Controle de papuã (Urochloa plantaginea) e produtividade de milho em solo argiloso através de formulação e doses de atrazina com liberação controlada / Control of alexandergrass and maize yield in a clay soil through concentrations and controlled release formulation and doses of atrazine

A utilização de herbicidas com formulações com liberação controlada poderá se constituir em uma ferramenta importante para reduzir problemas de lixiviação e garantir a eficácia desses produtos. O objetivo do presente trabalho foi comparar a eficiência de controle de Urochloa plantaginea (UROPL) e o rendimento de grãos de milho entre uma formulação de atrazina comercial (WG) e uma formulação de liberação controlada (xerogel). O delineamento utilizado foi o de blocos ao acaso, em parcelas subdivididas, com quatro repetições, em um esquema (2x7)+1. Nas parcelas principais, foram locadas as formulações de atrazina (WG e xerogel) e, nas subparcelas, as concentrações dos herbicidas (0, 2400, 3200, 3600, 4200, 5400 e 8000g de atrazina ha-1). Foram determinados os níveis de controle e densidade de plantas de UROPL e o rendimento de grãos da cultura do milho. A elevação das doses de atrazina resultou em aumento dos níveis de controle de UROPL. Em avaliações realizadas aos 28 e 35 dias após a aplicação, a atrazina xerogel demonstrou eficiência agronômica superior à formulação WG. Não ocorreram diferenças de rendimento de grãos de milho em parcelas tratadas com diferentes formulações e níveis de atrazina.

The use of herbicides with controlled release formulations may constitute important tool to reduce leaching problems and increase the efficacy of atrazine in soil. The aim of this study was to compare the efficiency of control of Urochloa plantaginea (UROPL) and corn grain yield from a commercial formulation (WG) of atrazine and a controlled-release formulation (xerogel). The design was randomized blocks in split plots with four replications in a scheme (2x7)+1. Factor A consisted of the formulations of atrazine (WG and xerogel), factor B concentrations of herbicide (0, 2400, 3200, 3600, 4200, 5400 and 8000ha atrazine g-1). Variables assessed consisted of control levels, plant density of UROPL and corn grain yield. The increasing levels of atrazine resulted in increased levels of control UROPL. In assessments made at 28 and 35 days after application, atrazine xerogel showed higher agronomic efficiency than the WG formulation. There were no differences in corn grain yield from plots treated with different formulations and atrazine levels.

Determination of Residual Acetochlor and Atrazine in Environment by GC-MS / 环境与健康杂志

Objective To establish a simple and rapid method for the extraction and detection of residual acetochlor and atrazine in environment. Methods Acetochlor and atrazine in environment were extracted and enriched efficiently by using automatic solid phase extraction system. The sample concentrations were determined by gas chromatography-mass spectroscopy with electron impact ionization and multipolar mass spectra Msn. Results The recovery rates and RSDs of the method were 79.2%-95.1% and 1.73%-8.31% respectively. The detection limit of acetochlor in water and soil were 0.1 ?g/L and 0.005 mg/kg respectively. The detection limit of atrazine in water and soil were 0.05 ?g/L and 0.002 5 mg/kg respectively. Linear range was 0-5 ?g/ml. Conclusion The SPE-GC-MS method can be used to determine acetochlor and atrazine in environment.