Hot water extracted organic matter: chemical composition and temporal variations in a long-term field experiment

Autor: H. R. Schulten, M. Körschens, Peter Leinweber
Rok vydání: 1995
Předmět:
Zdroj: Biology and Fertility of Soils. 20:17-23
ISSN: 1432-0789
0178-2762
DOI: 10.1007/bf00307836
Popis: Hot water-soluble organic matter was extracted from soil samples collected weekly between April and October in untreated and NPK+farmyard manure-fertilized plots in the 88-year-old Static Experiment (Loess Chernozem) at Bad Lauchstadt, Germany. As shown by solid-state 13C-nuclear magnetic resonance spectroscopy (13C-NMR) combined with pyrolysis-field ionization mass spectrometry this organic matter fraction was largely composed of carbohydrates and N-containing compounds, in particular amino-N species and amides. This composition and the low pyrolysis temperatures (mainly between 300 and 500°C) indicated its origin from soil biomass and root exudates and lysates, and its presence in the soil solution or weakly adsorbed by soil minerals and humic macromolecules. Long-term fertilization with NPK+farmyard manure resulted in larger mean concentrations of hot water-extracted C and N (0.933 and 0.094 g kg-1) than soil management without fertilization (0.511 and 0.056 g kg-1). The C and N extracted by hot water were in the range of 3–5% of total soil C and N. In the two treatments distinct temporal changes were observed, which appeared to be related to population dynamics of soil organisms, root growth and decomposition, and climatic influences on soil.
Databáze: OpenAIRE
Externí odkaz: