Selected kinetic parameters of soil microbial respiration in the A horizon of differently managed mountain forests and meadows of Moravian-Silesian Beskids Mts.

Abstract

The aim of this study was to find out the effect of intensity of thinning (FD-dense stand = 2044 trees/ha; FS-open stand = 1652 trees/ha) performed in young forest stands (99% spruce, 1% fir) in Moravian-Silesian Beskids Mts. (908 m a.s.l.; 49°30′10″ N, 18°32′20″ E) on VDS (C mineralization rate immediately after drying and re-wetting of soil), VBR (basal soil respiration at 60% w/w soil water content measured 5th day after rewetting of dry soil), VMAX (maximum respiration rate after glucose addition measured from 6th day after rewetting of dry soil), VDS/VMAX (heterotrophic respiratory potential) and ACDS/ACBR (the potential flush of biologically available C) in Ae horizon of Haplic and Entic Podzols. The ACDS/ACBR was calculated from three 24-hour respirations of 7-day incubation according to the equation ACDS/ACBR=VDSVMAX/(2VBR(VMAX−VDS)). The aim of the work was also to find the effect of circa 11-year abandonment of a mountain meadow in the locality (825–860 m a.s.l.; 49°30′17″ N, 18°32′28″ E) on the same parameters in Ah horizon of Gleyic Luvisol. The studied parameters were measured in the course of the vegetation season 2004 (May–September) at 30-day intervals. The higher intensity of thinning caused alternately higher or lower or very similar values of VDS, VBR, VMAX, VDS/VMAX and ACDS/ACBR in the course of the season. The abandonment of the meadow increased VDS, VBR, VMAX throughout the whole experiment. VDS/VMAX increased due to the abandonment except for the last sampling in September. Alternately higher or lower or very similar values of ACDS/ACBR in course of the season appeared on abandoned or moderately mown meadows. The lower intensity of thinning or abandonment of the meadow were connected with increasing number of significant (P < 0.05) correlations between the studied properties.