| Popis: |
The organic matter stability is regulated by the different protection mechanisms of the soil matrix and soil minerals. In spite of that, beyond the determination of the amount of fine fractions, relatively little research studied the mineralogical composition of these fractions and their organic matter stabilizing effects. Therefore, the aim of my work was to investigate the influence of the soil mineral phases on the decomposition of soil organic carbon pools of soils under forest vegetation.Maize residues were added to the 13 soil samples (depth of 0−20 cm) collected from Hungary. The samples were incubated at 20°C and 70% field capacity during 163 days. The soil respiration was measured at specified intervals (on day 3, 8, 15, 30, 51, 79, 107, 135 and 163) and trapped in 2M NaOH and quantified by titration with 1M HCl. Another aliquot of NaOH was mixed with 2MSrCl2 to get SrCO3 for δ13C analysis.The samples were analysed with an X-ray diffractometer (Rigaku Miniflex 600), a microwave plasma-atomic emission spectrometer (4200, Agilent Technologies) and an isotope ratio mass spectrometer (Delta plus XP, Thermo Finnigan). Carbon mineralization kinetics was modelled by fitting a first-order two pools model.The results showed that 1−6% and 2−18% of the organic carbon content of the soils was mineralized in the control and amended samples during the incubation, respectively. Carbon mineralization was mostly reduced by the illite content (R2=0,797; p2=0,708; p2=0,475; pThe priming effect was found to be influenced to the greatest extent by the pH (R2=0,715; p2=0,396; p2=0,389; p2=0,345; pThis work was supported by the Development and Innovation Fund of Hungary [Nr. NKFIH 123953]. |
