Ergosterol is generally assumed to be one of the best indicators of fungal
biomass and soil quality. The present case studies describe variations in e
rgosterol content in soil, sampled at three Danish Farms. One is organicall
y cultivated according to the biodynamical principles (ORG). The other two
are conventionally cultivated, one with animal husbandry (CONV-H) and one w
ith plant production (CONV-P). The analytical method combined extraction in
a microwave oven, clean-up with a new SPE sort,ent material (Oasis(TM)), a
nd quantification by HPLC. The average estimated concentrations of ergoster
ol were 1.66 mug g(-1) in ORG, 2.35 mug g(-1) in CONV-H and 1.13 mug g(-1)
in CONV-P. These results correlated well with some of the important variabl
es in the management systems of the soils (frequency of grass and clover, i
nput of animal manure, total-C, frequency of ploughing). However, the exact
causal relationships cannot be revealed using the case-study approach. The
statistical analysis of the spatial variation in ergosterol across the fie
ld demonstrated very clearly that in some soils, small-scale few cm(2)) var
iations in ergosterol concentrations may be quite large in comparison with
large scale (few hundred m(2)) variations. This should be taken into accoun
t when planning the sampling strategy.