Abstract

HERNANDEZ, Zulimar et al. Organic matter quality and phytotoxicity loss in progressive composting stages of olive pomace. Rev. de Ciências Agrárias [online]. 2022, vol.45, n.4, pp.211-220.  Epub Dec 01, 2022. ISSN 0871-018X.  https://doi.org/10.19084/rca.28423.

Four treatments of aerobic composting with different raw materials (BA: olive pomace, ES: manure, CA: almond husk) were evaluated during 176 days: pile A with 44%BA, 25%ES, 25%CA and turning; pile B with 44%BA, 11%ES, 44%CA and turning; C pile with 25%BA, 50% ES, 25%CA and turning; D pile with 44%BA, 11%ES, 44%CA and without turning over, in order to test the three limiting factors of BA: high C/N ratio, humidity and content of polyphenols. The routine variables analyzed bi-weekly were (n=160): density, humidity, coarse fraction, pH, electric conductivity (EC), organic matter (OM), ash and color; CHNO was determined by chemical elemental analysis and the phytotoxicity according to the Munoo-Liisa index (MLV). Van Krevelen diagram´s results (H/C vs O/C) show a slight dehydrogenation in the first 98 d, followed by a selective degradation of carbohydrates and an increase in the aromatization of the compounds after 120d. The principal component analises (PCA) showed that the greatest variability is explained by the OM quality axis (83%), where the C content (high C/N) decreases as the N availability and pH increases, on the other hand, the MLV was explained (52 %) by the aliphaticity of the organic constituents in the compost (high H/C).

Keywords : MLV; elemental analyses; Van Krevelen diagram; aliphaticity.

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