Normalized difference vegetation index for desiccation evaluation with glyphosate + 2,4-D in magnetized spray solution

Abstract

A magnetizaçâo da água e o geoprocessamento säo ferramentas cada vez mais utilizadas no manejo de ervas daninhas. Nosso objetivo foi estudar a influencia da magnetizaçâo da água na eficiencia do herbicida e verificar se existe uma relaçâo entre os escores de controle e o índice de vegetaçâo por diferença normalizada (NDVI). No experimento de laboratorio, a água foi submetida a magnetizaçâo e avaliada em relaçâo a quatro características. No experimento de campo, parcelas de capim-braquiária foram submetidas a tratamentos em esquema fatorial (6 x 2 + 1). Seis fatores herbicidas (doses de glyphosate e glyphosate + 2,4-D) e a magnetizaçâo ou ausencia de magnetizaçâo da calda foram avaliados e comparados com o tratamento controle (sem pulverizaçâo). Avaliaçoes de controle de plantas daninhas foram realizadas seis vezes. As imagens foram obtidas usando uma câmera multiespectral incorporada para determinar os valores de NDVI. Os dados relacionados as características da água foram analisados por meio do teste t. O controle de plantas daninhas e os dados de NDVI foram submetidos a análise de variância e säo apresentados em gráficos de regressäo. A análise de dispersäo dos dados NDVI foi realizada de acordo com os escores de controle. O processo de magnetizaçâo diminuiu o pH da água e aumentou a tensäo superficial, mas näo influenciou nos escores de controle ou no NDVI. Conforme a dose de glyphosate foi aumentada, os escores de controle foram maiores e os valores de NDVI foram menores. A água magnetizada näo afetou a eficiencia biológica dos herbicidas, e houve uma forte correlaçâo entre os escores de controle e os valores de NDVI.

Alternate abstract:

Water magnetization and geoprocessing are increasingly utilized tools in weed management. Our objective was to study the influence of water magnetization on herbicide efficiency and to verify whether there is a relationship between control scores and the normalized difference vegetation index (NDVI). In the laboratory experiment, water was subjected to magnetization and evaluated with respect to four characteristics. In the field experiment, plots of Brachiaria grass were subjected to treatments in a factorial scheme (6 x 2 + 1). Six herbicidal factors (doses of glyphosate and glyphosate + 2,4-D) and the magnetization or absence of magnetization of the spray solution were evaluated and compared against the control treatment (without spraying). Weed control assessments were carried out six times. Images were obtained using an embedded multispectral camera to determine the NDVI values. Data related to water characteristics were analyzed using the t test. Weed control and NDVI data were subjected to analysis of variance and are presented in regression graphs. Dispersion analysis of NDVI data was performed according to the control scores. The magnetization process decreased the pH of the water and increased the surface tension, but it did not influence the control scores or the NDVI. As the glyphosate dose was increased, the control scores were higher and the NDVI values were lower. Magnetized water did not affect the biological efficiency of the herbicides, and there was a strong correlation between the control scores and the NDVI values.