NUMBERS AND ACTIVITY OF LIPOLYTIC MICROORGANISMS IN PODZOLIC SOIL UNDER WILLOW CULTURE (SALIX VIMINALIS L.) SUBJECTED TO THE MULTI-YEAR EFFECT OF SEWAGE SLUDGE

摘要

The study was conducted on podzolic soil from a field fertilised with municipal-industrial sewage sludge at the following doses - 30 (1%), 75 (2.5%), 150 (5%), 300 (10%) and 600 Mg ha"1 (20%) - and then planted with basket willow (Salix viminalis L.).In the 4th, 5th and 9th years of maintaining the plantation, the following determinations were made in the soil: numbers of lipolytic bacteria and fungi, and lipase activity. It was demonstrated that in the 4th and 9th years of the study, for most of the experimental treatments, there was still continued stimulation of the growth of lipolytic bacteria and fungi in soils from the 0-20 cm layer. In that soil layer for all the years of the study there was a distinct stimulation of lipase activity. The positive effect of the sludge on the numbers and activity of the above microbial groups was also observed in soils from the 20-40 cm layer, but only for some of the experimental treatments.