Liming on picloram leaching in dystrophic Red Yellow Latosol/Calagem na lixiviacao do picloram em Latossolo Vermelho Amarelo distrofico

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

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.sup.-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 After ninety days, the different doses of picloram were applied on the surface of each pipe and these pipes were withdrawn after an accumulated rainfall of 128 mm, to perform the bioassay using cucumber plants (Cucumis sativus).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.sup.-1]. Key words: Cucumis sativus, herbicide dynamics, soil pH A pratica da calagem pode influenciar a lixiviacao de herbicidas nos solos, especialmente os com carater acido fraco, como e o caso do picloram. O estudo da lixiviacao mantendo-se a estrutura do solo e um fator importante quando se busca compreender a dinamica de herbicidas e possiveis impactos ambientais. Assim, objetivou-se avaliar o efeito da calagem na lixiviacao do picloram em um Latossolo Vermelho Amarelo distrofico, em condicoes 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 condicoes de solo (sem e com calagem) e 5 concentracoes do picloram (0; 384; 768; 1152; 1536 g [ha.sup.-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 repeticoes. Tubos foram introduzidos no solo, onde, em parte dos tratamentos, aplicou-se calcario superficialmente. Apos noventa dias