2024-03-28T12:40:21Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/585852019-08-06T09:28:30Zcom_10261_15com_10261_6col_10261_268
Nitrogen speciation and pyrolytic patterns of 15N-labelled soil and compost fractions
González-Vila, Francisco Javier
Almendros Martín, Gonzalo
Tinoco, Pilar
Comisión Interministerial de Ciencia y Tecnología, CICYT (España)
A mixture of urban waste, wheat straw and K 15NO3 was subjected to 80-day laboratory composting in order to analyse the qualitative and quantitative speciation patterns of the newly formed N compounds in the different compost fractions, i.e. water-soluble fraction (WS), colloidal fractions - humic acid-like (HA) and fulvic acid-like (FA), and alkali-insoluble organic fractions. In a further experiment, the compost was added to a mineral soil (3.1 g compost per 100 g soil), which was subjected to additional incubation for 80 days. The above organic fractions in addition to two particulate ones were isolated from the soil. The stable isotope ratios (15N/14N) of the resulting compost (incorporating 21.8% N as 15N) and soil fractions were analysed to monitor the distribution of the N in the different soil organo-mineral compartments. Finally, a preliminary identification of the major groups of nitrogen-bearing molecules in soil and compost fractions was carried out by Curie-point analytical pyrolysis. It was found that, after the incubation experiments, most of the newly formed N-compounds tend to concentrate in the alkali-insoluble residue (30% 15N enrichment) but, about 28% of the N remains in colloidal fractions (HA+FA). Upon pyrolysis, the FA yielded typical anhydrosugar and furan compounds suggesting an origin from carbohydrate material. The 15N in this soil fraction amount to 0.7% total soil nitrogen (TSN) (up to 9% of the N from the nitrate added). The HA showed a similar composition, but comparatively released higher amounts of carbohydrate-derived products, typical methoxyphenols and some nitrogen-containing compounds, suggesting a lignoprotein content (9% N derived from the nitrate added=1.7% of the TSN). The WS showed a very complex composition yielding after pyrolysis a series of methoxyphenols and carbohydrate-derived products and substantial yields of fatty acids. The slight differences between the pyrolytic patterns of the different soil and compost fractions suggest a predominantly physical incorporation of the compost to the soil, as well as a non-selective biodegradation of the different C and N forms. The isotopic ratios indicate that the tendency for accumulation of stable N forms followed the order soluble < colloidal < particulate soil fractions.
The Spanish CICyT for financial support (grant AMB99-0907)
Peer Reviewed
2012-10-22T12:04:12Z
2012-10-22T12:04:12Z
2001
2012-10-22T12:04:12Z
artículo
http://purl.org/coar/resource_type/c_6501
doi: 10.1016/S0165-2370(00)00139-X
issn: 0165-2370
Journal of Analytical and Applied Pyrolysis 58-59: 329- 339 (2001)
http://hdl.handle.net/10261/58585
10.1016/S0165-2370(00)00139-X
http://dx.doi.org/10.13039/501100007273
en
none
Elsevier