Influence of humic acid structure on the accumulation of oxyfluorfen in tropical soils of mountain agroecosystems.

Autor: Barbosa DR; Laboratory of Soil Chemistry. Soil Departament, Institute of Agronomy, Federal Rural University of Rio de Janeiro, Brazil., García AC; Laboratory of Soil Biological Chemistry. Soil Departament, Institute of Agronomy, Federal Rural University of Rio de Janeiro, Brazil., da Costa Barros de Souza C; Laboratory of Soil Chemistry. Soil Departament, Institute of Agronomy, Federal Rural University of Rio de Janeiro, Brazil. Electronic address: camila_souza@ufrrj.br., Brasil do Amaral Sobrinho NM; Laboratory of Soil Chemistry. Soil Departament, Institute of Agronomy, Federal Rural University of Rio de Janeiro, Brazil.
Jazyk: angličtina
Zdroj: Environmental pollution (Barking, Essex : 1987) [Environ Pollut] 2021 Sep 01; Vol. 284, pp. 117380. Date of Electronic Publication: 2021 May 27.
DOI: 10.1016/j.envpol.2021.117380
Abstrakt: Herbicide application is a practice commonly used in agricultural systems because it is an efficient method of weed control. An inherent characteristic of some herbicides used in mountain agriculture, such as oxyfluorfen, is high adsorption to soil organic matter (SOM). Thus, intensive management that changes the quantity and quality of SOM, such as soil tillage and the massive application of organic fertilizers such as poultry litter, may favor soil contamination by this herbicide and alter its dynamics in the environment. Therefore, this study aimed to characterize the structures of humic substances (HSs) in the soil of forest areas and areas with intensive production of vegetables, relating them to the accumulation of the herbicide oxyfluorfen in tropical mountain agroecosystems. Organic carbon content was quantified in HSs, humic acid (HAs) were structurally characterized by CP/MAS 13 C-NMR spectroscopy, and the oxyfluorfen molecule was detected and quantified using the QuEChERS residue detection method with subsequent analysis by LC-MS/MS. Oxyfluorfen was not detected in the forest areas, but it was detected in the vegetable growing areas at points with the lowest slope and high contents of organic matter and clay, with values of up to 0.13 mg kg -1 . The intensification in the SOM mineralization process, promoted by the intensive management adopted in the vegetable growing areas, resulted in a 16.46% reduction in COT, a 58.84% reduction in the carbon content in the form of SH and a reduction in the structures that give recalcitrance to the HA molecule (C Alkyl -H,R, C COO -H,R, C Aromatic -H,R, and C Aromatic -O) when compared to those values in the forest area, presenting HAs with more aliphatic and labile properties. Thus, due to the structural characteristics of the HAs in the vegetable production areas, the herbicide oxyfluorfen showed a close relationship with the more aliphatic oxygenated structures, namely, C Alkyl -O,N, C Alkyl -O and C Alkyl -di-O.
(Copyright © 2021 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: