Microbial activity and the diversity of their
catabolic potential would be stratified according to soil
profile as a result of differing content of soil organic C and
they would be altered by applying dairy sewage sludge
(DSS) to the surface and subsequently ploughing. We applied
26 Mg ha-1
of DSS and the same nutrient dose of
mineral fertilisers as an NPK reference to the soil before
sowing winter rape ( Brassica napus
) in the field experiment.
We evaluated the impact of the fertilisers on
microbial activity, measured with dehydrogenase and respiratory
activity, and diversity of the microbes’ catabolic
potential from non-rhizosphere and rhizosphere soil at selected
depths. In the surface rhizosphere soil, there were
significant increases in microbial catabolic potential
(>25 %) and respiratory activity (>20 %) due to DSS application.
All of the microbial parameter values in nonrhizosphere
soil were higher at 0–20 than at 25–30 cm.
These results are important for improving the management
approach of diary sewage sludge application to agricultural
soils in the context of increasing microbial activity in the
soil profile and reducing mineral fertiliser use.