Humic substances are the most important fraction of soil organic matter both in natural and an-thropic systems. Their elemental composition and chemical structure, influenced by the kind of organic residues and environment in which they are formed, are fundamental to preserve the soil fertility. Recently, emphasis has been devoted also on their effect on carbon (C) sequestration. The aim of the present study was to examine the effect of amendment with cow manure and crop residues added consecutively over a period of 30 yrs on soil humic acids. Briefly, the experimen-tal design included plots amended over a 30-year period with cattle manure and crop residues constituted by wheat straw or corn-stalks (wheat and corn were the two crops regularly cropped in succession), using un-amended soil as the control. The samples were taken from the 0-40 cm horizon of a long-term field experiment located in the experimental farm of the Agricultural Sci-ence Faculty of the Alma Mater Studiorum University of Bologna, Italy. The humic acids were characterized using chemical and spectroscopic techniques such as diffuse reflectance infrared Fourier spectroscopy (DRIFT), surface enhanced Raman spectroscopy (SERS) and nuclear magnetic resonance (13C NMR). The results showed that the quality of humic fraction was affected by the different agricultural practices, so that when the soil did not receive any amendment, the aromatic and carboxylic C decreased, whereas the aliphatic C increased as possible effect of the crop rotation. With the amendments the aromatic C generally increased, but with crop residues this increase was mainly due to preservation of undecomposed lignin components derived from the crop-residues added to the soil. With manure the composition of humic acids appeared enriched in carboxylic groups, aromatic rings highly substituted and alkyl-C. These results indicate the key role played by amendment practices on soil humic substances formation and on the ability of humic substances to sequester C.
Effect of amendment with crop residues and manure on soil humic acids composition / Francioso O.; Montecchio D.; Gioacchini P.; Sànchez-Cortés.; Tugnoli V.; Ciavatta C.. - STAMPA. - (2007), pp. 38-38. (Intervento presentato al convegno International Humic Substance Society, 11th Nordic-Baltic Symposium - Functioning of NOM in the Environment. tenutosi a Joensuu nel June 10-13).
Effect of amendment with crop residues and manure on soil humic acids composition.
FRANCIOSO, ORNELLA;MONTECCHIO, DANIELA;GIOACCHINI, PAOLA;TUGNOLI, VITALIANO;CIAVATTA, CLAUDIO
2007
Abstract
Humic substances are the most important fraction of soil organic matter both in natural and an-thropic systems. Their elemental composition and chemical structure, influenced by the kind of organic residues and environment in which they are formed, are fundamental to preserve the soil fertility. Recently, emphasis has been devoted also on their effect on carbon (C) sequestration. The aim of the present study was to examine the effect of amendment with cow manure and crop residues added consecutively over a period of 30 yrs on soil humic acids. Briefly, the experimen-tal design included plots amended over a 30-year period with cattle manure and crop residues constituted by wheat straw or corn-stalks (wheat and corn were the two crops regularly cropped in succession), using un-amended soil as the control. The samples were taken from the 0-40 cm horizon of a long-term field experiment located in the experimental farm of the Agricultural Sci-ence Faculty of the Alma Mater Studiorum University of Bologna, Italy. The humic acids were characterized using chemical and spectroscopic techniques such as diffuse reflectance infrared Fourier spectroscopy (DRIFT), surface enhanced Raman spectroscopy (SERS) and nuclear magnetic resonance (13C NMR). The results showed that the quality of humic fraction was affected by the different agricultural practices, so that when the soil did not receive any amendment, the aromatic and carboxylic C decreased, whereas the aliphatic C increased as possible effect of the crop rotation. With the amendments the aromatic C generally increased, but with crop residues this increase was mainly due to preservation of undecomposed lignin components derived from the crop-residues added to the soil. With manure the composition of humic acids appeared enriched in carboxylic groups, aromatic rings highly substituted and alkyl-C. These results indicate the key role played by amendment practices on soil humic substances formation and on the ability of humic substances to sequester C.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
