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Quantification of fate and retention process of glyphosate in contrasting texture soils aged with biochar

Grant number: 17/24799-9
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): February 01, 2018
Effective date (End): January 31, 2019
Field of knowledge:Agronomical Sciences - Agronomy
Principal Investigator:Kassio Ferreira Mendes
Grantee:Cássio de Souza Almeida
Home Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Glyphosate is a broad-spectrum herbicide applied in post-emergence and non-selective, being the most widely used in the world. In view of the exportation, the addition of biochar (vegetable charcoal) has gained recognition for its high sorption capacity of herbicides, influencing the bioavailability and residual effect in the soil for weeds, interfering negatively in the chemical management. Therefore, knowledge about the behavior of glyphosate in Brazilian tropical soils altered with aged biochar is still limited. Based on this the objective of the study will be to evaluate the quantification of the fate and retention process of glyphosate in contrasting soils aged with biochar derived from Eucalyptus. Soil samples will be collected from the superficial layer (0-10 cm) of cultivated areas at two different sites with contrasting texture not treated with glyphosate in the last three years. The biochar will be added to the soil at 0 (control - unamended) and 1%, corresponding to 0 and 12 t ha- 1, respectively. The biochar aging period will be 0, 30, 90 and 180 days after application. The biodegradation studies will be performed with 14C-glyphosate to quantify the extractable residues (parent product and metabolites), bound residues and mineralization at 1, 2, 4, 8, 12, 24, 36 and 54 days after application, with consecutive study of sorption-desorption. The present study will provide information for the understanding of the fate and retention of glyphosate in soils modified with aged biochar, as well as its possible bioavailability to weeds and impacts to the environment. (AU)