Sorção, dessorção, lixiviação e meia-vida do tebuthiuron em latosolos brasileiros

• Autor(a) principal: Faria, Autieres Teixeira
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4626
• topic: Herbicidas; Dinâmica no solo; CLAE; Bioensaio e eficiência técnica e ambiental; Herbicides; Dynamic soil; CLAE; Bioassay and technical and environmental efficiency; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

In tropical conditions occurs variety of soil and climate. In this region there is little research on the behavior of herbicides in soils. Applications of these products without the knowledge of their interactions with soil properties and climatic conditions can be a cause of inefficiency agronomic observed infrequently, and the high risk of contamination of surface and groundwater. The tebuthiuron is one of the most commonly used herbicides in sugar cane in Brazil and its dynamics in tropical soils is poorly studied. Thus, it was held that this work was to evaluate the sorption, desorption, half-life and leaching of the herbicide tebuthiuron in Red -Yellow humic Latosol ( LVAh ), Typic. For this methods were used high performance liquid chromatography (HPLC ) and the results verified by biological methods . Three experiments were conducted, the first to determine the sorption and desorption of tebuthiuron latosols the second herbicide leaching in the soil profile and the third, the half -life in these soils. Sorption tebuthiuron followed the same trend in different soils, characterized in two phases. Initially, the sorption occurred more quickly, and then displaying a slower phase. The sorption was directly proportional to the amount of organic matter and clay soils. On the other hand, desorption was inversely proportional herbicide sorption. The leaching of tebuthiuron was higher in LV pH 5,0 and pH 6,2 and pH 6,3 LA , being reduced by higher levels of organic matter and clay . The degradation of tebuthiuron in soil followed an exponential model, and its half-life in soil is influenced by soil organic matter content, CEC and clay content. In LVA pH 5,0, the half -life of tebuthiuron was 155 days. On the same soil, with pH changed to 5,9, the half-life of this herbicide was 117 days after its application. It is concluded that the sorption, desorption and leaching half-life tebuthiuron are influenced by the chemical characteristics (CEC and organic matter) and physical (content of clay) soil. Organic matter increased the sorption and desorption and reduced leaching of tebuthiuron. On the other hand, in soils with higher CEC persistence tebuthiuron was reduced. Biological assays can be used to confirm the results of chromatography.