title: Assessing the Effect of Organoclays and Biochar on the Fate of Abscisic Acid in Soil.
abstract: The potential use of allelopathic and signaling compounds as environmentally friendly agrochemicals is a subject of increasing interest, but the fate of these compounds once they reach the soil environment is poorly understood. This work studied how the sorption, persistence, and leaching of the two enantiomers of the phytohormone abscisic acid (ABA) in agricultural soil was affected by the amendments of two organoclays (SA-HDTMA and Cloi10) and a biochar derived from apple wood (BC). In conventional 24-h batch sorption experiments, higher affinity toward ABA enantiomers was displayed by SA-HDTMA followed by Cloi10 and then BC. Desorption could be ascertained only in BC, where ABA enantiomers presented difficulties to be desorbed. Dissipation of ABA in the soil was enantioselective with S-ABA being degraded more quickly than R-ABA, and followed the order unamended > Cloi10-amended > BC-amended > SA-HDTMA-amended soil for both enantiomers. Sorption determined during the incubation experiment indicated some loss of sorption capacity with time in organoclay-amended soil and increasing sorption in BC-amended soil, suggesting surface sorption mechanisms for organoclays and slow (potentially pore filling) kinetics in BC-amended soil. The leaching of ABA enantiomers was delayed after amendment of soil to an extent that depended on the amendment sorption capacity, and it was almost completely suppressed by addition of BC due to its irreversible sorption. Organoclays and BC affected differently the final behavior and enantioselectivity of ABA in soil as a consequence of dissimilar sorption capacities and alterations in sorption with time, which will affect the plant and microbial availability of endogenous and exogenous ABA in the rhizosphere.
authors.affiliation: Instituto de Recursos Naturales y Agrobiologı́a de Sevilla (IRNAS), CSIC , Avenida Reina Mercedes 10, 41012 Sevilla, Spain.
authors.forename: Beatriz
authors.identifier: http://orcid.org/0000-0002-7244-778X
authors.initials: B
authors.lastname: Gámiz
authors.affiliation: Instituto de Recursos Naturales y Agrobiologı́a de Sevilla (IRNAS), CSIC , Avenida Reina Mercedes 10, 41012 Sevilla, Spain.
authors.forename: Lucía
authors.initials: L
authors.lastname: Cox
authors.affiliation: Instituto de Recursos Naturales y Agrobiologı́a de Sevilla (IRNAS), CSIC , Avenida Reina Mercedes 10, 41012 Sevilla, Spain.
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Hermosín
authors.affiliation: Agricultural Research Service, U.S. Department of Agriculture , 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, Minnesota 55108, United States.
authors.forename: Kurt
authors.initials: K
authors.lastname: Spokas
authors.affiliation: Instituto de Recursos Naturales y Agrobiologı́a de Sevilla (IRNAS), CSIC , Avenida Reina Mercedes 10, 41012 Sevilla, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Celis
mesh_terms: D000040:Abscisic Acid / Q000737:chemistry*; D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D000077215:Clay; D052918:Environmental Restoration and Remediation / Q000295:instrumentation / Q000379:methods*; D010575:Pesticides / Q000737:chemistry*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry*; D013237:Stereoisomerism; D014934:Wood / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal; D000040:Abscisic Acid; D000077215:Clay
keywords: biodegradation; biopesticides; chiral pesticides; signaling compounds; soil amendments; sorption