Fitorremediation of contaminated soil with 2,4-D + picloram in Eastern Amazonia

Sandra Andréa Santos da Silva,Douglas Pereira Ferreira,Samia Cristina de Lima Lisboa,Lenilton Alex de Araujo Oliveira,Rainerio Meireles da Silva,Jéssica Paloma Pinheiro da Silva

doi:10.33448/rsd-v10i4.14372

Abstract

The objective of this work was to evaluate the potential of Urochloa brizantha cv. Marandu and Panicum maximum cv. Mombasa in phytoremediation of soil treated with 2,4-D + picloram herbicide, using Raphanus sativus Crimson Gigante as a bioindicator plant. The experiment was carried out in a greenhouse, in a completely randomized design in two stages. In the first stage the treatments were: cultivation of U. brizantha and P. maximum treated with and without the herbicide dose, with five replications. In the second stage, the treatments consisted of cultivating R. sativus in soil: free of herbicide residue; and soil contaminated with cultivation: prior to U. brizantha; P. maximum; and without previous cultivation of grass, with five replications. The units were treated with the herbicide, individually in pre-emergence, after 15 days the grasses were sown. After 50 days, forages were harvested and segregated in aerial and root parts, analyzing fresh and dry biomass (g) and height (cm). After removing phytoremediation plants, R. sativus was transplanted, evaluating visual phytotoxicity at 5, 10, 15 and 20 days after emergence (DAE) and at 20 DAE, the accumulation of green and dry matter (g), height (cm). The evaluated grasses have phytoremediation characteristics for auxinic herbicides; R. sativus can be used as a bioindicator of the herbicide 2,4-D + picloram; the evaluated period was not enough to fully remove the effects of the herbicide.

Highlights

Herbicides in the synthetic auxin group have selective action and are often used to control the growth of weeds worldwide (Song, 2014)
2,4-D acid, from the group of phenoxyacetic acids, is a herbicide known as synthetic auxin and has a high tendency to leach into the soil, due to its low adsorption
From the group of pyridinecarboxylic acids, is an auxin-mimicking herbicide, with a long residual effect on the soil, which characterizes a high risk of contamination of the groundwater (Brito et al, 2001; Oliveira Junior, 2011; Santos et al, 2006)

Summary

Introduction

Herbicides in the synthetic auxin group have selective action and are often used to control the growth of weeds worldwide (Song, 2014). Of this group, picloram (4-amino 3,5,6 trichloro-2-pyridinecarboxylic acid) and 2,4-D (2,4dichlorophenoxyacetic acid) make up the majority of registered products used in agriculture (Brazil, 2013). The selection of plant species for the phytoremediation program depends on the plant's own characteristics, such as tolerance to heavy metals, high growth rate, high biomass production, abundant root system and good adaptability to local edaphoclimatic conditions (Oliveira et al, 2007). In the Northern region of Brazil, studies that determine the action of remedial plants for soil contaminants, with species adapted to regional edaphoclimatic conditions, are scarce

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