title: Adsorption and desorption of herbicide monosulfuron-ester in Chinese soils.
abstract: Monosulfuron-ester is a new, low rate, sulfonylurea herbicide that is being promoted for annual broadleaf and gramineal weed control; however, there is a lack of published information on its behavior in soils. The adsorption and desorption of monosulfuron-ester by seven type soils were measured using a batch equilibrium technique. The results showed that the Freundlich equation fitted its adsorption and desorption well, and the Freundlich constant values (K(f-ads)) ranged from 0.88 to 5.66. Adsorption isotherms were nonlinear with 1/n(f-ads) values < 1. Soil pH, organic matter (OM), and clay content were the main factors influencing its adsorption and desorption. Adsorption and desorption were negatively correlated with pH 4.0-8.0 while positively correlated with OM and clay content. The adsorption of monosulfuron-ester was mainly a physical process, because its free energy (deltaG) in seven soils was less than 40 kJ/mol. Monosulfuron-ester adsorption by three soils increased with increasing CaCl2 concentration using CaCl2 as a background electrolyte. Monosulfuron-ester desorption was hysteretic in all tested soils.
authors.affiliation: College of Plant Protection, Southwest University, Chongqing 400716, China. wchx74120@163.com
authors.forename: Chunxian
authors.initials: C
authors.lastname: Wu
authors.forename: Suzhi
authors.initials: S
authors.lastname: Zhang
authors.forename: Guo
authors.initials: G
authors.lastname: Nie
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jinjun
authors.initials: J
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D002681:China; D004573:Electrolytes / Q000737:chemistry; D004952:Esters; D006540:Herbicides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009038:Motion; D010573:Pesticide Residues / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D013453:Sulfonylurea Compounds / Q000737:chemistry*
chemical_list: D004573:Electrolytes; D004952:Esters; D006540:Herbicides; D010573:Pesticide Residues; D011743:Pyrimidines; D012987:Soil; D013453:Sulfonylurea Compounds; C495688:monosulfuron