苯唑草酮在土壤中的吸附行为研究

苯唑草酮是玉米田新型广谱苗后除草剂，为了评价苯唑草酮在土壤中的环境行为，采用振荡平衡法研究苯唑草酮在5 种土壤中的吸附特性，以及腐殖酸对苯唑草酮吸附影响。结果表明：苯唑草酮在5种土壤中的吸附规律符合Freundich 吸附等温方程，吸附系数分别为农安黑钙土9.44、永吉白浆土8.98、梨树黑土16.02、前郭苏打盐碱土7.83、柳河灰棕壤29.37。苯唑草酮在灰棕壤中为中等易吸附，在其余4种土壤中较难吸附。自由能绝对值ΔG变化小于40 kJ/mol，属于物理吸附。土壤对苯唑草酮的吸附性与有机质含量呈正相关，与阳离子交换量也表现出很好的相关性，与pH呈明显的负相关。腐殖酸吸附系数为177.40，说明腐殖酸对苯唑草酮有很强的吸附性。在黑土和盐碱土中添加腐殖酸后，吸附系数为17.98和9.80，说明腐殖酸对苯唑草酮在土壤中的吸附有一定的影响。

Adsorption Characteristics of Topramezone in Soil

Topramezone was a new broad-spectrum herbicide used in corn field. The study was to evaluate the environmental behavior of topramezone in soil. The adsorption of topramezone in 5 soils was studied in the laboratory by using vibrating equilibrium method. The results indicated that adsorption of substance in 5 soil samples and adsorption of humic acid tested were well fitted with Freundlich model, with the adsorption coefficients respectively as Nong＇an calcium soil 9.44, Yongji white pulp soil 8.98, Lishu black soil 16.02,Qianguo sodic soil 7.83, Liuhe gray brown soil 29.37. Topramezone showed medium absorption in the gray brown soil, but more difficult adsorption in the remaining 4 soils. Adsorption with changes of free energy was less than 40 kJ/mol, which was a type of physical adsorption. The sorption constants of soil to topramezone were positively related to both the contents of soil organic matter and the contents of soil CEC, however negatively related to the contents of soil pH. Adsorption coefficient of humic acid was 177.40, demonstrating that humic acids had a strong adsorption with topramezone. After Adding humic acids in black soil and sodic soil, the adsorption coefficient changed to 17.98 and 9.80, proving that the humic acid has a certain influence on adsorption of topramezone in the soil.