Adsorption rate equation of herbicides in paddy soils

• Published in: Journal of Pesticide Science Vol. 25; no. 3; pp. 234 - 239
• Main Authors: Kibe, K. (Yokohama Univ. (Japan). Faculty of Engineering), Takahashi, M, Kameya, T, Urano, K
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo Pesticide Science Society of Japan 01.01.2000; Japan Science and Technology Agency
• Subjects: ADSORCION; ADSORPTION; Applied sciences; Biological and medical sciences; Biological and physicochemical properties of pollutants. Interaction in the soil; Chemical control; CHEMICOPHYSICAL PROPERTIES; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; HERBICIDAS; HERBICIDE; HERBICIDES; MATHEMATICAL MODELS; MODELE MATHEMATIQUE; MODELOS MATEMATICOS; paddy herbicides; PADDY SOIL; paddy soils; Parasitic plants. Weeds; Phytopathology. Animal pests. Plant and forest protection; Pollution; PROPIEDADES FISICOQUIMICAS; PROPRIETE PHYSICOCHIMIQUE; rate equation; Soil and sediments pollution; SOL DE RIZIERE; SUELO DE ARROZALES; Weeds; Process dynamics; Agricultural chemical product; Laboratory study; PADDY SOIL; Pollutant behavior; Pesticides; Property of soil; Model study; Pesticide fate; Modeling; Herbicide; Adsorption; Triazine derivatives; Rate equation; Environment; Organic amide; Soil interaction; Paddy field; Carbamate; Physicochemical properties
• ISSN: 0385-1559; 1348-589X; 1349-0923
• DOI: 10.1584/jpestics.25.234

It is vital not to under evaluate the adsorption rates of paddy herbicides, which influence their movement in the soil and water for environmental safety and agricultural practice. The adsorption rates of four herbicides, esprocarb, thiobencarb, pretilachlor and simetryn, in three kinds of paddy soil whose properties varied widely were investigated. It was found that the herbicides were absorbed in the soils in two steps characterized by fast and slow phases. The ratios of the fast adsorption α were independent of the initial concentration for each tested system of herbicide and soil. Then an adsorption rate equation was introduced from α and the approximated Boyd equation and its applicability was confirmed. The rate parameters of the slow adsorption Di′/r2 were obtained in the range of 3.4×10-7 to 7.3×10-7/s by the proposed equation. The differences among the herbicides and the soils were small.