title: Potential impacts of seasonal variation on atrazine and metolachlor persistence in andisol soil.
abstract: To estimate the potential effect of seasonal variation on the fate of herbicides in andisol soil, atrazine and metolachlor residues were investigated through the summer and winter seasons during 2013 and 2014 under field condition. The computed half-lives of atrazine and metolachlor in soil changed significantly through the two seasons of the trial. The half-lives were shorter in summer season with 16.0 and 23.5 days for atrazine and metolachlor, respectively. In contrast, the half-lives were longer during the winter season with 32.7 and 51.8 days for atrazine and metolachlor, respectively. The analysis of soil water balance suggested that more pesticide was lost in deeper soil layers through infiltration in summer than in winter. In addition, during the summer season, metolachlor was more likely to leach into deeper soil layer than atrazine possibly due to high water solubility of metolachlor.
authors.affiliation: Department of Agricultural and Environmental Engineering of the United Graduate School of Agriculture, Tokyo University of Agriculture and Technology (TUAT), Tokyo, Japan.
authors.forename: Piyanuch
authors.initials: P
authors.lastname: Jaikaew
authors.affiliation: Department of Agricultural and Environmental Engineering of the United Graduate School of Agriculture, Tokyo University of Agriculture and Technology (TUAT), Tokyo, Japan.
authors.forename: Julien
authors.initials: J
authors.lastname: Boulange
authors.affiliation: Department of Biological and Environmental Engineering, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Dang Quoc
authors.initials: DQ
authors.lastname: Thuyet
authors.affiliation: Department of Agricultural and Environmental Engineering of the United Graduate School of Agriculture, Tokyo University of Agriculture and Technology (TUAT), Tokyo, Japan.|Pesticide Residues and Environmental Pollution Department, Central Agricultural Pesticide Laboratory, Agriculture Research Center, Dokki, Giza, 12618, Egypt.
authors.forename: Farag
authors.initials: F
authors.lastname: Malhat
authors.affiliation: Agricultural Chemicals Inspection Station, Food and Agricultural Materials Inspection Center, Tokyo, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Ishihara
authors.affiliation: Department of Agricultural and Environmental Engineering of the United Graduate School of Agriculture, Tokyo University of Agriculture and Technology (TUAT), Tokyo, Japan. pochi@cc.tuat.ac.jp.
authors.forename: Hirozumi
authors.initials: H
authors.lastname: Watanabe
mesh_terms: D000081:Acetamides / Q000032:analysis*; D001280:Atrazine / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004784:Environmental Monitoring / Q000379:methods*; D006207:Half-Life; D006540:Herbicides / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010575:Pesticides / Q000032:analysis; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D000081:Acetamides; D006540:Herbicides; D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; D001280:Atrazine; C051786:metolachlor
keywords: Andisol soil; Atrazine and metolachlor; Persistence; Seasonal variation; Soil water balance