Division of Agricultural Chemicals, ICAR-Indian Agricultural Research Institute, New Delhi, India.
J Environ Sci Health B. 2020;55(6):550-557. doi: 10.1080/03601234.2020.1733363. Epub 2020 Mar 2.
The adsorption-desorption and leaching of flucetosulfuron, a sulfonylurea herbicide, was investigated in three Indian soils. Freundlich adsorption isotherm described the sorption mechanism of herbicide with adsorption coefficients (K) ranging from 17.13 to 27.99 and followed the order: Clayey loam > Loam > Sandy loam. The K showed positive correlation with organic carbon (OC) (r = 0.910) and clay content (r = 0.746); but, negative correlation with soil pH (r = -0.635). The adsorption isotherms were S-type suggesting that herbicide adsorption was concentration dependent and increased with increase in concentration. Desorption followed the sequence: sandy loam > clayey loam > loam . Hysteresis (H) was observed in all the three soils with H < 1. Leaching of flucetosulfuron correlated positively with the soil pH; but, negatively with the OC content. Sandy loam soil (OC- 0.40%, pH -7.25) registered lowest adsorption and highest leaching of flucetosulfuron while lowest leaching was found in the loam soil (pH - 7.89, OC - 0.65%). The leaching losses of herbicide increased with increase in the rainfall intensity. This study suggested that the soil OC content, pH and clay content played important roles in deciding the adsorption-desorption and leaching behavior of flucetosulfuron in soils.
研究了氟噻草酯（一种磺酰脲类除草剂）在印度三种土壤中的吸附-解吸和淋溶行为。弗伦德利希吸附等温线描述了除草剂的吸附机制，吸附系数（K）范围为 17.13 至 27.99，其顺序为：粘壤土>壤土>砂壤土。K 与有机碳（OC）（r = 0.910）和粘粒含量（r = 0.746）呈正相关；但与土壤 pH 值呈负相关（r = -0.635）。吸附等温线为 S 型，表明除草剂的吸附与浓度有关，随浓度增加而增加。解吸顺序为：砂壤土>粘壤土>壤土。在所有三种土壤中均观察到滞后现象（H），H < 1。氟噻草酯的淋溶与土壤 pH 值呈正相关；但与 OC 含量呈负相关。砂壤土（OC-0.40%，pH-7.25）的氟噻草酯吸附量最低，淋溶量最高，而壤土（pH-7.89，OC-0.65%）的淋溶量最低。除草剂的淋失量随降雨强度的增加而增加。本研究表明，土壤 OC 含量、pH 值和粘粒含量在决定氟噻草酯在土壤中的吸附-解吸和淋溶行为方面起着重要作用。
