The Effects of Glyphosate on the Growth of Birdsfoot Trefoil (Lotus corniculatus) and Its Interaction with Different Phosphorus Contents in Soil

Abstract

Glyphosate residues from applications or exuded by roots of treated crops and by senescing weeds could be absorbed by new crops. The aim of this work was to study the effect of glyphosate in soil on the growth of Lotus corniculatus and its interaction with phosphorus. A completely randomized 3 x 4 factorial design was used for the experiment, with 3 levels of phosphorus (0, 100, and 200 ppm) and 4 of glyphosate (0; 0.5; 1.0, and 2.0 times the recommended dosage, 4 L. ha -1 ), amended to soil. Glyphosate residues decreased growth parameters, chlorophyll and protein contents, and membrane stability. Glyphosate effect was increased by the greater availability of phosphorus, so there was a significant interaction between glyphosate and phosphorus. The findings of this study provide evidence of the detrimental effect of glyphosate present in soil as well as its remobilization through the presence of additional phosphorus in soil.

Consequences of phosphate application on glyphosate uptake by roots: Impacts for environmental management practices

“…Once applied in the field, glyphosate invariably penetrates into the soil, where it can be adsorbed onto soil particles, and phosphate (PO 4 3− ) content appears to be one of the most important factors driving this glyphosate binding (Borggaard, 2011). As PO 4 3− and the methylphosphonic group of glyphosate compete for the same adsorbing sites (Bott et al, 2011;Clua et al, 2012), the capacity of soils to adsorb PO 4 3− determines glyphosate availability in soil solutions, and increases in soil PO 4 3− concentrations may result in increased glyphosate availability (Bott et al, 2011). Phosphorous is an essential element for plants, participating in crucial physiological events, and PO 4 3− fertilization is a common agricultural practice (Lopes, 2004).…”

Impact of phosphate on glyphosate uptake and toxicity in willow

“…Inorganic phosphate (PO 4 3-) and glyphosate's methylphosphonic group compete for similar adsorbing sites [9,10], and, as a result, glyphosate sorption and its availability in soil solution are determined by the soil's capacity to adsorb PO 4 3-. Phosphorous is an essential nutrient, participating in crucial metabolic events, such as energy transfer and protein metabolism in plants [11], and PO 4 3-fertilization of soil is a common agricultural practice to assure plant growth and development [12]. PO 4 3-fertilization of agricultural fields submitted to glyphosate application may invariably influence the herbicide's bioavailability in soil solution, since the two compete for soil adsorbing sites [13].…”

Resposta Diferencial Das Culturas De Milho Rr E Soja Rr À Exposição a Glyphosate E Adubação Fosfatada

“…Casonatto et al (2014) verificaram que a altura de plantas e a massa fresca e seca da parte aérea foram menores nas plantas que receberam as maiores doses de glyphosate e que a maior disponibilidade de fósforo no solo, em menores doses de glyphosate, proporcionou menores sintomas de intoxicação nas plantas de soja RR. Resultados similares foram observados por Clua et al (2012) Resposta diferencial das culturas de milho RR e Soja RR à ... Bott et al (2008) observaram diminuição na elongação de raízes, além da redução de massa seca de soja RR exposta a glyphosate. A elongação de raízes, segundo Casonatto et al (2014), pode limitar a absorção de nutrientes por plantas submetidas à aplicação de glyphosate, influenciando o crescimento e o desenvolvimento, com reflexos no acúmulo de biomassa, como observado neste estudo.…”

“…Há interação entre a adubação fosfatada e o comportamento do glyphosate no solo (Sasal et al, 2015), além de haver evidências da interação entre o glyphosate e o fósforo do solo sobre a ação do herbicida nas plantas (Clua et al, 2012). Savin et al (2009) observaram alteração significativa na infecção por fungos micorrízicos arbusculares em soja, milho e algodão, resistentes ao glyphosate, submetidos à adubação fosfatada ou não, em solos pobres em fósforo; no entanto, essa alteração pode ser dependente de outras na microbiota do solo, por influência de outros fatores.…”