Seleção de espécies de adubos verdes visando à fitorremediação de diclosulam

Abstract

RESUMO -Espécies de adubos verdes tolerantes ao herbicida diclosulam podem ser utilizadas em rotação de culturas para diminuir o efeito fitotóxico subsequente desse herbicida em plantas sensíveis, como o girassol ou milho. Este estudo teve como objetivo avaliar a tolerância de adubos verdes ao diclosulam e a capacidade dessas plantas em diminuir o efeito fitotóxico do herbicida no bioindicador Helianthus annuus. Foram avaliadas, em casa de vegetação, três doses do herbicida diclosulam (0, 0,035 e 0,070 kg i.a. ha ) em pré-emergência dos adubos verdes Dolichos lablab, Cajanus cajan, Canavalia ensiformis, Crotalaria juncea, C. breviflora, C. spectabilis, Mucuna deeringiana, M. cinerea, M. aterrima, Lupinus albus, Helianthus annuus, Pennisetum glaucum, Avena strigosa, Raphanus sativus e Calopogonium muconoides. Entre estas espécies, C. cajan, C. ensiformis, M. cinerea e M. aterrima foram selecionadas como as mais tolerantes, sendo avaliadas no campo com o herbicida diclosulam nas doses de 0, 0,035 e 0,070 kg i.a. ha 1 , em esquema fatorial 4 x 3 e quatro repetições. A parte aérea dessas plantas foi coletada após 60 dias da emergência, sendo semeado H. annuus como bioindicador do herbicida diclosulam. Os resultados evidenciaram C. cajan como a espécie mais promissora em diminuir o efeito fitotóxico do diclosulam em culturas agrícolas sensíveis.Palavras-chave: adubos verdes, impacto ambiental, descontaminação, seleção de plantas, agroquímicos.ABSTRACT -The tolerance of green manure species to diclosulam can be used in crop rotation schemes aiming to reduce the subsequent phytotoxic effect of this herbicide on sensitive plants, such as sunflower or corn plants. This study evaluated the tolerance of green manure to diclosulan and the capacity of these plants in reducing the phytotoxic effect of this herbicide on Helianthus annuus (sunflower). Three rates of diclosulam (0; 0.035, and 0.070 kg a.i. ha -1 ) were evaluated under greenhouse conditions in pre-emergence of the following green manures: Dolichos lablab, Cajanus cajan, Canavalis ensiformis, Crotalaria juncea, C. breviflora, C. spectabilis, Mucuna deeringiana, M. cinerea, M. aterrima, Lupinus albus, Helianthus annuus, Pennisetum glaucum, Avena strigosa, Raphanus sativus and Calopogonium muconoides. C. cajan, C. ensiformis, M. cinerea, and M. aterrima were selected as the most tolerant ones, being evaluated in the field with diclosulan at the rates of 0, 0.035, and 0.070 kg a.i. ha -1 in a 4 x 3 factorial scheme, with four repetitions. The shoots of these plants were collected 60 days after emergence, and H. annuus was sown as bio indicator of diclosulam. The results showed that C. cajan was the most promising species to reduce the phytotoxic effect of diclosulam on susceptible cultures.

Phytomass production and nutrient accumulation by green manure species

“…The contrasts between the species were established as shown in Table 1. The contrast 1 (C1) compared the sunn hemp, which is widely used as green manure and reported as the Fabaceae of greatest phytomass input (Amabile et al, 2000;Teodoro et al, 2011;Monquero et al, 2013). The contrast 2 (C2) compared the dwarf mucuna, which is considered as more rustic, more resistant to water deficit, with lower fertility requirement and lower sensitivity to acidity compared to other Fabaceae (Embrapa Agrobiologia, 2009).…”

Sulfentrazone Phytoremediation Under Field Conditions

“…Several studies have showed that the cultivation of certain plant species can decontaminate areas where xenobiotics, such as soilapplied herbicides, are present (ANDERSON et al, 1994;ANDERSON;COATS, 1995;PERKOVICH et al, 1996;WILSON et al, 2000;BELO et al, 2011;MONQUERO et al, 2013). In recent years, especially in Brazil, studies involving phytoremediation, in addition to its environmental relevance (MADALÃO et al, 2012;SANTOS et al, 2013b), have received great stimulus for use in agricultural areas.…”

“…Some studies have shown that it is possible to use plants to reduce the phytotoxicity of herbicides (the carryover effect) to susceptible crops grown in areas that have received such compounds (SANTOS et al, 2007;ASSIS et al, 2010;BELO et al, 2011;MADALÃO et al, 2012;MONQUERO et al, 2013). This reduction indicates that phytoremediation may shorten the time required before an area becomes available for the cultivation of said species (NASCIMENTO et al, 2015), which can lead to greater optimization of land use, with greater economic returns for agricultural activity.…”

Seletividade inicial de herbicidas aplicados em pós-emergência da crotalária

“…A crotalária apresenta grande capacidade de tolerância ao diclosulam em estudos para avaliação de espécies fitorremediadoras (Monquero et al, 2013 Os maiores efeitos fitotóxicos foram observados para os herbicidas atrazine (500 e 1000 g ha -1 ), atrazine + flumioxazin + carfentrazone-ethyl, oxadiazon e mesotrione em todas as avaliações realizadas (Tabela 3).…”