title: Pedotransfer functions for isoproturon sorption on soils and vadose zone materials.
abstract: BACKGROUND
  Sorption coefficients (the linear K(D) or the non-linear K(F) and N(F)) are critical parameters in models of pesticide transport to groundwater or surface water. In this work, a dataset of isoproturon sorption coefficients and corresponding soil properties (264 K(D) and 55 K(F)) was compiled, and pedotransfer functions were built for predicting isoproturon sorption in soils and vadose zone materials. These were benchmarked against various other prediction methods.
  
  
  RESULTS
  The results show that the organic carbon content (OC) and pH are the two main soil properties influencing isoproturon K(D) . The pedotransfer function is K(D) = 1.7822 + 0.0162 OC(1.5) - 0.1958 pH (K(D) in L kg(-1) and OC in g kg(-1)). For low-OC soils (OC < 6.15 g kg(-1)), clay and pH are most influential. The pedotransfer function is then K(D) = 0.9980 + 0.0002 clay - 0.0990 pH (clay in g kg(-1)). Benchmarking K(D) estimations showed that functions calibrated on more specific subsets of the data perform better on these subsets than functions calibrated on larger subsets.
  
  
  CONCLUSIONS
  Predicting isoproturon sorption in soils in unsampled locations should rely, whenever possible, and by order of preference, on (a) site- or soil-specific pedotransfer functions, (b) pedotransfer functions calibrated on a large dataset, (c) K(OC) values calculated on a large dataset or (d) K(OC) values taken from existing pesticide properties databases.
authors.affiliation: Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden. Julien.Moeys@slu.se
authors.forename: Julien
authors.initials: J
authors.lastname: Moeys
authors.forename: Valérie
authors.initials: V
authors.lastname: Bergheaud
authors.forename: Yves
authors.initials: Y
authors.lastname: Coquet
mesh_terms: D000042:Absorption; D006540:Herbicides / Q000737:chemistry*; D008956:Models, Chemical; D015233:Models, Statistical; D010671:Phenylurea Compounds / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D006540:Herbicides; D010671:Phenylurea Compounds; D012987:Soil; D012989:Soil Pollutants; C028904:isoproturon