DISCRIMINATION OF MICROBIAL DIVERSITY BY FATTY-ACID PROFILES OF PHOSPHOLIPIDS AND LIPOPOLYSACCHARIDES IN DIFFERENTLY CULTIVATED SOILS

The effects of long-term management practices on the diversity of the microbial community were examined by analyzing the composition of fatty acids (FAs) in phospholipids (PL,) and lipopolysaccharides (LPS). According to the Principal Component Analysis (PCA) of total fatty acids the soils were divided in two groups: a) Black fallow soil (1) and soils cropped with potatoes (3, 4), and b) green fallow soil (2), soils cropped with wheat (5, 6), crop rotation (7) and grassland (8). The PCA for saturated FAs and for hydroxy FAs of both PL and LPS shows that the green fallow soil (2) can be distinguished from the other soils. For monounsaturated FAs the grassland soil (8) and for polyunsaturated FAs the wheat with vetch soil (6) clearly differed from the other soils. Fatty acids with biomarker quality such as 15:0 for bacteria and 18:2(omega 6 for fungi were used for determining the ratio between bacteria and fungi: the black fallow soil (1) and the soil managed with crop rotation (7) contained significantly higher proportions of bacteria than the other soils. The largest proportion of the indicator fatty acid i15:0 for Grampositive bacteria was measured in the black fallow soil (1), while the P-hydroxy FAs indicative of Gram-negative bacteria most frequently occurred in manured potato cropped soil (4). Both indicator fatty acids 18:2 omega 6 for fungi and cy19:0 for anaerobic bacteria had their highest concentrations in the manured potato cropped soil (4).