Abstract

GALAN-PEREZ*, Jose Antonio; GAMIZ, Beatriz  and  CELIS, Rafael. Organoclay granules as a sorbent to increase the persistence of the allelochemical scopoletin in soil. Rev. de Ciências Agrárias [online]. 2022, vol.45, n.4, pp.661-670.  Epub Dec 01, 2022. ISSN 0871-018X.  https://doi.org/10.19084/rca.28566.

Allelochemicals have been proposed as eco-friendly herbicides, but they often display a limited performance under field conditions because of a short persistence in soils. In this study, incorporation into organoclay granules was investigated as a strategy to protect the allelochemical scopoletin from rapid biodegradation processes and prolong its persistence and bioactivity in soil. A kinetic study revealed that the adsorption of scopoletin on the granules was slower than on the organoclay powder and indicated an intraparticle pore diffusion mechanism. After being incorporated into the organoclay granules, the half-life of scopoletin in a Mediterranean soil increased from 0.34 to 14.4 days under laboratory conditions, and from 0.54 to 20.1 days under field conditions, compared to the free compound. The granules also favored the expression of the phytotoxicity of scopoletin in the field experiment, reducing the germination and root growth of Lactuca sativa L. to a greater extent than the free, non-granulated allelochemical. The results of this work indicate that incorporation into organoclay granules could represent a suitable technological approach to protect allelochemicals from rapid dissipation losses in soil, which may help increase their persistence for a better performance as crop protection products.

Keywords : allelochemicals; bioherbicides; phytotoxicity; granules; organoclays.

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