Soil Persistence of Chlorimuron-Ethyl and Metsulfuron-Methyl and Phytotoxicity to Corn Seeded as a Succeeding Crop

Abstract

Two experiments were carried out to evaluate soil persistence of chlorimuron-ethyl and metsulfuron-methyl and phytotoxicity to corn seeded as a succeeding crop. One experiment was conducted with chlorimuron-ethyl applied at 20 g ha-1, and one with metsulfuron-methyl applied at 3.96 g ha-1. Treatments were arranged in a factorial design with two types of soil (sandy and clay), three irrigation regimes (daily, weekly and no irrigation) and four application timings (90, 60 and 30 days before corn seeding, as well as untreated plots). Soil persistence of the herbicides was influenced by water availability, molecule water solubility (leaching potential) and application timings prior to corn seeding. In sandy soil, with adequate water availability, leaching probably had the greatest influence, reducing the persistence of the products, and consequently allowing less time between product application and corn seeding. In clay soil, microbial degradation was probably more important, because it was assumed that the lesser time available for microorganism activity, the lesser the damage was observed for corn, as long as the crop had enough water availability. Metsulfuron-methyl was the least phytotoxic herbicide, possibly as a result of the properties of its molecule and its higher leaching potential.

Toxicity by metsulfuron-methyl in the establishment of the soybean crop submitted to seed treatment

“…This herbicide has lower adsorption on clay and higher adsorption in organic matter (VENCILL, 2002), and residues of metsulfuron-methyl bound previously to the soil matrix may be again released and cause damage to rotation or substitution crops (YE; SUN;WUB, 2003). Thus, in soils with adequate water availability and microbial degradation, the higher leaching potential reduces the persistence of herbicides in soil (CARVALHO et al, 2015). The herbicide degradation rate can be accelerated with high temperatures, and its mobility can be increased at pH values of more than six (BIANCHI, 2009;EUROPEAN FOOD SAFETY AUTHORITY, 2015).…”

Herbicidas pré-emergentes para manejo de milho voluntário RR® na cultura da soja

“…Em solos com maiores teores desses componentes o chlorimuron-ethyl sofre maior sorção, restringindo sua mobilidade (Suyal et al, 2013). Entretanto devido suas outras características químicas é considerado um herbicida com alto potencial de lixiviação, conforme a precipitação e do pH no solo (pH > pKa 4,2), sugerindo, segundo Carvalho et al (2015), que a camada de cobertura (palhada) é um impedimento fraco para o ingrediente sofrer escorrimento superficial run-off e/ou lixiviação dentro do perfil do solo. Esse comportamento corrobora com o mostrado neste estudo, em que o herbicida atingiu médias acima de 70% de injúria e 50% de inibição da emergência do milho RR ® , ponto importante já que essas plantas podem causar perdas significativas no cultivo da soja (López-Ovejero et al, 2016).…”

Evaluating the effects of manual hoeing and selective herbicides on maize (Zea mays L.) productivity and profitability

“…[ 59 ] on nicosulfuron [ 60 ], on thifensulfuron-methyl [ 61 ], on halosulfuron, then on nicosulfuron, rimsulfuron and foramsulfuron [ 7 ]. On the other hand [ 62 ], showed an increase in the production of cabbage, sweet potato, tomato and sweet maize sown 12 months after application of chlorimuron-ethyl [ 63 ]. had also made this known on maize sown several dozen days after spraying chlorimuron-ethyl or metsulfuron-methyl.…”