METAL CHELATOR EFFECT OF GLYPHOSATE APPLICATION IN SOIL ON MICRONUTRIENTS AVAILABILITY

Abstract

This paper presents the effects of glyphosate treatments on vineyard soil from Tohani Dealu-Mare on soil reaction and concentration of mobile forms of metals (copper, iron and manganese) on two depths: 0-30 cm (D₁) and 30-60 cm (D₂). Treatments applied in five different concentrations, as it follows: 5.04 mmol∙L^-1 (S₁), 15.12 mmol∙L^-1 (S₂),
30.24 mmol∙L^-1 (S₃), 45.36 mmol∙L^-1 (S₄), 60.48 mmol∙L^-1 (S₅) provided in soil glyphosate levels of 0.021 mmol∙kg^-1 (C₁), 0.063 mmol∙kg^-1 (C₂), 0.126 mmol∙kg^-1 (C₃), 0.189 mmol∙kg^-1 (C₄), 0.252 mmol∙kg^-1 (C₅). Soil analyses were performed at three different moments: before application (T₀), 7 days (T₁) and 14 days (T₂) after glyphosate treatments. The obtained results evidenced decrease of pH values due to glyphosate acidifying effect. It was found significant correlation between pH and glyphosate concentrations at T₁, T₂ moments and D₁ depth, also at T₂ at D₂ depth. In addition, it was evidenced that glyphosate concentrations influence metals mobility. For instance, the mobile manganese concentrations found at two depths present a significant correlation at T₁ and D₁ (r =0.8340*) and at T₂ and D₂ (r = 0.8333*) with glyphosate treatments. Also, chelation effect of glyphosate on microelements is related with applied concentration.