Leś. Pr. Bad., 2009, Vol. 70 (4): 383–394.

Ocena aktywności biochemicznej gleb leśnych w różnych typach siedliskowych terenów górskich
Evaluation of biochemical activity in soils of different mountain forest site types

Grażyna Olszowska
Instytut Badawczy Leśnictwa, Zakład Siedliskoznawstwa, ul. Braci Leśnej 3, 05-090 Raszyn, Fax +48 227150539, e-mail: G.Olszowska@ibles.waw.pl
Abstract. The rate of biochemical reactions and the microbiological status of soils in spruce stands was determined in different mountain forest site types between 2005–2007. Plots included mixed coniferous mountain forest site type (BMG) and mixed deciduous mountain forest site type (LMG), each with stands of Picea abies representing age classes I, II and III. In addition, similar measurements were made in deciduous mountain forest site type (LG) with stands in age classes I and II.
Soils of the LG and LMG forest site types were characterized by higher fertility, richer basic nutrients and larger sorption complex with alcalines than soil representing BMG. Values of these parameters were clearly associated  with stand quality, particulary for the mountain forest site type. The microbiological status of the soil was dependent on site fertility and stand quality. The proportion of Cmic in Corg and  intensity of organic matter mineralization were significantly higher on the richer LG and LMG sites than on BMG. Stands of poorer quality with a higher metabolic quotient (qCO2), related to a lower efficiency of microbial growth, resulting in a depletion of available nutrition in the soils. Enzyme  activities (urease, asparaginase, acid phosphatase and dehydrogenases) depended on site quality and were significantly lower in BMG compared to LG and generally became lower with a decrease in stand quality. A significant correlation between microbial  biomass, intensity of carbon mineralization and activity of enzymes and chemical properties of soil was found. This correlation between values of the forest site types fertility indicator (F) and stand quality for BMG, LMG and LG justifies the use of these measurements for diagnostics of mountain sites. 
Key words: soil biological activity, forest site type, stand quality, fertility indicator.