its dissipation rate in unamended soil (DT₅₀ increased from 4.75 to 8.15 days) and amended soils (DT₅₀ increased from 11.7 to 28.2 days in S+GC and from 17.7 to 37.9 in S+SS), whereas the repeated application of pethoxamid increased its dissipation rate in all the treatments, and the rate for triasulfuron increased only in amended soils. The highest DT₅₀ values for pethoxamid (12.3 days) and triasulfuron (57.1 days) were in S+GC, and the lowest in S+SS (8.35 and 24.7 days). Soil DHA was stimulated by the presence of GC in the soil and by the first application of mesotrione. The second application of mesotrione and pethoxamid positively affected soil DHA, but this did not occur for triasulfuron. The repeated applications of herbicides and soil organic amendments have different effects on herbicide dissipation, adsorption, and soil DHA, and they should be taken into account when assessing soil quality and other potential environmental implications of pesticide use.

某些农业实践，例如反复向土壤中施用除草剂或有机改良剂，可能会影响除草剂的消散。这项研究研究了甲基磺草酮，石霉酰胺和三氟磺隆的两次重复施用对未改良土壤（S）和经绿色堆肥（S + GC）或污水污泥（S + SS）改良的土壤中的消散率的影响。耗散实验还包括评估土壤对三种除草剂的吸附以及土壤脱氢酶活性（DHA）的变化。改良土壤（Kf范围为0.83-2.98）对三种除草剂的吸附高于未改良土壤（Kf范围为0.20-0.64）。S + SS对甲基磺草酮和三氟磺隆的吸附系数（Kd）较高，而S + GC对石霉酰胺的吸附系数（Kd）较高，₅₀）和吸附系数可以确定。重复施用甲基磺草酮降低了其在未改良土壤中的耗散率（DT ₅₀从4.75天增加到8.15天）和改良土壤（DT ₅₀在S + GC中从11.7天增加到28.2天，在S + SS中从17.7天增加到37.9天），而在所有处理中，重复使用石霉胺均会增加其耗散率，而仅在改良土壤中三氟磺隆的使用率才会增加。最高DT ₅₀S + GC中的石霉胺（12.3天）和三氟磺隆（57.1天）的值，S + SS中的最低值（8.35和24.7天）。土壤中GC的存在和甲基磺草酮的首次施用刺激了土壤DHA的生长。甲基磺草酮和石霉酰胺的第二次施用对土壤DHA产生了积极影响，但对于三氟磺隆则没有。除草剂和土壤有机改良剂的重复施用对除草剂的散失，吸附和土壤DHA具有不同的影响，在评估土壤质量和使用农药的其他潜在环境影响时，应考虑这些因素。