Phytotoxicity and chelating capacity of spent coffee grounds: Two contrasting faces in its use as soil organic amendmen Cervera Mata, Ana Gloria Navarro Alarcón, Miguel Rufián Henares, José Ángel Pastoriza de la Cueva, Silvia Montilla Gómez, Javier Delgado Calvo-Flores, Gabriel Spent coffee grounds (SCG) are a bioresidue generated in large amounts worldwide, which could be employed as either fresh or transformed organic soil amendment, by means of different treatments in order to improve its agronomic qualities. An in vitro experiment was conducted in order to evaluate the effect of using different bioamendments derived from spent coffee grounds (SCG) on biomass and Zn, Cu and Fe content of lettuces. Ap plication of 7.5% (w/w) fresh SCG, vermicompost, compost, biochars (at 270 and 400 °C; pyrolysis), SCG washed with ethanol and water, and hydrolysed SCG was carried out in an agricultural soil (Cambic Calcisol). In order to compare with conventional agriculture, the addition of NPK fertilizer was also assessed. Only vermicompost and biochar at 400 °C overcome the growth limitation of SCG. However, these treatments diminished Zn, Cu and Fe concentrations in lettuce probably due to the destruction (microbial degradation/thermal treatment) of naturalchelating components (polyphenols). Increase in mineral content was observed in those treatments that did not completely eliminate polyphenols. NPK fertilizer gave rise to lettuces with higher biomass but lower micronutri ents content. The results lead us to the possible solution for the use of SCG as organic amendment by vermicom posting and biocharization in order to eliminate toxicit 2024-02-01T10:37:57Z 2024-02-01T10:37:57Z 2020-02-12 info:eu-repo/semantics/article A. Cervera-Mata, M. Navarro-Alarcón,, J.A. Rufián-Henares, S. Pastoriza, J. Montilla-Gómez, G. Delgado. Phytotoxicity and chelating capacity of spent coffee grounds: two contrasting faces in its use as soil organic amendment. Science of the Total Environment 2020, 717, 137247, 1-10 https://hdl.handle.net/10481/87905 https://doi.org/10.1016/j.scitotenv.2020.137247 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess Attribution-NonCommercial-NoDerivatives 4.0 Internacional Elsevier