EDAFOLOGIA, Vol. 10 (2), pp. 147-153, 2003
EVOLUCIÓN DE LAS PROPIEDADES FÍSICAS Y LA MATERIA ORGÁNICA DEL SUELO CON ENMIENDAS ORGÁNICAS Y FERTILIZACIÓN MINERAL
C. LÓPEZ-FANDO1, J. DORADO1, F.J. GONZÁLEZ-VILA2, M.C. ZANCADA1, G. ALMENDROS1
1Centro de Ciencias Medioambientales, CSIC, Serrano 115 bis, 28006 Madrid, Proyecto CICyT AGL2002-04186 2Instituto de Recursos Naturales y Agrobiología, CSIC, Avenida de Reina Mercedes 10, 41012 Sevilla
After 16 years of continuous amendment either with farmyard manure or crop wastes and two levels of mineral N fertilisation in a Calcic Haploxeralf at Toledo (central Spain), significant changes in soil physical properties, soil fertility and in the amount and characteristics of soil organic matter have been found. Such changes depended on the type of organic matter applied, the N dose (0 and 100 kg ha- 1 NH4NO3) and their interaction. When compared with control plots, visible spectroscopy suggested that the organic matter accumulated in the amended plots was less transformed, with a more marked aliphat- ic character, its humification degree decreasing when increasing N inputs. Curie-point pyrolysis of the humic acids showed a selective biodegradation of the alkyl domain favoured by external N inputs, where- as the degradation of the lignin-inherited structures seems to be more efficient in those plots with high C/N ratio.
Key Words: Humus, humic acids, organic amendments, biodegradation.