Tebuthiuron herbicide behavior in sugar cane soil using modified drainage lysimeter / Comportamento do herbicida tebuthiuron em solo de cultivo de cana-de-açucar utilizando lisimetro de drenagem modificado

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Tebuthiuron is one of the most used herbicides in sugar cane, in São Paulo State. Studies have been carried through to determine the tebuthiuron leaching index and to monitor its presence in superficial and groundwater sources, without still a definitive conclusion. With the objective to evaluate, in field conditions, the vertical movement of the herbicide Tebuthiuron in Clayey Distroferric Red Soil, sugar cane crop characteristic in São Paulo State, tested the hypothesis that the use of the herbicide tebuthiuron, in controlled environment, is adsorbed to the clayey and high organic matter soils, showing low vertical mobility and small potential of groundwater contamination. The work was conducted in the Experimental Field College of Agricultural Engineering - UNICAMP, using a modified drainage lysimeter with 2 meters of diameter and 3 meters of depth, with 10 vertical points through which were collected water samples of rain. The 6 first samples had been collected 1 day after rains, from March to July - 2006 and the 4 last ones, in the August month, after irrigation area for aspersion, simulating rains of January in same year. The samples was submitted by High Performance Liquid Chromatography (HPLC).The found, correlated and evaluated data had indicated a decreasing presence of the herbicide in samples collected to long of time ? March to August of 2006: sample 1 - 0,020 g i.a. (5,3 %); 2 ? 0,016 g i.a. (4,3 %); 3 - 0,015 g i.a. (4,0 %); 4 - 0,014 g i.a. (3,7 %); 5 - 0,014 g i.a. (3,7 %); 6 - 0,007 g i.a. (1,9 %); 7 - 0,002 g i.a. (0,5 %); 8 - 0,001 g i.a. (0,3 %) - total applied in lysimeter area (0,3768 g i.a.), confirming the hypothesis a low vertical mobility of tebuthiuron in Clayey Distroferric Red Soil, clayey texture, in one decreasing curve to the long of time and indicating, for this soil, small potential of contamination of groundwater

ASSUNTO(S)

sugar cane tebuthiuron cana-de-açucar herbicidas leaching lisimetro lixiviação drainage lysimeter

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