三种磺酰脲类除草剂在土壤中的降解及吸附特性

采用室内模拟试验方法,研究了氟胺磺隆、氯吡嘧磺隆和磺酰磺隆3种磺酰脲类除草剂在5种不同种类土壤(江西红壤、太湖水稻土、东北黑土、南京黄棕壤、陕西潮土)中的降解及吸附特性.结果表明,这3种磺酰脲类除草剂在这5种不同土壤中的降解速率均比较快,且降解过程均遵循一级动力学方程,土壤pH值是影响土壤降解速率的主要因素.3种磺酰脲类除草剂在土壤中的吸附均符合Frendlich模型,且具有较低的吸附容量.3种磺酰脲类除草剂在不同土壤中的吸附自由能变化均小于40kJ.mol-1,吸附主要以物理吸附为主,吸附常数随土壤pH值的增大而逐渐减小.

Degradation and adsorption characteristics of three sulfonylurea herbicides in different soils

The degradation and adsorption of 3 sulfonylurea herbicides (triflusulfuron-methyl, halosulfuron-methyl and sulfosulfuron) in 5 typical soils were investigated under laboratory conditions with the governing factors explored. The results showed that these three sulfonylurea herbicides degraded quickly in soils and the degradation behaviors of these three sulfonylurea herbicides could be described by first-order kinetics very well. The pH of soils was the main factor controlling degradation rate. Furthermore, the results showed that the adsorption of these three sulfonylurea herbicides in 3 typical soils all fitted Freundlich equation well, and they all had weak adsorption capability in different soils. Free energy for adsorption in soils of these three sulfonylurea herbicides were less than 40 kJ·mol^-1, suggesting that the adsorption of these three sulfonylurea herbicides in soils was physical reaction, and the adsorption constant K_d decreased with increasing pH.