Liming on picloram leaching in dystrophic Red Yellow Latosol

• Published in: Revista brasileira de engenharia agrícola e ambiental 2019-02, Vol.23 (2), p.103-108
• Main Authors: Franceschi, Mauricio, Arantes, Sayonara A. do C. M., Andrade, Ednaldo A. de, Rocha, Adriano M. da, Arantes, Kelte R., Yamashita, Oscar M.
• Format: Article
• Language: English
• Subjects: AGRICULTURAL ENGINEERING; ENVIRONMENTAL SCIENCES
• ISSN: 1415-4366; 1807-1929; 1807-1929
• DOI: 10.1590/1807-1929/agriambi.v23n2p103-108

ABSTRACT The practice of liming may influence the leaching of herbicides in soils, especially those with weak acid character, such as picloram. The study on leaching, preserving soil structure, is an important factor when one intends to understand the dynamics of herbicides and environmental impacts. Thus, the effect of liming on picloram leaching in a dystrophic Red Yellow Latosol under field conditions was studied using a bioindicator plant. The experiment was set up in a completely randomized design (CRD), in split-plot scheme, with factorial in the plot. The factors of the plot corresponded to two soil conditions (presence and absence of liming) and 5 picloram concentrations (0; 384; 768; 1152; 1536 g ha-1), and the factor of the subplot was 5 soil depths (0-8, 8-16, 16-24, 24-32 and 32-40 cm), with four replicates. Pipes were introduced into the soil and, in part of the treatments, limestone was applied superficially. After ninety days, the different doses of picloram were applied on the surface of each pipe and these pipes were withdrawn after an accumulated rainfall of 128 mm, to perform the bioassay using cucumber plants (Cucumis sativus). Evaluations of plant development (phytotoxicity and shoot biomass) were carried out 21 days after sowing. It was concluded that picloram showed high leaching rate under all studied conditions and liming increased picloram leaching at doses lower than 768 g ha-1. RESUMO A prática da calagem pode influenciar a lixiviação de herbicidas nos solos, especialmente os com caráter ácido fraco, como é o caso do picloram. O estudo da lixiviação mantendo-se a estrutura do solo é um fator importante quando se busca compreender a dinâmica de herbicidas e possíveis impactos ambientais. Assim, objetivou-se avaliar o efeito da calagem na lixiviação do picloram em um Latossolo Vermelho Amarelo distrófico, em condições de campo, a partir de planta bioindicadora. O experimento foi organizado em delineamento inteiramente casualizado (DIC), no esquema de parcela subdividida, com fatorial na parcela. Os fatores da parcela corresponderam a duas condições de solo (sem e com calagem) e 5 concentrações do picloram (0; 384; 768; 1152; 1536 g ha-1), e o fator da subparcela foram 5 profundidades do solo (0-8, 8-16, 16-24, 24-32 e 32-40 cm), com quatro repetições. Tubos foram introduzidos no solo, onde, em parte dos tratamentos, aplicou-se calcário superficialmente. Após noventa dias, as diferentes doses do picloram foram aplicadas na superfíc