Influence of soil moisture on concentrations and 13C NMR profiles of lipids in three Albeluvisols

The lipid fraction of organic matter can serve as a diagnostic index of soil biological activity. Total lipid fractions isolated from Siltic Albeluvisol, Silti-Stagnic Albeluvisol and Stagni-Histic Albeluvisol (Siltic) were studied to determine the effect of soil moisture on the contents and molecular patterns of lipids. Using CPMAS 13C NMR spectroscopy, lipids extracted in alcohol-benzene were found to be mainly composed of aliphatic fatty acids and their esters. The paramagnetic activity of lipids was also evaluated. It was shown that unpaired electrons were present only in lipids from organic horizons. Chlorophyll and/or chlorophyll-like pigments were present in litter only, and their amounts were directly related to the degree of soil moisture.