Quantitative and qualitative characterization of soil organic matter in the long-term fallow experiment with different fertilization and tillage

Abstract

Changes of soil organic matter under different tillage and fertilization system of the long-term fallow experiment established in 1958 in Prague were evaluated in the period of 1972 – 2004. This experiment consists of seven variants (control [no tillage, no manuring]; farmyard manure compost [FYM]; 2FYM; mineral fertilization [NPK]; 2NPK; reduced tillage [RT] and conventional tillage [CT]). Content of aliphatic compounds, organic C and total N and fulvic (FA) and humic acids (HA) were analysed in archived soil samples. Besides, the FTIR spectra of soil organic components were qualitatively evaluated. Highly significant positive correlations (r = 0.976; p < 0.05) between aliphatic compounds content and C_ox and between HA and aliphatic compounds (r = 0.946; p < 0.05) and HA and C_ox (r = 0.956; p < 0.05) were determined. Organic manuring increased the organic C and total N content significantly. HA content in the individual plots was similar to both the C_ox and the aliphatic compounds content rather than the FA content. In addition, the FTIR subtractive spectra of organic matter in soil samples were recorded and three of the most informative spectra regions were analysed. Their intensity differed depending on the fertilization and tillage used in the individual variants.

Keywords:

• Long-term fallow experiment
• aliphatic compounds
• organic carbon and total nitrogen
• fulvic and humic acids
• FTIR subtractive spectra

Acknowledgements

This work was supported by the Ministry of Agriculture of the Czech Republic, research project No. MZe 0002700601.